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PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 2: Methods in Chronic
Disease Epidemiology
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PHC 331: Chronic Disease Epidemiology and Prevention
• The science of public health
• Greek epi (upon), demos (people), logos (study)
• Now includes injury, disability, risk factors, quality of life, and,
traditionally, disease
• Center for Disease Control (CDC) defines epidemiology as “the
study of the distribution and determinants of health-related
states in specified populations, and the application of this
study to the control of health problems.”
Definition of Epidemiology
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PHC 331: Chronic Disease Epidemiology and Prevention
• Based on the CDC’s definition, a breakdown of the
terms:
• Study – quantitative, statistic- and research-based
• Distribution – characterized through people and how health events
happen in populations
• Determinants – causes, factors, implemented in analytical
epidemiology
• Health-related states – not just diseases, a spectrum of ailments
• Populations – groups of people, not just individuals
• Control – implement decision-making processes to prevent health
issues
Definition of Epidemiology, contd.
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PHC 331: Chronic Disease Epidemiology and Prevention
• Diseases of known microorganisms (AIDS, flu, etc.) focus the
study of epidemiologists
• Likewise, injuries are acute, with often immediate health
consequences (car accidents, falling, etc.)
• However, many chronic diseases originate early in life through
unhealthy behaviors, which, in turn, increase the risk in later
life to develop these diseases
• This (detailed below) is called the chronic disease continuum
The Chronic Disease Continuum
Descriptive Epidemiology, Analytic Epidemiology, Intervention/Evaluative Research
Developmental,
social, environmental,
genetic determinants
Health risk behaviors
and other factors
Chronic conditions Chronic diseases Adapted from
Remington et al.
(2010)
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PHC 331: Chronic Disease Epidemiology and Prevention
• An important question is at what point are
epidemiologist trying to “control” a chronic
disease? At which stage of the continuum?
• Controlling has become not only achieving lower mortality rates,
but also lowering detrimental effects of the disease
• Both of these factors are used to describe the
natural history of a given disease
The Chronic Disease Continuum, contd.
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PHC 331: Chronic Disease Epidemiology and Prevention
• Uses readily available data to examine a disease
and who it affects in populations by time, place, or
person
• Assesses burden, at risk groups, trends
• Public tends to focus on incurable diseases or
environmental diseases, instead of chronic
diseases that fall on the continuum.
Descriptive Epidemiology
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PHC 331: Chronic Disease Epidemiology and Prevention
• Frequently, the count of affected individuals is seen as the
fundamental measure
• Implemented when analyzing the need for healthcare to aide in lessening the
burden
• Count is a simple way to present this burden to the general
public, but it is dependent on the population size
• Other measures can be used by epidemiologists to highlight
different elements of the disease
The Burden of Disease
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PHC 331: Chronic Disease Epidemiology and Prevention
• Rates are used to compare populations – incidence and prevalence
• Incidence rate – new cases over period ÷ person-years
• Person-years = persons × period monitored
• Cumulative incidence – probability of developing a disease,
ranging from 0 to 1
• Prevalence – another proportion, this one measured at a point in
time instead of a period
• Less valuable than incidence in identifying causes
Calculating Rates
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PHC 331: Chronic Disease Epidemiology and Prevention
• Compared using risk ratios/relative risks
• Rate ratio – incidence rate of one group compared to
another
• Rate difference – subtracting the rates from one another
• Calculates how much risk is different given certain variables in the
study
• Rates also used to aim program targeting goals
• At-risk subgroups are found within populations
• Can assist healthcare professionals in joint interventions
Comparing Rates
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PHC 331: Chronic Disease Epidemiology and Prevention
Mortality Rate
Disease Smokers (a) Nonsmokers (b) Ratio (a/b) Difference(a-b)
Lung cancer 131 11 11.9 120
Coronary heart
disease
275 153 1.8 122
Difference between rat ratio and rate difference
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PHC 331: Chronic Disease Epidemiology and Prevention
• Randomized controlled trials (RCTs) – the most
thorough and scientific study
• Subjects assigned to prevention or non-prevention
• Disease and death-rates monitored and observed over time
• Often impractical/impossible
• Need comparison groups for analysis
• Comparisons between (least effective) national data
and (most effective) concurrent collection vary in
appropriateness
Study Designs
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PHC 331: Chronic Disease Epidemiology and Prevention
Experimental Studies
1- RCT :-Randomized controlled trials (RCTs) are considered the
most scientifically rigorous type of epidemiological study. In an RCT, subjects are randomly
assigned to either receive or not receive a preventive or therapeutic procedure, such as a
clinical smoking cessation intervention or a new drug. The disease course or mortality patterns
are then observed over time to assess the effectiveness of the preventive or therapeutic
procedure (Remington et al, 2010)
Study Designs in Chronic Disease Epidemiology
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PHC 331: Chronic Disease Epidemiology and Prevention
• Comparison groups vary in their appropriateness for disease intervention
studies. Least convincing are comparisons with national data or populations in
other studies. Subjects assigned to prevention or non-prevention
• Disease and death-rates monitored and observed over time
• Often impractical/impossible
• Need comparison groups for analysis
Advantages of RCT
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PHC 331: Chronic Disease Epidemiology and Prevention
Study Designs, contd.
Adapted from Remington et al. (2010)
• Historical or retroactive studies can also be a viable
option, if the correct records are available
• Downsides include that no incidence rates or cumulative incidence
can be gathered
• Upsides include that, in certain cases, information was found that
affected risks which could be modified and benefit a population in
the future
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PHC 331: Chronic Disease Epidemiology and Prevention
• Since RCTs can be unethical, epidemiologists need to
observe without intervention
• Based on doctor recommendations
• Prospective cohort – exposures not randomly assigned, but
first identified
• Active and intense measurements can be made
Observational Studies
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PHC 331: Chronic Disease Epidemiology and Prevention
Study Type Strengths Limitations
Experimental studies
Randomized clinical trial *Controls randomly assigned *High cost
*Impractical long-term
*Impractical exposures
Randomized community trial *Population-wide scope
*Multicomponent effectiveness
*Very expensive
*Small number of study groups
Quasi-experimental study *Real-world policy/program intervention
*Multiple comparison groups
*Potential bias
*Lack of control – confounders
Observational studies
Prospective cohort *Measure risk before disease occurs
*Multiple outcomes
*Yields incidence rates/relative risks
*Expensive
*Large number of subjects required
*Lengthy follow-ups
*Hard to control exposure factors
Case-control *Rare diseases
*Inexpensive
*Quick results
*Possible risk-factor bias
*Possible bias in control group selection
*Identified might not represent population
Strengths/Limitations of Study Designs
Adapted from Remington et al. (2010)
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PHC 331: Chronic Disease Epidemiology and Prevention
• Most chronic disease studies are from observational
studying
• Therefore, errors are present in a number of different
ways:
• Measurement, selection of subjects, bias, etc.
• Experts are needed to quantify uncertainty in research
methods and decide quality studies
• Confounding and bias are important types of error in
epidemiological studies
Assessing Valid Study Results
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PHC 331: Chronic Disease Epidemiology and Prevention
• “The influence of an exposure of interest is mixed
with the effect of another” (Remington et al. 2010)
• In RCT, confounders can be equally distributed
among each study group
• In observational studies, confounders have to be
measured and adjusted
• As long as confounders are measurable and
adjusted, then no need for concern
• However, some confounders are difficult to measure or
unknown
Confounding
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PHC 331: Chronic Disease Epidemiology and Prevention
• Faulty sampling methods or refusal to participate leads to
samples with higher or lower measurement risk
• Poorly arranged control groups are major threats to
accuracy
• Phone samples introduce bias when families without landlines are not
taken into account
• Classification errors also present a potential bias
• Also known as information bias
Selection/Information Bias
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PHC 331: Chronic Disease Epidemiology and Prevention
• Attributable Risk
• How much burden is lessened is exposure is eliminated
• Relative risk - 1 ÷ relative risk
• Population Attributable Risk
• How common the exposure is
• Rate (total pop.) - rate (unexposed) ÷ rate (total pop.)
• Also Pe (relative risk - 1) ÷ 1 + Pe (relative risk - 1)
• Where Pe proportion of population exposure
Prevention through Intervention
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PHC 331: Chronic Disease Epidemiology and Prevention
• Often, critical analyses will lead to “important” or
“groundbreaking” new information, but this must be taken
lightly
• One study is never sufficient to answer all or even one question about a
chronic disease.
• Validity must be measured through repetition and variety or
intervention
Single vs. Series
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PHC 331: Chronic Disease Epidemiology and Prevention
• Systematic reviews
• Researchers consolidate information using comprehensive
methods to assess relevant science behind a single health
issue
• Increasingly, meta-analysis is used in these systematic
reviews
• Meta-analysis
• Identify relevant studies, inclusion/exclusion criteria, data
abstraction, heterogeneity across statistical analysis
Systematic Reviews, Meta-analysis, Expert Panels
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PHC 331: Chronic Disease Epidemiology and Prevention
• An approach to looking at risks posed by adverse
exposures like pollutants
• A “bridge” between the scientific community and
those who create policies and protocol
• Four steps to proper risk assessment:
• Hazard identification, risk characterization, exposure
assessment and risk estimation
• Expert panels used to assess validity of
epidemiological studies through peer review
Risk Assessment/Expert panels
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PHC 331: Chronic Disease Epidemiology and Prevention
• Incidence rate – New events in a specified
period / persons exposed to risk within period
• Relative risk – Risk of death or disease in
population exposed to risk / risk of death or
diseased in unexposed population
• Population attributable risk – Rate of disease
in population attributed to risk factor / total
rate of disease
Key Concepts
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PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 3: Intervention
Methods for Chronic Disease
Control
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PHC 331: Chronic Disease Epidemiology and Prevention
• Behavior changes in individuals can often prevent many
chronic diseases
• CDC estimates that 80% of heart disease, type II diabetes and 40% of
cancer would be eliminated if poor diet, inactivity and smoking were
also eliminated
• Obesity is now seen more frequently among both adults
and children
Behavioral Determinants
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PHC 331: Chronic Disease Epidemiology and Prevention
• The high cost of treating chronic diseases is another reason
they are increasing
• Secondary prevention can find many diseases earlier when they are cheaper
to treat and more beneficial to lifestyle change, and also lead to fewer visits in
later years (which will lower health costs)
• Lack of incentives for prevention services in US healthcare
system
Healthcare Determinants
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PHC 331: Chronic Disease Epidemiology and Prevention
• Features like sidewalks, parks, bike trails, community pools all
encourage healthier choices
• Households with multiple televisions and computers also
promote a less-active culture which affects the amount of
exercise being done
• Nutritional choices also under consideration in built
environments – menus, work cafeterias, highlight lower costs
for less nutritional foods
Environmental Determinants
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PHC 331: Chronic Disease Epidemiology and Prevention
• Population health is emerging as just as important as
individual health
• Policymakers are quick to blame individual choices for chronic illness,
when, in reality, there are an amplitude of environmental, cultural and
economic factors at play
• Social determinants are often a large result of health
disparities
Social Determinants
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PHC 331: Chronic Disease Epidemiology and Prevention
• Victim-blaming fails to account environmental and social –
ecological approach acknowledges that we live in a world full
of interactions
• Intrapersonal factors
• Interpersonal factors
• Organizational factors
• Community factors
• Policy factors
Levels of Intervention
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PHC 331: Chronic Disease Epidemiology and Prevention
• Early attempt to use theory to study preventive behaviors
• If subject perceives moderate severity and susceptibility, then choose
preventative action
• Often criticized and used to explain how people rarely adopt preventative
behaviors
• Content of Health Belief Model:-
• Perceived Suscessiability
• Perceived severity
• Perceived benefits
• Perceived barrier
• Cuss to action
• self- efficacy
Health Belief Model
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PHC 331: Chronic Disease Epidemiology and Prevention
Perceived susceptibility - This refers to a person's subjective perception of the risk of acquiring an illness or disease.
There is wide variation in a person's feelings of personal vulnerability to an illness or disease.
Perceived severity - This refers to a person's feelings on the seriousness of contracting an illness or disease (or leaving
the illness or disease untreated). There is wide variation in a person's feelings of severity, and often a person
considers the medical consequences (e.g., death, disability) and social consequences (e.g., family life, social
relationships) when evaluating the severity.
Perceived benefits - This refers to a person's perception of the effectiveness of various actions available to reduce the
threat of illness or disease (or to cure illness or disease). The course of action a person takes in preventing (or
curing) illness or disease relies on consideration and evaluation of both perceived susceptibility and perceived
benefit, such that the person would accept the recommended health action if it was perceived as beneficial.
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PHC 331: Chronic Disease Epidemiology and Prevention
Perceived barriers - This refers to a person's feelings on the obstacles to performing a recommended health
action. There is wide variation in a person's feelings of barriers, or impediments, which lead to a
cost/benefit analysis. The person weighs the effectiveness of the actions against the perceptions that it
may be expensive, dangerous (e.g., side effects), unpleasant (e.g., painful), time-consuming, or
inconvenient.
Cue to action - This is the stimulus needed to trigger the decision-making process to accept a recommended
health action. These cues can be internal (e.g., chest pains, wheezing, etc.) or external (e.g., advice from
others, illness of family member, newspaper article, etc.).
Self-efficacy - This refers to the level of a person's confidence in his or her ability to successfully perform a
behavior. This construct was added to the model most recently in mid-1980. Self-efficacy is a construct in
many behavioral theories as it directly relates to whether a person performs the desired behavior.
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PHC 331: Chronic Disease Epidemiology and Prevention
Health Belief Model
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PHC 331: Chronic Disease Epidemiology and Prevention
• Also known as Stages of Change Model
• Not everyone at the same stage to drastically change health behavior, so each
plan fits to different characteristics
• Series of stages, from pre-contemplation (no change) to termination (problem
no longer acceptable) or relapse (retroactively choosing less healthy behavior)
Trans theoretical Model
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PHC 331: Chronic Disease Epidemiology and Prevention
• Individuals are fueled by
behavioral intentions
• An attitude of a positive behavior
is “is the sum of all the positive
feelings…or negative
feelings…about performing the
behavior” (Remington et al.
2010).
• Places normative beliefs on
people’s perceptions and
readiness to change
Theory of Planned Behavior
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PHC 331: Chronic Disease Epidemiology and Prevention
• Expectancy is important when
considering control – where, who, what
is/are responsible?
• If there is belief that a plan of action will
result in an outcome, a person is more
likely to pursue that option
• Control moves from internal (self) to
external (higher powers, luck, fate, etc.)
• Those who lean toward external control
are more likely reached through policy
changes
Health Locus of Control
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PHC 331: Chronic Disease Epidemiology and Prevention
• Addresses dynamic of society that
influence health and methods for
behavioral change
• Triadic, dynamic, reciprocal models
• Emphasis placed on highlighting
capability and self-confidence
• Self-efficacy through mastery of task
• Applicable to wide variety of
populations
Social Cognitive Theory
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PHC 331: Chronic Disease Epidemiology and Prevention
• Monopolizes on existing string of social network (family)
to implement support
• Family trained to assist in weight loss program, for
example
• “Family Matters” program to prevent youth smoking and
alcoholism
Family-Based Interventions
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PHC 331: Chronic Disease Epidemiology and Prevention
• Mentor programs, buddy systems, self-help groups
• Creating a new social network with the sole purpose of
intervening
• Especially important in adolescent interventions
Friends and Social Networks
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PHC 331: Chronic Disease Epidemiology and Prevention
• Social support
• Emotional support
• Instrumental support
• Informational support
• Appraisal support
• Either strengthening existing networks or creating new ones to
assist in the problem-solving process
Social Support and Social Networks
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PHC 331: Chronic Disease Epidemiology and Prevention
• A member of a social network who gains trust and
respect through his or her abilities to offer support
and guidance
• These strategies are seen frequently in urban and
rural settings
• Natural helpers are either found in a community
organically, or is given specialized training (this is
known as a lay health advisor)
Natural Helpers
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PHC 331: Chronic Disease Epidemiology and Prevention
• Effective in providing screening/follow-ups
• However, often underutilized in primary prevention (see
Slide 3)
• Brief interventions are low cost alternative to high cost
visits
• Short, private, non-confrontational, 5-60 minute meeting with
counseling and informative education
• Can be leveraged depending on a person’s aptitude and readiness
for change
Health Care System and Clinical Services
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PHC 331: Chronic Disease Epidemiology and Prevention
• Youth are a spirited, receptive audience for prevention
messages
• Establishing healthier habits at an earlier age is essential in
stopping or slowing chronic illness
Schools
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PHC 331: Chronic Disease Epidemiology and Prevention
• US adult population spends half or more of the day at
work, so it becomes a useful tool in dispensing
knowledge about prevention education
• Leaders are understanding that chronic diseases are
costing more and more (employee absence,
insurance costs, etc.) and are mediating this through
health knowledge at the workplace. Results:
• Improved productivity
• Reduced absences
• Reduced health risks/health care costs
• Improved company image
Work Sites
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PHC 331: Chronic Disease Epidemiology and Prevention
• Selected based on priorities of population in question
• Priority population partners – participatory, collaborative, local,
empowering, research and action blend
• Community coalitions
• Media advocacy – seen today in suicide prevention, and lead
poisoning, to name a few
Examples of Community-Level Health Planning Approaches
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PHC 331: Chronic Disease Epidemiology and Prevention
• Process planning
• Plan with people
• Plan with data
• Institutionalization
• Priorities
• Short- and long-term outcomes
• Evaluation
Community-Level Health Planning
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PHC 331: Chronic Disease Epidemiology and Prevention
• Mobilizing the community
• Developing a community profile
• Selection behavior/audiences
• Formative research
• Strategy development
• Program development
• Program implementation
• Tracking
Community-Based Prevention Marketing
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PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 4: Chronic Disease
Surveillance
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PHC 331: Chronic Disease Epidemiology and Prevention
Conceptual Model of Health Surveillance
Define the
Problem
Program Process
Evaluate
the Effect
Find
Programs
that Work
Information
Dissemination
Data Collection
Data Analysis
Data
Interpretation
Epidemiologic Process
Adapted from Remington et al. (2010)
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PHC 331: Chronic Disease Epidemiology and Prevention
• Council of State and Territorial Epidemiologists modifies this
list each year
• Includes primarily infectious diseases, but also contains some
noncommunicable diseases, as well
• In 1996, CSTE included smoking, the first behavior on the list
• 2004 list contains 92 disease systems
• Chronic Disease Indicators website includes definitions and data of each in the
United States
Notifiable Disease Systems
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PHC 331: Chronic Disease Epidemiology and Prevention
• Collected information from birth and death
• An initial cornerstone of surveillance since the mid-19th century and
perhaps earlier
• Death certificates are used to list immediate causes of
death and a string of events that caused death
(underlying cause)
• Limitation – incomplete certificate, lack of clinical history
Vital Statistics
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PHC 331: Chronic Disease Epidemiology and Prevention
• One symptom or a string of symptoms, disease,
disability, etc.
• Effectiveness yet to be proven by research
• Could potentially identify outbreaks or bioterrorism
Sentinel Surveillance
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PHC 331: Chronic Disease Epidemiology and Prevention
• Used in monitoring trends
• Usually mandated in state laws
• Most common disease registries – cancer
• Hospital-based or population-based registries
Chronic Disease Registries
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PHC 331: Chronic Disease Epidemiology and Prevention
• Implemented when collecting information from self-reported
health practices (general pop.)
• CDC established a phone-based surveillance system of
questionnaires
• Some surveys go beyond questionnaires and access physical
exams and samples
• Collected at mobile examination centers
Health Surveys
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PHC 331: Chronic Disease Epidemiology and Prevention
• Primarily hospital discharge data
• Used to locate hospitalization patterns of chronic diseases
• Limitations – incomplete records, unreliable
imputation of data, missing variables,
measurement errors, only focus on hospital
setting, not outpatient care
Administrative Data Collection Systems
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PHC 331: Chronic Disease Epidemiology and Prevention
• Each 10 years, the United States government censuses the
entire population – collects detailed information on individual
and household
• Limitations – census does not include everyone; inevitably
some are missed
• Minority racial/ethnic groups
• Geographic areas
Census Data
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PHC 331: Chronic Disease Epidemiology and Prevention
• Charts the variety of a disease given their personal
attributions
• Race, age, gender, etc.
