Alcohol consumption and risk of inflammatory bowel disease among three prospective US cohorts

Background and aims There are limited data on alcohol dose and types and risk of Crohn's Disease (CD) and Ulcerative Colitis (UC). We therefore sought to comprehensively examine the association between alcohol consumption and risk of CD and UC. Methods We conducted a prospective cohort study of 237,835 participants from the Nurses' Health Study, Nurses' Health Study II, and Health Professional Follow-Up Study. Alcohol consumption was obtained through questionnaires submitted every four years; additional covariates were obtained at two or four-year intervals. Cases were confirmed independently by two physicians through medical record review. We used Cox proportional hazards regression to estimate age and multivariable-adjusted hazards ratios and 95% confidence intervals. Results Across 5,170,474 person-years of follow-up, 370 cases of CD and 486 cases of UC were documented. Increased consumption of alcohol intake was not associated with CD (Ptrend = 0.455) or UC (Ptrend = 0.745). Compared to non-users, the MV-adjusted HRs for 15.0 + g/day of alcohol intake group were 0.84 (95% CI 0.56, 1.24) for CD and 1.08 (95% CI 0.77, 1.51) for UC. In analyses of alcohol subtypes, we observed that only moderate consumption of beer (>1-4 servings/week) was marginally associated with reduced risk of CD, while consumption of >4 servings/week of liquor was associated with an increased risk of UC. Conclusion This prospective study did not identify a relationship between overall alcohol consumption and risk of CD or UC. Our suggestive associations between alcohol types and risk of CD and UC deserve additional investigation.