• Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University-Purdue University, Indianapolis, Indiana, USA.
• Department of Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health and School of Medicine, Indiana University-Purdue University, Indianapolis, Indiana, USA.
• Department of Nutrition and Dietetics, School of Health and Human Sciences, Indiana University-Purdue University, Indianapolis, Indiana, USA.

OBJECTIVE: It remains elusive whether prediagnostic BMI trajectory is associated with pancreatic cancer.

METHODS: This study investigated this question among 145,489 participants who gave rise to 696 incident cases of pancreatic cancer over a median follow-up of 12 years in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. At baseline, participants were asked to recall their weight at ages 20, 50, and 55 to 74 years (at enrollment), as well as their height.

RESULTS: At age 50 years, people with obesity had a significantly increased risk of pancreatic cancer compared with those with a normal weight after adjustment for confounders (hazard ratio [95% CI]: 1.27 [1.01-1.60]). Individuals who had overweight at age 20 years experienced a marginally significant elevated risk of pancreatic cancer (hazard ratio [95% CI]: 1.22 [0.99-1.50]). Compared with individuals who maintained a steady normal weight during follow-up, no significantly altered risk of pancreatic cancer was observed for those whose weight status changed from normal weight to overweight, from normal weight to obesity, and from overweight to obesity.

CONCLUSIONS: The present study revealed that prediagnostic adulthood BMI trajectory was not associated with pancreatic cancer risk, but overweight at young adulthood and obesity at middle adulthood may confer an elevated risk of this malignancy.