meta-analysis. The older study by Whitfield et al.(7) published in 2002, included 22 studies (17 publications) between ADH1B His and alcoholism. In contrast, our meta-analysis included the largest sample size up to the present (9,638 cases and 9,517 controls) from both 72 English and six Chinese-language publications (it was important to include Chinese-language publications as well); used both strict and extended criteria to measure the effect estimates; performed both allelic and genotypic analyses under the strict random effects model; applied systematic analysis procedure, as shown in the results, to study additional questions not answered in those previous meta-analyses; and found consistently stronger evidence of associations for ADH1B His with both AD and alcohol-induced diseases (our results have the same direction as a recent study(110) showing that Arg48/Arg48 can increase the risk of esophageal cancer among drinkers). Our results also provided significant evidence of association of this polymorphism (also Cys) with drug dependence although those studies were excluded from meta-analyses of AD. In addition, the procedure of extended-quality score suggested in our previous study(8) was also applied to assist the assessment of quality of the individual association studies.
