All the combined studies of AD and alcohol abuse, in particular, the Asian studies, showed strong association, with allelic (Arg vs. His) P values of 1×10−36 (OR = 2.06 (1.84, 2.31)) and 7×10−42 (OR = 2.24 (1.99, 2.51)), respectively (Table 1). The strong association was also found under both dominant (ArgArg + ArgHis vs. HisHis) and recessive (ArgArg vs. ArgHis + HisHis) models (P < 9×10−23 in all the populations and P < 2×10−31 in Asians) with much lower heterogeneity under the dominant model (P > 0.01). Strong association was also revealed in the combined Asian and European-ancestry studies (allelic P = 2×10−36), however, it was moderate in the European (P = 0.0002) and non-Asian studies (P = 2×10−5). The strict random effects model was applied when evidence for significant heterogeneity between studies was found throughout this meta-analysis.