• Realizing differences in these factors helps design
effective and group-specific prevention or control
programs
Person Analyses
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PHC 331: Chronic Disease Epidemiology and Prevention
• Charts a disease that occurs in one geographic region
against another region
• Typically found in situations when a city or county is
compared to state or country
• Needs to understand and interpret age structure
between areas by age-standardization
• Cluster analysis – in acute geographic areas –
monitored to avoid health risks specific to a very small
area (neighborhoods, communities, suburbs, etc.)
Place Analyses
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PHC 331: Chronic Disease Epidemiology and Prevention
• Charts trends that appear over time
• Used to detect outbreaks, transmission patterns,
intervention strategies
• Temporal trends, regional analysis
• Interventions based on variables specific to a certain
time in a certain era
Time Analyses
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PHC 331: Chronic Disease Epidemiology and Prevention
• Data dissemination is the final step in disease
monitoring
• Often composed in documents with technical
language, with little linkage to public health promotion
• Epidemiologists asked to disseminate the information
collected into health department reports
• Five steps in data analysis:
• Establish the message, set an objective, define the audience, select
the channel, evaluate the impact
Data Dissemination
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PHC 331: Chronic Disease Epidemiology and Prevention
• Arguably the most important element of data
presentations
• The role of the epidemiologist is to convey a clear
message, one that is worthwhile and somewhat easy to
understand
• “Less is more” approach
• Main points must be easy to understand
Message
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PHC 331: Chronic Disease Epidemiology and Prevention
• Goal of epidemiologist is to establish an objective for a
piece of writing
• Goals vary – sometimes there is no goal, simply that there is
something to be reported, other times objective is for general public
education
• Sometimes the ideal objective is public action
Objective
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PHC 331: Chronic Disease Epidemiology and Prevention
• Target audience varies, but has traditionally been both
local health departments and health care providers
• These agencies are charged with implementing any strategies for
managing disease control
• Today, a broader spectrum of target audience exists –
from policymakers and legislators, or to the general
public, advocacy agencies to promote their efforts
Audience
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PHC 331: Chronic Disease Epidemiology and Prevention
• The method or medium that an epidemiologist “channels” his
or her work
• Journals, paper/electronic mail, radio/television, blogs, print/digital media,
etc.
• Frequently mailed to healthcare facilities
• Sometimes a press release is required
• Selective channeling aides research in reaching target
audience
Channel
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PHC 331: Chronic Disease Epidemiology and Prevention
• Final step is evaluating how the information was distributed
using the previous four methods
• This can be measured in various ways – number of items
distributed, where and how, readership, coverage, hits on a
webpage, web searches
• The success of the previous methods outline the impact that a
particular public health campaign may have
Impact
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PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 5: Tobacco Use
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PHC 331: Chronic Disease Epidemiology and Prevention
Significance
According to WHO,2017: The tobacco epidemic is one of the biggest public health
threats the world has ever faced, killing more than 8 million people a year around the world.
More than 7 million of those deaths are the result of direct tobacco use while around 1.2
million are the result of non-smokers being exposed to second-hand smoke.
• Smoking harms every organ of the body, with diseases including
• Cardiovascular diseases
• Cancers – lip, mouth, esophagus, lung, kidney, etc.
• Respiratory problems
• Reproductive disorders
• SIDS, cataracts, slow wound healing
• Low bone density
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PHC 331: Chronic Disease Epidemiology and Prevention
Cardiovascular Disease
• Smoking a major risk factor in developing congenital
heart disease
• Ability of blood to delivery oxygen is reduced
• Secondhand smoking causes prothrombotic effects
and endothelial cell dysfunctions
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PHC 331: Chronic Disease Epidemiology and Prevention
Cancer
• “Mainstream tobacco smoke (MS) contains nearly 5,000
chemicals…and more than 60 known carcinogens” (Remington
et al. 2010)
• These carcinogens have been linked to tobacco-related
cancers
• Nitrosamines/polyaromatic hydrocarbons – lung cancer
• N-nitrosodimethylmine – kidney tumors
• Nitrosamine NNK – pancreatic cancer
• Benzene, polonium-210, lead-210 – myeloid leukemia
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PHC 331: Chronic Disease Epidemiology and Prevention
Chronic Lung/Other Respiratory Disease
• When you smoke, additional biological processes like
inflammation, degradation of structural proteins and oxidant
stress are developed, which can cause alveolar injury
• Results in COPD
• Hypoxemia
• Decline in pulmonary function
• Reduction of tracheal mucus velocity
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PHC 331: Chronic Disease Epidemiology and Prevention
Nicotine Dependence
• Nicotine distribution absorbs rapidly to the brain in both oral
and inhalation of tobacco – around ten seconds upon initial
use
• Crosses blood-brain barrier and binds to receptors in brain, which releases
neurotransmitters
• Effects dependent on rate of use, tolerance
• Withdrawal symptoms include irritability, frustration,
increased appetite, weight gain, and generally occur within
one day and maintain for ten days, though cravings for
regular smokers last for years
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PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Groups
• In the United States, estimated 43 million smokers
• Higher for men (22%) than women (17%)
• 10% - Asians; 13% - Hispanics; 20% - African Americans; 21% - Caucasians; 36% - Native Americans
and Alaska Natives (Remington et al. 2010)
• A 2005 study found that 51% of men and 50% of women were smokers at one
time but had quit
• Estimated 4,000 young people smoke their first cigarette each year
• According to the Global Burden of Disease study more than 8 million people
died prematurely as a result of smoking in 2017.
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PHC 331: Chronic Disease Epidemiology and Prevention
Number of tobacco users global by sex ( WHO,2019)
The number apparently peaked in 2018 at
1093 million tobacco users. Between 2000
and 2005, the number of male tobacco
users increased by 22 million; between
2005 and 2010, the increase slowed to 13
million, and slowed again to a 7 million
increase between 2010 and 2015. The
number of users is projected to decrease
going forward from 2018, decreasing by 2
million to 1 091 million in 2020, then by
another 4 million to 1 087 million in 2025,
assuming countries maintain current
efforts in tobacco control.
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PHC 331: Chronic Disease Epidemiology and Prevention
Global trends in prevalence of tobacco use by sex ( WHO, 2019)
In 2000, around half of men aged 15 years and
older were current users of some form of tobacco.
By 2015, the proportion of men using tobacco had
declined to 40.3%. By 2025, the rate is projected to
decline to 35.1%.
In 2000, around one in six women (16.7%) aged 15
years and older were current users of some form of
tobacco. By 2015, the proportion of women using
tobacco had declined to under one in ten (9.5%). By
2025, the rate is projected to decline to 6.7%.
any form of tobacco was three times in 2000, the
proportion of males using e proportion of users
among women. By 2015 the rate for males was
more than four times the rate for females. By 2025
the rate for males is expected to be five times the
rate for females.
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PHC 331: Chronic Disease Epidemiology and Prevention
Trends in current tobacco use among people aged ≥15 years
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PHC 331: Chronic Disease Epidemiology and Prevention
Time Trends
• Peak cigarette sales in the United States in 1963 – steadily
declining since
• Over time, the gap between men (historically higher rates) and
women (lower) has been narrowing, but the declination rate is
lowering at a comparable rate
• From 2002, more former smokers than current smokers
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PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors
• Societal and individual factors – exposure in popular films,
perception of safeness among certain brand
• Advertising and promotion – media sponsorship, high budget
spend on advertisement from tobacco companies
• “Safer” tobacco – low-tar branding
• Access – vending machines and some sales counters selling to
minors
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PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors, contd.
• Social norms – societal, local, familial, peer communities all
affecting smoking; when access to tobacco exists in these
communities, it becomes easier to acquire
• Individual psychosocial factors – weaker attachment to
parents, stronger attachment to peers, rebelliousness and risk-
taking
• Continued tobacco use – the role of genetics in treatment
response; the effect of advertising and “safer” products
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PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors, contd.
• Inadequate understanding – underestimation of smoking-
related deaths; assumption that young people will stop before
potentially harmful side effects occur
• Adults not aware of hazards, which can be attributed to underrepresentation
of anti-smoking literature and media
• Lower price – the lower the price, the more cigarettes and
tobacco are consumed
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PHC 331: Chronic Disease Epidemiology and Prevention
Population-Attributable Risk
• Several recent studies have suggested the influence that risk
factors play when defining tobacco use
• One study postulated that 33% of experimentation with tobacco among youth
attributed to advertisements;
• Two others speculate that cinema/Hollywood glorification of tobacco leads to
higher risks;
• A third looks at youth with nonsmoking parents smoking as a direct result of
movies and popular culture
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PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control
• Price
• Increasing the price of tobacco can help stymy sales, especially among youth
• Sales would have to increase across all types of tobacco to be effective
• Countermarketing campaigns
• Pointed at youth prevention, but need to be sustained to be effective
• Challenge social norms about tobacco use, educate youth on prevention
• Advertising bans
• Mixed evidence on effectiveness
• When a ban is in place, tobacco companies shift to other forms of delivery –
electronic, billboards, points of sale
83
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control, contd.
• Minors’ access restrictions
• More stringent interventions are needed to lower youth accessibility of
tobacco
• School-based tobacco prevention programs
• Effective when taught alongside community interventions
• Emphasize tobacco-free campuses, negative health effects
• Eliminating secondhand smoke
• Eliminating smoking indoors helps, but cannot prevent complete exposure
• Also helps reduce cigarette consumption in general
84
PHC 331: Chronic Disease Epidemiology and Prevention
Screening and Treatment
• Best practice in the medical field – ask about past history
with tobacco use
• Should be acquired during every visit and thoroughly documented in a
medical record
• Those who smoke should be screened so effective treatment can be given
as needed
• Cotinine can be measured in blood, saliva, urine – though
acquiring these levels not particularly routine in medical
care, except in the case of pregnant women’s tobacco intake
85
PHC 331: Chronic Disease Epidemiology and Prevention
List of Evidence-Based Interventions
• Comprehensive tobacco prevention and control programs:
• Estimated that prevention programs have added 21 years to the life
expectancy between 1964 and 1992 for 1.6 million Americans
• California spearheaded the prevention programs, and has lower cases of lung
cancer, lowest per capita consumption, and low youth smoking rate than the
rest of the United States
• Tobacco excise taxes
• Increased taxation on cigarettes, though remedied by tobacco companies by
coupons and other discounting strategies
86
PHC 331: Chronic Disease Epidemiology and Prevention
List of Evidence-Based Interventions, contd.
• Countermarketing campaigns
• Smoke-free policies
• Public and private insurance coverage
• Minors’ access restrictions
• Telephone cessation quitlines
• Usually not enough funding to sustain
• Product changes
87
PHC 331: Chronic Disease Epidemiology and Prevention
Future Research and Demonstration
• Key issues for continued research:
• Promised public health interventions
• Evaluating state prevention and control programs
• Industry practice monitoring and counteraction
• Translating the decline in youth and adult dependence
• Disparate population interventions
• Health impacts of changing products
• Most cost-effective interventions locally and internationally
88
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 6: Diet and Nutrition
89
PHC 331: Chronic Disease Epidemiology and Prevention
Consequences and Causes of Poor Nutrition Chart
Causes
*Social and cultural factors
*Poor social/family
support
*School lunch policies
*Lack of education about
diet
*Food industry marketing
(esp. to children)
*Eating out
*Watch television
At-risk Populations
*Infants/elderly
*Poor
*Undereducated
*Urban populations
*Racial/ethnic minorities
*Family with both parents
working outside the home
Consequences
*Obesity
*CHD
*Diabetes
*Selected cancers
*Dental caries
*High blood pressure
*Psychological effect
Poor Diet/Nutrition:
*High in total calories,
saturated fat, animal
meat, sugar, salt, and
alcohol
*Low in fruit, vegetables,
whole grains, fiber,
unsaturated oils
Adapted from Remington et al. (2010)
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PHC 331: Chronic Disease Epidemiology and Prevention
Significance
• Cardiovascular disease and cancer, followed closely by Type II
diabetes, are the three main causes of mortality in the world,
and are chiefly caused by an imbalance of nutrition
• High blood pressure/cholesterol
• Inversely, micronutrient deficiencies account for 15% of
childhood diseases
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PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Fruits and Vegetables
• Lowers chronic disease risk
• High levels of dietary fiber, vitamin C, E, folic acid, etc.
• Antioxidants and beta-carotenes
• Reduction of serum cholesterol
• Manages body weight through high contents of water, fiber,
low fat content
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PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Dietary Fiber
• Studies show that an increase in dietary fiber result in a lower
chance of CHD/certain cancers
• Increases stool bulk, increases food’s entry and exit times,
lowers risk for carcinogens in the body
• Soluble fiber can lower cholesterol
• Binds bile acids and prevents reabsorption
• High fiber, research shows, has an inverse relationship with
insulin levels
93
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Dietary Fat and Red Meat
• Different kinds of fat
• Trans fat and saturated fats – adverse toward health
• Omega-3 fatty acids and monounsaturated fats – benefit health
• Reduction of saturated fat by intake by small increments lowers
heart attack risk rates by 25%
• Hypothesis is that omega-3 fatty acids alter the immune
system’s response to cancer
• Red meat – both positive and negative effects
• + — high in iron, vitamins A, B12, protein
• - — risk of colorectal cancer, formation of mutagenic free radicals in stomach
94
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Dairy Products and Milk
• Low fat milk intake shown to lower risk of
osteoporosis, CVD, colon cancer
• Contains fatty acids
• Calcium content lowers lipid collection and higher lipid
excretion rates
• 2% and whole milk are high in saturated fat and
calories
95
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Sugar-Sweetened Beverages
• Caloric sweeteners – “all caloric carbohydrate sweeteners,
such as table sugar, honey, and high fructose corn syrup, and
excludes naturally occurring sugars and artificial sweeteners”
(Remington et al. 2010)
• Consumption of beverages with caloric sweeteners increases risk of obesity
and cavities
• Increased consumption over the last 30 years has shown
spiked levels of excessive consumption
96
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Sex
• U.S. men – higher intake of red meat, dairy
• U.S. women – higher intake of fruits, vegetables, salts,
cholesterol
• Greater importance on eating healthily
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PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Age and Life Course
• Young and old are susceptible to poor nutrition
• Young – targeted by food industry to eat energy-
dense foods; poor diet habits developed in youth
tend to carry into adulthood
• Old – lower metabolism and physical activity,
changes in taste and smell; 80% of elderly need
improvements
98
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Race and Ethnicity
• African Americans and Caucasians increased total
energy-dense foods from 1971 and 2002
• Racially diverse populations, on average in the United
States, have lower access to fresh fruits and vegetables
• Sociocultural and behavioral factors influence the dietary
variety of the three major racial groups in the United
States
• African American, Caucasian (white), and Mexican American
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PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Income
• As wealth decreases, direct relationship between the ability
to acquire healthy foods
• Similarly, energy-dense foods are more likely to be
consumed by those with lower income
• This is partly due to the inaccessibility, such as the high price and the lack
of larger stores that support a variety of nutritional fruits and vegetables
in urban/low-income areas
10
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Education
• Income and education have a corollary
relationship, so both affect chronic disease
outcome at similar rates
• Higher consumption of fruits/vegetables has been
linked to higher education, and those with the
most education are more likely to spend more per
capita on these foods
10
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations – Other
• Geographic distribution
• Developed countries have higher diets with animal products and saturated
fats
• Fish consumed more frequently in coastal regions
• Industrial development and immigration
• As a country shifts from underdeveloped to developed, chronic disease
patterns can occur in as little as one generation
• Time trends
• Larger portion sizes appeared over time
• Higher kcal consumption for both men (+196kcal) and women (+283 kcal)
10
PHC 331: Chronic Disease Epidemiology and Prevention
Barriers to Healthy Eating
• Individual preference
• Appearance, taste, texture
• Community and family
• Environments that support positive food choices make it easier to follow a
healthy diet
• Lowest cost foods – least nutritious
• Fast-food density has been shown to be connected to poor nutrition
• Parental modeling affects familial diet among adolescents
• Families with both parents working outside the home have increased chances of
seeking nutrition in energy-dense, unhealthy foods
10
PHC 331: Chronic Disease Epidemiology and Prevention
Primary Prevention Policy
• Dietary Guidelines created
by the US Department of
Health and Human Service
• Areas of consideration include
adequate nutrients within
calorie needs, weight
management, physical activity,
fats, carbohydrates, sodium
and potassium, alcoholic
beverages, food safety
• Emphasizes a balanced diet
• From “Basic Seven” to
“MyPlate” An early nutritional guide developed in the 1940s by the U.S.
Department of Agriculture, CC BY 2.0, via Wikimedia Commons
10
PHC 331: Chronic Disease Epidemiology and Prevention
Primary Prevention Policy, contd.
The current nutritional policy, MyPlate, developed in 2011.
Image by OpenStax College, CC BY 3.0, via Wikimedia Commons
Food Pyramid nutritional policy, developed in 1992 by the USDA.
Image by the USDA College, Public Domain, via Wikimedia
Commons
10
PHC 331: Chronic Disease Epidemiology and Prevention
Surveillance
• Various nutritional analyses that make up the
National Nutrition Monitoring System
• Food disappearance programs chart the available
consumable foods
• Food questionnaires used by epidemiologists to
chart frequency of intake and a list of consumed
foods
• Effective because participants are likely to remember recent food
choices, as opposed to long-term dietary analyses
10
PHC 331: Chronic Disease Epidemiology and Prevention
Large-Scale Initiatives
• Origins in the 1980s – National Cancer Institute/Kelloggs
Campaign
• National Fruit and Vegetable Program
• 1% or Less Campaign
• Site-based interventions
• Workplace
• Schools
• Faith-based
10
PHC 331: Chronic Disease Epidemiology and Prevention
Large-Scale Initiatives, contd.
• Population-specific initiatives
• Community approaches in urban areas
• Federal safety net
• School lunch programs
• Supplemental Nutrition Assistance Program (formerly Food
Stamps)
• Eliminating racial disparities
• Heart to Heart Program
10
PHC 331: Chronic Disease Epidemiology and Prevention
Large-Scale Initiatives, contd.
• Policy approaches
• Agricultural policies – which crops are produced
• Nutrition right-to-know – advocacy groups attempt to make
nutritional assessments in restaurants more accessible
• School wellness policies – improved physical activity programs and
healthy food options in vending machines
• Advertising to children
10
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 7: Physical Activity
11
PHC 331: Chronic Disease Epidemiology and Prevention
Consequences
• Affects physiological, psychological, societal of
health
• Reduces chance of premature death, developing
CHD/diabetes/colon cancer
• Promotes healthy bones and joints
• Less falls and functional dependency in older adults
11
PHC 331: Chronic Disease Epidemiology and Prevention
Consequences, contd.
Causes
*Psychosocial (motivation
*Self-efficacy
*Social/cultural factors
*Physical environment
*Perceptions of
competence in sports
*Enjoyment
At-risk Populations
*Older adults
*Adolescents
*Women
*Those with low incomes
*Overweight adults
*Those with conditions
that limit movement
*Injured or disabled
individuals
Consequences
*Obesity
*CHD
*Diabetes
*Colon cancer
*High blood pressure
*Falls/osteoporosis
*Psychological effects
Physical Inactivity
Adapted from Remington et al. (2010)
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PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology
• Physical activity – movement produced by
skeletomuscular system that burns energy
• Occupational and nonoccupational
• Contrasted with exercise
• Exercise
• Repetitive movement used to maintain physical fitness
• Physical fitness
• Achievable attributes related to physical activity
• Cardiorespiratory, muscular, metabolic, morphological, motor
• Frequency – number of times PA is performed
• Duration – minutes/hours PA is performed
11
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology, contd.
