In the Asian populations where ADH1B*2 is common, there is very strong evidence that it is protective against alcohol dependence (Chen et al. 1999; Edenberg 2007; Li et al. 2007; Thomasson et al. 1991; Whitfield 2002). An analysis among Han Chinese in Taiwan showed that the relative risk of alcohol dependence was reduced to 0.2 if a person carried a single ADH1B*2 allele and to 0.12 for homozygotes (Chen et al. 1999). A more recent meta-analysis similarly showed a very strong protective effect for the ADH1B*2 allele in Asians (odds ratio ∼ 0.44; P < 10−36) (Li et al. 2007). It has been more difficult to detect the effect of ADH1B*2 in Europeans; the meta-analysis by Li and colleagues (2007) showed an odds ratio of 0.65 and P = 0.04 in alcohol-dependent people without secondary disease. A study in European Americans found that each ADH1B*2 allele lowered the number of symptoms of alcoholism as specified in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM–IV) and also reduced the maximum number of drinks consumed in one sitting (Sherva
