Los estudios de casos y controles como parte de una investigación de una epidemia

Abstract

Case-control studies have a place when situations emerge such as 1) the condition or disease of interest is rare or 2) the population at-risk is hard to identify. They are observational epidemiological studies in which a series of cases, preferably of new occurrence, are compared in terms of their exposure with members of the underlying population or cohort from which the cases arise, that is, had those subjects had the condition or disease, such individuals selected as controls would have been in the case series. In this review we compare case-control studies with cohort studies, define what they are, and other issues such as case definition, selection of controls, measurement of exposure, biases, and its analysis explaining how is that the odds ratio approximates the risk or rate ratio.