• Intensity
• METs – Metabolic cost divided by resting metabolic rate
• MET-minutes – MET multiplied by minutes
• Kcal – MET-minutes times body weight
• Light intensity - <3 METs
• Moderate intensity – 3 to 6 METs
• Vigorous intensity - >6 METs
• Activity dose
• Leisure – free choice periods of PA
• Occupation PA – done during paid employment
11
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology, contd.
• Transportation PA – done while traveling to a
destination
• Household PA – done during the maintenance
of the home
• Family PA – done when performing the care of
others
• PA affects all body systems that deal with the
production of energy
• Lower risk of CHD
11
PHC 331: Chronic Disease Epidemiology and Prevention
Distribution
• Needs constant updating to chart meaningful activity
patterns
• Two primary population-based surveys used to
measure physical activity:
• National Health Interview Survey
• Household survey
• Frequency, self-assessed intensity, duration
• Behavioral Risk Factor Surveillance System
• Phone-based survey
• Type, frequency, duration
11
PHC 331: Chronic Disease Epidemiology and Prevention
Distribution, contd.
• Surveillance estimations of PA were created to unify
results across the board:
• Recommended PA – moderate-intensity workouts, 30
minutes/day, 5 days/week; vigorous-intensity workouts, 20
minutes/day, 3 days/week
• Insufficient PA – more than 10 minutes spent doing moderate- to
vigorous-intensity workouts, but infrequent levels
• Inactivity – Less than 10 minutes/week spent doing moderate- to
vigorous-intensity workouts
11
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Groups
• Physical inactivity increases with age and is more
common among women and ethnic minorities
• Highest among men between 18-24 years old
• Among adolescents, two guidelines for physical
activity:
• Daily physical movement in lifestyle, and
• Three+ sessions of vigorous physical activity per week
11
PHC 331: Chronic Disease Epidemiology and Prevention
Geographic Distribution
• Highest prevalence of activity was in urban
centers, and the lowest in rural areas
• Built environments may play a part in how much
physical activity a population performs
• Land use patterns, transportation systems, sidewalk
development, trail systems, etc.
11
PHC 331: Chronic Disease Epidemiology and Prevention
Time Trends
• Though promoted thoroughly, proportion of
adults who regularly exercise hasn’t undergone
major growth over the years
• Adolescents have the same trend over time
12
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors
• Personal, psychological, and confidence levels all
attribute to a person’s choice to have a physically
active lifestyle
• Barriers include “lack of time, motivation, social
support, facilities, and knowledge of ways to become
more physically active” (Remington et al. 2010)
• Health conditions also contribute to physical
inactivity, and the positive response felt by not being
inactive may worsen the health condition
12
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention
• In the United States, national health objectives are
developed to set guidelines for activity objectives
• Healthy People 2010
• US Preventative Services Task Force
• The Guide to Clinical Preventive Services
• Goals include to establish recommendations for
population health, increase overall physical activity in
a variety of strata, reduce leisure time that lacks
physical activity, etc.
12
PHC 331: Chronic Disease Epidemiology and Prevention
Environmental and Policy Factors
• Policy changes frequently begin as grassroots
programs
• Recently, however, many coordinated efforts between school
systems, public health offices, and these grassroots programs have
been implemented
• Examples of policy efforts include ease of access to
bicyclists and walkers, requiring physical education in
school, activity programs through local recreation
departments
• Environmental factors include the inclusion of safe
stairwells in lobbies, providing an alternative to
elevators
12
PHC 331: Chronic Disease Epidemiology and Prevention
Public Health Interventions
• Transtheoretical Model
• Precontemplation, contemplation, action, maintenance, relapse
• Project Active – an individual-based project
• Home exercise vs. traditional exercise (health club/gym)
• Home exercise group aimed for thirty minutes of moderate
activity per day, unique to the user’s lifestyle, whereas
traditional group took exercise programs offered by the health
club
• By the end of the study, smaller decline in home exercise group
12
PHC 331: Chronic Disease Epidemiology and Prevention
Public Health Interventions, contd.
• Work sites, schools, assisted living facilities – all are options
for intervention-based programs
• Transdisciplinary partnerships are very effective ways of
promotion
• Example – teams from the Department of Transportation, state education
systems, nonprofit organizations, and healthcare facilities worked together
to form the National Safe Routes to School Task Force
• National Coalition for Promoting Physical Activity
• President’s Council on Physical Fitness and Sports
• State Governor’s Council on Physical Fitness
• State Health Department Physical Activity Initiatives and Campaigns
12
PHC 331: Chronic Disease Epidemiology and Prevention
Measurement of Physical Activity – Future Research
• More work done with questionnaire development and
surveys
• Quantification of popular trends in physical activities
• A difficulty to overcome in the research is inaccuracy
due to self-analysis
12
PHC 331: Chronic Disease Epidemiology and Prevention
Adolescent Physical Activity – Future Research
• Relatively recent adoption of guidelines for school
programs that promote physical activity established a
framework for analysis
• Additional studies needed to strengthen findings,
especially in young women, and the balance between
adequate nutrition and activity levels
12
PHC 331: Chronic Disease Epidemiology and Prevention
Environmental and Policy Changes – Future Research
• Continued efforts required to effect policy changes
designed to promote activity in communities
• Working with neighborhood coalitions
• Writing to local papers
• Lobbying for changes made by city planners
• Forming position statements for agencies
• Funding is required to research effectiveness of
already established programs, especially those in
disadvantaged communities
12
PHC 331: Chronic Disease Epidemiology and Prevention
Older Adults – Future Research
• Baby boomer generation in need of study to understand
efficacy and effectiveness of policies centered around
the elderly
12
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 10: Diabetes
13
PHC 331: Chronic Disease Epidemiology and Prevention
Significance
• One of the ten major causes
of death in the United
States since the 1930s
• Responsible for hundreds
of thousands of deaths
each year
• Underreported because
diabetes leads to the cause
of death but doesn’t cause
death itself
By Blausen.com Staff. "Blausen gallery 2014".
Wikiversity Journal of Medicine. (Own work) CC BY
3.0, via Wikimedia Commons
13
PHC 331: Chronic Disease Epidemiology and Prevention
Diabetes is a chronic disease that occurs when the pancreas is no longer
able to make insulin, or when the body cannot make good use of the
insulin it produces.
Insulin is a hormone made by the pancreas, that acts like a key to let
glucose from the food we eat pass from the blood stream into the cells
in the body to produce energy. All carbohydrate foods are broken down
into glucose in the blood. Insulin helps glucose get into the cells.
Not being able to produce insulin or use it effectively leads to raised
glucose levels in the blood (known as hyperglycaemia). Over the long-
term high glucose levels are associated with damage to the body and
failure of various organs and tissues.
Diabetes Mellitus
13
PHC 331: Chronic Disease Epidemiology and Prevention
Significance of Diabetes Mellitus
About 422 million people worldwide have diabetes, the majority living in
low-and middle-income countries, and 1.6 million deaths are directly
attributed to diabetes each year. Both the number of cases and the
prevalence of diabetes have been steadily increasing over the past few
decades. There is a globally agreed target to halt the rise in diabetes and
obesity by 2025.(WHO, 2020)
Types of Diabetes Mellitus:-
1- Type 1 Diabetes
2- Type 2 Diabetes
3- Gestational Diabetes
13
PHC 331: Chronic Disease Epidemiology and Prevention
Significance, contd.
• Diabetes leads to various life-threatening
complications:
• CVD
• Blindness
• Kidney failure
• Injury, infection, amputation of limbs
• Depression
• Diabetes carries a huge economic impact
• Partly due to long-term complications and prescription costs
13
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology
• In general, Type II diabetics are unable to utilize
insulin in the liver/muscle despite regular insulin
production in these places
• As disease progresses, pancreas fails to increase
insulin secretion
• Prediabetics:
• Impaired glucose tolerance (IGT)
• Impaired fasting glucose (IFG)
• Two classifications of diabetes complications
• Microvascular
• Macrovascular
13
PHC 331: Chronic Disease Epidemiology and Prevention
Descriptive Epidemiology
• Relies on health survey data for monitoring
• No distinction between Types I and II
• Type II accounts for the majority of all diabetes cases,
estimated at around 90%-95%
• Type II usually found in older adults, whereas Type I is
associated with minors and adolescents
13
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Groups
• Not an equal distribution
• The elderly, racial minorities, lower socioeconomic status, family
history
• Increased exposure to a variety of health complications, all of
which increase substantially with age
• Tend to be higher in minority populations in the United
States
• Native Americans/Alaska Natives two to three times higher than
other US adults
13
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Groups, contd.
• Those with lower socioeconomic status, i.e. those
with lower education and income, have an
increased risk, as well
• Common factors include less access to care, less
opportunities for education about diabetes, high stress levels
• Family history of diabetes strongly affects risk
factor
• 2.4 times greater odds of acquiring Type II when there is a
moderate familial risk
• 5.8 times greater when there is a high familial risk
13
PHC 331: Chronic Disease Epidemiology and Prevention
Geographic Distribution
• In the United States, clear geographic regions
show patterns in developing diabetes
• South/Southeastern at high risk, due to ethic makeup and
obesity
• Where there are higher levels of obesity there
are higher levels of diabetes
• Susceptibility to Type I diabetes shows a
similarity across the different regions of the
world
13
PHC 331: Chronic Disease Epidemiology and Prevention
Time Trends
• Over time, diabetes has been one of the only CVD risk
that has increased
• Due to age, ethnic diversity, obesity problem
• Increasing in all demographics over time
• This is true for both Types I and II
• However, due to timely response, medications and
therapies, there hasn’t been an increase in diabetes-
related complications over time
14
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors – Type I
• Very few modifiable risks for Type I diabetes
• However, research has shown that there is some
correlation between environmental factors
• Nutrition and viruses may come into play
• Type I patients were 43% more likely to have breastfed for less
than 3 months and 63% more likely to consume cow’s milk before
age three
• Enteroviruses
• Stress, higher maternal age at birth, birth order, birth
weight, overnutrition are other possible risks
14
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors – Type II
• Obesity – 80% of patients obese at diagnosis
• Distribution of fat also plays a role
• Those with a higher hip-to-waist ratio are more susceptible
• Dietary elements
• Whole grains, coffee, magnesium, peanut butter/nuts, low-fat
dairy products, moderate alcohol consumption all been shown to
reduce risk
• High saturated fat diets and increase red meat consumption have
been linked to an increased risk of Type II
14
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors – Type II, contd.
• Lack of physical activity
• Almost a linear relationship between frequency/intensity to
diminished risks of Type II Diabetes
• Smoking
• Increased risk factor
• Factors that reduce chance of developing Type II:
• Relatively low BMI, high fiber diet, high polyunsaturated fat diet,
30 minutes of moderate exercise a day, smoke-free, less than half
a serving of alcohol per day
14
PHC 331: Chronic Disease Epidemiology and Prevention
Risk factors of Gestational Diabetes Mellitus
14
PHC 331: Chronic Disease Epidemiology and Prevention
Symptoms of Type 1 Diabetes
14
PHC 331: Chronic Disease Epidemiology and Prevention
Symptoms of Type 2 Diabetes
14
PHC 331: Chronic Disease Epidemiology and Prevention
Complications
• Often external factors that are
intrinsic to developing Type II
often increase the risk of
complications
• Risks can be reduced by working
with health care professionals to
manage macro- and
microvascular complications
14
PHC 331: Chronic Disease Epidemiology and Prevention
Major complications of Diabetes
14
PHC 331: Chronic Disease Epidemiology and Prevention
Causes, Consequences, Risk Populations Chart
Causes
*Obesity
*Physical inactivity
*Poor diet
*Smoking
At-risk Populations
*Elderly
*Poor
*Less educated
*Minorities
*Persons with a family
history of diabetes
Consequences
*Coronary heart disease
*Stroke
*Peripheral vascular
disease
*End-stage renal disease
*Blindness
*Lower leg amputations
*Disability
*Depression
*Poor pregnancy
outcomes
*Premature mortality
Type 2 Diabetes
Adapted from Remington et al. (2010)
14
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control – Type I
• Prevention starts with
identification of disease
• Diabetes Prevention Trial
(DPT)
• Locating effective
prevention strategies isn’t
currently economical or
relatively easy
15
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control – Type II
• Unlike Type I, there are clear
plans for prevention – both
lifestyle and pharmacological
interventions
• Studies in both China, Finland
and the United States, where
screenings of diabetics were
calculated and then controlled
through differing variables –
exercise, diet, etc.
• Results were conclusive – reduction in
diabetes after a few years of
participation
15
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control in Youth – Type II
• Not many studies conducted to
research Type II diabetes in youth
because so few cases exist
• Interventions done in school systems to
increase physical activity were enforced,
but insulin levels were not measured
• There has been increased
development in plans to prevent
Type II, as opposed to treat it in
youth
• Early detection of prediabetes
15
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and control of Gastetional diabetes
15
PHC 331: Chronic Disease Epidemiology and Prevention
Screening and Early Detection
• Prediabetes – blood glucose between
100-126 mg/dL
• Type I – not recommended
• Type II – not cost effective, but utilized
in “high risk” groups; fasting glucose
>126mg/dL considered diagnostic
• Gestational Diabetes – shown to
reduce fetal morbidity/mortality;
recommended for “high risk” groups;
100g OGTT administered upon positive
test
15
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment, Rehab, Recovery
• Type I
• Diabetes Control and Complications Trial
• Physical activity an important goal for
treatment
• Type II
• Weight management, caloric restriction,
physical activity
• Pharmacotherapy – BP, tobacco nonuse,
aspiration may be just as important as
glucose control in many cases
• Treatment involves hands-on patient
interaction
• Frequent evaluations
15
PHC 331: Chronic Disease Epidemiology and Prevention
Public Interventions
• National Diabetes Prevention and Control Program
• Defining the Diabetes Burden
• Conducting Applied Translation Research
• State-Based Diabetes Control Programs
• National Diabetes Partnerships and Programs
• Prevention Research Centers, Racial and Ethnic Approaches to
Community Health, Steps to a Healthier US
• Indian Health Service Division of Diabetes Treatment/Prevention
• Diabetes Research and Training Centers
15
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 11: High Blood
Pressure
15
PHC 331: Chronic Disease Epidemiology and Prevention
Hypertension - or elevated blood pressure - is a serious medical
condition that significantly increases the risks of heart, brain,
kidney and other diseases.
An estimated 1.13 billion people worldwide have hypertension, most
(two-thirds) living in low- and middle-income countries. In 2015, 1 in
4 men and 1 in 5 women had hypertension. Fewer than 1 in 5 people
with hypertension have the problem under control (WHO,2019)
Significance
15
PHC 331: Chronic Disease Epidemiology and Prevention
Hypertension is a major cause of premature death worldwide.
One of the global targets for no communicable diseases is to reduce
the prevalence of hypertension by 25% by 2025 (baseline 2010).
Blood pressure is the force exerted by circulating blood against the
walls of the body’s arteries, the major blood vessels in the body.
Hypertension is when blood pressure is too high.
Blood pressure is written as two numbers. The first (systolic) number
represents the pressure in blood vessels when the heart contracts
or beats.
Blood Pressure
15
PHC 331: Chronic Disease Epidemiology and Prevention
The second (diastolic) number represents the pressure in the
vessels when the heart rests between beats.
Hypertension is diagnosed if, when it is measured on two
different days, the systolic blood pressure readings on both
days is ≥140 mmHg and/or the diastolic blood pressure
readings on both days is ≥90 mmHg.(WHO,2019)
16
PHC 331: Chronic Disease Epidemiology and Prevention
Causes, Consequences, High-Risk Groups
Causes
*Obesity
*Physical inactivity
*Alcohol intake
*Dietary sodium and
potassium intake
*Genetics
At-risk Populations
*African American
ancestry
*Family history of high
blood pressure
*Men
*Older women
Consequences
*Cardiovascular disease
*Neurological disease
(stroke)
*Kidney disease
*Renal failure
*Premature death
High Blood Pressure
Adapted from Remington et al. (2010)
16
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology
• “Mean arterial pressure is the product
of cardiac output…and systematic
vascular resistance” (Remington et al.
2010).
• Kidney, sympathetic nervous system,
renin-angiotensin system all play
central roles BP regulation
• A “normal” body maintains intake and
output in equilibrium
16
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology, contd.
• The various types of
hypertension exhibit impaired
pressure natriuresis
• Either intra- or extrarenal
• Increased activity of the
sympathetic nervous system
also associated with
hypertension
• Vasoconstriction/sodium
retention
16
PHC 331: Chronic Disease Epidemiology and Prevention
Significance
• Across all populations, HBP is a severe issue for
healthcare workers
• Second largest contributor to disease in developed and developing
countries
• 7.1 million of annual deaths are attributed to high
blood pressure
• The correlation between HBP and CV mortality higher
in younger subjects, though mortality naturally occurs
in older populations
16
PHC 331: Chronic Disease Epidemiology and Prevention
Significance, contd.
• HBP is the leading contributor to stroke – shown
as consistent across a variety of studies
• More than twice as high in hypertensive category
• Nondependent on race/sex
• Higher chance of congestive heart failure
• Higher chance of cardiovascular disease
• The effects of high blood pressure do vary
slightly depending on race, age, regions
16
PHC 331: Chronic Disease Epidemiology and Prevention
High-Risk Populations
• Age
• As we age, our average blood pressure increases across most
populations
• True for both men and women
• Systolic blood pressure increases throughout lifespan
• Diastolic blood pressure Increases until 50 years old, and then
remains constant and then decreases
• Data is limited because lack of followup
• Those with starting SBP < 140 mmHg and DBP 85-89
mmHg are more likely to develop HBP
16
PHC 331: Chronic Disease Epidemiology and Prevention
Time Trends
• Over time, 1971-1991 a steady decline in both
systolic and diastolic BP had been seen across all
observable age groups, races, sexes
• Omitting African American men, 50+, who suffered a small
increase
• This downward movement indicates that
environmental/behavioral effects mitigated higher BP
• Increase began after 1991 in the United States,
especially in the elderly ad in women
• Corollary to increased BMI
16
PHC 331: Chronic Disease Epidemiology and Prevention
Causes – Genetic Factors
• Those predisposed to high blood pressure are
susceptible
• Difficult to assess genetic causes
• Alteration of specific non-allelic gene difficult to trace
because HBP looks the same in everyone
• Alleles and haplotypes inspection is compromised 90% of the
time
16
PHC 331: Chronic Disease Epidemiology and Prevention
Causes – Obesity
• In the United States, those with higher BMIs
progressively experience blood pressure problems
• 50% of new cases attributable to being overweight
• Corroborated by nonpharmacological interventions
16
PHC 331: Chronic Disease Epidemiology and Prevention
Causes – Salt Intake
• Sodium chloride intake attributable to the
development of HBP
• Salt compromises kidneys
• After a long exposure to high salt intake, no longer able
to excrete sodium, which leads to increased volume of
blood in the body
• Confirmed by random control testing of sodium
reduction in diets
17
PHC 331: Chronic Disease Epidemiology and Prevention
Causes – Potassium Intake
• Increased potassium – lower blood pressure
• SBP and DBP
• “Administration of dietary potassium increases renal
sodium and chloride excretion, reduces blood
volume, and decreases blood pressure” (Remington
et al. 2010)
17
PHC 331: Chronic Disease Epidemiology and Prevention
Causes – Alcohol Intake
• Unclear direct link between high blood pressure
and high alcohol intake, but hypertensive
effects of extensive alcohol use shown in
various studies
• When a reduction in alcohol intake is reported,
lower blood pressure is also reported
17
PHC 331: Chronic Disease Epidemiology and Prevention
Symptoms of Hypertension
17
PHC 331: Chronic Disease Epidemiology and Prevention
Screening and Early Prevention
• Screening is beneficial because
testing methods are reliable and
effective for those with
hypertension
• Screening is inexpensive, but
should be targeted toward high-
risk patients in particular
• 76% of hypertension victims are
aware of their condition, despite
readily available testing By National Heart Lung and Blood Insitute (NIH)
[Public Domain], via Wikimedia Commons
17
PHC 331: Chronic Disease Epidemiology and Prevention
Types of Hyptersion
17
PHC 331: Chronic Disease Epidemiology and Prevention
Complications of Hypertension
17
PHC 331: Chronic Disease Epidemiology and Prevention
Lifestyle Changes, contd.
