the ADH1B*2 allele is found at moderate frequencies and reduces binge drinking (Luczak et al. 2002) and risk for alcoholism (Hasin et al. 2002). Overall, the protective effect of ADH1B*2 appears to be weaker in European than in Asian populations (Whitfield 2002). This difference could result from different social and environmental factors. Alternatively, the allele could be co-inherited with other, as-yet-unidentified ADH variations that might affect the risk of alcoholism and which could differ between Europeans and Asians.
