Quantitative association between body mass index and the risk of cancer: A global Meta-analysis of prospective cohort studies.

Numerous studies have suggested that excess body weight is associated with increased cancer risk. To examine this putative association, we performed a systematic review and quantitative meta-analysis of cohort studies reporting body mass index (BMI) and the risk of 23 cancer types. PubMed, Embase, and Web of Science were searched for cohort studies, yielding 325 articles with 1,525,052 cases. Strong positive associations were observed between BMI and endometrial cancer (RR: 1.48), esophageal adenocarcinoma (RR: 1.45), and kidney cancer (RR: 1.20); weaker associations (RR < 1.20) were also found for several other cancer types. Interestingly, we found significant inverse associations between BMI and oral cavity (RR: 0.93), lung (RR: 0.91), premenopausal breast (RR: 0.95), and localized prostate (RR: 0.97) cancers. A male-specific association was found for colorectal cancer (p = 0.023), and a female-specific association was found for cancer in brain (p = 0.025) or kidney (p = 0.035). With respect to geography, the strongest positive association was found for total cancer in North America (p = 0.038). This comprehensive meta-analysis provides epidemiological evidence supporting the association between BMI and cancer risk. These findings can be used to drive public policies and to help guide personalized medicine in order to better manage body weight, thereby reducing the risk of developing obesity-related cancer.