• Nonpharmacological, lifestyle choices, contd.
• Dietary pattern – not one factor that influences diet, but large-
scale changes
• DASH Trial: three various diets observed for 11 weeks; one – low
fruits, veggies, dairy, average United States fat content; two –
fruits and vegetables; three – DASH diet (high fruits, vegetables,
low-fat dairy, reduced saturated and total fat
• DASH diet effective for those with HBP
• DASH diet current recommendation for lowering high blood
pressure
17
PHC 331: Chronic Disease Epidemiology and Prevention
Lifestyle Changes
• Nonpharmacological, lifestyle choices
• Weight reduction – less drug therapy needed if following a diet
aimed at fat/weight reduction
• Salt reduction – especially effective for hypertensive as opposed to
normotensive
• Less drug therapy needed for those with a low-salt diet
• Increase in dietary potassium – inverse relationship with higher
potassium consumption and blood pressure in various meta-
analyses
• Especially effective for hypertensive and African Americans
17
PHC 331: Chronic Disease Epidemiology and Prevention
Lifestyle Changes, contd.
• Nonpharmacological, lifestyle choices, contd.
• Alcohol intake moderation – 25% reduction lowers SBP by 3.3
mmHg and DPB by 2.0 mmHg
• Limited intake to 2 drinks per day (men) and 1 drink per day
(women and low-weight individuals
• Physical activity – SBP reduction 3.5 mmHg and DBP reduction
2.5 mmHg
• Study of physical activity currently limited; inconclusive toward
women, African Americans, and weight training (aerobic only)
17
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention and Control of Hypertension
18
PHC 331: Chronic Disease Epidemiology and Prevention
Secondary Prevention: Pharmacological Treatment
• Goal of secondary prevention: avoiding the
negative effects of HBP
• Recommended for both hypertensive individuals
with no complications (risk factors)
• Thiazide diuretic initially
• Calcium channel blockers
• Angiotensin-converting enzyme inhibitors
• Angiotensin type I receptor blockers
• Beta-blockers
18
PHC 331: Chronic Disease Epidemiology and Prevention
Population-level Changes
• Aim of intervention is to lower blood
pressure across an entire population
• Various community-based projects
aim to translation research into
action and management of blood
pressure
• The processes for lowering blood
pressure at a population-level are
the same as those outlined in
individual-based programs, outline
above
18
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 12: High Blood
Cholesterol
18
PHC 331: Chronic Disease Epidemiology and Prevention
Cholesterol
18
PHC 331: Chronic Disease Epidemiology and Prevention
Definition :- is a waxy, fat-like substance that's found in all the cells in
your body. Your body needs some cholesterol to make hormones,
vitamin D, and substances that help you digest foods.
Cholesterol is transmitted in the blood through Lipoprotein
Cholesterol
18
PHC 331: Chronic Disease Epidemiology and Prevention
Lipoprotien
Intermediate density – cholesterol + triglycerides transport
Very low density – triglycerides
LDL : Low density consist of High Fat, Low Protein
HDL : High density :Low Fat, High Protein
18
PHC 331: Chronic Disease Epidemiology and Prevention
Lipoprotein
18
PHC 331: Chronic Disease Epidemiology and Prevention
Fat
18
PHC 331: Chronic Disease Epidemiology and Prevention
Significance
• Many different people are at risk for coronary heart
disease
• Hypercholesterolemia
• 16.5% of population between 20-74 have high
cholesterol in the United States, and nationally high
average
• Many healthcare resources needed to be expended to
screen and treat hypercholesterolemia
18
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology and Genetics
• Insoluble in water
• Transported in lipoproteins throughout bloodstream
• Lipids + apoproteins = lipoproteins
• 4 types of lipoproteins:
• Low density – integral to atherosclerotic development
• Very low density – triglycerides
• Intermediate density – cholesterol + triglycerides transport
• High density – cholesterol removed from the body transport
• Inverse correlation between high density lipoproteins and coronary
heart disease
19
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology and Genetics, contd.
• Cholesterol is needed to maintain regular bodily
function
• Problems arise when abundance of cholesterol is
present
• Accumulates in artery walls
• Plaque can develop
• Fatty streaks are earliest signs of accumulation
• Atheromas are advanced
• Can be calcified, hemorrhage, ulcerate
• Genetics important to assigning cholesterol levels
• Abnormalities include hyperlipidemia/dyslipidemia
19
PHC 331: Chronic Disease Epidemiology and Prevention
Causes, Consequences, High-Risk Groups
Causes
*Diets with high saturated
fats
*Genetics
*Obesity and metabolic
disorders
*Physical inactivity
*Smoking
*Hypothyroidism
*Renal disease
*Diabetes mellitus
*Steroid therapy
At-risk Populations
*Men 45 and older
*Women 55 and older
*Low socioeconomic status
*Diabetics
*Those with:
-Known atherosclerosis
-Genetic lipid disorder
-Chronic kidney disease
-History of a prior stroke
-History of coronary artery disease
Consequences
*Coronary heart disease
*Atherosclerosis
*Stroke
*End organ damage
*Premature death and
disability
*High health care costs
and treatment
High Cholesterol
Adapted from Remington et al. (2010)
19
PHC 331: Chronic Disease Epidemiology and Prevention
High-risk populations
• Highest risk – known atherosclerotic cardiovascular
disease
• Rate increases when prior CV event occurs
• Older are at more risk
• Especially men older than 45 and women older than 55
19
PHC 331: Chronic Disease Epidemiology and Prevention
Geographic Distribution
• Beijing, China had the lowest hypercholesterolemia
among men/women
• Ticino, Switzerland / Novi Sa, Yugoslavia had the
highest
• European countries in general are more disposed
to high serum cholesterol levels
19
PHC 331: Chronic Disease Epidemiology and Prevention
Time Trends
• Steadily decreasing in the United States since
the 60s
• Contributed directly to the decline in coronary
heart diseases in the United States in recent
years
19
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors
• Biggest modification – reduction in dietary
fat/saturated fat
• Dose response relationship among saturated/trans fat intake and
low-density lipoprotein levels
• Three types of fat:
• Saturated – saturated with hydrogen; no double bonds
• Monounsaturated – one double bond
• Polyunsaturated – two or more bonds
• Saturated fatty acids raise cholesterol levels by
decreasing activity of low density lipoprotein
receptors
19
PHC 331: Chronic Disease Epidemiology and Prevention
Modifiable Risk Factors, contd.
• Polyunsaturated fatty acids – omega-6 and omega-3
• Omega-6 lowers LDLs and some HDLs
• Omega-3 lowers triglyceride and LDL levels
• Monounsaturated fatty acids
• Reduces LDLs and minimally reduces HDL
• Trans fatty acids
• Raises LDLs and lower HDLs, raises triglycerides
• Obesity is also positive-corollary to total cholesterol
levels
• Smoking/inactivity – lower HDLs and higher risk of
CHD
19
PHC 331: Chronic Disease Epidemiology and Prevention
Prevention
• Diet is the cornerstone for change when it
comes to lowering cholesterol levels, however:
• Cholesterol-lowering medication also substantially
beneficial
• Two approaches to prevention:
• Population strategy – lifestyle alteration
• Clinical strategy – addressing the needs of those with
direct cause for cholesterol reduction
19
PHC 331: Chronic Disease Epidemiology and Prevention
Top food to increase (HDL) Cholesterol
19
PHC 331: Chronic Disease Epidemiology and Prevention
Screening
• Screening is a fivefold process with treatment,
nutritional changes, weight management, increased
physical activity
• Lipid panels are obtained in a fasting state
• Recommended for those over 20 years old, every five years
• Baseline total cholesterol levels vary by 5 mg/dL on a
given day
• HDL levels by 1.5 mg/dL
20
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment – Population-based
• An emphasis is placed first on community education
• Dietary Guidelines for Americans details goals to
decrease diseases like coronary heart disease
• Recommended for use starting as early as two years old
• Those with immediate cholesterol disorder, or those
who have had a recent CHD event should be stricter
and should follow a more rigid clinical approach
20
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment – Patient-based
• Lipoprotein count should be gathered if:
• 200 mg/dL cholesterol or higher
• HDL cholesterol lower than 40 mg/dL
• CHD risk factors (3+)
• Framingham 10-year Risk Score measures the risk
percentage of having a CHD event based on risk
factors, and outlines a goal level of low-density
lipoproteins to have
20
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment – Antioxidants
• Historically, antioxidant use has been shown to
decrease oxidation of LDLs
• However, now shown that antioxidants do not
decrease atherosclerotic burden or prevent CHD
events; further, vitamin intake with antioxidants may
increase an event, and increase chance of lung cancer
• No longer recommended for lipid therapy
20
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment – Hormone Replacement Therapy
• Not recommended for lipid disorder treatment
• Increased risk suggested
20
PHC 331: Chronic Disease Epidemiology and Prevention
Treatment – Children and Adolescents
• Atherosclerosis begins in childhood; progression
linked to later high cholesterol
• High cholesterol is maintained in familial setting due
to similar genetics and home environment
• Population approach – the same change in diet as
adults, with an emphasis on fruits/vegetables
• Individualized approach – designed for at-risk youth
20
PHC 331: Chronic Disease Epidemiology and Prevention
Public Health Interventions
• Public education, screening, intervention
• Community interventions from various groups
• Stanford Five City Project
• Pawtucket Heart Health Program
• Minnesota Heart Health Program
20
PHC 331: Chronic Disease Epidemiology and Prevention
Future Research
• Due to substantial variation in medication benefits
across a span of variables, more research needed
to find a more even fit
• Optimal diet research
• Cholesterol disorders need further evaluation
• Behavior change and adherence need further
initiatives
20
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 13: Cardiovascular
Disease
20
PHC 331: Chronic Disease Epidemiology and Prevention
Types of Heart diseases
20
PHC 331: Chronic Disease Epidemiology and Prevention
Causes, Consequences, High-Risk Groups
Causes
*High blood pressure
*Elevated blood
cholesterol
*Cigarette smoking and
environmental tobacco
smoke
*Physical inactivity
*Obesity (abdominal)
*Poor diet
*Diabetes
At-risk Populations
*Elderly
*Poor
*Less educated
*Minorities
*Family history
Consequences
*Disability
*Lost productivity
*Large costs to health care
system
*Depression
*Premature mortality
Cardiovascular Disease
(heart disease, stroke, and
peripheral vascular
disease)
Adapted from Remington et al. (2010)
21
PHC 331: Chronic Disease Epidemiology and Prevention
Significance
Cardiovascular diseases (CVDs) are the number 1 cause of death globally,
taking an estimated 17.9 million lives each year. CVDs are a group
of disorders of the heart and blood vessels and include coronary heart
disease, cerebrovascular disease, rheumatic heart disease and other
conditions. Four out of 5CVD deaths are due to heart attacks and strokes,
and one third of these deaths occur prematurely in people under 70 years of
age.(WHO,2020)
• Variation by age, race, sex
• Highest mortality rates for CVD in the United States
• Leading cause of death of women in the United States
• Wide range of complications associated with CVD – disability, stroke, high blood
pressure
21
PHC 331: Chronic Disease Epidemiology and Prevention
Significance of Cardiovascular Diseases
21
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology of CVD
• Cardiovascular disease is closely related to
atherosclerosis
• Atherosclerosis – “A slowly progressive condition in
which the inner layers of the artery walls become thick,
irregular, and rigid” (Remington et al. 2010)
• Typically seen during middle-age or later, though
atherosclerosis manifests in childhood
• Coronary heart disease, stroke, peripheral artery disease,
congestive heart failure
• Each each associated with certain risk factors:
• CHD – high cholesterol
• Stroke – high blood pressure
• PAD – smoking/diabetes
21
PHC 331: Chronic Disease Epidemiology and Prevention
Coronary Heart Disease – Significance, Pathophysiology
• Also known as ischemic heart disease or coronary artery
disease
• “Several disorders that reduce the blood supply to the heart muscle”
(Remington et al. 2010)
• Largest cause of mortality of U.S men and women
• Huge financial burden on healthcare, large risk (52% of all CVD deaths)
• Initial symptoms – angina pectoris, myocardial infarction,
sudden death
21
PHC 331: Chronic Disease Epidemiology and Prevention
Coronary Heart Disease – High Risk Populations, Distribution
• Men have higher CHD mortality rates on average
• Increases with age
• More prevalent among African Americans
• Family history of CHD increases the risk that it will
develop
• Higher risk among those of low socioeconomic status
• Strong variation of CHD death rates in various regions
of the United States, similar situations in Europe
21
PHC 331: Chronic Disease Epidemiology and Prevention
Coronary Heart Disease – Time Trends, Causes
• Since 1968, there has been a steady decline in mortality,
uniform across all groups
• Factors not full answered, but theories point to lifestyle changes, less risk
factors, and improvements in medical care
• High blood pressure is a leading contributor to CHD mortality
• 5-6mmHg change in DBP can reduce CHD up to 20-25%
• Tobacco use another contributor among men and women
• Twice the risk of heart attack
21
PHC 331: Chronic Disease Epidemiology and Prevention
Coronary Heart Disease – Causes, contd.
• Cholesterol is another factor to consider
• Higher LDLs, higher risk of CHD; higher HDLs, less risk of CHD
• C-reactive proteins (CRP) also contribute to CHD
• Elevated fibrinogen – “a circulating glycoprotein that acts as
the final step in…coagulation” (Remington et al. 2010) levels are
another risk for CHD
• As well as homocysteine
• Diabetes mellitus
• Obesity
• Physical inactivity
21
PHC 331: Chronic Disease Epidemiology and Prevention
Coronary Heart Disease – Prevention and Control
• Modest approach to prevention – changing just one at-risk
variable can have a widespread effect
• Screenings involve assessing blood pressure/cholesterol
levels, diet, tobacco use, activity level
• Electrocardiograms recommended only for at-risk groups
• Treatments tailored to each patient – healthy lifestyle
changes, medication, surgery, and gene therapy are viable
options
21
PHC 331: Chronic Disease Epidemiology and Prevention
2- Cerebrovascular Disease
• Stroke – third leading cause of
death in the United States
• High societal-related costs,
including medical care and
time lost due to inactivity
• Short- and long-term
disabilities
• Observed regional differences
21
PHC 331: Chronic Disease Epidemiology and Prevention
Types of stroke
22
PHC 331: Chronic Disease Epidemiology and Prevention
Cerebrovascular Disease – Pathophysiology, Descriptive Epidemiology
• Occurs when an artery of the brain is clogged/ruptured and
artery is unable to supply nutrients to brain tissue
• Ischemic or hemorrhagic
• Ischemic – thrombus, embolus, narrowing artery due to atherosclerotic plaque
• Hemorrhagic – intracerebral or subarachnoid
• Age is a strong risk factor
• After 55, stroke rate doubles each decade thereafter
• Men at higher risk of death than women
• Family history increases chance
22
PHC 331: Chronic Disease Epidemiology and Prevention
Cerebrovascular Disease – Causes, Risks
• Hypertension, non-valvular atrial fibrillation, diabetes,
cigarette smoking, physical inactivity, obesity,
dyslipidemia
• Hypertension – most significant changeable risk factor
• Those who suffer from AF are predisposed to worse
outcomes of a stroke
• Uncontrolled diabetes causes increased arterial damage,
which leads to stroke
22
PHC 331: Chronic Disease Epidemiology and Prevention
Signs of Stroke
22
PHC 331: Chronic Disease Epidemiology and Prevention
Cerebrovascular Disease – Prevention and Control
• Framingham Stroke Profile
• NIH Stroke Scale
• Controlling hypertension
• Screening should be implemented to survivors of a
stroke to regulate risk factors
• Treatments start by discovering specific causes of
stroke
• Minimizing brain damage
22
PHC 331: Chronic Disease Epidemiology and Prevention
Heart Failure – Significance, Pathophysiology
• 300,000 annual deaths
• Heart failure cases are increasing, with poor prognoses
“Multisystem disorder characterized by abnormalities of cardiac function, skeletal
muscle, and renal function, stimulation of the sympathetic nervous system, and a
complex pattern of neurohormonal change that impairs the ability of either
ventricle to fill or eject blood” (Remington et al. 2010, p. 409)
• Cardiorenal, cardiocirculatory (hemodynamic), neurohormonal
models/hypotheses
22
PHC 331: Chronic Disease Epidemiology and Prevention
Heart Failure – Descriptive Epidemiology
• Most patients who experience heart
failure are aged 65+
• Sufferers of coronary heart disease,
hypertension, diabetes are at
particular risk
• Time trends illuminate that there is a
strong male prevalence, and that,
over time, cases of heart failure have
increased in both sexes
22
PHC 331: Chronic Disease Epidemiology and Prevention
Heart Failure – Causes, Prevention and Control
• CHD, hypertension, diabetes, arrhythmias, congenital heart
disease, cardiomyopathy
• Extra strain on the heart is not beneficial
• Prevention and control begins by finding and altering
modifiable risk factors
• Stage A Through D Prevention
22
PHC 331: Chronic Disease Epidemiology and Prevention
Signs and Symptoms of Heart failure
22
PHC 331: Chronic Disease Epidemiology and Prevention
Peripheral Arterial Disease – Significance, Pathophysiology
• Atherosclerosis of lower
extremities
• Measurable by ankle-brachial
index
• Functional morbidity with
increased risks of other CVD
complications
• A burden due to its correlation with
other risks
• Strong indicator of atherosclerotic
formations elsewhere
By National Heart Lung and Blood Insitute (NIH)
[Public Domain], via Wikimedia Commons
22
PHC 331: Chronic Disease Epidemiology and Prevention
Chapter 15: Chronic Respiratory
Diseases
23
PHC 331: Chronic Disease Epidemiology and Prevention
Causes, Consequences, High-Risk Groups
Causes
*Cigarette smoking
*Occupational exposures
*Dust mites
*Allergens from pets,
cockroaches, rodents
*Environmental tobacco
smoke
*Molds
*Obesity
At-risk Populations
*Poor
*Less educated
*Minorities
*Workers
*Persons with a family
history
Consequences
*Shortness of breath
*Disability
*Social stigma
*Depression and anxiety
*High healthcare costs for
treatment
*Premature death
Chronic Respiratory
Diseases
Adapted from Remington et al. (2010)
23
PHC 331: Chronic Disease Epidemiology and Prevention
Chronic respiratory diseases are chronic diseases of the airways and
other structures of the lung. Some of the most common are: asthma,
chronic obstructive pulmonary disease (COPD),respiratory allergies
occupational lung diseases and pulmonary hypertension.
Hundreds of millions of people suffer every day from chronic respiratory
diseases. According to the latest WHO estimates (2004), currently 235
million people have asthma, 64 million people have chronic obstructive
pulmonary disease (COPD) while millions have allergic rhinitis and
other often-underdiagnosed chronic respiratory diseases (WHO, 2020)
Significance
23
PHC 331: Chronic Disease Epidemiology and Prevention
Significance – Chronic Respiratory Diseases
• Major result of CRDs is dyspnea (pathologic breathlessness)
• Inability to perform aerobic tasks like climbing stairs
• Constant breathlessness
• Difficulty sleeping
• Overactive mucous production
• Reduced lung capacity
• Extended viral/bacterial infections
• Terminology problem when describing respiratory diseases
• COPD – can describe multiple sets of symptoms all associated with different
diseases
• See chart on page 471 for a breakdown of various CRDs
23
PHC 331: Chronic Disease Epidemiology and Prevention
Pathophysiology – Chronic Respiratory Diseases
• Various tests depending on the chronic respiratory disease
• Bronchitis – clinical signs; symptoms
• Asthma and other COPD – clinical evaluation; spirometric tests
• Emphysema – lung biopsy; CT scan
• Symptoms of COPD can be similar to gastroesophageal reflux
• Spirometric tests are simple, noninvasive
• “Spirometry measures the expired volume as a function of time” (Remington
et al. 2010).
