Body mass index, effect modifiers, and risk of pancreatic cancer: a pooled study of seven prospective cohorts

Abstract
Objective To investigate whether the positive association of body mass index (BMI, kg/m2) with risk of pancreatic cancer is modified by age, sex, smoking status, physical activity, and history of diabetes. Methods In a pooled analysis of primary data of seven prospective cohorts including 458,070 men and 485,689 women, we identified 2,454 patients with incident pancreatic cancer during an average 6.9 years of follow-up. Cox proportional hazard regression models were used in data analysis. Results In a random-effects meta-analysis, for every 5 kg/m2 increment in BMI, the summary relative risk (RR) was 1.06 (95% confidence interval (CI) 0.99–1.13) for men and 1.12 (95% CI 1.05–1.19) for women. The aggregate analysis showed that compared with normal weight (BMI: 18.5 to 2 increment in BMI was associated with an increased risk of pancreatic cancer among never and former smokers, but not among current smokers (P-interaction = 0.08). Conclusion The present evidence suggests that a high BMI is an independent risk factor of pancreatic cancer.