Lifetime alcohol intake, drinking patterns over time, and risk of stomach cancer: a pooled analysis of data from two prospective cohort studies

Alcohol consumption is causally linked to several cancers but the evidence for stomach cancer is inconclusive. In our study, the association between long-term alcohol intake and risk of stomach cancer and its subtypes was evaluated. We performed a pooled analysis of data collected at baseline from 491,714 participants in the European Prospective Investigation into Cancer and Nutrition and the Melbourne Collaborative Cohort Study. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated for incident stomach cancer in relation to lifetime alcohol intake and group-based life course intake trajectories, adjusted for potential confounders including Helicobacter pylori infection. 1,225 incident stomach cancers (78% non-cardia) were diagnosed over 7,094,637 person-years; 984 in 382,957 study participants with lifetime alcohol intake data (5,455,507 person-years). Although lifetime alcohol intake was not associated with overall stomach cancer risk, we observed a weak positive association with non-cardia cancer (HR=1.03, 95% CI: 1.00-1.06 per 10 g/day increment), with a HR of 1.50 (95% CI: 1.08-2.09) for ≥60 g/day compared with 0.1-4.9 g/day. A weak inverse association with cardia cancer (HR=0.93, 95% CI: 0.87-1.00) was also observed. HRs of 1.48 (95% CI: 1.10-1.99) for non-cardia and 0.51 (95% CI: 0.26-1.03) for cardia cancer were observed for a life course trajectory characterized by heavy decreasing intake compared with light stable intake (phomogeneity =0.02). These associations did not differ appreciably by smoking or Helicobacter pylori infection status. Limiting alcohol use during lifetime, particularly avoiding heavy use during early adulthood, might help prevent non-cardia stomach cancer. Heterogeneous associations observed for cardia and non-cardia cancers may indicate etiologic differences.