Several issues prompted us to carry out an updated meta-analysis to seek further evidence regarding the proposed association with ADH1B. First, the findings of case-control studies have been controversial and nonconclusive. Second, rates of AD differ across the ethnic populations, even among Asian populations. Third, the low prevalence of ADH1B His/His individuals in subjects of European ancestry makes it particularly difficult to determine the effect of homozygous His/His in that population due to the need for very large sample size. The previous meta-analyses(3, 6, 7) regarding the role of ADH1B His in alcoholism, however, involved relatively small numbers of subjects available at the time of the analyses and thus the results were limited or incomplete. Therefore, a new meta-analysis with systematic statistical approaches is required.
