under an additive genetic model using logistic regression for CC phenotype and linear regression for quantitative FS phenotype. As covariates, we used sex and age at interview, as they were significant predictors of the phenotypes. Ancestry principal components were estimated for each sample and included on a sample-by-sample basis depending on their correlation with the outcome phenotypes. The quantile-quantile (Q-Q) plot was used to evaluate overall significance of the association test results and the genomic control factor λ.
