Association analysis of case-control status was performed on the entire sample using logistic regression with gender and race as covariates. This analysis highlights SNPs that have similar effect in both EAs and AAs. The full genetic model is: (Equation 1)ln(P1−P)=α+β1g+β2s+β3G, where P is the probability of being a case, g is gender (0=male, 1=female), s is race (0=EA, 1=AA), and G is genotype, coded as the number of copies of the minor allele in the EA sample, corresponding to a log-additive (multiplicative) model. The term β3G is tested for significance by the standard likelihood chi-square with one degree of freedom. We then analyzed AAs and EAs separately with gender as a covariate. Association tests were carried out using PLINK [29] and SAS (Cary, NC).
