1 Introduction to public Health.pptx

Measurement of Health And Disease
Abraham L. (B.Sc, MPHE)
Course code: SPH-2012
EtCTS: 4

Teaching and Assessment Methods
Teaching Methods
• Interactive Lecture
• Group discussion (if possible)
• Reading Assignments
Methods of Assessment
• quiz 5%
• Reflective portfolio /community visit (15 %) (if possible)
• Test (20%)
• Assignment and/or student presentation (15 %)
• Class participation 5%
• Final Written exam (40 %)
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Objectives
At the end of this session, the students will be able to:
• Define health, disease and public health
• Describe the different concepts and perspectives of health
• Describe philosophy, history, development, core functions and services of
public health
• List public health science, their scope and use in medicine
• Define Epidemiology
• Describe basic assumptions of Epidemiology
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Definition and concepts
What is Health?
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Definition and concepts…
Definition of health has negative and positive models:
1. Negative model- defines health as the absence of the constraints of health.
• That is you are healthy if you are not ill.
• The renewal of health in a diseased individual is the removal of the disease.
• This model equates health with the absence of disease.
2. Positive model is by WHO- a state of complete physical, mental and social well being and not merely
the absence of disease or infirmity. (WHO, 1948)
• This definition is also simplified to “ The ability to lead a socially and economically productive
life”
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• Therefore, health is taken to be a multifaceted/ versatile concept; It consists of:
• Physical health
• Mental health
• Social health
• Emotional health
• Spiritual health and
• Occupational health
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Physical health- anatomical integrity and physiological functioning of the body.
• It means the ability to perform routine tasks without any physical restriction.
• E.g., Physical fitness is needed to walk from place to place.
Mental Health- ability to learn and think clearly and coherently.
• E.g., a person who is not mentally fit (retarded) could not learn something new at
a pace in which an ordinary normal person learns.
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Social health- ability to make and maintain acceptable interaction with other
people.
• E.g. to celebrate during festivals; to mourn when a close family member dies;
to create and maintain friendship and intimacy, etc.
Emotional health- ability of expressing emotions in the appropriate way, for
example to fear, to be happy, and to be angry.
• Emotional health is related to mental health and includes feelings.
• It also means maintaining one’s own integrity in the presence of stressful
situation such as tension, depression and anxiety.
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Spiritual Health- Some people relate health with religion; for others it has to do
with personal values, beliefs, principles and ways of achieving mental satisfaction, in
which all are related to their spiritual wellbeing.
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 Disease- is a physiological/psychological dysfunction
 Illness- a subjective state of the person who feels aware of not being well
 Sickness- is a state of social dysfunction that is a role that the individual assumes
when ill
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Different perspectives on health
• Health is viewed as a right, as consumption good, and as an investment.
Health as right:
“ . . . the enjoyment of the highest attainable standard of health is one of the fundamental rights of
every human being without distinction of race, religion, political belief, economic or social condition”.
(WHO)
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Different perspectives on health…
 Health as consumption good:
• health is an important individual objective of material aspect.
Health as an investment:
• indicates health as an important prerequisite for development because of its
consequence on the overall production through its effect on the productive
ability of the productive force.
• These different views indicate differences in the emphases given to health by
governments.
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What is public health?
• Public health is the science and art of preventing diseases, prolonging life,
promoting health and efficiencies through organized community effort.
• It is concerned with the health of the whole population and the prevention of
disease from which it suffers.
• It is also one of the efforts organized by society to protect, promote, and restore the
peoples’ health.
• It is the combination of sciences, skills and beliefs that is directed to the
maintenance and improvement of the health of all the people through collective
social actions.
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History and development of PH
• The history of public health goes back to almost as long as history of civilization.
• Possible traditions during civilization may be, taboos against waste disposal within
communal areas or near drinking water sources; rites associated with burial of the
dead; and communal assistance during birth.
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History and development of PH…
• Ancient Societies (before 500 BC)
• archeological findings from the Indus valley (North India) around 2000 BC with
the evidence of bathrooms and drains in homes and sewer below street level.
• evidence of drainage systems in the middle kingdom of ancient Egypt in the
time 2700 -2000 BC.
• written records concerning public health, codes of Hammurabi of Babylon, 3900
years ago.
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• The Book Of Leviticus (1500 BC)
• guidelines for personal cleanliness, sanitation of campsites, disinfection of
wells, isolation of lepers, disposal of refuses and hygiene of maternity.
