Adiposity and the risk of colorectal adenomatous polyps: a meta-analysis

The findings from epidemiological studies addressing the association between adiposity and the risk of colorectal adenomatous polyps are inconsistent. We performed a meta-analysis of epidemiological studies including cross-sectional, case-control, and cohort studies. We searched PubMed and EMBASE in June, 2010. All searched articles were reviewed and selected independently by two evaluators according to pre-determined selection criteria. We included 25 studies (nine cross-sectional studies, eleven case-control studies, and five prospective cohort studies) that comprised a total of 300,671 participants and 20,903 cases in the final analysis. When all studies were pooled, the odds ratio (OR) or relative risk (RR) of adiposity and abdominal adiposity for colorectal adenomatous polyp risk was 1.43 (95% confidence interval (CI) 1.23-1.67; n = 22) and 1.42 (95% CI 1.30-1.56; n = 12), respectively. Similarly, an increased risk of colorectal adenomatous polyps was observed in most of the subgroup meta-analyses. Overall, we found that adiposity and abdominal adiposity significantly increased the risk of colorectal adenomatous polyps in a meta-analysis of epidemiological studies.