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 et al. 2009). Another analysis across three large, well-characterized samples of European Americans demonstrated a strong effect of ADH1B*2, close to what is seen in Asian populations (odds ratio <0.4; P < 10−8) (Bierut et al. 2012). The ADH1B*2 allele also was associated with hypersensitivity to alcohol in a Scandinavian population (Linneberg et al. 2010), as well as with significantly less drinking before and during pregnancy in European women (Zuccolo et al. 2009). Finally, both maternal and fetal ADH1B*2 reduced the risk for fetal alcohol spectrum disorders in a mixed population from South Africa (Warren and Li 2005).
