Because the DIGS does not query maximum drinks or flushing, we added two questions for the purposes of this study: “What is the largest number of alcoholic drinks you have ever consumed in a day?” and “Does your face flush after drinking a little alcohol?” (approximate back-translations from Chinese). This wording is similar, but not identical to that used to query maximum drinks in the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) and Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) instruments also used in studies of alcoholism and drug dependence (Gelernter et al. 2005; Pierucci-Lagha et al. 2005; Bucholz et al. 1994). The most common form of alcohol consumed by people in this district is fortified rice wine, which is approximately 30% ethanol by volume. Drinks were calculated as equivalents of one shot of hard liquor (including fortified rice wine), one glass of wine, or one bottle of beer; however, many responses were given in the local unit “liang,” which was converted to 1.32 standard units based on volume. Demographic and phenotypic distributions of males and females in the full sample can be seen in Table 1.
