A significance level of 0.05 was used and all presented P‐values are empirical estimates unless otherwise specified. P‐values for main outcome variables (i.e. AUDIT and smoking) were Bonferroni corrected for three models, three SNPs and two primary endpoints (i.e. 18) and designated pc. The statistical analysis was carried out using SPSS for Mac (Version 19.0.0.1, SPSS, Chicago, IL, USA) and R (Team RDC 2011).