Although our study is based on a large sample, we are still underpowered to conduct additional analyses to dissect the differences in the polygenic architecture of excessive drinking behaviors between sexes and age classes. MaxAlc, although a valid and useful phenotype, has previously been used only rarely. The high correlation with AUD per se may encourage more use in future studies, in the context of the results we report here. Additionally, the MVP uses an array that, while adequate for studies of EUR, is sparse for AFR and accordingly leaves much of the genome unstudied (64). This is the case because AFR are a genetically older population than EUR and have lower linkage disequilibrium genomewide; hence each SNP tends to query a shorter genomic region. For studies including large AFR populations, a more informative array would, ideally, be employed.
