BACKGROUND Alcohol may increase gastric cancer risk. Alcohol can be more carcinogenic in persons who possess inactive ALDH2. The aim of this meta-analysis was to evaluate whether ALDH2 polymorphism can affect alcohol-induced gastric carcinogenesis.

METHODS We searched the PubMed, EMBASE, and Cochrane databases to identify relevant articles published between January 2000 and September 2019. Eligible articles were selected according to inclusion and exclusion criteria. The data were analyzed using Review Manager 5.3.

RESULTS A total of 7 case-control studies on ALDH2 rs671 polymorphism consisting of 3,251 gastric cancer cases and 4,943 controls were included in the analysis. Inactive ALDH2 genotypes (G/A or A/A) were associated with an increased risk of gastric cancer (odds ratio [OR] = 1.26, 95% confidence interval [CI]: 1.04 to 1.52, p = 0.02, I² = 64%), compared with active ALDH2 (G/G genotype). Subgroup analysis by alcohol consumption showed that inactive ALDH2 increased risk for gastric cancer in moderate to heavy drinkers (OR = 1.85, 95% CI: 1.52 to 2.25, p < 0.01, I² = 6%) more than in nondrinkers or mild drinkers (OR = 1.19; 95% CI: 1.05 to 1.36, p < 0.01, I² = 6%). Moderate/heavy alcohol consumption increased gastric cancer risk in individuals with inactive ALDH2 (OR = 2.23, 95% CI: 1.63 to 3.05, p < 0.01, I² = 30%) more than those with active ALDH2 (OR = 1.40, 95% CI: 0.98 to 2.01, p = 0.07, I² = 85%).

CONCLUSIONS The ALDH2 polymorphism modifies the risk of gastric cancer. Moderate/heavy drinkers are more susceptible to gastric cancer than non-drinkers or light drinkers with inactive ALDH2.