1. Demography is the study of population characteristics including size, composition, births, deaths, and migration. Census and vital statistics provide data on population attributes like age, sex, urban/rural distribution, and disease incidence and mortality rates. 2. Health indicators like crude birth rate, death rate, life expectancy, and infant mortality rate are calculated from vital statistics and measure the health status of a population. Rates and ratios reveal risks of diseases and deaths among groups. 3. Epidemiology studies disease distribution and determinants in populations to aid disease prevention and control. It examines historical disease patterns, diagnoses community health issues, evaluates health services, and estimates disease risks.

1. HEALTH STATISTICS AND
EPIDEMIOLOGY

2. 1. Tools
1. Demography
 Study of population size, composition and spatial distribution as affected by
births, deaths and migration.
a. Sources of Data
 Census – complete enumeration of the population
2 Ways of Assigning People
1. De Jure – People were assigned to the place where assigned to the place
they usually live regardless of where they are at the time of census.
2. De Facto – People were assigned to the place where they are physically
present at are at the time of census regardless, of their usual place of
residence.

3. b. Population Size
c. Composition
 Age Distribution
 Sex Ratio
 Population Pyramid
 Median age – age below which 50% of the population falls and above which 50% of the
population falls. The lower the median age, the younger the population (high fertility, high
death rates).
 Age – Dependency Ratio – used as an index of age-induced economic drain on human
resources

4.  Other characteristics:
 a. occupational groups
 b. economic groups
 c. educational attainment
 d. ethnic group
d. Distribution
 Urban-Rural – shows the proportion of people living in urban compared to
the rural areas
 Crowding Index – indicates the ease by which a communicable disease can
be transmitted from 1 host to another susceptible host.
 Population Density – determines congestion of the place

5. 2. Health Indicators

6. VITALSTATISTICS
 Statistics refers to a systematic approach of
obtaining, organizing and analyzing numerical
facts so that conclusion may be drawn from
them.
 Vital statistics refers to the systematic study of
vital events such as births, illnesses, marriages,
divorce, separation and deaths.
 Statistics of disease(morbidity) and
death(mortality) indicate the state of health of
the community and the success or failure of the
health work.
 Statistic on population and the characteristic
such as age and sex, distribution are obtained
from the National Statistics Office(NSO).

7. Use of Vital Statistics:
 Indices of the health and illness status of a
community.
 Serves as bases for planning, implementing,
monitoring and evaluating community health
nursing programs and services.
 Sources of Data:
 Population census
 Registration of vital data
 Health survey
 Studies and researches

8.  Rates and Ratios:
 Rate- shows the relationship between a vital
event and those persons exposed to the
occurrence of said event, within a given area
and during a specifies unit of time.
 Ratio- is used to describe the relationship
between two (2) numerical quantities or
measures of events without taking particular
considerations to the time or place.
 Crude or General Rates- referred to the total
living population.
 Specific Rate- specific population, class or
group.

9.  Crude Birth Rate- measure of one characteristic of the natural growth or
increase of a population.
Total No. of live births registered in a given calendar year
CBR= ---------------------------------------------------------------- X 1,000
Estimated population as of July 1 of same year
 Crude Death Rate- a measure of one mortality from all causes which may
result in a decrease of population
Total No. of live deaths registered in a given calendar year
CDR= ---------------------------------------------------------------------- X 1,000
Estimated population as of July 1 of same year

10.  Infant Mortality Rate- measure the risk of dying during the first year of life.
Total No. of live death under 1 year of age registered in a given calendar year
IMR= -------------------------------------------------------------------------- X 1,000
Total No. of registered live births of same calendar year
 Maternal Mortality Rate- measure the risk of dying from all causes related to
pregnancy, childbirth and puerperium.
Total No. deaths from maternal causes registered each year
MMR= ------------------------------------------------------------------------- X 1,000
Total No. of registered live births of same year

