The ADH1B*2 allele, occurring at a frequency of 0.75 in East Asians, is uncommon in other populations with a frequency of ≤ 0.01 in Caucasians, African Americans and American Indians [24]. However, studies in large non-East Asian datasets of several thousand individuals have likewise demonstrated a strong protective effect of ADH1B*2 on alcoholism [25,26], and a study in 4500 largely Caucasian Australian twins found an association between ADH1B*2, flushing and alcohol consumption [27]. Other than in East Asians, the highest frequency for the protective ADH1B*2 allele is in Jewish populations, ranging from 0.20 to 0.31 [28–30]. Finally, the ADH1B*3 allele has been associated with a protective effect on risk for alcoholism in African-Americans and American Indians [31,32].
