ALDH2 and alcohol dependence: A meta-analysis of 15 Asian (Chinese, Japanese, Korean, and Thai) studies with data from over 4,500 alcohol-dependent and control subjects collected between 1979 and 2004 found possession of one variant ALDH2*2 allele was associated with a fivefold reduction in alcohol is dependence and possession of two ALDH2*2 alleles was associated with a nine-fold reduction (Luczak et al. 2006).3