We identified multiple significant loci for peak daily alcohol consumption (MaxDrinks) in a large sample of EAs and AAs, thus expanding the existing literature in several ways. First, the association of the functional ADH1B SNP rs1229984 with MaxDrinks in EAs is consistent with previous observations. This finding provides additional support for a role of that locus in determining alcohol consumption, as well as increasing confidence in our findings implicating other loci relevant to drinking behavior. Second, this is the first report of a significant association of rs2066702 at ADH1B with MaxDrinks in an AA population – this finding is not unexpected, as it is similar to the finding in EAs. Third, additional protective loci, i.e., alleles mapped to genes not previously associated with either MaxDrinks or AD, were identified in both EA and AA populations. It is also noteworthy that the significant genes or alleles associated with MaxDrinks were population-specific (in all cases except ADH1B), suggesting that different genes and perhaps different biological pathways may be involved in this trait in different populations. This pattern of findings also reinforces the importance of stratifying populations for gene discovery when using a GWAS approach.
