The summary statistics of the recent GWAS of AUDIT-C and AUDIT-P in 121,604 unrelated individuals of European ancestry from the UK Biobank cohort (Sanchez-Roige et al., 2018) were used to construct PRS for alcohol-related outcomes in four independent target samples. The UK Biobank (UKB, www.ukbiobank.ac.uk) is a population-based sample of 502,629 participants who were recruited from 22 assessment centers across the United Kingdom from 2006 to 2010 (Bycroft et al., 2018); the AUDIT was delivered as part of the online Mental Health Questionnaire follow-up (Davis et al., 2018). Discovery GWAS analyses were performed using BGENIE (Bycroft et al., 2018), version 1.1, with AUDIT scores (AUDIT-C score, and AUDIT-P score, tested independently) as the outcome variable and age, sex, genotyping array, and the first 20 principal components derived from genotype data as covariates to account for any remaining population stratification. Further details regarding the discovery GWAS are provided in the Supplemental Materials.
