Purpose: Pancreatic cancer has the highest fatality rate of all cancers. Adulthood obesity is an established risk factor for pancreatic cancer; however, life-course obesity is not well understood. The aim of this study was to evaluate the association between body mass index (BMI) trajectories throughout the life-course and pancreatic cancer risk.
Methods: A population-based case-control study was conducted (2011-2013) in Ontario, Canada. Cases were recruited from the Ontario pancreas cancer study (n = 310) and controls from the Ontario cancer risk factor study (n = 1258). Questionnaires captured self-reported height and weight at four timepoints (adolescence, 20 s, 30-40 s, 50-60 s). BMI trajectories were identified using latent class growth mixture modeling. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from multivariable logistic regression.
Results: Five BMI trajectories were identified: stable-normal weight (38.9%), progressively overweight (42.2%), persistent overweight (12.6%), progressive obesity (4.2%), and persistent obesity (2.1%). The persistent overweight (OR = 1.55; 95% CI 1.02, 2.39) and progressive obesity trajectories (OR = 1.49; 95% CI 0.77, 2.87) compared to stable-normal weight were associated with increased odds of pancreatic cancer. When BMI was evaluated separately the strongest associations with pancreatic cancer emerged in young and mid-adulthood.
Conclusion: BMI trajectories characterized by overweight in early adulthood were associated with increased pancreatic cancer risk suggesting a life-course approach to disease risk.
Keywords: Body mass index; Life-course; Obesity; Pancreatic cancer; Trajectory.