11.  Infant Mortality Rate- measure the risk of dying during the first year of life.
Total No. of live death under 1 year of age registered in a given calendar year
IMR= -------------------------------------------------------------------------- X 1,000
Total No. of registered live births of same calendar year
 Maternal Mortality Rate- measure the risk of dying from all causes related to
pregnancy, childbirth and puerperium.
Total No. deaths from maternal causes registered in a given year
MMR= -------------------------------------------------------------------------- X 1,000
Total No. of registered live births of same year

12.  Specific Death Rate- describes more accurately the risk of exposure
of certain classes or groups to a particular disease.
Deaths in specific class/group registered in a given calendar year
Specific Death Rate= ------------------------------------------------------- X 100,000
Estimated population as of July 1 in same specified class/group of said year

13.  Adjusted or Standardized Rate
Methods:
 By applying observed specific rates to some standard population
 By applying specific rates of standard population to corresponding classes or
groups of the local population
 Case Fatality Ratio- index of a killing power of disease and is influenced by
incomplete reporting and poor morbidity data.
No. of registered deaths from a specific disease for a given year
PM= -------------------------------------------------------------- X 100
No. of registered cases from specific disease in same year

14. Presentation of Data
 Line or curved graphs- shows peaks, valleys and seasonal trends
 Bar graphs- represents or expresses a quantity in terms of rates or
percentages of a particular observation
 Area Diagram- (Pie Charts)- shows the relative importance of parts
to the whole.
Functions of the Nurse
 Collects data
 Tabulates data
 analyzes and interprets data
 Evaluates data
 Recommends redirection and/ or strengthening of specific areas
of health programs as needed.

15. Philippine Health Situation
Population
 Chart and table of Philippines population from 1950 to 2020. United Nations
projections are also included through the year 2100.
 The current population of Philippines in 2020 is 109,581,078, a 1.35% increase
from 2019.
 The population of Philippines in 2019 was 108,116,615, a 1.37% increase from
2018.
 The population of Philippines in 2018 was 106,651,394, a 1.41% increase from
2017.
 The population of Philippines in 2017 was 105,172,925, a 1.46% increase from
2016.

16. Life Expectancy
 Chart and table of Philippines life expectancy from 1950 to 2020.
United Nations projections are also included through the year
2100.
 The current life expectancy for Philippines in 2020 is 71.28 years, a
0.18% increase from 2019.
 The life expectancy for Philippines in 2019 was 71.16 years, a
0.18% increase from 2018.
 The life expectancy for Philippines in 2018 was 71.03 years, a
0.23% increase from 2017.
 The life expectancy for Philippines in 2017 was 70.87 years, a
0.23% increase from 2016.

17. Crude Birth Rate
 Chart and table of the Philippines birth rate from 1950 to
2020. United Nations projections are also included through
the year 2100.
 The current birth rate for Philippines in 2020 is 20.177
births per 1000 people, a 0.98% decline from 2019.
 The birth rate for Philippines in 2019 was 20.377 births per
1000 people, a 0.97% decline from 2018.
 The birth rate for Philippines in 2018 was 20.576 births per
1000 people, a 3.31% decline from 2017.
 The birth rate for Philippines in 2017 was 21.280 births per
1000 people, a 3.2% decline from 2016.

18. Infant Mortality Rate
 Chart and table of the Philippines infant mortality rate from
1950 to 2020. United Nations projections are also included
through the year 2100.
 The current infant mortality rate for Philippines in 2020 is
18.815 deaths per 1000 live births, a 2.2% decline from 2019.
 The infant mortality rate for Philippines in 2019 was 19.239
deaths per 1000 live births, a 2.16% decline from 2018.
 The infant mortality rate for Philippines in 2018 was 19.663
deaths per 1000 live births, a 3.96% decline from 2017.
 The infant mortality rate for Philippines in 2017 was 20.474
deaths per 1000 live births, a 3.81% decline from 2016.

