Sex as an effect modifier in the association between alcohol intake and gastric cancer risk

BACKGROUND: The results of previous meta-analyses evaluating the association between the alcohol intake and gastric cancer risk have reported that a statistical significance only for men. AIM: To investigate the different association between alcohol intake and gastric cancer risk between men and women. METHODS: The selection criteria included a prospective cohort study for evaluating alcohol intake and gastric cancer risk, with relative risks adjusted for potential confounders. Adjusted relative risk (RR) for the potential confounders and its 95% confidence interval (CI) in the highest vs lowest level were extracted from each study and a random-effects meta-analysis was conducted. Subgroup analyses by region, level of adjustment for smoking status, adjusting for body mass index, and year of publication were conducted. RESULTS: A meta-analysis of all 27 cohorts showed that alcohol intake increased the risk of gastric cancer (summary RR = 1.13, 95%CI: 1.04-1.23, I(2) = 58.2%). Further, 13 men’s cohorts had higher summary RR while maintaining statistical significance, and only seven women’s cohorts had no statistical significance. CONCLUSION: The present review suggests that alcohol consumption increases the risk of gastric cancer in men. These findings showed that the sex variable in the association between alcohol intake and gastric cancer risk seemed to be an effect modifier with an interaction term. It is necessary to re-estimate follow-up outcomes after stratifying for sex.