Definition “The study of the distribution and determinants of health-related states or events in specified population, and the application of the results of this study to the control of health problems”
1. Distribution: It is to study pattern of distribution of diseases or health events or states in the various groups / subgroups of population in terms of person, place and time by asking
Who (persons), is affected more by a disease or who remain free from it within a population.
Where (place) a health related event has occurred
When, (time) such event has occurred or existed.
2. Determinants:
Include both causes and factors that influence the risk of disease. They are grouped under epidemiological triad as-agent factors, host factors and environmental factors