Publication bias is an important issue in meta-analysis. In the present study, no evidence of significant publication bias was found in the studies of AD and alcohol abuse with European samples (P(T) > 0.05) for either allelic or genotypic analysis. However, evidence of publication bias was found in those studies with Asian samples as well as when all the populations were combined as described below. For the allelic analysis, in the studies of AD and alcohol abuse with Asian samples, the Egger's regression P value (1-tailed) was 0.0002, and Kendall's tau (Begg and Mazumdar rank correlation)(89) P value (1-tailed) was 0.005; the analysis of Duval and Tweedie's trim and fill showed that there might potentially be eight missing studies, and the adjusted overall effect size was 2.50(2.21, 2.83) under the random effects model; in all the populations the Egger's regression P value was 0.0001, and Kendall's tau P value was 0.04; the trim and fill analysis showed that there might be six potential missing studies, and the adjusted effect size was 2.17(1.93, 2.43) under the random effects model. For the
