Effect sizes and effect alleles were derived from a GWAS of N = 112,117 unrelated European ancestry individuals in the UK Biobank (Clarke et al., 2017). Participants were asked about their current drinking status (never, previous, current, prefer not to say) and their average weekly and monthly consumption of a variety of alcoholic beverages (e.g. red wine, white wine, beer, spirits). An overall measure of average alcohol intake per week was derived from these measures. Age and weight were then regressed onto alcohol consumption in units per week in males and females separately, and the residuals from these regressions were then pooled (males + females) to form the alcohol consumption phenotype of interest. A GWAS was conducted with 12,489,782 quality-controlled SNPs and UKB assessment center, genotyping batch and 15 principal components included as additional covariates. In COGA, after removing palindromic/ambiguous SNPs from the summary statistics, PRS were coded for every individual by multiplying an individual’s number of effect alleles at a particular SNP by that SNP’s effect size (beta) from the discovery GWAS, then averaging across SNPs to create one