22. EPIDEMIOLOGY
 Epidemiology is the study of occurrences and distribution of diseases as well as
the distribution and determinants of health states or events in specified
population, and the application of this study to the control of health problems.
This emphasizes that epidemiologist are concerned not only with deaths, illness
and disability, but also with more positive health states and with the means to
improve health.
 Two main areas of investigation are concerned in the definition, the study of the
distribution of disease and the search for the determinants (causes) of the
disease and its observed distributions. The first area describes the distribution of
health status in terms of age, gender, race, geography, time and so on might be
considered in an expansion of the discipline of demography to health and
diseases. The second area involves explanations of the patterns of disease
contribution in terms of casual factors.
 Epidemiology , therefore is the backbone of the prevention disease.

23. Uses of Epidemiology:
According to Morris, epidemiology is used to:
 Study the history of the health population and the rise and fall of diseases
and changes in their character.
 Diagnose the health of the community and the condition of people to
measure the distribution and dimension of illness in terms of incidence,
prevalence, disability and mortality, to set health problems in perspective
and to define their relative importance and to identify groups needing
special attention.
 Study the work of health services with the view of improving them.
Operational research shows how the community expectations can result in
the actual provisions of service .
 Estimate the risk of disease, accidents , defects and the changes of avoiding
them.
 Identify syndromes by describing the distribution and association of clinical
phenomena in the population.
 Complete the clinical picture of chronic disease and describe their natural
history.
 Search for causes of health and disease by comparing the experience of
groups that are clearly defined by their composition, inheritance,
experience, behavior and environments.

24.  Figure 4- The Epidemiology Triangle
HOST
AGENT
ENVIRONMENT

25. The Epidemiology Triangle
 The Epidemiology Triangle consists of three component –
host, environment and agent. The model implies that each
must be analyzed and understood for comprehensions and
prediction of patterns of a disease. A change in any of the
component will alter an existing equilibrium to increase or
decrease of the disease.
 The host is any organism that harbors and provides
nourishment for another organism.
 Agent is the intrinsic property of microorganism to survive
and multiply in the environment to produce disease.
 Environment is the sum total of all external condition and
influences that effects the development of an organism
which can be biological, social and physical.

26. The three component of the environment:
 Physical Environment – composed of the inanimate
surroundings such as the geophysical conditions of
the climate.
 Biological environment makes up the living things
around us such as plants and animal life.
 Socio-economic environment which may be in the
form of level of economic development of the
community, presence of social disruptions and the
like.

27.  Approach to Disease and its Determinants
 The present epidemiology approach is based on
the interaction of the host, the causative agent,
and the environment.
 The presence of infectious materials varies with
the duration and the extent of its excretion from
an infected person the climactic conditions
affecting survival of the agent, route of entry into
the host and the existence of alternative
reservoirs or host of the agent.

28. Classifications of Agents, Hosts and Environmental Factors which determine the
occurrence of Disease in Human Population
1.Agents of Disease
a. Nutritive elements
b. Chemical agents
c. Physical agents
d. Infectious agents

29. 2. Host factors ( Intrinsic Factors) – influences
exposure, susceptibility or response to agents.
a.Genetic
b. Age
c. Sex
d. Ethnic group
e. Physiologic
f. Immunologic Experience
g. Inter- current or pre-existing disease
h. Human behavior

30. 3. Environmental factors (Extrinsic factors)
– influences existence of the agent,
exposure, or susceptibility to agent.
A. Physical environment
B. Biologic environment
C. Socio-economic environment

31. Disease Distribution
 The methods and technique of epidemiology are
desired to detect the cause of a disease in
relation to the characteristics of the person who
ahs it or to a factor present in his environment.
Since neither population and environment of
different times or places are similar, these
characteristics and factors are called
epidemiology variables.

32. Time refers to both the period during which the cases of the
disease being studied were exposed to the source of infection
and the period during which the illness occurred.
Persons refers to the characteristics of the individual who were
exposed and who contacted the infection or the disease in
question.
Place refers to the features, factors or conditions which existed
in or described the environment in which the disease
occurred.

