Lifestyle factors, obesity and the risk of colorectal adenomas in EPIC-Heidelberg.

OBJECTIVE: We investigated the association of lifestyle and obesity with colorectal adenoma risk in a prospective setting. METHODS: At recruitment (1994-1998), information on diet, anthropometry, lifestyle, and medication was assessed in 25,540 participants of the EPIC-Heidelberg cohort. Until June 2007, 536 verified incident colorectal adenomas were identified. Furthermore, participants with negative colonoscopy (n = 3966) were included in the analytic cohort. RESULTS: In multivariate logistic regression analyses, participants with highest alcohol intake had an increased adenoma risk (odds ratio [OR] = 1.63; 95% CI 1.21-2.22) compared with lowest intake group. Folate consumption modified the ethanol effect (p-interaction = 0.03). Current smokers had a significantly increased adenoma risk compared with never smokers (OR = 1.40; 95% CI 1.16-1.84). Regular NSAID intake was associated with lower risk in subjects who reported their use at least twice compared with nonusers (OR = 0.70; 95% CI 0.53-0.93). Physical activity, body mass index, and waist-to-hip ratio were not consistently associated with adenoma risk. CONCLUSIONS: The results of this prospective cohort study showed that alcohol intake and smoking are important risk factors for colorectal adenoma, and regular NSAID use decreases the risk. The relationship between alcohol consumption and adenoma risk was modified by folate intake. However, we could not confirm an effect of obesity or physical activity on adenoma risk.