• Chest radiograph is most helpful, though often expense and
feasibility are factors that inhibit its use in the pre-risk phase of
CRDs
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slidebank331

  • 1. 1 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 2: Methods in Chronic Disease Epidemiology
  • 2. 2 PHC 331: Chronic Disease Epidemiology and Prevention • The science of public health • Greek epi (upon), demos (people), logos (study) • Now includes injury, disability, risk factors, quality of life, and, traditionally, disease • Center for Disease Control (CDC) defines epidemiology as “the study of the distribution and determinants of health-related states in specified populations, and the application of this study to the control of health problems.” Definition of Epidemiology
  • 3. 3 PHC 331: Chronic Disease Epidemiology and Prevention • Based on the CDC’s definition, a breakdown of the terms: • Study – quantitative, statistic- and research-based • Distribution – characterized through people and how health events happen in populations • Determinants – causes, factors, implemented in analytical epidemiology • Health-related states – not just diseases, a spectrum of ailments • Populations – groups of people, not just individuals • Control – implement decision-making processes to prevent health issues Definition of Epidemiology, contd.
  • 4. 4 PHC 331: Chronic Disease Epidemiology and Prevention • Diseases of known microorganisms (AIDS, flu, etc.) focus the study of epidemiologists • Likewise, injuries are acute, with often immediate health consequences (car accidents, falling, etc.) • However, many chronic diseases originate early in life through unhealthy behaviors, which, in turn, increase the risk in later life to develop these diseases • This (detailed below) is called the chronic disease continuum The Chronic Disease Continuum Descriptive Epidemiology, Analytic Epidemiology, Intervention/Evaluative Research Developmental, social, environmental, genetic determinants Health risk behaviors and other factors Chronic conditions Chronic diseases Adapted from Remington et al. (2010)
  • 5. 5 PHC 331: Chronic Disease Epidemiology and Prevention • An important question is at what point are epidemiologist trying to “control” a chronic disease? At which stage of the continuum? • Controlling has become not only achieving lower mortality rates, but also lowering detrimental effects of the disease • Both of these factors are used to describe the natural history of a given disease The Chronic Disease Continuum, contd.
  • 6. 6 PHC 331: Chronic Disease Epidemiology and Prevention • Uses readily available data to examine a disease and who it affects in populations by time, place, or person • Assesses burden, at risk groups, trends • Public tends to focus on incurable diseases or environmental diseases, instead of chronic diseases that fall on the continuum. Descriptive Epidemiology
  • 7. 7 PHC 331: Chronic Disease Epidemiology and Prevention • Frequently, the count of affected individuals is seen as the fundamental measure • Implemented when analyzing the need for healthcare to aide in lessening the burden • Count is a simple way to present this burden to the general public, but it is dependent on the population size • Other measures can be used by epidemiologists to highlight different elements of the disease The Burden of Disease
  • 8. 8 PHC 331: Chronic Disease Epidemiology and Prevention • Rates are used to compare populations – incidence and prevalence • Incidence rate – new cases over period ÷ person-years • Person-years = persons × period monitored • Cumulative incidence – probability of developing a disease, ranging from 0 to 1 • Prevalence – another proportion, this one measured at a point in time instead of a period • Less valuable than incidence in identifying causes Calculating Rates
  • 9. 9 PHC 331: Chronic Disease Epidemiology and Prevention • Compared using risk ratios/relative risks • Rate ratio – incidence rate of one group compared to another • Rate difference – subtracting the rates from one another • Calculates how much risk is different given certain variables in the study • Rates also used to aim program targeting goals • At-risk subgroups are found within populations • Can assist healthcare professionals in joint interventions Comparing Rates
  • 10. 10 PHC 331: Chronic Disease Epidemiology and Prevention Mortality Rate Disease Smokers (a) Nonsmokers (b) Ratio (a/b) Difference(a-b) Lung cancer 131 11 11.9 120 Coronary heart disease 275 153 1.8 122 Difference between rat ratio and rate difference
  • 11. 11 PHC 331: Chronic Disease Epidemiology and Prevention • Randomized controlled trials (RCTs) – the most thorough and scientific study • Subjects assigned to prevention or non-prevention • Disease and death-rates monitored and observed over time • Often impractical/impossible • Need comparison groups for analysis • Comparisons between (least effective) national data and (most effective) concurrent collection vary in appropriateness Study Designs
  • 12. 12 PHC 331: Chronic Disease Epidemiology and Prevention Experimental Studies 1- RCT :-Randomized controlled trials (RCTs) are considered the most scientifically rigorous type of epidemiological study. In an RCT, subjects are randomly assigned to either receive or not receive a preventive or therapeutic procedure, such as a clinical smoking cessation intervention or a new drug. The disease course or mortality patterns are then observed over time to assess the effectiveness of the preventive or therapeutic procedure (Remington et al, 2010) Study Designs in Chronic Disease Epidemiology
  • 13. 13 PHC 331: Chronic Disease Epidemiology and Prevention • Comparison groups vary in their appropriateness for disease intervention studies. Least convincing are comparisons with national data or populations in other studies. Subjects assigned to prevention or non-prevention • Disease and death-rates monitored and observed over time • Often impractical/impossible • Need comparison groups for analysis Advantages of RCT
  • 14. 14 PHC 331: Chronic Disease Epidemiology and Prevention Study Designs, contd. Adapted from Remington et al. (2010) • Historical or retroactive studies can also be a viable option, if the correct records are available • Downsides include that no incidence rates or cumulative incidence can be gathered • Upsides include that, in certain cases, information was found that affected risks which could be modified and benefit a population in the future
  • 15. 15 PHC 331: Chronic Disease Epidemiology and Prevention • Since RCTs can be unethical, epidemiologists need to observe without intervention • Based on doctor recommendations • Prospective cohort – exposures not randomly assigned, but first identified • Active and intense measurements can be made Observational Studies
  • 16. 16 PHC 331: Chronic Disease Epidemiology and Prevention Study Type Strengths Limitations Experimental studies Randomized clinical trial *Controls randomly assigned *High cost *Impractical long-term *Impractical exposures Randomized community trial *Population-wide scope *Multicomponent effectiveness *Very expensive *Small number of study groups Quasi-experimental study *Real-world policy/program intervention *Multiple comparison groups *Potential bias *Lack of control – confounders Observational studies Prospective cohort *Measure risk before disease occurs *Multiple outcomes *Yields incidence rates/relative risks *Expensive *Large number of subjects required *Lengthy follow-ups *Hard to control exposure factors Case-control *Rare diseases *Inexpensive *Quick results *Possible risk-factor bias *Possible bias in control group selection *Identified might not represent population Strengths/Limitations of Study Designs Adapted from Remington et al. (2010)
  • 17. 17 PHC 331: Chronic Disease Epidemiology and Prevention • Most chronic disease studies are from observational studying • Therefore, errors are present in a number of different ways: • Measurement, selection of subjects, bias, etc. • Experts are needed to quantify uncertainty in research methods and decide quality studies • Confounding and bias are important types of error in epidemiological studies Assessing Valid Study Results
  • 18. 18 PHC 331: Chronic Disease Epidemiology and Prevention • “The influence of an exposure of interest is mixed with the effect of another” (Remington et al. 2010) • In RCT, confounders can be equally distributed among each study group • In observational studies, confounders have to be measured and adjusted • As long as confounders are measurable and adjusted, then no need for concern • However, some confounders are difficult to measure or unknown Confounding
  • 19. 19 PHC 331: Chronic Disease Epidemiology and Prevention • Faulty sampling methods or refusal to participate leads to samples with higher or lower measurement risk • Poorly arranged control groups are major threats to accuracy • Phone samples introduce bias when families without landlines are not taken into account • Classification errors also present a potential bias • Also known as information bias Selection/Information Bias
  • 20. 20 PHC 331: Chronic Disease Epidemiology and Prevention • Attributable Risk • How much burden is lessened is exposure is eliminated • Relative risk - 1 ÷ relative risk • Population Attributable Risk • How common the exposure is • Rate (total pop.) - rate (unexposed) ÷ rate (total pop.) • Also Pe (relative risk - 1) ÷ 1 + Pe (relative risk - 1) • Where Pe proportion of population exposure Prevention through Intervention
  • 21. 21 PHC 331: Chronic Disease Epidemiology and Prevention • Often, critical analyses will lead to “important” or “groundbreaking” new information, but this must be taken lightly • One study is never sufficient to answer all or even one question about a chronic disease. • Validity must be measured through repetition and variety or intervention Single vs. Series
  • 22. 22 PHC 331: Chronic Disease Epidemiology and Prevention • Systematic reviews • Researchers consolidate information using comprehensive methods to assess relevant science behind a single health issue • Increasingly, meta-analysis is used in these systematic reviews • Meta-analysis • Identify relevant studies, inclusion/exclusion criteria, data abstraction, heterogeneity across statistical analysis Systematic Reviews, Meta-analysis, Expert Panels
  • 23. 23 PHC 331: Chronic Disease Epidemiology and Prevention • An approach to looking at risks posed by adverse exposures like pollutants • A “bridge” between the scientific community and those who create policies and protocol • Four steps to proper risk assessment: • Hazard identification, risk characterization, exposure assessment and risk estimation • Expert panels used to assess validity of epidemiological studies through peer review Risk Assessment/Expert panels
  • 24. 24 PHC 331: Chronic Disease Epidemiology and Prevention • Incidence rate – New events in a specified period / persons exposed to risk within period • Relative risk – Risk of death or disease in population exposed to risk / risk of death or diseased in unexposed population • Population attributable risk – Rate of disease in population attributed to risk factor / total rate of disease Key Concepts
  • 25. 25 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 3: Intervention Methods for Chronic Disease Control
  • 26. 26 PHC 331: Chronic Disease Epidemiology and Prevention • Behavior changes in individuals can often prevent many chronic diseases • CDC estimates that 80% of heart disease, type II diabetes and 40% of cancer would be eliminated if poor diet, inactivity and smoking were also eliminated • Obesity is now seen more frequently among both adults and children Behavioral Determinants
  • 27. 27 PHC 331: Chronic Disease Epidemiology and Prevention • The high cost of treating chronic diseases is another reason they are increasing • Secondary prevention can find many diseases earlier when they are cheaper to treat and more beneficial to lifestyle change, and also lead to fewer visits in later years (which will lower health costs) • Lack of incentives for prevention services in US healthcare system Healthcare Determinants
  • 28. 28 PHC 331: Chronic Disease Epidemiology and Prevention • Features like sidewalks, parks, bike trails, community pools all encourage healthier choices • Households with multiple televisions and computers also promote a less-active culture which affects the amount of exercise being done • Nutritional choices also under consideration in built environments – menus, work cafeterias, highlight lower costs for less nutritional foods Environmental Determinants
  • 29. 29 PHC 331: Chronic Disease Epidemiology and Prevention • Population health is emerging as just as important as individual health • Policymakers are quick to blame individual choices for chronic illness, when, in reality, there are an amplitude of environmental, cultural and economic factors at play • Social determinants are often a large result of health disparities Social Determinants
  • 30. 30 PHC 331: Chronic Disease Epidemiology and Prevention • Victim-blaming fails to account environmental and social – ecological approach acknowledges that we live in a world full of interactions • Intrapersonal factors • Interpersonal factors • Organizational factors • Community factors • Policy factors Levels of Intervention
  • 31. 31 PHC 331: Chronic Disease Epidemiology and Prevention • Early attempt to use theory to study preventive behaviors • If subject perceives moderate severity and susceptibility, then choose preventative action • Often criticized and used to explain how people rarely adopt preventative behaviors • Content of Health Belief Model:- • Perceived Suscessiability • Perceived severity • Perceived benefits • Perceived barrier • Cuss to action • self- efficacy Health Belief Model
  • 32. 32 PHC 331: Chronic Disease Epidemiology and Prevention Perceived susceptibility - This refers to a person's subjective perception of the risk of acquiring an illness or disease. There is wide variation in a person's feelings of personal vulnerability to an illness or disease. Perceived severity - This refers to a person's feelings on the seriousness of contracting an illness or disease (or leaving the illness or disease untreated). There is wide variation in a person's feelings of severity, and often a person considers the medical consequences (e.g., death, disability) and social consequences (e.g., family life, social relationships) when evaluating the severity. Perceived benefits - This refers to a person's perception of the effectiveness of various actions available to reduce the threat of illness or disease (or to cure illness or disease). The course of action a person takes in preventing (or curing) illness or disease relies on consideration and evaluation of both perceived susceptibility and perceived benefit, such that the person would accept the recommended health action if it was perceived as beneficial.
  • 33. 33 PHC 331: Chronic Disease Epidemiology and Prevention Perceived barriers - This refers to a person's feelings on the obstacles to performing a recommended health action. There is wide variation in a person's feelings of barriers, or impediments, which lead to a cost/benefit analysis. The person weighs the effectiveness of the actions against the perceptions that it may be expensive, dangerous (e.g., side effects), unpleasant (e.g., painful), time-consuming, or inconvenient. Cue to action - This is the stimulus needed to trigger the decision-making process to accept a recommended health action. These cues can be internal (e.g., chest pains, wheezing, etc.) or external (e.g., advice from others, illness of family member, newspaper article, etc.). Self-efficacy - This refers to the level of a person's confidence in his or her ability to successfully perform a behavior. This construct was added to the model most recently in mid-1980. Self-efficacy is a construct in many behavioral theories as it directly relates to whether a person performs the desired behavior.
  • 34. 34 PHC 331: Chronic Disease Epidemiology and Prevention Health Belief Model
  • 35. 35 PHC 331: Chronic Disease Epidemiology and Prevention • Also known as Stages of Change Model • Not everyone at the same stage to drastically change health behavior, so each plan fits to different characteristics • Series of stages, from pre-contemplation (no change) to termination (problem no longer acceptable) or relapse (retroactively choosing less healthy behavior) Trans theoretical Model
  • 36. 36 PHC 331: Chronic Disease Epidemiology and Prevention • Individuals are fueled by behavioral intentions • An attitude of a positive behavior is “is the sum of all the positive feelings…or negative feelings…about performing the behavior” (Remington et al. 2010). • Places normative beliefs on people’s perceptions and readiness to change Theory of Planned Behavior
  • 37. 37 PHC 331: Chronic Disease Epidemiology and Prevention • Expectancy is important when considering control – where, who, what is/are responsible? • If there is belief that a plan of action will result in an outcome, a person is more likely to pursue that option • Control moves from internal (self) to external (higher powers, luck, fate, etc.) • Those who lean toward external control are more likely reached through policy changes Health Locus of Control
  • 38. 38 PHC 331: Chronic Disease Epidemiology and Prevention • Addresses dynamic of society that influence health and methods for behavioral change • Triadic, dynamic, reciprocal models • Emphasis placed on highlighting capability and self-confidence • Self-efficacy through mastery of task • Applicable to wide variety of populations Social Cognitive Theory
  • 39. 39 PHC 331: Chronic Disease Epidemiology and Prevention • Monopolizes on existing string of social network (family) to implement support • Family trained to assist in weight loss program, for example • “Family Matters” program to prevent youth smoking and alcoholism Family-Based Interventions
  • 40. 40 PHC 331: Chronic Disease Epidemiology and Prevention • Mentor programs, buddy systems, self-help groups • Creating a new social network with the sole purpose of intervening • Especially important in adolescent interventions Friends and Social Networks
  • 41. 41 PHC 331: Chronic Disease Epidemiology and Prevention • Social support • Emotional support • Instrumental support • Informational support • Appraisal support • Either strengthening existing networks or creating new ones to assist in the problem-solving process Social Support and Social Networks
  • 42. 42 PHC 331: Chronic Disease Epidemiology and Prevention • A member of a social network who gains trust and respect through his or her abilities to offer support and guidance • These strategies are seen frequently in urban and rural settings • Natural helpers are either found in a community organically, or is given specialized training (this is known as a lay health advisor) Natural Helpers
  • 43. 43 PHC 331: Chronic Disease Epidemiology and Prevention • Effective in providing screening/follow-ups • However, often underutilized in primary prevention (see Slide 3) • Brief interventions are low cost alternative to high cost visits • Short, private, non-confrontational, 5-60 minute meeting with counseling and informative education • Can be leveraged depending on a person’s aptitude and readiness for change Health Care System and Clinical Services
  • 44. 44 PHC 331: Chronic Disease Epidemiology and Prevention • Youth are a spirited, receptive audience for prevention messages • Establishing healthier habits at an earlier age is essential in stopping or slowing chronic illness Schools
  • 45. 45 PHC 331: Chronic Disease Epidemiology and Prevention • US adult population spends half or more of the day at work, so it becomes a useful tool in dispensing knowledge about prevention education • Leaders are understanding that chronic diseases are costing more and more (employee absence, insurance costs, etc.) and are mediating this through health knowledge at the workplace. Results: • Improved productivity • Reduced absences • Reduced health risks/health care costs • Improved company image Work Sites
  • 46. 46 PHC 331: Chronic Disease Epidemiology and Prevention • Selected based on priorities of population in question • Priority population partners – participatory, collaborative, local, empowering, research and action blend • Community coalitions • Media advocacy – seen today in suicide prevention, and lead poisoning, to name a few Examples of Community-Level Health Planning Approaches
  • 47. 47 PHC 331: Chronic Disease Epidemiology and Prevention • Process planning • Plan with people • Plan with data • Institutionalization • Priorities • Short- and long-term outcomes • Evaluation Community-Level Health Planning
  • 48. 48 PHC 331: Chronic Disease Epidemiology and Prevention • Mobilizing the community • Developing a community profile • Selection behavior/audiences • Formative research • Strategy development • Program development • Program implementation • Tracking Community-Based Prevention Marketing
  • 49. 49 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 4: Chronic Disease Surveillance
  • 50. 50 PHC 331: Chronic Disease Epidemiology and Prevention Conceptual Model of Health Surveillance Define the Problem Program Process Evaluate the Effect Find Programs that Work Information Dissemination Data Collection Data Analysis Data Interpretation Epidemiologic Process Adapted from Remington et al. (2010)
  • 51. 51 PHC 331: Chronic Disease Epidemiology and Prevention • Council of State and Territorial Epidemiologists modifies this list each year • Includes primarily infectious diseases, but also contains some noncommunicable diseases, as well • In 1996, CSTE included smoking, the first behavior on the list • 2004 list contains 92 disease systems • Chronic Disease Indicators website includes definitions and data of each in the United States Notifiable Disease Systems
  • 52. 52 PHC 331: Chronic Disease Epidemiology and Prevention • Collected information from birth and death • An initial cornerstone of surveillance since the mid-19th century and perhaps earlier • Death certificates are used to list immediate causes of death and a string of events that caused death (underlying cause) • Limitation – incomplete certificate, lack of clinical history Vital Statistics
  • 53. 53 PHC 331: Chronic Disease Epidemiology and Prevention • One symptom or a string of symptoms, disease, disability, etc. • Effectiveness yet to be proven by research • Could potentially identify outbreaks or bioterrorism Sentinel Surveillance
  • 54. 54 PHC 331: Chronic Disease Epidemiology and Prevention • Used in monitoring trends • Usually mandated in state laws • Most common disease registries – cancer • Hospital-based or population-based registries Chronic Disease Registries
  • 55. 55 PHC 331: Chronic Disease Epidemiology and Prevention • Implemented when collecting information from self-reported health practices (general pop.) • CDC established a phone-based surveillance system of questionnaires • Some surveys go beyond questionnaires and access physical exams and samples • Collected at mobile examination centers Health Surveys
  • 56. 56 PHC 331: Chronic Disease Epidemiology and Prevention • Primarily hospital discharge data • Used to locate hospitalization patterns of chronic diseases • Limitations – incomplete records, unreliable imputation of data, missing variables, measurement errors, only focus on hospital setting, not outpatient care Administrative Data Collection Systems
  • 57. 57 PHC 331: Chronic Disease Epidemiology and Prevention • Each 10 years, the United States government censuses the entire population – collects detailed information on individual and household • Limitations – census does not include everyone; inevitably some are missed • Minority racial/ethnic groups • Geographic areas Census Data
  • 58. 58 PHC 331: Chronic Disease Epidemiology and Prevention • Charts the variety of a disease given their personal attributions • Race, age, gender, etc. • Realizing differences in these factors helps design effective and group-specific prevention or control programs Person Analyses
  • 59. 59 PHC 331: Chronic Disease Epidemiology and Prevention • Charts a disease that occurs in one geographic region against another region • Typically found in situations when a city or county is compared to state or country • Needs to understand and interpret age structure between areas by age-standardization • Cluster analysis – in acute geographic areas – monitored to avoid health risks specific to a very small area (neighborhoods, communities, suburbs, etc.) Place Analyses
  • 60. 60 PHC 331: Chronic Disease Epidemiology and Prevention • Charts trends that appear over time • Used to detect outbreaks, transmission patterns, intervention strategies • Temporal trends, regional analysis • Interventions based on variables specific to a certain time in a certain era Time Analyses
  • 61. 61 PHC 331: Chronic Disease Epidemiology and Prevention • Data dissemination is the final step in disease monitoring • Often composed in documents with technical language, with little linkage to public health promotion • Epidemiologists asked to disseminate the information collected into health department reports • Five steps in data analysis: • Establish the message, set an objective, define the audience, select the channel, evaluate the impact Data Dissemination
  • 62. 62 PHC 331: Chronic Disease Epidemiology and Prevention • Arguably the most important element of data presentations • The role of the epidemiologist is to convey a clear message, one that is worthwhile and somewhat easy to understand • “Less is more” approach • Main points must be easy to understand Message
  • 63. 63 PHC 331: Chronic Disease Epidemiology and Prevention • Goal of epidemiologist is to establish an objective for a piece of writing • Goals vary – sometimes there is no goal, simply that there is something to be reported, other times objective is for general public education • Sometimes the ideal objective is public action Objective
  • 64. 64 PHC 331: Chronic Disease Epidemiology and Prevention • Target audience varies, but has traditionally been both local health departments and health care providers • These agencies are charged with implementing any strategies for managing disease control • Today, a broader spectrum of target audience exists – from policymakers and legislators, or to the general public, advocacy agencies to promote their efforts Audience
  • 65. 65 PHC 331: Chronic Disease Epidemiology and Prevention • The method or medium that an epidemiologist “channels” his or her work • Journals, paper/electronic mail, radio/television, blogs, print/digital media, etc. • Frequently mailed to healthcare facilities • Sometimes a press release is required • Selective channeling aides research in reaching target audience Channel
  • 66. 66 PHC 331: Chronic Disease Epidemiology and Prevention • Final step is evaluating how the information was distributed using the previous four methods • This can be measured in various ways – number of items distributed, where and how, readership, coverage, hits on a webpage, web searches • The success of the previous methods outline the impact that a particular public health campaign may have Impact
  • 67. 67 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 5: Tobacco Use
  • 68. 68 PHC 331: Chronic Disease Epidemiology and Prevention Significance According to WHO,2017: The tobacco epidemic is one of the biggest public health threats the world has ever faced, killing more than 8 million people a year around the world. More than 7 million of those deaths are the result of direct tobacco use while around 1.2 million are the result of non-smokers being exposed to second-hand smoke. • Smoking harms every organ of the body, with diseases including • Cardiovascular diseases • Cancers – lip, mouth, esophagus, lung, kidney, etc. • Respiratory problems • Reproductive disorders • SIDS, cataracts, slow wound healing • Low bone density
  • 69. 69 PHC 331: Chronic Disease Epidemiology and Prevention Cardiovascular Disease • Smoking a major risk factor in developing congenital heart disease • Ability of blood to delivery oxygen is reduced • Secondhand smoking causes prothrombotic effects and endothelial cell dysfunctions
  • 70. 70 PHC 331: Chronic Disease Epidemiology and Prevention Cancer • “Mainstream tobacco smoke (MS) contains nearly 5,000 chemicals…and more than 60 known carcinogens” (Remington et al. 2010) • These carcinogens have been linked to tobacco-related cancers • Nitrosamines/polyaromatic hydrocarbons – lung cancer • N-nitrosodimethylmine – kidney tumors • Nitrosamine NNK – pancreatic cancer • Benzene, polonium-210, lead-210 – myeloid leukemia
  • 71. 71 PHC 331: Chronic Disease Epidemiology and Prevention Chronic Lung/Other Respiratory Disease • When you smoke, additional biological processes like inflammation, degradation of structural proteins and oxidant stress are developed, which can cause alveolar injury • Results in COPD • Hypoxemia • Decline in pulmonary function • Reduction of tracheal mucus velocity
  • 72. 72 PHC 331: Chronic Disease Epidemiology and Prevention Nicotine Dependence • Nicotine distribution absorbs rapidly to the brain in both oral and inhalation of tobacco – around ten seconds upon initial use • Crosses blood-brain barrier and binds to receptors in brain, which releases neurotransmitters • Effects dependent on rate of use, tolerance • Withdrawal symptoms include irritability, frustration, increased appetite, weight gain, and generally occur within one day and maintain for ten days, though cravings for regular smokers last for years
  • 73. 73 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Groups • In the United States, estimated 43 million smokers • Higher for men (22%) than women (17%) • 10% - Asians; 13% - Hispanics; 20% - African Americans; 21% - Caucasians; 36% - Native Americans and Alaska Natives (Remington et al. 2010) • A 2005 study found that 51% of men and 50% of women were smokers at one time but had quit • Estimated 4,000 young people smoke their first cigarette each year • According to the Global Burden of Disease study more than 8 million people died prematurely as a result of smoking in 2017.