• The Classical Cultures (500 BC - 500 AD)
• public health was practiced as Olympics for physical fitness, community
sanitation and water wells in the era golden age of ancient Greek; and
aqueducts to transport water, sewer system, regulation on street cleaning
and infirmaries for slaves by Romans.
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• Middle ages (500 - 1500 AD)
• Health problems were considered as having spiritual cause and solutions.
• They were supernatural powers for pagans and punishments for sins for
Christians.
• Deadliest epidemics resulted from failure to consider physical and biological
cause.
• E.g., Leprosy, plague (Black Death) during the 14th century and syphilis.
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• Era of renaissance and exploration (1500 - 1700 AD)
• rebirth of thinking of about nature of the world and humankind.
• There was a growing belief that diseases were caused by environment, not by
spirits and critical thinking about disease causation e.g. "malaria" - bad air.
• 18th century
• problems of industrialization, urban slums leading to unsanitary conditions and
unsafe work places.
• Edward Jenner(1796) demonstrated vaccination against smallpox.
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• 19th century
• there were still problems of industrialization but agricultural development led to
improvements in nutrition
• real progress towards understanding the causes of communicable diseases
towards the last quarter of the century.
• The Luis Pasture's germ theory (1862) and Koch's Postulate (1876) were
remarkable progresses.
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• 20th century has been period of
• health resources development (1900-1960),
• social engineering (1960 - 1973),
• health promotion (Primary Health Care), and
• market period (1985 and beyond)
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• The challenge in the 21st century are:
• reducing the burden of excess morbidity and mortality among the poor;
• counter reacting the threats of economic crisis,
• unhealthy environment and lifestyle;
• developing more effective health system and investing in expanding knowledge
base.
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Core functions and services of PH
1. Assessment
• “. . . regularly and systematically collect, assemble, analyze, and make available
information on the health of the community, including statistics on health status,
community health needs, and epidemiologic and other studies of health problems.”
(IOM, 1988)
Essential services
• Monitor health status to identify community health problems
• Diagnose and investigate health problems and health hazards in the community
• Evaluate effectiveness, accessibility, and quality of personal and population-based health services
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Core functions and services of PH…
2. Policy Development
• “. . . serve the public interest in the development of comprehensive public health
policies by promoting use of the scientific knowledge base in decision-making about
public health and by leading in developing public health policy.” (IOM, 1988)
Essential Services
• Develop policies and plans that support individual and community health efforts
• Enforce laws and regulations that protect health and ensure safety.
• Research for new insights and innovative solutions to health problems
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Core functions and services of PH…
3. Assurance
• “. . . assure their constituents that services necessary to achieve agreed upon goals are
provided, either by encouraging actions by other entities (private or public sector),by
requiring such action through regulation, or by providing services directly.” (IOM, 1988)
Essential services
• Link people to needed personal health services and assure the provision of health care when
otherwise unavailable
• Assure a competent public health and personal health care workforce
• Inform, educate, and empower people about health issues
• Mobilize community partnerships to identify and solve health problems
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PH sciences, their scope and use in Medicine
Major Disciplines In Public Health include:
 Nutrition: is the science of food, the nutrients and other substances therein, their
action, interaction and balance in relation to health and disease.
Reproductive health: is a state of complete physical, mental and social being not
only absence of disease or infirmity, in all matters relating to reproductive system and
to its functions and process.
Health Education: is combination of learning experiences designed to facilitate
voluntary actions conducive to health. It is an essential part of health promotion.
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PH sciences, their scope and use in Medicine…
Epidemiology: is the study of frequency, distribution, and determinants of diseases
and other related states or events in specified populations and application of this
study to the promotion of health and to the prevention and control of health
problems is evident.
Biostatistics: is the application of statistics to biological problems; application of
statistics especially to medical problems, but its real meaning is broader.
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Environmental Health:
• identify specific biologic, chemical, social and physical factors that represent hazards
to health or well-being and to modify the environment in a manner that protects
people from harmful exposures.
Health Economics: is concerned with the alternative uses of resources in the
health services sector and with the efficient utilization of economic resources such as
manpower, material and financial resources.
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Health Service Management: is getting people to work harmoniously together and
to make efficient use of resources in order to achieve objectives.
Ecology: is the study of relationship among living organisms and their environment.
