Obesity and incident gastrointestinal cancers: overall body size or central obesity measures, which factor matters?

BMI does not reflect the location or amount of body fat. We aimed to investigate the role of general and central obesity measures in the prediction of incident gastrointestinal cancers. In this analysis of the Golestan Cohort Study, we included 47 586 cancer-free individuals followed for 12.3 years (IQR: 10.5-13.2). We investigated the association of obesity measures including BMI, waist circumference and waist-to-hip ratio (WHR) at enrollment and the incidence of esophageal, gastric, colorectal and pancreatic cancers. Cox proportional hazard models were used to estimate the association between covariates and gastrointestinal cancer risk. We observed no significant associations between obesity measures and incidence of the above-mentioned gastrointestinal cancers in men. In women, BMI, waist circumference and WHR were associated with significant reductions in the risk of esophageal squamous cell carcinoma (ESCC): hazard ratio (HR): 0.67 [95% confidence interval (CI): 0.56-0.81], HR: 0.71 (95% CI: 0.60-0.84) and HR: 0.80 (95% CI: 0.68- 0.94), respectively. In addition, WHR was associated with significantly increased risks for colorectal cancer (HR: 1.39, 95% CI: 1.08-1.78) and gastric cancer (HR: 1.24, 95% CI: 1.01-1.51) in women. In this study, statistically significant associations between obesity measures and incident esophageal, gastric and colorectal cancers were seen in women.