Epidemiology

Epidemiology

Definition:

The term Epidemiology is derived from the word ‘epidemic’ (epi means among; demos means people and logos means study).

Modern Definition of Epidemiology:

The latest definition of epidemiology has been given by John M. Last in 1988 as:

        “The study of the distribution and determinants of health related states or events in specified populations, and the application of this study to the control of health problems.”

Aims/ Objects of Epidemiology:

      According to the International Epidemiological Association (IEA), epidemiology has 3 main arms:

(i) To describe the distribution and size of disease problems in human populations.

(ii) To identity etiological factors in the pathogenesis of disease, and

(ii) To provide the date essential to the planning, implementation and evaluation of services for the prevention, control and treatment of disease and to the setting up of priorities among those services.

The ultimate aim of epidemiology is to lead to effective action.

(i) To eliminate or reduce the health problem or its consequences; and

(ii) To promote the health and well-being of society as a whole by preventing its occurrence in future.

Uses of Epidemiology:

      Study of the distribution and determinants of disease in a defined population helps to:

1. Identify factors that cause disease.

2. Identify factors or conditions that can be used or modified to prevent the occurrence or spread of disease.

3. Explain how and why diseases and epidemics occur.

4. Evaluate the effectiveness of vaccines and different forms of therapy.

5. Establish a clinical diagnosis of disease.

6. Identify the health needs of the community.

7. Evaluate the effectiveness of health programmers.

8. Predict the future health needs of a population.

Epidemiologic methods:

1. Observational Studies:

            a. Descriptive studies.

            b. Analytical studies.

            (i) Ecological or Correlational.

            (ii) Cross-sectional or Prevalence,

            (iii) Case-control or Case-reference,

            (iv) Cohort or Follow-up

2. Experimental studies Intervention studies.

            a. Randomized controlled trials or, Clinical trials

            b. Field trials or Community intervention studies.

            c. Community trials.