Re: Population Stratification in Epidemiologic Studies of Common Genetic Variants and Cancer: Quantification of Bias

Abstract

Epidemiologists have long suspected that, in populations with racial or ethnic subgroups, spurious associations may arise between genetic markers and disease (1). Incomplete mixing of subgroups, known as population stratification or admixture, can lead to bias if one more or subgroups carries both a higher prevalence of an allele and a higher risk of disease (2). The magnitude and direction of the resulting bias are not well understood. Recently, a variety of alternative study designs have been proposed to avoid the problem of population stratification, including case–parent and case–sibling methods (2).