  • 74. 74 PHC 331: Chronic Disease Epidemiology and Prevention Number of tobacco users global by sex ( WHO,2019) The number apparently peaked in 2018 at 1093 million tobacco users. Between 2000 and 2005, the number of male tobacco users increased by 22 million; between 2005 and 2010, the increase slowed to 13 million, and slowed again to a 7 million increase between 2010 and 2015. The number of users is projected to decrease going forward from 2018, decreasing by 2 million to 1 091 million in 2020, then by another 4 million to 1 087 million in 2025, assuming countries maintain current efforts in tobacco control.
  • 75. 75 PHC 331: Chronic Disease Epidemiology and Prevention Global trends in prevalence of tobacco use by sex ( WHO, 2019) In 2000, around half of men aged 15 years and older were current users of some form of tobacco. By 2015, the proportion of men using tobacco had declined to 40.3%. By 2025, the rate is projected to decline to 35.1%. In 2000, around one in six women (16.7%) aged 15 years and older were current users of some form of tobacco. By 2015, the proportion of women using tobacco had declined to under one in ten (9.5%). By 2025, the rate is projected to decline to 6.7%. any form of tobacco was three times in 2000, the proportion of males using e proportion of users among women. By 2015 the rate for males was more than four times the rate for females. By 2025 the rate for males is expected to be five times the rate for females.
  • 76. 76 PHC 331: Chronic Disease Epidemiology and Prevention Trends in current tobacco use among people aged ≥15 years
  • 77. 77 PHC 331: Chronic Disease Epidemiology and Prevention Time Trends • Peak cigarette sales in the United States in 1963 – steadily declining since • Over time, the gap between men (historically higher rates) and women (lower) has been narrowing, but the declination rate is lowering at a comparable rate • From 2002, more former smokers than current smokers
  • 78. 78 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors • Societal and individual factors – exposure in popular films, perception of safeness among certain brand • Advertising and promotion – media sponsorship, high budget spend on advertisement from tobacco companies • “Safer” tobacco – low-tar branding • Access – vending machines and some sales counters selling to minors
  • 79. 79 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors, contd. • Social norms – societal, local, familial, peer communities all affecting smoking; when access to tobacco exists in these communities, it becomes easier to acquire • Individual psychosocial factors – weaker attachment to parents, stronger attachment to peers, rebelliousness and risk- taking • Continued tobacco use – the role of genetics in treatment response; the effect of advertising and “safer” products
  • 80. 80 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors, contd. • Inadequate understanding – underestimation of smoking- related deaths; assumption that young people will stop before potentially harmful side effects occur • Adults not aware of hazards, which can be attributed to underrepresentation of anti-smoking literature and media • Lower price – the lower the price, the more cigarettes and tobacco are consumed
  • 81. 81 PHC 331: Chronic Disease Epidemiology and Prevention Population-Attributable Risk • Several recent studies have suggested the influence that risk factors play when defining tobacco use • One study postulated that 33% of experimentation with tobacco among youth attributed to advertisements; • Two others speculate that cinema/Hollywood glorification of tobacco leads to higher risks; • A third looks at youth with nonsmoking parents smoking as a direct result of movies and popular culture
  • 82. 82 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control • Price • Increasing the price of tobacco can help stymy sales, especially among youth • Sales would have to increase across all types of tobacco to be effective • Countermarketing campaigns • Pointed at youth prevention, but need to be sustained to be effective • Challenge social norms about tobacco use, educate youth on prevention • Advertising bans • Mixed evidence on effectiveness • When a ban is in place, tobacco companies shift to other forms of delivery – electronic, billboards, points of sale
  • 83. 83 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control, contd. • Minors’ access restrictions • More stringent interventions are needed to lower youth accessibility of tobacco • School-based tobacco prevention programs • Effective when taught alongside community interventions • Emphasize tobacco-free campuses, negative health effects • Eliminating secondhand smoke • Eliminating smoking indoors helps, but cannot prevent complete exposure • Also helps reduce cigarette consumption in general
  • 84. 84 PHC 331: Chronic Disease Epidemiology and Prevention Screening and Treatment • Best practice in the medical field – ask about past history with tobacco use • Should be acquired during every visit and thoroughly documented in a medical record • Those who smoke should be screened so effective treatment can be given as needed • Cotinine can be measured in blood, saliva, urine – though acquiring these levels not particularly routine in medical care, except in the case of pregnant women’s tobacco intake
  • 85. 85 PHC 331: Chronic Disease Epidemiology and Prevention List of Evidence-Based Interventions • Comprehensive tobacco prevention and control programs: • Estimated that prevention programs have added 21 years to the life expectancy between 1964 and 1992 for 1.6 million Americans • California spearheaded the prevention programs, and has lower cases of lung cancer, lowest per capita consumption, and low youth smoking rate than the rest of the United States • Tobacco excise taxes • Increased taxation on cigarettes, though remedied by tobacco companies by coupons and other discounting strategies
  • 86. 86 PHC 331: Chronic Disease Epidemiology and Prevention List of Evidence-Based Interventions, contd. • Countermarketing campaigns • Smoke-free policies • Public and private insurance coverage • Minors’ access restrictions • Telephone cessation quitlines • Usually not enough funding to sustain • Product changes
  • 87. 87 PHC 331: Chronic Disease Epidemiology and Prevention Future Research and Demonstration • Key issues for continued research: • Promised public health interventions • Evaluating state prevention and control programs • Industry practice monitoring and counteraction • Translating the decline in youth and adult dependence • Disparate population interventions • Health impacts of changing products • Most cost-effective interventions locally and internationally
  • 88. 88 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 6: Diet and Nutrition
  • 89. 89 PHC 331: Chronic Disease Epidemiology and Prevention Consequences and Causes of Poor Nutrition Chart Causes *Social and cultural factors *Poor social/family support *School lunch policies *Lack of education about diet *Food industry marketing (esp. to children) *Eating out *Watch television At-risk Populations *Infants/elderly *Poor *Undereducated *Urban populations *Racial/ethnic minorities *Family with both parents working outside the home Consequences *Obesity *CHD *Diabetes *Selected cancers *Dental caries *High blood pressure *Psychological effect Poor Diet/Nutrition: *High in total calories, saturated fat, animal meat, sugar, salt, and alcohol *Low in fruit, vegetables, whole grains, fiber, unsaturated oils Adapted from Remington et al. (2010)
  • 90. 90 PHC 331: Chronic Disease Epidemiology and Prevention Significance • Cardiovascular disease and cancer, followed closely by Type II diabetes, are the three main causes of mortality in the world, and are chiefly caused by an imbalance of nutrition • High blood pressure/cholesterol • Inversely, micronutrient deficiencies account for 15% of childhood diseases
  • 91. 91 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Fruits and Vegetables • Lowers chronic disease risk • High levels of dietary fiber, vitamin C, E, folic acid, etc. • Antioxidants and beta-carotenes • Reduction of serum cholesterol • Manages body weight through high contents of water, fiber, low fat content
  • 92. 92 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Dietary Fiber • Studies show that an increase in dietary fiber result in a lower chance of CHD/certain cancers • Increases stool bulk, increases food’s entry and exit times, lowers risk for carcinogens in the body • Soluble fiber can lower cholesterol • Binds bile acids and prevents reabsorption • High fiber, research shows, has an inverse relationship with insulin levels
  • 93. 93 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Dietary Fat and Red Meat • Different kinds of fat • Trans fat and saturated fats – adverse toward health • Omega-3 fatty acids and monounsaturated fats – benefit health • Reduction of saturated fat by intake by small increments lowers heart attack risk rates by 25% • Hypothesis is that omega-3 fatty acids alter the immune system’s response to cancer • Red meat – both positive and negative effects • + — high in iron, vitamins A, B12, protein • - — risk of colorectal cancer, formation of mutagenic free radicals in stomach
  • 94. 94 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Dairy Products and Milk • Low fat milk intake shown to lower risk of osteoporosis, CVD, colon cancer • Contains fatty acids • Calcium content lowers lipid collection and higher lipid excretion rates • 2% and whole milk are high in saturated fat and calories
  • 95. 95 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Sugar-Sweetened Beverages • Caloric sweeteners – “all caloric carbohydrate sweeteners, such as table sugar, honey, and high fructose corn syrup, and excludes naturally occurring sugars and artificial sweeteners” (Remington et al. 2010) • Consumption of beverages with caloric sweeteners increases risk of obesity and cavities • Increased consumption over the last 30 years has shown spiked levels of excessive consumption
  • 96. 96 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Sex • U.S. men – higher intake of red meat, dairy • U.S. women – higher intake of fruits, vegetables, salts, cholesterol • Greater importance on eating healthily
  • 97. 97 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Age and Life Course • Young and old are susceptible to poor nutrition • Young – targeted by food industry to eat energy- dense foods; poor diet habits developed in youth tend to carry into adulthood • Old – lower metabolism and physical activity, changes in taste and smell; 80% of elderly need improvements
  • 98. 98 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Race and Ethnicity • African Americans and Caucasians increased total energy-dense foods from 1971 and 2002 • Racially diverse populations, on average in the United States, have lower access to fresh fruits and vegetables • Sociocultural and behavioral factors influence the dietary variety of the three major racial groups in the United States • African American, Caucasian (white), and Mexican American
  • 99. 99 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Income • As wealth decreases, direct relationship between the ability to acquire healthy foods • Similarly, energy-dense foods are more likely to be consumed by those with lower income • This is partly due to the inaccessibility, such as the high price and the lack of larger stores that support a variety of nutritional fruits and vegetables in urban/low-income areas
  • 100. 10 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Education • Income and education have a corollary relationship, so both affect chronic disease outcome at similar rates • Higher consumption of fruits/vegetables has been linked to higher education, and those with the most education are more likely to spend more per capita on these foods
  • 101. 10 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations – Other • Geographic distribution • Developed countries have higher diets with animal products and saturated fats • Fish consumed more frequently in coastal regions • Industrial development and immigration • As a country shifts from underdeveloped to developed, chronic disease patterns can occur in as little as one generation • Time trends • Larger portion sizes appeared over time • Higher kcal consumption for both men (+196kcal) and women (+283 kcal)
  • 102. 10 PHC 331: Chronic Disease Epidemiology and Prevention Barriers to Healthy Eating • Individual preference • Appearance, taste, texture • Community and family • Environments that support positive food choices make it easier to follow a healthy diet • Lowest cost foods – least nutritious • Fast-food density has been shown to be connected to poor nutrition • Parental modeling affects familial diet among adolescents • Families with both parents working outside the home have increased chances of seeking nutrition in energy-dense, unhealthy foods
  • 103. 10 PHC 331: Chronic Disease Epidemiology and Prevention Primary Prevention Policy • Dietary Guidelines created by the US Department of Health and Human Service • Areas of consideration include adequate nutrients within calorie needs, weight management, physical activity, fats, carbohydrates, sodium and potassium, alcoholic beverages, food safety • Emphasizes a balanced diet • From “Basic Seven” to “MyPlate” An early nutritional guide developed in the 1940s by the U.S. Department of Agriculture, CC BY 2.0, via Wikimedia Commons
  • 104. 10 PHC 331: Chronic Disease Epidemiology and Prevention Primary Prevention Policy, contd. The current nutritional policy, MyPlate, developed in 2011. Image by OpenStax College, CC BY 3.0, via Wikimedia Commons Food Pyramid nutritional policy, developed in 1992 by the USDA. Image by the USDA College, Public Domain, via Wikimedia Commons
  • 105. 10 PHC 331: Chronic Disease Epidemiology and Prevention Surveillance • Various nutritional analyses that make up the National Nutrition Monitoring System • Food disappearance programs chart the available consumable foods • Food questionnaires used by epidemiologists to chart frequency of intake and a list of consumed foods • Effective because participants are likely to remember recent food choices, as opposed to long-term dietary analyses
  • 106. 10 PHC 331: Chronic Disease Epidemiology and Prevention Large-Scale Initiatives • Origins in the 1980s – National Cancer Institute/Kelloggs Campaign • National Fruit and Vegetable Program • 1% or Less Campaign • Site-based interventions • Workplace • Schools • Faith-based
  • 107. 10 PHC 331: Chronic Disease Epidemiology and Prevention Large-Scale Initiatives, contd. • Population-specific initiatives • Community approaches in urban areas • Federal safety net • School lunch programs • Supplemental Nutrition Assistance Program (formerly Food Stamps) • Eliminating racial disparities • Heart to Heart Program
  • 108. 10 PHC 331: Chronic Disease Epidemiology and Prevention Large-Scale Initiatives, contd. • Policy approaches • Agricultural policies – which crops are produced • Nutrition right-to-know – advocacy groups attempt to make nutritional assessments in restaurants more accessible • School wellness policies – improved physical activity programs and healthy food options in vending machines • Advertising to children
  • 109. 10 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 7: Physical Activity
  • 110. 11 PHC 331: Chronic Disease Epidemiology and Prevention Consequences • Affects physiological, psychological, societal of health • Reduces chance of premature death, developing CHD/diabetes/colon cancer • Promotes healthy bones and joints • Less falls and functional dependency in older adults
  • 111. 11 PHC 331: Chronic Disease Epidemiology and Prevention Consequences, contd. Causes *Psychosocial (motivation *Self-efficacy *Social/cultural factors *Physical environment *Perceptions of competence in sports *Enjoyment At-risk Populations *Older adults *Adolescents *Women *Those with low incomes *Overweight adults *Those with conditions that limit movement *Injured or disabled individuals Consequences *Obesity *CHD *Diabetes *Colon cancer *High blood pressure *Falls/osteoporosis *Psychological effects Physical Inactivity Adapted from Remington et al. (2010)
  • 112. 11 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology • Physical activity – movement produced by skeletomuscular system that burns energy • Occupational and nonoccupational • Contrasted with exercise • Exercise • Repetitive movement used to maintain physical fitness • Physical fitness • Achievable attributes related to physical activity • Cardiorespiratory, muscular, metabolic, morphological, motor • Frequency – number of times PA is performed • Duration – minutes/hours PA is performed
  • 113. 11 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology, contd. • Intensity • METs – Metabolic cost divided by resting metabolic rate • MET-minutes – MET multiplied by minutes • Kcal – MET-minutes times body weight • Light intensity - <3 METs • Moderate intensity – 3 to 6 METs • Vigorous intensity - >6 METs • Activity dose • Leisure – free choice periods of PA • Occupation PA – done during paid employment
  • 114. 11 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology, contd. • Transportation PA – done while traveling to a destination • Household PA – done during the maintenance of the home • Family PA – done when performing the care of others • PA affects all body systems that deal with the production of energy • Lower risk of CHD
  • 115. 11 PHC 331: Chronic Disease Epidemiology and Prevention Distribution • Needs constant updating to chart meaningful activity patterns • Two primary population-based surveys used to measure physical activity: • National Health Interview Survey • Household survey • Frequency, self-assessed intensity, duration • Behavioral Risk Factor Surveillance System • Phone-based survey • Type, frequency, duration
  • 116. 11 PHC 331: Chronic Disease Epidemiology and Prevention Distribution, contd. • Surveillance estimations of PA were created to unify results across the board: • Recommended PA – moderate-intensity workouts, 30 minutes/day, 5 days/week; vigorous-intensity workouts, 20 minutes/day, 3 days/week • Insufficient PA – more than 10 minutes spent doing moderate- to vigorous-intensity workouts, but infrequent levels • Inactivity – Less than 10 minutes/week spent doing moderate- to vigorous-intensity workouts
  • 117. 11 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Groups • Physical inactivity increases with age and is more common among women and ethnic minorities • Highest among men between 18-24 years old • Among adolescents, two guidelines for physical activity: • Daily physical movement in lifestyle, and • Three+ sessions of vigorous physical activity per week
  • 118. 11 PHC 331: Chronic Disease Epidemiology and Prevention Geographic Distribution • Highest prevalence of activity was in urban centers, and the lowest in rural areas • Built environments may play a part in how much physical activity a population performs • Land use patterns, transportation systems, sidewalk development, trail systems, etc.
