Our study has some limitations. First, harmful drinking is a complex trait that is likely influenced by multiple genetic variants reflecting multiple mechanisms. We have shown that the age-adjusted mean AUDIT-C score is more strongly associated with variation in ADH1B than the other phenotypes evaluated. However, it is an empirical question as to whether this phenotype would yield an advantage in detecting other genetic variants that could contribute to risk of harmful drinking via other (e.g., pharmacodynamic) mechanisms. We are in the process of examining the utility of the age-adjusted mean AUDIT-C score as an ordinal trait in a GWAS using the MVP sample. Second, because the VA EHR only includes the first three items of the AUDIT (AUDIT-C), we were not able to compare it against the full AUDIT. Third, the MVP sample is predominantly male, over 50 years of age, and in health care. Our study may not generalize well to women or younger adults. Of note, older male veterans do not drink more than age- and sex-matched comparators. According to the National Surveys on Drug Use and