33. Patterns of Occurrence and
Distribution
 The variables of disease as to person, time, and place are
reflected in distinct patterns of occurrence and distribution in
each community.
1.Sporadic occurrence is the intermittent occurrence of e few
isolated and unrelated cases in each locality. The cases are few
and scattered, so that there is no apparent relationship
between them, and they occur on and off, intermittently,
through a period.
2.Endemic occurrence is the continuous occurrence throughout a
period, of the usual number of cases in each locality. The
disease is therefore always occurring in the locality and the
level of occurrence is less or more constant through a period.

34. 3.Epidemic occurrence is of unusually large number
of cases in a relatively short period of time.
There is no disproportionate relationship
between the number of cases and the period of
occurrence, the more acute is the disproportion,
the more urgent and serious is the problem.
4. Pandemic is the simultaneous occurrence of
epidemic of the same disease in several
countries.

35. Epidemics
Factor’s Contributory to Epidemic Occurrence:
 Agent Factor – the result of the introduction of new
disease agents in the population.
 Host Factors – are related to lower resistance as a result
of exposure to the elements during floods or other disaster,
to relaxed supervision of water and milk supply or sewage
disposal, or to changed habit of eating.
 Environmental factors – changes in the physical
environment: temperature, humidity, rainfall may directly
or indirectly influence equilibrium of agent and host.

36. Outline of Plan for Epidemiological Investigation
1. Establish fact of presence of epidemic
2. Establish time and space relationship
of the disease
3. Establish time and space relationship
of the disease
4. Correlation of all data

37. Epidemiology and Surveillance Units
 Epidemiology and Surveillance Units have been established
in regional and some local office as support to the public
health system. As an epidemiologic information service, the
unit is mainly responsible for providing timely and accurate
information on diseases in the locality.
Among its responsibility includes:
 Surveillance of infectious diseases with outbreak potential
 Assisting local government units in investigation of outbreak
and their control
 Developing information package on public health.
 Providing technical assistance related to epidemiology.

38. Public Health Surveillance
Public Health Surveillance is an on-going systematic
collection, analysis, interpretation and
dissemination of health data.
Surveillance system is often considered in
information loops or cycles involving health care
providers, public health agencies and the public.

39. ROLEOFTHENURSEIN SURVEILLANCE
One of the areas where public health nurse function as
researcher is disease surveillance.
Surveillance is a continuous collection and analysis of data of
cases and death.
 The objectives of surveillance are:
 1.To measure the magnitude of the problem.
 2. To measure the effect of the control program.

40. The National Epidemic Sentinel Surveillance
System (NESSS) and its Role
National Epidemic Sentinel Surveillance System
is a hospital-based information system that
monitors the occurrence of infectious diseases
with outbreak potential. It also serves as a
supplemental information system of the
Development of Health.

41. Objectives:
 To provide early warning on occurrence of outbreaks
 To provide program managers, policy makers, and public
administrators, rapid accurate and timely information so
that inventive and control measures can be instituted.
The NESSS Data shows:
 Trends of cases across time
 Demographic characteristics of cases
 Estimates of case fatality ratio
 Clustering of cases in geographical area
 Information to formulate hypothesis for disease causation

42. Disease Under Surveillance (NESSS)
 Laboratory Diagnosed
Cholera
Hepatitis A
Hepatitis B
Malaria
Typhoid Fever

43. Clinically Diagnosed
 Dengue Hemorrhagic Fever
 Diphtheria
 Measles
 Meningococcal disease
 Neonatal tetanus
 Non neonatal tetanus
 Pertussis
 Rabies
 Leptospirosis
 Acute Flaccid Paralysis (poliomyelitis)

44.  Under Surveillance System:
Acute Flaccid paralysis
Measles
Maternal and neonatal tetanus
Paralytic shellfish poisoning
fireworks and related injury
HIV / AIDS