  • 119. 11 PHC 331: Chronic Disease Epidemiology and Prevention Time Trends • Though promoted thoroughly, proportion of adults who regularly exercise hasn’t undergone major growth over the years • Adolescents have the same trend over time
  • 120. 12 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors • Personal, psychological, and confidence levels all attribute to a person’s choice to have a physically active lifestyle • Barriers include “lack of time, motivation, social support, facilities, and knowledge of ways to become more physically active” (Remington et al. 2010) • Health conditions also contribute to physical inactivity, and the positive response felt by not being inactive may worsen the health condition
  • 121. 12 PHC 331: Chronic Disease Epidemiology and Prevention Prevention • In the United States, national health objectives are developed to set guidelines for activity objectives • Healthy People 2010 • US Preventative Services Task Force • The Guide to Clinical Preventive Services • Goals include to establish recommendations for population health, increase overall physical activity in a variety of strata, reduce leisure time that lacks physical activity, etc.
  • 122. 12 PHC 331: Chronic Disease Epidemiology and Prevention Environmental and Policy Factors • Policy changes frequently begin as grassroots programs • Recently, however, many coordinated efforts between school systems, public health offices, and these grassroots programs have been implemented • Examples of policy efforts include ease of access to bicyclists and walkers, requiring physical education in school, activity programs through local recreation departments • Environmental factors include the inclusion of safe stairwells in lobbies, providing an alternative to elevators
  • 123. 12 PHC 331: Chronic Disease Epidemiology and Prevention Public Health Interventions • Transtheoretical Model • Precontemplation, contemplation, action, maintenance, relapse • Project Active – an individual-based project • Home exercise vs. traditional exercise (health club/gym) • Home exercise group aimed for thirty minutes of moderate activity per day, unique to the user’s lifestyle, whereas traditional group took exercise programs offered by the health club • By the end of the study, smaller decline in home exercise group
  • 124. 12 PHC 331: Chronic Disease Epidemiology and Prevention Public Health Interventions, contd. • Work sites, schools, assisted living facilities – all are options for intervention-based programs • Transdisciplinary partnerships are very effective ways of promotion • Example – teams from the Department of Transportation, state education systems, nonprofit organizations, and healthcare facilities worked together to form the National Safe Routes to School Task Force • National Coalition for Promoting Physical Activity • President’s Council on Physical Fitness and Sports • State Governor’s Council on Physical Fitness • State Health Department Physical Activity Initiatives and Campaigns
  • 125. 12 PHC 331: Chronic Disease Epidemiology and Prevention Measurement of Physical Activity – Future Research • More work done with questionnaire development and surveys • Quantification of popular trends in physical activities • A difficulty to overcome in the research is inaccuracy due to self-analysis
  • 126. 12 PHC 331: Chronic Disease Epidemiology and Prevention Adolescent Physical Activity – Future Research • Relatively recent adoption of guidelines for school programs that promote physical activity established a framework for analysis • Additional studies needed to strengthen findings, especially in young women, and the balance between adequate nutrition and activity levels
  • 127. 12 PHC 331: Chronic Disease Epidemiology and Prevention Environmental and Policy Changes – Future Research • Continued efforts required to effect policy changes designed to promote activity in communities • Working with neighborhood coalitions • Writing to local papers • Lobbying for changes made by city planners • Forming position statements for agencies • Funding is required to research effectiveness of already established programs, especially those in disadvantaged communities
  • 128. 12 PHC 331: Chronic Disease Epidemiology and Prevention Older Adults – Future Research • Baby boomer generation in need of study to understand efficacy and effectiveness of policies centered around the elderly
  • 129. 12 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 10: Diabetes
  • 130. 13 PHC 331: Chronic Disease Epidemiology and Prevention Significance • One of the ten major causes of death in the United States since the 1930s • Responsible for hundreds of thousands of deaths each year • Underreported because diabetes leads to the cause of death but doesn’t cause death itself By Blausen.com Staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. (Own work) CC BY 3.0, via Wikimedia Commons
  • 131. 13 PHC 331: Chronic Disease Epidemiology and Prevention Diabetes is a chronic disease that occurs when the pancreas is no longer able to make insulin, or when the body cannot make good use of the insulin it produces. Insulin is a hormone made by the pancreas, that acts like a key to let glucose from the food we eat pass from the blood stream into the cells in the body to produce energy. All carbohydrate foods are broken down into glucose in the blood. Insulin helps glucose get into the cells. Not being able to produce insulin or use it effectively leads to raised glucose levels in the blood (known as hyperglycaemia). Over the long- term high glucose levels are associated with damage to the body and failure of various organs and tissues. Diabetes Mellitus
  • 132. 13 PHC 331: Chronic Disease Epidemiology and Prevention Significance of Diabetes Mellitus About 422 million people worldwide have diabetes, the majority living in low-and middle-income countries, and 1.6 million deaths are directly attributed to diabetes each year. Both the number of cases and the prevalence of diabetes have been steadily increasing over the past few decades. There is a globally agreed target to halt the rise in diabetes and obesity by 2025.(WHO, 2020) Types of Diabetes Mellitus:- 1- Type 1 Diabetes 2- Type 2 Diabetes 3- Gestational Diabetes
  • 133. 13 PHC 331: Chronic Disease Epidemiology and Prevention Significance, contd. • Diabetes leads to various life-threatening complications: • CVD • Blindness • Kidney failure • Injury, infection, amputation of limbs • Depression • Diabetes carries a huge economic impact • Partly due to long-term complications and prescription costs
  • 134. 13 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology • In general, Type II diabetics are unable to utilize insulin in the liver/muscle despite regular insulin production in these places • As disease progresses, pancreas fails to increase insulin secretion • Prediabetics: • Impaired glucose tolerance (IGT) • Impaired fasting glucose (IFG) • Two classifications of diabetes complications • Microvascular • Macrovascular
  • 135. 13 PHC 331: Chronic Disease Epidemiology and Prevention Descriptive Epidemiology • Relies on health survey data for monitoring • No distinction between Types I and II • Type II accounts for the majority of all diabetes cases, estimated at around 90%-95% • Type II usually found in older adults, whereas Type I is associated with minors and adolescents
  • 136. 13 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Groups • Not an equal distribution • The elderly, racial minorities, lower socioeconomic status, family history • Increased exposure to a variety of health complications, all of which increase substantially with age • Tend to be higher in minority populations in the United States • Native Americans/Alaska Natives two to three times higher than other US adults
  • 137. 13 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Groups, contd. • Those with lower socioeconomic status, i.e. those with lower education and income, have an increased risk, as well • Common factors include less access to care, less opportunities for education about diabetes, high stress levels • Family history of diabetes strongly affects risk factor • 2.4 times greater odds of acquiring Type II when there is a moderate familial risk • 5.8 times greater when there is a high familial risk
  • 138. 13 PHC 331: Chronic Disease Epidemiology and Prevention Geographic Distribution • In the United States, clear geographic regions show patterns in developing diabetes • South/Southeastern at high risk, due to ethic makeup and obesity • Where there are higher levels of obesity there are higher levels of diabetes • Susceptibility to Type I diabetes shows a similarity across the different regions of the world
  • 139. 13 PHC 331: Chronic Disease Epidemiology and Prevention Time Trends • Over time, diabetes has been one of the only CVD risk that has increased • Due to age, ethnic diversity, obesity problem • Increasing in all demographics over time • This is true for both Types I and II • However, due to timely response, medications and therapies, there hasn’t been an increase in diabetes- related complications over time
  • 140. 14 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors – Type I • Very few modifiable risks for Type I diabetes • However, research has shown that there is some correlation between environmental factors • Nutrition and viruses may come into play • Type I patients were 43% more likely to have breastfed for less than 3 months and 63% more likely to consume cow’s milk before age three • Enteroviruses • Stress, higher maternal age at birth, birth order, birth weight, overnutrition are other possible risks
  • 141. 14 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors – Type II • Obesity – 80% of patients obese at diagnosis • Distribution of fat also plays a role • Those with a higher hip-to-waist ratio are more susceptible • Dietary elements • Whole grains, coffee, magnesium, peanut butter/nuts, low-fat dairy products, moderate alcohol consumption all been shown to reduce risk • High saturated fat diets and increase red meat consumption have been linked to an increased risk of Type II
  • 142. 14 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors – Type II, contd. • Lack of physical activity • Almost a linear relationship between frequency/intensity to diminished risks of Type II Diabetes • Smoking • Increased risk factor • Factors that reduce chance of developing Type II: • Relatively low BMI, high fiber diet, high polyunsaturated fat diet, 30 minutes of moderate exercise a day, smoke-free, less than half a serving of alcohol per day
  • 143. 14 PHC 331: Chronic Disease Epidemiology and Prevention Risk factors of Gestational Diabetes Mellitus
  • 144. 14 PHC 331: Chronic Disease Epidemiology and Prevention Symptoms of Type 1 Diabetes
  • 145. 14 PHC 331: Chronic Disease Epidemiology and Prevention Symptoms of Type 2 Diabetes
  • 146. 14 PHC 331: Chronic Disease Epidemiology and Prevention Complications • Often external factors that are intrinsic to developing Type II often increase the risk of complications • Risks can be reduced by working with health care professionals to manage macro- and microvascular complications
  • 147. 14 PHC 331: Chronic Disease Epidemiology and Prevention Major complications of Diabetes
  • 148. 14 PHC 331: Chronic Disease Epidemiology and Prevention Causes, Consequences, Risk Populations Chart Causes *Obesity *Physical inactivity *Poor diet *Smoking At-risk Populations *Elderly *Poor *Less educated *Minorities *Persons with a family history of diabetes Consequences *Coronary heart disease *Stroke *Peripheral vascular disease *End-stage renal disease *Blindness *Lower leg amputations *Disability *Depression *Poor pregnancy outcomes *Premature mortality Type 2 Diabetes Adapted from Remington et al. (2010)
  • 149. 14 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control – Type I • Prevention starts with identification of disease • Diabetes Prevention Trial (DPT) • Locating effective prevention strategies isn’t currently economical or relatively easy
  • 150. 15 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control – Type II • Unlike Type I, there are clear plans for prevention – both lifestyle and pharmacological interventions • Studies in both China, Finland and the United States, where screenings of diabetics were calculated and then controlled through differing variables – exercise, diet, etc. • Results were conclusive – reduction in diabetes after a few years of participation
  • 151. 15 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control in Youth – Type II • Not many studies conducted to research Type II diabetes in youth because so few cases exist • Interventions done in school systems to increase physical activity were enforced, but insulin levels were not measured • There has been increased development in plans to prevent Type II, as opposed to treat it in youth • Early detection of prediabetes
  • 152. 15 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and control of Gastetional diabetes
  • 153. 15 PHC 331: Chronic Disease Epidemiology and Prevention Screening and Early Detection • Prediabetes – blood glucose between 100-126 mg/dL • Type I – not recommended • Type II – not cost effective, but utilized in “high risk” groups; fasting glucose >126mg/dL considered diagnostic • Gestational Diabetes – shown to reduce fetal morbidity/mortality; recommended for “high risk” groups; 100g OGTT administered upon positive test
  • 154. 15 PHC 331: Chronic Disease Epidemiology and Prevention Treatment, Rehab, Recovery • Type I • Diabetes Control and Complications Trial • Physical activity an important goal for treatment • Type II • Weight management, caloric restriction, physical activity • Pharmacotherapy – BP, tobacco nonuse, aspiration may be just as important as glucose control in many cases • Treatment involves hands-on patient interaction • Frequent evaluations
  • 155. 15 PHC 331: Chronic Disease Epidemiology and Prevention Public Interventions • National Diabetes Prevention and Control Program • Defining the Diabetes Burden • Conducting Applied Translation Research • State-Based Diabetes Control Programs • National Diabetes Partnerships and Programs • Prevention Research Centers, Racial and Ethnic Approaches to Community Health, Steps to a Healthier US • Indian Health Service Division of Diabetes Treatment/Prevention • Diabetes Research and Training Centers
  • 156. 15 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 11: High Blood Pressure
  • 157. 15 PHC 331: Chronic Disease Epidemiology and Prevention Hypertension - or elevated blood pressure - is a serious medical condition that significantly increases the risks of heart, brain, kidney and other diseases. An estimated 1.13 billion people worldwide have hypertension, most (two-thirds) living in low- and middle-income countries. In 2015, 1 in 4 men and 1 in 5 women had hypertension. Fewer than 1 in 5 people with hypertension have the problem under control (WHO,2019) Significance
  • 158. 15 PHC 331: Chronic Disease Epidemiology and Prevention Hypertension is a major cause of premature death worldwide. One of the global targets for no communicable diseases is to reduce the prevalence of hypertension by 25% by 2025 (baseline 2010). Blood pressure is the force exerted by circulating blood against the walls of the body’s arteries, the major blood vessels in the body. Hypertension is when blood pressure is too high. Blood pressure is written as two numbers. The first (systolic) number represents the pressure in blood vessels when the heart contracts or beats. Blood Pressure
  • 159. 15 PHC 331: Chronic Disease Epidemiology and Prevention The second (diastolic) number represents the pressure in the vessels when the heart rests between beats. Hypertension is diagnosed if, when it is measured on two different days, the systolic blood pressure readings on both days is ≥140 mmHg and/or the diastolic blood pressure readings on both days is ≥90 mmHg.(WHO,2019)
  • 160. 16 PHC 331: Chronic Disease Epidemiology and Prevention Causes, Consequences, High-Risk Groups Causes *Obesity *Physical inactivity *Alcohol intake *Dietary sodium and potassium intake *Genetics At-risk Populations *African American ancestry *Family history of high blood pressure *Men *Older women Consequences *Cardiovascular disease *Neurological disease (stroke) *Kidney disease *Renal failure *Premature death High Blood Pressure Adapted from Remington et al. (2010)
  • 161. 16 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology • “Mean arterial pressure is the product of cardiac output…and systematic vascular resistance” (Remington et al. 2010). • Kidney, sympathetic nervous system, renin-angiotensin system all play central roles BP regulation • A “normal” body maintains intake and output in equilibrium
  • 162. 16 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology, contd. • The various types of hypertension exhibit impaired pressure natriuresis • Either intra- or extrarenal • Increased activity of the sympathetic nervous system also associated with hypertension • Vasoconstriction/sodium retention
  • 163. 16 PHC 331: Chronic Disease Epidemiology and Prevention Significance • Across all populations, HBP is a severe issue for healthcare workers • Second largest contributor to disease in developed and developing countries • 7.1 million of annual deaths are attributed to high blood pressure • The correlation between HBP and CV mortality higher in younger subjects, though mortality naturally occurs in older populations
  • 164. 16 PHC 331: Chronic Disease Epidemiology and Prevention Significance, contd. • HBP is the leading contributor to stroke – shown as consistent across a variety of studies • More than twice as high in hypertensive category • Nondependent on race/sex • Higher chance of congestive heart failure • Higher chance of cardiovascular disease • The effects of high blood pressure do vary slightly depending on race, age, regions
  • 165. 16 PHC 331: Chronic Disease Epidemiology and Prevention High-Risk Populations • Age • As we age, our average blood pressure increases across most populations • True for both men and women • Systolic blood pressure increases throughout lifespan • Diastolic blood pressure Increases until 50 years old, and then remains constant and then decreases • Data is limited because lack of followup • Those with starting SBP < 140 mmHg and DBP 85-89 mmHg are more likely to develop HBP
  • 166. 16 PHC 331: Chronic Disease Epidemiology and Prevention Time Trends • Over time, 1971-1991 a steady decline in both systolic and diastolic BP had been seen across all observable age groups, races, sexes • Omitting African American men, 50+, who suffered a small increase • This downward movement indicates that environmental/behavioral effects mitigated higher BP • Increase began after 1991 in the United States, especially in the elderly ad in women • Corollary to increased BMI
  • 167. 16 PHC 331: Chronic Disease Epidemiology and Prevention Causes – Genetic Factors • Those predisposed to high blood pressure are susceptible • Difficult to assess genetic causes • Alteration of specific non-allelic gene difficult to trace because HBP looks the same in everyone • Alleles and haplotypes inspection is compromised 90% of the time
  • 168. 16 PHC 331: Chronic Disease Epidemiology and Prevention Causes – Obesity • In the United States, those with higher BMIs progressively experience blood pressure problems • 50% of new cases attributable to being overweight • Corroborated by nonpharmacological interventions
  • 169. 16 PHC 331: Chronic Disease Epidemiology and Prevention Causes – Salt Intake • Sodium chloride intake attributable to the development of HBP • Salt compromises kidneys • After a long exposure to high salt intake, no longer able to excrete sodium, which leads to increased volume of blood in the body • Confirmed by random control testing of sodium reduction in diets
  • 170. 17 PHC 331: Chronic Disease Epidemiology and Prevention Causes – Potassium Intake • Increased potassium – lower blood pressure • SBP and DBP • “Administration of dietary potassium increases renal sodium and chloride excretion, reduces blood volume, and decreases blood pressure” (Remington et al. 2010)
  • 171. 17 PHC 331: Chronic Disease Epidemiology and Prevention Causes – Alcohol Intake • Unclear direct link between high blood pressure and high alcohol intake, but hypertensive effects of extensive alcohol use shown in various studies • When a reduction in alcohol intake is reported, lower blood pressure is also reported
  • 172. 17 PHC 331: Chronic Disease Epidemiology and Prevention Symptoms of Hypertension
  • 173. 17 PHC 331: Chronic Disease Epidemiology and Prevention Screening and Early Prevention • Screening is beneficial because testing methods are reliable and effective for those with hypertension • Screening is inexpensive, but should be targeted toward high- risk patients in particular • 76% of hypertension victims are aware of their condition, despite readily available testing By National Heart Lung and Blood Insitute (NIH) [Public Domain], via Wikimedia Commons
  • 174. 17 PHC 331: Chronic Disease Epidemiology and Prevention Types of Hyptersion
  • 175. 17 PHC 331: Chronic Disease Epidemiology and Prevention Complications of Hypertension
