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 lifetime 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.