Body mass index increases risk for colorectal adenomas based on meta-analysis

Abstract

Background & Aims: There have been inconsistent results published about the relationship between excess body weight, expressed as increased body mass index (BMI), and risk of colorectal adenoma (CRA). We conducted a meta-analysis to explore this relationship. We focused on whether the relationship varied based on the sex of the study subjects, study design, features of the polyps, or potential confounders, including alcohol use, nonsteroidal anti-inflammatory drug use, smoking, and exercise. Methods: We identified studies by performing a literature search of Medline, EMBASE, and ISI Web of Science through July 31, 2011, and by searching the reference lists of pertinent articles. We analyzed 36 independent studies, which included 29,860 incident cases of CRA. Summary relative risks with their 95% confidence intervals (CIs) were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and I2 analyses. Results: Overall, a 5-unit increase in BMI (calculated as kg/m2) increased the risk for CRA (summary relative risk = 1.19; 95% CI: 1.131.26), although there was a high level of heterogeneity among studies (Pheterogeneity