package in R. The analyses of AD for the strongest signals were conducted using the GWAF, an R package for genome-wide association analyses with family data (Chen and Yang, 2010). A logistic regression model was employed with gender, age and cohort included as covariates, and a log additive model for each SNP was tested for association. The generalized estimating equation (GEE) framework was used to control for relatedness. The association of individual SNPs with SC was performed using PROC GLIMMIX from SAS (http://support.sas.com/rnd/app/da/glimmix.html). Birth cohorts and gender were included as covariates for the association analysis.
