What we're talking about when we talk about race.

It has been pointed out repeatedly (1,2) that reported associations between race and illness should be subject to careful scrutiny. Establishing race as an independent risk factor for a disease is even more complicated than the usually difficult task of establishing epidemiologic association. Among the usual difficulties are selection of a representative sample, collection of accurate data, identification of appropriate controls, and adjustment for confounders. Unlike other variables in epidemiologic studies, however, race has complex social and biologic implications.