  • 176. 17 PHC 331: Chronic Disease Epidemiology and Prevention Lifestyle Changes, contd. • Nonpharmacological, lifestyle choices, contd. • Dietary pattern – not one factor that influences diet, but large- scale changes • DASH Trial: three various diets observed for 11 weeks; one – low fruits, veggies, dairy, average United States fat content; two – fruits and vegetables; three – DASH diet (high fruits, vegetables, low-fat dairy, reduced saturated and total fat • DASH diet effective for those with HBP • DASH diet current recommendation for lowering high blood pressure
  • 177. 17 PHC 331: Chronic Disease Epidemiology and Prevention Lifestyle Changes • Nonpharmacological, lifestyle choices • Weight reduction – less drug therapy needed if following a diet aimed at fat/weight reduction • Salt reduction – especially effective for hypertensive as opposed to normotensive • Less drug therapy needed for those with a low-salt diet • Increase in dietary potassium – inverse relationship with higher potassium consumption and blood pressure in various meta- analyses • Especially effective for hypertensive and African Americans
  • 178. 17 PHC 331: Chronic Disease Epidemiology and Prevention Lifestyle Changes, contd. • Nonpharmacological, lifestyle choices, contd. • Alcohol intake moderation – 25% reduction lowers SBP by 3.3 mmHg and DPB by 2.0 mmHg • Limited intake to 2 drinks per day (men) and 1 drink per day (women and low-weight individuals • Physical activity – SBP reduction 3.5 mmHg and DBP reduction 2.5 mmHg • Study of physical activity currently limited; inconclusive toward women, African Americans, and weight training (aerobic only)
  • 179. 17 PHC 331: Chronic Disease Epidemiology and Prevention Prevention and Control of Hypertension
  • 180. 18 PHC 331: Chronic Disease Epidemiology and Prevention Secondary Prevention: Pharmacological Treatment • Goal of secondary prevention: avoiding the negative effects of HBP • Recommended for both hypertensive individuals with no complications (risk factors) • Thiazide diuretic initially • Calcium channel blockers • Angiotensin-converting enzyme inhibitors • Angiotensin type I receptor blockers • Beta-blockers
  • 181. 18 PHC 331: Chronic Disease Epidemiology and Prevention Population-level Changes • Aim of intervention is to lower blood pressure across an entire population • Various community-based projects aim to translation research into action and management of blood pressure • The processes for lowering blood pressure at a population-level are the same as those outlined in individual-based programs, outline above
  • 182. 18 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 12: High Blood Cholesterol
  • 183. 18 PHC 331: Chronic Disease Epidemiology and Prevention Cholesterol
  • 184. 18 PHC 331: Chronic Disease Epidemiology and Prevention Definition :- is a waxy, fat-like substance that's found in all the cells in your body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Cholesterol is transmitted in the blood through Lipoprotein Cholesterol
  • 185. 18 PHC 331: Chronic Disease Epidemiology and Prevention Lipoprotien Intermediate density – cholesterol + triglycerides transport Very low density – triglycerides LDL : Low density consist of High Fat, Low Protein HDL : High density :Low Fat, High Protein
  • 186. 18 PHC 331: Chronic Disease Epidemiology and Prevention Lipoprotein
  • 187. 18 PHC 331: Chronic Disease Epidemiology and Prevention Fat
  • 188. 18 PHC 331: Chronic Disease Epidemiology and Prevention Significance • Many different people are at risk for coronary heart disease • Hypercholesterolemia • 16.5% of population between 20-74 have high cholesterol in the United States, and nationally high average • Many healthcare resources needed to be expended to screen and treat hypercholesterolemia
  • 189. 18 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology and Genetics • Insoluble in water • Transported in lipoproteins throughout bloodstream • Lipids + apoproteins = lipoproteins • 4 types of lipoproteins: • Low density – integral to atherosclerotic development • Very low density – triglycerides • Intermediate density – cholesterol + triglycerides transport • High density – cholesterol removed from the body transport • Inverse correlation between high density lipoproteins and coronary heart disease
  • 190. 19 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology and Genetics, contd. • Cholesterol is needed to maintain regular bodily function • Problems arise when abundance of cholesterol is present • Accumulates in artery walls • Plaque can develop • Fatty streaks are earliest signs of accumulation • Atheromas are advanced • Can be calcified, hemorrhage, ulcerate • Genetics important to assigning cholesterol levels • Abnormalities include hyperlipidemia/dyslipidemia
  • 191. 19 PHC 331: Chronic Disease Epidemiology and Prevention Causes, Consequences, High-Risk Groups Causes *Diets with high saturated fats *Genetics *Obesity and metabolic disorders *Physical inactivity *Smoking *Hypothyroidism *Renal disease *Diabetes mellitus *Steroid therapy At-risk Populations *Men 45 and older *Women 55 and older *Low socioeconomic status *Diabetics *Those with: -Known atherosclerosis -Genetic lipid disorder -Chronic kidney disease -History of a prior stroke -History of coronary artery disease Consequences *Coronary heart disease *Atherosclerosis *Stroke *End organ damage *Premature death and disability *High health care costs and treatment High Cholesterol Adapted from Remington et al. (2010)
  • 192. 19 PHC 331: Chronic Disease Epidemiology and Prevention High-risk populations • Highest risk – known atherosclerotic cardiovascular disease • Rate increases when prior CV event occurs • Older are at more risk • Especially men older than 45 and women older than 55
  • 193. 19 PHC 331: Chronic Disease Epidemiology and Prevention Geographic Distribution • Beijing, China had the lowest hypercholesterolemia among men/women • Ticino, Switzerland / Novi Sa, Yugoslavia had the highest • European countries in general are more disposed to high serum cholesterol levels
  • 194. 19 PHC 331: Chronic Disease Epidemiology and Prevention Time Trends • Steadily decreasing in the United States since the 60s • Contributed directly to the decline in coronary heart diseases in the United States in recent years
  • 195. 19 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors • Biggest modification – reduction in dietary fat/saturated fat • Dose response relationship among saturated/trans fat intake and low-density lipoprotein levels • Three types of fat: • Saturated – saturated with hydrogen; no double bonds • Monounsaturated – one double bond • Polyunsaturated – two or more bonds • Saturated fatty acids raise cholesterol levels by decreasing activity of low density lipoprotein receptors
  • 196. 19 PHC 331: Chronic Disease Epidemiology and Prevention Modifiable Risk Factors, contd. • Polyunsaturated fatty acids – omega-6 and omega-3 • Omega-6 lowers LDLs and some HDLs • Omega-3 lowers triglyceride and LDL levels • Monounsaturated fatty acids • Reduces LDLs and minimally reduces HDL • Trans fatty acids • Raises LDLs and lower HDLs, raises triglycerides • Obesity is also positive-corollary to total cholesterol levels • Smoking/inactivity – lower HDLs and higher risk of CHD
  • 197. 19 PHC 331: Chronic Disease Epidemiology and Prevention Prevention • Diet is the cornerstone for change when it comes to lowering cholesterol levels, however: • Cholesterol-lowering medication also substantially beneficial • Two approaches to prevention: • Population strategy – lifestyle alteration • Clinical strategy – addressing the needs of those with direct cause for cholesterol reduction
  • 198. 19 PHC 331: Chronic Disease Epidemiology and Prevention Top food to increase (HDL) Cholesterol
  • 199. 19 PHC 331: Chronic Disease Epidemiology and Prevention Screening • Screening is a fivefold process with treatment, nutritional changes, weight management, increased physical activity • Lipid panels are obtained in a fasting state • Recommended for those over 20 years old, every five years • Baseline total cholesterol levels vary by 5 mg/dL on a given day • HDL levels by 1.5 mg/dL
  • 200. 20 PHC 331: Chronic Disease Epidemiology and Prevention Treatment – Population-based • An emphasis is placed first on community education • Dietary Guidelines for Americans details goals to decrease diseases like coronary heart disease • Recommended for use starting as early as two years old • Those with immediate cholesterol disorder, or those who have had a recent CHD event should be stricter and should follow a more rigid clinical approach
  • 201. 20 PHC 331: Chronic Disease Epidemiology and Prevention Treatment – Patient-based • Lipoprotein count should be gathered if: • 200 mg/dL cholesterol or higher • HDL cholesterol lower than 40 mg/dL • CHD risk factors (3+) • Framingham 10-year Risk Score measures the risk percentage of having a CHD event based on risk factors, and outlines a goal level of low-density lipoproteins to have
  • 202. 20 PHC 331: Chronic Disease Epidemiology and Prevention Treatment – Antioxidants • Historically, antioxidant use has been shown to decrease oxidation of LDLs • However, now shown that antioxidants do not decrease atherosclerotic burden or prevent CHD events; further, vitamin intake with antioxidants may increase an event, and increase chance of lung cancer • No longer recommended for lipid therapy
  • 203. 20 PHC 331: Chronic Disease Epidemiology and Prevention Treatment – Hormone Replacement Therapy • Not recommended for lipid disorder treatment • Increased risk suggested
  • 204. 20 PHC 331: Chronic Disease Epidemiology and Prevention Treatment – Children and Adolescents • Atherosclerosis begins in childhood; progression linked to later high cholesterol • High cholesterol is maintained in familial setting due to similar genetics and home environment • Population approach – the same change in diet as adults, with an emphasis on fruits/vegetables • Individualized approach – designed for at-risk youth
  • 205. 20 PHC 331: Chronic Disease Epidemiology and Prevention Public Health Interventions • Public education, screening, intervention • Community interventions from various groups • Stanford Five City Project • Pawtucket Heart Health Program • Minnesota Heart Health Program
  • 206. 20 PHC 331: Chronic Disease Epidemiology and Prevention Future Research • Due to substantial variation in medication benefits across a span of variables, more research needed to find a more even fit • Optimal diet research • Cholesterol disorders need further evaluation • Behavior change and adherence need further initiatives
  • 207. 20 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 13: Cardiovascular Disease
  • 208. 20 PHC 331: Chronic Disease Epidemiology and Prevention Types of Heart diseases
  • 209. 20 PHC 331: Chronic Disease Epidemiology and Prevention Causes, Consequences, High-Risk Groups Causes *High blood pressure *Elevated blood cholesterol *Cigarette smoking and environmental tobacco smoke *Physical inactivity *Obesity (abdominal) *Poor diet *Diabetes At-risk Populations *Elderly *Poor *Less educated *Minorities *Family history Consequences *Disability *Lost productivity *Large costs to health care system *Depression *Premature mortality Cardiovascular Disease (heart disease, stroke, and peripheral vascular disease) Adapted from Remington et al. (2010)
  • 210. 21 PHC 331: Chronic Disease Epidemiology and Prevention Significance Cardiovascular diseases (CVDs) are the number 1 cause of death globally, taking an estimated 17.9 million lives each year. CVDs are a group of disorders of the heart and blood vessels and include coronary heart disease, cerebrovascular disease, rheumatic heart disease and other conditions. Four out of 5CVD deaths are due to heart attacks and strokes, and one third of these deaths occur prematurely in people under 70 years of age.(WHO,2020) • Variation by age, race, sex • Highest mortality rates for CVD in the United States • Leading cause of death of women in the United States • Wide range of complications associated with CVD – disability, stroke, high blood pressure
  • 211. 21 PHC 331: Chronic Disease Epidemiology and Prevention Significance of Cardiovascular Diseases
  • 212. 21 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology of CVD • Cardiovascular disease is closely related to atherosclerosis • Atherosclerosis – “A slowly progressive condition in which the inner layers of the artery walls become thick, irregular, and rigid” (Remington et al. 2010) • Typically seen during middle-age or later, though atherosclerosis manifests in childhood • Coronary heart disease, stroke, peripheral artery disease, congestive heart failure • Each each associated with certain risk factors: • CHD – high cholesterol • Stroke – high blood pressure • PAD – smoking/diabetes
  • 213. 21 PHC 331: Chronic Disease Epidemiology and Prevention Coronary Heart Disease – Significance, Pathophysiology • Also known as ischemic heart disease or coronary artery disease • “Several disorders that reduce the blood supply to the heart muscle” (Remington et al. 2010) • Largest cause of mortality of U.S men and women • Huge financial burden on healthcare, large risk (52% of all CVD deaths) • Initial symptoms – angina pectoris, myocardial infarction, sudden death
  • 214. 21 PHC 331: Chronic Disease Epidemiology and Prevention Coronary Heart Disease – High Risk Populations, Distribution • Men have higher CHD mortality rates on average • Increases with age • More prevalent among African Americans • Family history of CHD increases the risk that it will develop • Higher risk among those of low socioeconomic status • Strong variation of CHD death rates in various regions of the United States, similar situations in Europe
  • 215. 21 PHC 331: Chronic Disease Epidemiology and Prevention Coronary Heart Disease – Time Trends, Causes • Since 1968, there has been a steady decline in mortality, uniform across all groups • Factors not full answered, but theories point to lifestyle changes, less risk factors, and improvements in medical care • High blood pressure is a leading contributor to CHD mortality • 5-6mmHg change in DBP can reduce CHD up to 20-25% • Tobacco use another contributor among men and women • Twice the risk of heart attack
  • 216. 21 PHC 331: Chronic Disease Epidemiology and Prevention Coronary Heart Disease – Causes, contd. • Cholesterol is another factor to consider • Higher LDLs, higher risk of CHD; higher HDLs, less risk of CHD • C-reactive proteins (CRP) also contribute to CHD • Elevated fibrinogen – “a circulating glycoprotein that acts as the final step in…coagulation” (Remington et al. 2010) levels are another risk for CHD • As well as homocysteine • Diabetes mellitus • Obesity • Physical inactivity
  • 217. 21 PHC 331: Chronic Disease Epidemiology and Prevention Coronary Heart Disease – Prevention and Control • Modest approach to prevention – changing just one at-risk variable can have a widespread effect • Screenings involve assessing blood pressure/cholesterol levels, diet, tobacco use, activity level • Electrocardiograms recommended only for at-risk groups • Treatments tailored to each patient – healthy lifestyle changes, medication, surgery, and gene therapy are viable options
  • 218. 21 PHC 331: Chronic Disease Epidemiology and Prevention 2- Cerebrovascular Disease • Stroke – third leading cause of death in the United States • High societal-related costs, including medical care and time lost due to inactivity • Short- and long-term disabilities • Observed regional differences
  • 219. 21 PHC 331: Chronic Disease Epidemiology and Prevention Types of stroke
  • 220. 22 PHC 331: Chronic Disease Epidemiology and Prevention Cerebrovascular Disease – Pathophysiology, Descriptive Epidemiology • Occurs when an artery of the brain is clogged/ruptured and artery is unable to supply nutrients to brain tissue • Ischemic or hemorrhagic • Ischemic – thrombus, embolus, narrowing artery due to atherosclerotic plaque • Hemorrhagic – intracerebral or subarachnoid • Age is a strong risk factor • After 55, stroke rate doubles each decade thereafter • Men at higher risk of death than women • Family history increases chance
  • 221. 22 PHC 331: Chronic Disease Epidemiology and Prevention Cerebrovascular Disease – Causes, Risks • Hypertension, non-valvular atrial fibrillation, diabetes, cigarette smoking, physical inactivity, obesity, dyslipidemia • Hypertension – most significant changeable risk factor • Those who suffer from AF are predisposed to worse outcomes of a stroke • Uncontrolled diabetes causes increased arterial damage, which leads to stroke
  • 222. 22 PHC 331: Chronic Disease Epidemiology and Prevention Signs of Stroke
  • 223. 22 PHC 331: Chronic Disease Epidemiology and Prevention Cerebrovascular Disease – Prevention and Control • Framingham Stroke Profile • NIH Stroke Scale • Controlling hypertension • Screening should be implemented to survivors of a stroke to regulate risk factors • Treatments start by discovering specific causes of stroke • Minimizing brain damage
  • 224. 22 PHC 331: Chronic Disease Epidemiology and Prevention Heart Failure – Significance, Pathophysiology • 300,000 annual deaths • Heart failure cases are increasing, with poor prognoses “Multisystem disorder characterized by abnormalities of cardiac function, skeletal muscle, and renal function, stimulation of the sympathetic nervous system, and a complex pattern of neurohormonal change that impairs the ability of either ventricle to fill or eject blood” (Remington et al. 2010, p. 409) • Cardiorenal, cardiocirculatory (hemodynamic), neurohormonal models/hypotheses
  • 225. 22 PHC 331: Chronic Disease Epidemiology and Prevention Heart Failure – Descriptive Epidemiology • Most patients who experience heart failure are aged 65+ • Sufferers of coronary heart disease, hypertension, diabetes are at particular risk • Time trends illuminate that there is a strong male prevalence, and that, over time, cases of heart failure have increased in both sexes
  • 226. 22 PHC 331: Chronic Disease Epidemiology and Prevention Heart Failure – Causes, Prevention and Control • CHD, hypertension, diabetes, arrhythmias, congenital heart disease, cardiomyopathy • Extra strain on the heart is not beneficial • Prevention and control begins by finding and altering modifiable risk factors • Stage A Through D Prevention
  • 227. 22 PHC 331: Chronic Disease Epidemiology and Prevention Signs and Symptoms of Heart failure
  • 228. 22 PHC 331: Chronic Disease Epidemiology and Prevention Peripheral Arterial Disease – Significance, Pathophysiology • Atherosclerosis of lower extremities • Measurable by ankle-brachial index • Functional morbidity with increased risks of other CVD complications • A burden due to its correlation with other risks • Strong indicator of atherosclerotic formations elsewhere By National Heart Lung and Blood Insitute (NIH) [Public Domain], via Wikimedia Commons
  • 229. 22 PHC 331: Chronic Disease Epidemiology and Prevention Chapter 15: Chronic Respiratory Diseases
  • 230. 23 PHC 331: Chronic Disease Epidemiology and Prevention Causes, Consequences, High-Risk Groups Causes *Cigarette smoking *Occupational exposures *Dust mites *Allergens from pets, cockroaches, rodents *Environmental tobacco smoke *Molds *Obesity At-risk Populations *Poor *Less educated *Minorities *Workers *Persons with a family history Consequences *Shortness of breath *Disability *Social stigma *Depression and anxiety *High healthcare costs for treatment *Premature death Chronic Respiratory Diseases Adapted from Remington et al. (2010)
  • 231. 23 PHC 331: Chronic Disease Epidemiology and Prevention Chronic respiratory diseases are chronic diseases of the airways and other structures of the lung. Some of the most common are: asthma, chronic obstructive pulmonary disease (COPD),respiratory allergies occupational lung diseases and pulmonary hypertension. Hundreds of millions of people suffer every day from chronic respiratory diseases. According to the latest WHO estimates (2004), currently 235 million people have asthma, 64 million people have chronic obstructive pulmonary disease (COPD) while millions have allergic rhinitis and other often-underdiagnosed chronic respiratory diseases (WHO, 2020) Significance
  • 232. 23 PHC 331: Chronic Disease Epidemiology and Prevention Significance – Chronic Respiratory Diseases • Major result of CRDs is dyspnea (pathologic breathlessness) • Inability to perform aerobic tasks like climbing stairs • Constant breathlessness • Difficulty sleeping • Overactive mucous production • Reduced lung capacity • Extended viral/bacterial infections • Terminology problem when describing respiratory diseases • COPD – can describe multiple sets of symptoms all associated with different diseases • See chart on page 471 for a breakdown of various CRDs
  • 233. 23 PHC 331: Chronic Disease Epidemiology and Prevention Pathophysiology – Chronic Respiratory Diseases • Various tests depending on the chronic respiratory disease • Bronchitis – clinical signs; symptoms • Asthma and other COPD – clinical evaluation; spirometric tests • Emphysema – lung biopsy; CT scan • Symptoms of COPD can be similar to gastroesophageal reflux • Spirometric tests are simple, noninvasive • “Spirometry measures the expired volume as a function of time” (Remington et al. 2010). • Chest radiograph is most helpful, though often expense and feasibility are factors that inhibit its use in the pre-risk phase of CRDs