Table 1 displays descriptive statistics for the total sample and by genotype groups, adjusted for sex. Bivariate comparisons revealed no significant sex differences with regard to family adversity, obstetric complications, and negative life events, with the exception that females were somewhat older than males. Sex had an effect on all drinking measures, indicating that males drank more hazardously, had more drinking days and consumed a higher total number of drinks than females (data not shown). The genotype groups did not differ on any of these variables. However, consistent differences according to genotype were observed for the drinking measures. Carriers of the minor G allele had less drinking days than homozygotes for the A allele and, as a trend, consumed a lower number of drinks. Similar results with regard to control variables, life events and drinking measures were obtained in the subgroup of regular alcohol users (Table 1).
