ABSTRACT

A distinction is sometimes made between descriptive methods in epidemiology, such as the determination of incidence and prevalence, and analytical methods in which hypotheses are said to be tested. The case-control study has several attractions for the epidemiologist. One of the issues that must be considered in a case-control study is that of confounding. A confounding factor – or confounder – is one that satisfies two conditions: it is a risk factor for the disease under study and it is associated with the study exposure but is not a consequence of it. In palaeoepidemiology the case-control approach can be used inter alia to test associations between conditions or to test the proposition that a disease may be more common in one group than another. The chapter explores the differences between the odds ratio and the risk ratio.