Based on all these samples, the frequency of the protective ADH1B His allele varied widely across the populations: high in the Asian normal populations 69% (19% – 91%) and affected subjects, 51% (9% – 93%); low in the European normal populations 5.5% (1% – 43%) and affecteds, 6.9% (0% – 51%); and rare in the Mexican normal populations 3% (2% – 7%) and affecteds, 4% (2% – 8%). On average, the frequencies of the His allele were 34% and 45% in the combined patients and controls, respectively. The ADH1B Cys allele was found in African Americans, native Americans, and Trinidadians with frequencies of 11% (1% – 30%) in controls and 7% (0% – 18%) in affecteds. In the 48 Asian studies, 45 studies showed lower frequency in cases than in controls; in the 21 European studies, 16 showed lower frequency in cases than in controls; in the four Mexican American studies, two showed lower frequency; and all the four studies of the Cys allele, that allele showed lower frequency in cases than in controls. Only the studies of AD and alcohol abuse were included in the following meta-analysis.
