Lifetime adiposity and risk of pancreatic cancer in the NIH-AARP Diet and Health Study cohort

Background: The association of excess body weight across a life-time with pancreatic cancer has not been examined extensively. Objective: We determined the association for body mass index (BMI) at different ages and adiposity duration and gain with incident pancreatic adenocarcinoma in the NIH-AARP Diet and Health Study cohort. Design: Participants aged 50-71 y completed questionnaires at baseline (1995-1996) and 6 months later that queried height and weight history. We calculated HRs and 95% CIs by using Cox proportional hazards models adjusted for age, smoking, sex, and intakes of energy and total fat. Results: Over an average follow-up of 10.5 y, 1206 and 2122 pancreatic cancer cases were identified in the subcohort who completed the second questionnaire (n = 273,975) and the baseline cohort (n = 501,698), respectively. Compared with normal weight, overweight or obesity at ages 18, 35, 50, or >50 y (baseline BMI) was significantly associated with pancreatic cancer, with HRs ranging from 1.15 to 1.53. A longer duration of BMI (in kg/m(2)) >25.0 was significantly associated with pancreatic cancer (overall HR per 10-y increment of duration: 1.06; 95% CI: 1.02, 1.09), with individuals who reported diabetes having the greatest risk (HR per 10-y increment of duration: 1.18; 95% CI: 1.05, 1.32; P-interaction = 0.01) and rates. A substantial gain in adiposity (>10 kg/m(2)) after age 50 y was significantly associated with increased pancreatic cancer risk. The etiologic fraction of pancreatic cancer explained by adiposity at any age was 14% overall and 21% in never smokers. Conclusion: Overweight and obesity at any age are associated with increased pancreatic cancer.