Adjusting for confounding due to population admixture when estimating the effect of candidate genes on quantitative traits

When analyzing the relationship between allelic variability and traits, a p otential source of confounding is population admixture. An approach to adju sting for potential confounding due to population admixture when estimating the influence of allelic variability at a candidate gene is presented. The approach involves augmenting linear regression models with additional regr essors. Family genotype data are used to define the regressors, and inclusi on of the regressors ensures that, even in the presence of population admix ture, the estimates of the regression coefficients that parameterize the in fluence of allelic variability on the trait are unbiased. The approach is i llustrated through an analysis of the influence of apolipoprotein E genotyp e on plasma low density lipoprotein cholesterol concentrations. Copyright ( C) 2000 S. Karger AG, Basel.