epidemiology and biostatistics

2. “It is the study of distribution and determinants
of health related states and events in
population and the application of this study to
control health problem.”

3.  Primary determinant:
bacteria, viruses, parasites ( in case of communicable disease)
specific nutrient deficiency ( in case of nutritional disorder)
vehicles ( in case of automobile accidents)
 Secondary determinant:
socio economic factors ( in case of malnutrition)
physical environment ( in case of respiratory infection)

4. Component of epidemiological model are
 Agent
 Host
 Environment

6. 1) Agent:
 biological agent ( viruses, bacteria, any infection)
 Nutritive agent ( protein, fat, carbohydrate, vit,
mineral)
 Physical agent ( heat, cold, humidity, pressure,
radiation, electricity, sound)
 Chemical agent (endogenous agent, exogenous agent )
 Mechanical agent ( crushing, tearing, sprain,
dislocation)
 social agent ( smoking, poverty, social isolation, drug
abuse, unhealthy life style)

7. 2) Host:
 Demographic factor ( age, sex, ethnicity)
 Biological factor ( genetic, blood group, immunological
factor)
 Socio economic factor ( status, education, occupation,
stress, housing, marital status)
 Life style ( personality traits, living habits, nutrition,
physical exercise, use of alcohol, behavioral pattern)

8. 3) Environment:
 Physical environment
 Biological environment
 Psychosocial environment

9.  According to this concept “ effects never depend on single
cause but rather develop as a result of chain of causation”
 Risk factor are often suggestive, but absolute proof of cause
and effect b/w a risk factor and disease is usually lacking
i.e. presence of a risk factor doesn’t imply that the disease
will occur and absence does not imply that the disease will
not occur.
 Types of risk factor:
 A) truly causative e.g. smoking
 B) contributory factor e.g. lack of physical exercise
 C) predictive factor e.g. illiteracy

10. Component of epidemiology:
 A) Studies Of Disease Frequency
measurement of frequency of disease, disability, or
death
 B) Distribution Of Disease
it consist of time, place, person
 C) Determinants Of Disease
this includes the testing to etiological hypothesis and
identifying the underlying causes or risk factors of
disease.

11.  A) time : whether there has been an increase/ decrease of
disease over time span.
 B) place : whether there has been a higher conc. Of disease in
one demographic area than in other.
 C) person : whether the disease occurs more often in men or in
a particular age group.

12. time place person
Year
Season
Month
Week
Hour of onset
duration
Climatic zone
Country
Region( urban/rural)
Town
Cities
institution
Age
Sex
Martial status
Occupation
Social status
Education
Birth order
Family size
Height and weight
Blood pressure
Blood group
Personal habits

13.  Descriptive studies
 Analytical studies
 Experimental studies

14.  Descriptive epidemiology studies are concerned with
the following
• when is the disease occurring? ( time distribution)
• Where it is occurring? ( place distribution)
• who is getting the disease? ( person distribution)

15. 1. Provide data regarding the magnitude of the disease
load and types of disease problem in the community
in terms of morbidity and mortality rates ratio.
2. Provides clues to disease etiology and help in the
formation of an etiological hypothesis.
3. Provide background data for planning organization,
and evaluating preventive and curative services
4. Contributes to research by describing occurrence by
time, place and person.

16.  Public health and community medicine by muhammad
lliyas edition 2006.

17. Thank you