45. Importance of Outbreak Investigation:
 Control and prevention measure
 Severity and risk to others
 Research opportunities
 Public, political or legal concerns
 Training
Sources:
 Surveillance data
 Medical practitioner
 Affected persons / group
 Concerned citizen
 Media

46. Steps in Outbreak Investigation:
Step 1 – Prepare for field work
 Investigation
 Scientific knowledge
 Supplies / equipment
 Administration
 Administrative procedures like travel documents, allowance
 Consultation
 Know expected role
 Local contact person

47. Step 2 – Establish the existence or an outbreak
 Cluster – is an aggregation of cases in each are over a
particular period without regards to whether the number of
cases is more than the expected.
 Outbreak or an epidemic – is the occurrence of more cases of
disease rather than expected in each area or among a specific
group of people over a particular period.
 Compare the current number of cases with the numbers of
cases from comparable period during the previous years.
 Surveillance records
 Hospital records, registries, mortality statistics
 Data from neighboring areas
 Community survey

48. Step 3 – Verify diagnosis
 Ensure proper diagnosis of reported cases
 Rule out laboratory error as basis for the
increase in diagnosed cases
 Reviews clinical findings
 Review laboratory results
 Summarize clinical findings with the frequency
distribution
 Visit patients

49. Step 4 – Define and Identify cases
 A. Establish a case definition
 Standards set of criteria for the health condition;
 Clinical criteria ( signs and symptoms)
 Restrictions by time, place, persons
 Apply without bias
 Note – exposure or risk factor is not included in the case
definition
 B. Identify and count cases
 Identify information – name, address, contact number
 Demographic information – age, sex, race and occupation
 Clinical information – death of onset, hospitalization,
death
 Risk factors information – food or water sources, toilet
facility
 Reporter information

50. Step 5 – Perform descriptive
epidemiology
 Describe and orient the data in terms of time, place and
person
 Characterized by time
 Characterized by place
 Characterized by persons

51. Step 6 – Developing Hypothesis
 Consider
 Source of agent
 Mode of transmission
 Vectors of transmission
 Risk Factors
 Hypothesis should be testable

52. Step 7 – Evaluate hypothesis by:
Comparing with established facts
Use of analytical epidemiology
Case control studies
Retrospective control studies

53. Step 8 – Refine hypothesis and execute
additional studies because:
 Unrevealing analytical studies = poor hypothesis
 May need more specific exposure histories
 May need mire specific control group
Step 9 – Implement control and prevention
measures
 Prevent additional cases
 Prevent outbreaks in the future

54. Step 10 – Communicate findings
 Through;
 Writing and disseminating full report
 Meetings and discussions
 Local and mass media
Step 11 - Follow- up Recommendations
What activities have been undertaken?
If health status has improved
If health problems has been reduced

55. Function of the Epidemiology Nurse:
 Implement public health surveillance
 Monitor local health personnel conducting disease
surveillance
 Conduct and / or assist other health personnel in
outbreak investigation
 Assist in the conduct of rapid surveys and
surveillance during disasters
 Assist in the conduct of surveys, program evaluation,
and other epidemiologic studies.
 Assist in the conduct of training course in
epidemiology
 Assist the epidemiologist in preparing the annual
report and financial plan.
 Responsible for inventory and maintenance of
epidemiology and surveillance unit (ESU) equipment

56. Specific Role during Epidemiological
Investigations:
 Maintains surveillance of the occurrence of
notifiable disease.
 Coordinates with other members of the health
team during the disease outbreak
 Participates in case findings and collection of
laboratory specimens
 Isolates cases of communicable disease.
 Renders nursing care, teaches and supervises
giving care.
 Performs and teach household members
method, concurrent and terminal disinfection.

57.  Gives health teachings to prevent further spreads of
disease to individual and families.
 Follow up cases and contacts
 Organizes, coordinates and conducts community
health education campaign / meetings.
 Refers cases when necessary
 Coordinates with other concerned community
agencies.
 Accomplishes and keeps records and reports and
submits to proper office / agency.

58. Activity: