We considered the possibility of hidden population substructure explaining the main result for rs1229984. This variant is one of the most ethnically stratified, exhibiting a wide range of MAFs: from 2–5% in Western European populations to 60–70% in North-East Asia (40), and alcohol intake is strongly culturally-dependent (41). For this reason, we limited the analyses to women of self-reported white ethnicity and conducted sensitivity analyses by further excluding women reporting at least one parent of non-white ethnicity or likely to be ‘non-white’ based on ancestry-informative markers genotype or self-reported Jewish faith, yet results were unchanged. The lack of genome-wide data on this sample prevented us from running further checks.
