We collected AUDIT (7) and genotype data from three population-based cohorts: UK Biobank (nmax=147,267), the Netherlands Twin Register (nmax=9,975), and the Avon Longitudinal Study of Parents and Children (ALSPAC, nmax=3,582). We used the same phenotyping strategies across the three cohorts, which are described in the Supplementary Material 2. AUDIT scores and demographics for each cohort are reported in Table S2. Genotyping, imputation and quality control procedures have been extensively described in previous publications (10–12). Because AUDIT was administered with skip logic in UK Biobank, we used multiple imputation by chained equations to minimize the impact of missing data on our item-level GWAS (see Supplementary Material 2.1 for details).
