Epidemiology
Chapter 2: Different types of epidemiological studies
1. Overview of epidemiological studies
1.2 Principles and scope of epidemiology
Disease outbreaks are not haphazard. The causal factors (risk or protective) must be identified by applying rigorous methods to various populations at different periods of times and in different locations.
To measure the frequency of diseases :
To quantify the occurrence or the onset of illnesses
To determine the distribution of illnesses
Who is ill? Where is the population ill? When is the population ill?
To compare groups or sub-groups of individuals or different periods of times to find these answers.
To identify the determinants (risk factors) of illnesses.