of acetaldehyde, which is toxic and leads to undesirable reactions, including nausea.56, 59 Early work demonstrated the strong effect of a single non-functional allele at this locus, as heterozygotes and homozygotes for rs671 (GA and AA genotypes) are deficient in ALDH2 activity, suggesting that rs671 allele A is dominant.60 Therefore, individuals who carry at least one copy of rs671 drink typically less, and are protected against heavy alcohol use and alcohol use disorders.50, 61 Consistently, we found that GERA subjects who carried even a single deficient metabolizing allele of ALDH2 rs671 were less likely to consume alcohol. Thus, the current study adds further evidence of an effect on average alcohol drinking of ADH1B and ALDH2, whereas much of the extensive prior literature is on effects on lifetime measures, such as risk of alcohol dependence.25, 61–64
