3. What is epidemiology?
Epidemiology is the study of the distribution and
determinants of health states or events in specified
populations, and the application of this study to
control health problems. (adapted from Porta and
International Epidemiological Association, 2008).
Target of study in epidemiology is usually human
population
4. Epidemiology is the cornerstone of public health.
It employs intense methods and a quantitative
approach to study the health of populations rather
than individuals.
Epidemiological methods are used to;
identify the causes of poor health,
measure the strength of association between causes
and outcomes,
evaluate interventions and
monitor changes in population health over time.
5. Purpose of epidemiology
The study of epidemiology provides the evidence-
base for appropriate public health policy, planning
and practice.
To evaluate the effectiveness of preventive and
therapeutic health programs and services in
improving the health of the population.
6. Used for descriptive purposes, such as
surveillance of the occurrence (incidence) of a
particular illness or injury .
For analytic purposes, e.g. studying levels
of risk factors for disease development.
To assess the performance of diagnostic tests.
7. Used to study the progression or natural history
of a disease.
Epidemiologic methods can be used to
study prognostic factors, which are
determinants of the progression of a disease.
Epidemiology can be used to evaluate
treatments for a disease.
9. Incidence
Refers to the occurrence of new cases of disease,
injury or other medical condition in a given
period of time in a specified population
For instance, if there were 12 new cases of
malaria in your area which has 1,200 people in
January, then the incidence of malaria in January
would be (12/1200 = 0.01) 1 case per 100 people
in the population.
10. Prevalence
Refers to the total number of cases of a disease or
condition that are present at a particular time -
whether new or old cases.
For example, if on the 1 January you did a survey
of your area, containing 1,000 people and found
that the total number of cases of malaria was 41,
you would say that the prevalence of malaria on 1
January was 41 cases per 1,000 people in that
area.
11. In epidemiology data on the frequency and
distribution of disease is used in order to help one
understand whether the disease is an epidemic,
endemic or sporadic.
Epidemic : increase, often sudden in the number
of cases of a disease above what is normally
expected in that population in that area.
Gives rise to many new cases in a short period of
time. Also referred to as an outbreak
12. An endemic disease is one that is present all the
time in a community.
An endemic disease is that which occurs at a
constant rate over a long duration of time
(several years or decades) in a given population.
In some parts of Kenya, malaria is an endemic
disease as it is present in the population all the
time.
13. Ct… definitions
Hyperendemic refers to persistent, high levels of
disease occurrence.
Pandemic: a disease affecting wide geographical
area and affecting an exceptionally high proportion
of the population
A sporadic disease is one that occurs only
occasionally and without a regular pattern.
14. Principles of epidemiology
1.Study
Epidemiology is a scientific discipline and is data
driven.
Relies on a systematic and unbiased approach to the
collection, analysis, and interpretation of data.
Epidemiology also draws on methods from other
scientific fields including biostatistics and behavioral
sciences.
Epidemiological studies describe the distribution of
these health outcomes in terms of frequency and
pattern.
15. Ct…principles
2.Distribution;epidemiology is concerned with the
frequency and pattern of health events in a
population
Frequency is the number of occurrences of within
a given time period and the relationship of that
number to the size of the population.
The resulting rate allows epidemiologists to
compare disease occurrence across different
populations.
16. Pattern refers to the occurrence of the health
related events by time, place and person or
population characteristics.
Time-annual, seasonal, daily, hourly
Place-geographical variation, urban/rural differences
Personal characteristics: age, sex, marital status and
socioeconomic status
This characterization of events by time, place and
person is known as descriptive epidemiology
17. Ct…..principles
3.Determinants: are the causes or other
factors that influence the occurrence of disease
and other health related events..
The determinants of health and wellbeing
include the social, economic and physical
environment, as well as individual behaviours
and characteristics.
Epidemiologist assume that illness happens
when there is right accumulation of risk factors
or determinants exists in a population
18. ct…..principles
4. Health related states or events: anything that
affects the wellbeing of a particular population.
such as diseases, injuries, birth defects, maternal
child health, occupational and environmental
health
Many epidemiologists use the term “disease” as
shorthand for the wide range of health related
states or events that are studied.
19. Ct…principles
5. Specified populations:
Epidemiologist are concerned with collective health
of the people in a community or population.
Focus is on ;
Identifying the exposure or source that caused the
illness;
the number of persons who may have been exposed;
the potential for further spread in the community
and
to prevent additional cases or recurrences
20. Ct..principles
6.Applications: applying the knowledge gained in the
study to community based practice.
Epidemiologists uses scientific methods of
descriptive and analytic epidemiology and
experience, epidemiologic judgment, and
understanding of local conditions in “diagnosing”
the health of a community and
proposing appropriate, practical, and acceptable
public health interventions to control and prevent
disease in the community.
Editor's Notes
Personal xtstics:increase a person’s risk of illness;injury,disability