• It is the science, which deals with the inter-relationships between the various
organisms living in an area and their relationship with the physical environment.
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Research: is a conscious action to acquire deeper knowledge or new facts about
scientific or technical subjects.
• It is a systematic investigation towards increasing knowledge.
Demography: is the study of population, especially with reference to size and
density, fertility, mortality, growth, age distribution, migration, and the interaction of
all those with social and economic conditions.
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Community Vs Clinical Medicine
 Community- refers to a group of people who share some thing in common.
• Examples of common denominators may be neighborhood, work place, race,
religion or social activity.
• Communities are characterized by people’s engagement in activities that demand
interrelationship of efforts, they give rise to shared culture, and they are often
sited in a particular geographic location.
 Community medicine- is a system of delivery of comprehensive health care to the
people by a health team to improve the health of a community.
• Thus it embraces the preventive and social medicine along with curative and
promotive health services.
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Community Vs Clinical Medicine…
Clinical medicine- medical care of individuals.
• Typically these are sick people who have presented for help.
• In community medicine, the community replaces the individual patients as the
primary focus of concern.
 Community diagnosis- is the process of identification and detailed description
of the most important problems of a given community.
• It may be broad or narrow in scope, and may deal with only a single topic or a single
sub group.
• The task of community diagnosis requires statistical knowledge in addition to
medical skills
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Methods of Community Diagnosis
1. Discussion with community leaders and health workers-community felt health problems
2. Attending community gatherings- community felt health problems
3. Survey of available health records
4. Field survey
5. Analysis of data collected and compilation of report in order to reach at community
diagnosis
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Community diagnosis provides basis for
• Decision on the need for intervention,
• Type of intervention needed,
• Target group at whom intervention should be directed and
• Provide baseline for later intervention
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What is epidemiology?
Definition of Epidemiology
The study of the frequency, distribution and determinants of health and
health-related states or events in specified populations, and the application of this
study to prevention and control of health problems
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Components of the definitions
Study- Epidemiology is a scientific discipline, sometimes called “the basic science of
public health”
• It has, at its foundation, sound methods of scientific inquiry
Frequency: Epidemiology is a quantitative science; How many?
• Frequency includes not only the number of events in a population, but also the
rate or risk of disease in the population
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Components of the definitions …
Distribution- Epidemiology is concerned with the pattern of health events in a
population
• Who? Where? And When? of occurrence of health and health related events
• Time: include annual occurrence, seasonal occurrence, & daily/even hourly
occurrence during an epidemic
• Place: characteristics include geographic variation, urban-rural differences, and
location of worksites or schools
• Personal characteristics include Socio-demographic & economic factors
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Determinants- factor which may be event, characteristic or any definable entity that
brings about change in health and health related conditions
• It refers to “why diseases occur in certain places? In a certain period? Or in a
certain population groups?”
• Epidemiology is used to search for causes and other factors that influence the
occurrence of health related events
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Health related states or events or conditions-
 Epidemiology is concerned not only with disease but also with other health
related conditions because every thing around us and what we do also affects our
health
 Health related conditions are conditions which directly or indirectly affect or
influence health
 These may be injuries, births, health related behaviors like smoking,
unemployment, poverty etc
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Populations: this element characterizes a basic difference between epidemiology and
clinical medicine, both concerned with disease and the control of disease
They differ greatly in how they view “the patient”
Clinicians are concerned with the health of an individual;
Epidemiologists are concerned with the collective health of the people in a
community or other area
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• Example, When facing with a patient with diarrheal disease, for example, the clinician and
the epidemiologist have different responsibilities
• Although both are interested in establishing the correct diagnosis
• The clinician usually focuses on treating and caring for the individual
• The epidemiologist focuses on the Exposure (action or source that caused the illness), the
number of other persons who may have been similarly exposed, the potential for further
spread in the community, and interventions to prevent additional cases or recurrences
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Application to control…
 Epidemiology is more than “The study of.”
