Three studies have investigated the moderating role of social context on the protective effects of the higher activity ADH1B allele (ADH1B*2) and the inactive ALDH2 allele (ALDH2*2). Higuchi et al. (1994) assessed the role of ALDH2*2 on AD risk based on clinical admissions data obtained between 1979 and 1992, a time period when socio-cultural shifts led to increases in per capita alcohol consumption in Japan. Results indicated that individuals with two copies of the inactive ALDH2*2 allele were completely protected from AD in all cohorts. However, individuals with one inactive and one active ALDH2*2 allele followed the cultural norm and increased their drinking dramatically over time, some even to the point of developing AD. The proportions of alcohol dependent individuals with one copy of the ALDH2*2 allele were: 2.5%, 8.0%, and 13.1%, respectively, in 1979, 1986, and 1992. Likewise, in a small sample of East Asian adolescents adopted into western homes, those with an ALDH2*2 allele were more likely to have consumed alcohol and gotten drunk if they had a sibling that did the same (Irons, McGue, Iacono, & Oetting,
