3. Types of epidemiological studies

3.2 Analytic studies

3.2.1 Observational studies

A. Case-control studies
Figure 6: The principle of a case-control study (retrospective observation)

Figure 6: The principle of a case-control study (retrospective observation)

Subjects are selected according to the presence of the disease (cases) or absence of the disease (controls).

The medical history of the subjects is examined retrospectively for the absence (no exposure) or presence (exposure) of the risk factor being studied.

This is a retrospective observation. Exposure to the risk factor between cases and controls is compared.

Example of an analytical study that is an observational study > case-control study