The case-control study can help us determine if an exposure is associated with an outcome
Relatively easy to apply – compared to other study designs – the case-control is one of the more frequently used study designs in epidemiology. They begin with the identification of clearly defined cases (people with the disease or health outcome) and controls (people without the disease). These two groups are then compared. Interestingly the data on risk factors are collected retrospectively!
This means that bias is a particular problem that has to be carefully considered during the planning and implementation of a case-control study.
We use age-related macular degeneration as our example of eye disease as we examine case-control studies. By the end of the session you should be able to:
1. Discuss the epidemiology of age-related macular degeneration
2. Assess the selection and sources of cases and controls in case-control studies
3. Understand recall and observer bias as sources of error in measurement of exposure.
4. Critique the strengths and weaknesses of case-control studies
5. Calculate the association between disease and exposure
6. Describe nested case-control studies.