As a discipline within public health, epidemiology provides data for directing public
health action
It makes explicit the aim of epidemiology-to promote, protect, and restore health
Epidemiology is an applied science
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History of Epidemiology
In 5th century B.C. – Hippocrates
• Father of Modern Medicine
• He suggested that the development of human disease might be related to the
external as well as personal and environmental factors
43
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History of Epidemiology…
John Graunt (1662): was the first person to precisely quantify occurrence of birth,
death and disease
• He used records of the medical statistics in England and noticed discrepancy in
rates of occurrence of disease and death b/n:
• Male and Female
• Urban and Rural
• The different seasons of the year
• He also noticed a very high infant mortality rate
44
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James Lind (1747): was the first person to use experimental study in human
population
• He used fresh fruit to treat bleeding gums in Sailors (“scurvy”) and
indicated that the cause of scurvy is deficiency of citrus fruit
• This led to the lime juice be a requirement in seamen’s diet
45
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William Farr (1839): established the tradition of the application of vital statistical
data for the evaluation of the health problems
• systematically collect and analyze Britain’s mortality statistics.
• He extended the epidemiologic analysis of morbidity and mortality data, looking at
effects of marital status, occupation, and altitude.
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John Snow (1813–58): Father of modern epidemiology
• He showed that the risk of mortality due to cholera was related to a
drinking water long before a single thing is known about cholera
• He linked an epidemic of cholera to a specific pump, the “Broad Street
Pump” in London by doing an out break investigation for the first time
in the history of public health
• Basing his evidence of the investigation, he removed the handle of the
water supply and aborted the epidemic of cholera in London
47
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48
Developments in modern epidemiology
• DOLL & HILL (1950): Used a case-control design to describe and test the
association between smoking and lung cancer
• FRANCES at al. (1950): Huge formal field trial of the Poliomyelitis
vaccine in school children
• DAWBER et al. (1955): The Framingham Heart Study(cohort) 10,000
residents gave baseline information; Follow-up is now more than 70 years
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Brief historical evolution of epidemiology

Scope of Epidemiology
Scope of epidemiology: originally, it was concerned with epidemics of
communicable diseases and epidemic investigations
• later it was extended to endemic communicable diseases and non
communicable diseases
• At present epidemiologic methods are being applied to
• Infectious and non infectious disease, cancer
• Injuries and accidents, occupational health
• Nutritional deficiencies, Environmental health
• Mental disorder, health behaviors
• MCH, violence
• Congenital anomalies etc.
50
All disease
conditions
Other health
related events
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2/15/2023 51
Scope Of Epidemiology…
Since 5th
century
Middle of
20th century
Past 25 yrs
recently
Epidemic of communicable diseases
Endemic communicable diseases &
Non communicable diseases
Chronic diseases, injuries,
birth defects, MCH,
Occupational health,
Env’tal health
Health related behavior
Genetic markers of disease risks
▲ +
▲+
▲+
▲+

Scope Of Epidemiology…
• Some of the important factors that lead to progressive development of
epidemiology are:
• The need for quantitative reasoning in public health
• Possibility of conducting comparative studies
• Increasing availability of vital statistics system
• Hygienic and public health movement
• Improvements in diagnosis and classification
• Advances in the field of statistics
• Advances in computer applications and development statistical software
• Increasing availability of personal computers
• Biotechnology revolution
• Advances in genomics
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uses of epidemiology in public health
1. Elucidate the natural history of disease.
2. Describe the health status of the population.
3. Establish causation of disease.
4. Provide understanding of what causes or sustains disease in populations.
5. Define standards and ranges for normal values of biological and social
measures.
6. Guide health and healthcare policy and planning.
7. Assist in the management and care of health and disease in individuals.
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Basic Assumptions in Epidemiology
1. Non-random distribution of diseases: i.e. disease occurrence in a population is
not random or by chance
• Disease is not randomly distributed throughout a population
• Why certain individuals/group acquire disease and others not?
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Basic assumptions …
2. Human disease has causal and protective factors: that can be identified
through systematic investigation of different population or subgroups of
individuals within population in different places or at different times
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Two Broad Types of Epidemiology
1. Descriptive epidemiology: as the name implies, concerned with describing the
general characteristics of the distribution of a disease, particularly in relation to
person (who is ill?), time (when did they become ill?) and place (where could
they have been exposed to the illness?).
Person, Place and Time are the basic triad of descriptive epidemiology
56
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Two Broad Types of Epidemiology…
2. Analytical epidemiology: This aspect of epidemiology concerned with why
and how a health problem occurs
 Analytic epidemiology uses comparison groups to provide baseline data so that
associations between exposures outcomes can be quantified and hypotheses
about the cause of the problem can be tested
57
2/15/2023

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