Genetic polymorphism in alcohol dehydrogenase 2 (ADH2) gene and alcoholic liver cirrhosis risk

The alcohol dehydrogenase 2 (ADH2) gene has been implicated in the development of alcoholic liver cirrhosis (ALC). However, the results are inconsistent. In this study, a meta-analysis was performed to assess the associations between the ADH2 polymorphism and the risk of ALC. Relevant studies were retrieved by searching PubMed, Web of Science, CNKI, Wanfang and VIP databases up to January 10, 2015. The pooled odds ratio (OR) with a 95% confidence interval (CI) was calculated using the fixed- or random effects model. A total of 21 case-control studies included 1812 cases and 3468 controls were included. Overall, the ADH2 polymorphism was associated with a decreased risk of ALC in all four genetic models (dominant model: OR=0.56, 95% CI: 0.38-0.83; recessive model: OR=0.59, 95% CI: 0.39-0.91; *1/*2 vs. *1/*1: OR=0.58, 95% CI: 0.40-0.85; *2/*2 vs *1/*1: OR=0.35, 95% CI: 0.16-0.75). Besides, in stratification analysis by ethnicity, similar results were observed in Asian populations, however, we detected no association in Caucasian populations under recessive and homozygote comparison model. The pooled evidence suggests that ADH2 polymorphism may be an important protective factor for alcoholic liver cirrhosis, especially for Asians.