Body Mass Index Trajectories Across the Adult Life Course and Pancreatic Cancer Risk

Body mass index (BMI) during adulthood has been associated with pancreatic ductal adenocarcinoma (PDAC), however, patterns of body size across the adult life course have not been studied extensively. We comprehensively evaluated the association between adiposity across adulthood and PDAC.We conducted a prospective analysis of 269 480 (162 735 males, 106 745 females) National Institutes of Health-AARP Diet and Health Study participants, aged 50-71 years (1995-1996) who self-reported height and weight history. Participants were followed through December 31, 2011. We examined associations between BMI (kg/m2) at ages 18, 35, 50, and 50-71 (baseline) years, their trajectories determined from latent-class trajectory modeling, and incident PDAC. Cox proportional hazard models were used to calculate multivariable adjusted hazards ratios (HRs) and 95% confidence intervals (CIs).During up to 15.2 years of follow-up, 3092 (2020 males, 1072 females) patients with incident PDAC were identified. BMI at all 4 ages were statistically significantly associated with increased PDAC (per 5-unit increase, HR = 1.09-1.13) with higher magnitude associations in males than females at ages 35 years and older (Pinteraction < .05). Four BMI trajectories were created. Compared with normal-weight maintainers, normal-to-overweight, normal-to-obese class I, and overweight-to-obese class III trajectories had hazard ratios of 1.15 (95% CI = 1.06 to 1.25), 1.39 (95% CI = 1.25 to 1.54), and 1.48 (95% CI = 1.18 to 1.87), respectively (Pinteraction by sex = .07).High BMI and BMI trajectories that result in overweight or obesity during adulthood were positively associated with PDAC, with stronger associations among those with early onset adiposity and those with male sex. Avoidance of excess body weight throughout the adult life course may prevent PDAC.