LAUSR

Background The association between coffee and colorectal adenoma risk remains controversial. We conducted a meta-analysis of cohort and case–control studies to sum up the existing proof about this matter. Methods We searched Pubmed, Medline, and Embase for studies published before 1 September 2018 on coffee consumption and colorectal adenoma in any language. The different ORs were calculated for cohort and case–control studies in this study, and we use a random-effects model to aggregate the relative risks of individual studies and conduct dose response, heterogeneity, and publication bias. Results A total of 8 studies (6 case–control studies, 2 cohort studies) were identified, including 7090 subjects. In a summary analysis of all studies, high coffee intake (compared the highest with the lowest categories) was associated with a reduced risk of colorectal adenoma (odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.55–0.90). The results of subgroup analysis of adenoma location were similar with the pooled analysis, except for rectal adenoma. In the dose–response meta-analysis study, the estimated total odds ratio for increasing coffee consumption by 150 ml per day (about one cup) was 0.91 (95% CI = 0.87–0.95). Conclusions The meta-analysis demonstrates possible evidence that increased coffee intake is related to a reduced risk of colon adenoma. However, because of latent confusion and different exposure classification, this finding should be carefully considered.