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1. EPIDEMIOLOGY

2. OVER VIEW
• What is Epidemiology
• Aims and Uses of epidemiology
• SCOPE- Areas and Fields of Epidemiology.
• Epidemiological Approaches
• Methods of Epidemiology.
• Concept of causation of Disease and Screening.

3. INTRODUCTION
• The term Epidemiology is derived from the Greek word
Epidemic – “Epi means Among, upon” “Demos means study of
population or people” and “Logos means scientific study”.
• The origin of epidemiology had been from the time of
Hippocrates. But the foundation of modern epidemiology was
laid down in the 19th century when infectious and
communicable disease was most prevalent in the world.

4. Contd….
• It is the scientific study of the disease pattern in human
population. In broad sense, it is the study of effects of multiple
factors on human health.
• Epidemiology focus on communicable as well as non-
communicable diseases.

5. DEFINITION
 According to Lilenfield (1980), “Epidemiology is the study of
distribution of disease or physiological condition in human
population and of the factors that influence this distribution”.
OR

6. DEFINITION
 “The study of the distribution and determinants of health related
states or events in specified population and the application of
the study to control of health problems”. (J.M. Last,1988)
OR

7. DEFINITION
 According to Maxcy, “Epidemiology is the field of medical
science which is concerned with the relationship of various
factors, conditions which determine the frequencies and
distributions of an infectious process, a disease or a physiologic
state in a human community”.

8. AIMS OF EPIDEMIOLOGY
According to International Epidemiological Association
(IEA):
 To describe the distribution and magnitude of health
and disease problems in human population.
 To identify etiological factors in the pathogenesis of
disease.

9. Contd…..
• To determine the characteristics of the agent or causative
factors.
• To provide the data essential to the planning, implementation and
evaluation of service for the prevention, control and treatment of
disease and to the setting up of priorities among those services.

10. USES OF EPIDEMIOLOGY
• Investigation of causation of disease.
Genetic Factors
Good Health ill Health
Environmental factors

11. USES OF EPIDEMIOLOGY
• Study of the natural history and prognosis of
diseases.
• Description of the health status of the populations.
• Evaluation of the interventions
• Planning health services, public policy and
programs.

12. SCOPE OF EPIDEMIOLOGY
MAJOR AREAS OF
EPIDEMIOLOGY:
2. Disease
Occurrence.
1. Disease
Definition
3. Disease
Causation
6. Disease
Prevention.
4. Disease
Outcome
5. Disease
Management.

13. Contd….
• Disease Definition: - Characteristics or combination of character
that best discriminate disease from non- diseased.
• Disease Occurrence: - The rate of development of new case in
population. The proportion of current disease within population.

14. Contd…..
• Disease Causation: - The risk factors for disease development
and their relative strength with respect to an individual and
population.
• Disease Outcome: - The outcome following disease onset and of
the risk factor.

15. Contd…..
• Disease Management: - The relative effectiveness of proposed
therapeutic interventions.
• Disease Prevention: - The relative effectiveness of proposed
preventive strategies including screening.

16. VARIOUS FIELD OF EPIDEMIOLOGY: -
1. Aging epidemiology: Examines the public health impact of aging
societies, and the multifactorial changes associated with aging
that make health issues for older persons important and unique.
2. Applied public health epidemiology: Areas of focus include
population health status assessment; infectious and chronic

17. contd…
disease surveillance and control; maternal and child health
epidemiology; and environmental health epidemiology.
3. Cancer Epidemiology: Cancer epidemiology is the study of
the distribution and determinants of the likelihood of cancer
development.

18. Contd….
4.Cardiovascular and diabetes epidemiology: It is the study of the
distribution and determinants of the likelihood of cardiovascular
disease and diabetes development.
5. Clinical trials and methods: The activities of the epidemiologic
methods group contribute to all areas of emphasis, specializing
in design and conduct of studies including adaptive trials,

19. Contd….
survey sampling, and statistical methods.
6. Environmental epidemiology: Environmental epidemiology is a
branch of epidemiology concerned with determining how
environmental exposures impact human health. This field
seeks to understand how various external risk factors may
predispose to or protect against diseases, injury or death.

20. 7. Global health epidemiology: Global health epidemiology
addresses the causes and consequences of morbidity and
mortality that cross-regional or national boundaries, with
emphasis on research in resource-poor countries and
application of research findings to the implementation of
programs to promote health in those areas.

21. 8. Infectious disease epidemiology: The study of the incidence and
spread of infectious diseases in populations over time. Host,
pathogen and environmental factors are monitored to determine
the dynamics of infection, the ultimate goal of which is to devise
intervention strategies.

22. 9. Injury prevention epidemiology: Emphasis on the application of
epidemiologic methods in population and clinical settings to
understand key risk and prognostic factors for primary and
secondary prevention of injury.
10. Forensic epidemiology: The discipline of forensic epidemiology,
a branch of forensic medicine, provides a systematic approach

23. Contd….
to the assessment of general and specific (individual) causation,
with the results suitable for presentation in a court of law.
11.Molecular and genetic epidemiology: Molecular epidemiology is
a branch of epidemiology and medical science that focuses on
the contribution of potential genetic and environmental risk
factors, identified at the molecular level, to the aetiology,

24. distribution, and prevention of disease within families and
across populations.
12. Population neuroscience: Focuses on the application of
epidemiology methods and cutting-edge neuroimaging
methodologies in population and clinical studies to enhance
etiological research and evaluation of specific therapies in the
disorders of the central nervous system.

25. 13. Occupational epidemiology: Occupational epidemiology is a
sub discipline of epidemiology that focuses on investigations of
workers and the workplace.
14. Reproductive, perinatal, and paediatric epidemiology: This
area focuses on the determinants of health and disease in
reproduction and childhood development.

26. Contd….
15.Prevention, lifestyle, and physical activity epidemiology.
16.Women’s health epidemiology: Women’s health epidemiologists
conduct research to improve the physical and mental health,
safety and well-being of the maternal and child health.

27. Contd….
17.Psychiatric epidemiology: The psychiatric epidemiology area
of emphasis focuses on the acquisition of epidemiological, bio
statistical, and psychiatric concepts and methods, and on their
application to research in the field of psychiatric disorders.
18.Obesity and nutritional epidemiology: The study of nutrition
and other behavioral factors and their relation with population
health.

28. TERMINOLOGIES USED IN EPIDEMIOLOGY
• INFECTION: The entry and development or multiplication of an
infectious agent in the body of man or animal.
• INFESTATION: Infested article are those which harbor or gives
shelter to animal forms, especially arthropods and rodents.

29. TERMINOLOGIES USED IN EPIDEMIOLOGY
• EPIDEMIC: A widespread occurrence of an infectious disease in
a community at a particular time.
• ENDEMIC: It refers to the constant presence of a disease or
infectious agent within a given geographical area or population
group, without importation from outside. For example, common
cold is endemic.

30. TERMINOLOGIES USED IN EPIDEMIOLOGY
• SPORADIC: It occurring at irregular intervals, only in a few
place scattered or isolated..eg.. Polio, Herpes etc.
• PANDEMIC: An epidemic usually affecting a large proportion of
the population occurring over a wide geographic area such as a
section of nation. Eg. Influenza pandemics of 1918 and 1957.

31. THANK YOU