Prediagnosis diabetes, life-course body mass index and physical activity, and pancreatic cancer survival in older adults.

[BACKGROUND] Diabetes and excess body weight are established risk factors for pancreatic ductal adenocarcinoma (PDAC); however, few studies have evaluated their association with PDAC survival. No studies have examined prediagnosis body size and physical activity across the adult life course and their impact on PDAC survival.

[METHODS] We evaluated survival by prediagnosis self-reported diabetes and adult life course body mass index (BMI) and leisure-time physical activity from late adolescence to older age (eg, ≥50 years). We determined trajectories for BMI and leisure-time physical activity using latent class modeling. We included 2522 participants diagnosed with PDAC in the National Institutes of Health-AARP cohort between 1996 and 2018. Vital status was followed through December 31, 2019. We calculated hazard ratios (HRs) and 95% CIs for PDAC survival using multivariable Cox proportional hazard models. Significance tests were 2 sided.

[RESULTS] Diabetes (vs without diabetes) was associated with reduced PDAC survival (HR = 1.36, 95% CI = 1.17 to 1.59), with similar associations by sex. Body mass index and leisure-time physical activity and their trajectories were not associated with PDAC survival. Among patients with unknown cancer stage (n = 1385), compared with low to normal BMI (≥18.5 to <22.5), obesity at age 18 years (HR = 1.56, 95% CI = 1.09 to 2.22) and high normal, overweight, and obese BMI at ages 51 to 70 years (HR = 1.33 to 1.56) were associated with reduced PDAC survival.

[CONCLUSIONS] Prediagnosis diabetes was associated with reduced PDAC survival. Life-course BMI and leisure-time physical activity were not associated with PDAC survival overall. Higher early-adulthood and older-adulthood BMIs were associated with poorer survival among patients with unstaged disease; however, stage is an important determinant of survival that we were unable to control for in this group.