• Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD.

Environmental exposures such as cadmium might be contributing to the increasing incidence of pancreatic cancer. Few prospective studies have examined the association between trace elements and pancreatic ductal adenocarcinoma (PDAC). We conducted a nested case-control study in participants aged 55-74 years at baseline from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort to examine the association between 12 trace elements measured in predignostic whole blood and PDAC. From May 1998 through December 2014, 318 incident PDAC cases were identified during follow-up to 16.7 years. Two controls (n = 636) alive when each case was diagnosed were selected and matched by age (+ 5 years), sex, calendar date of blood draw (2-month blocks), and race and ethnic group. We used multivariable adjusted conditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). Cadmium and molybdenum were associated with PDAC [highest compared to lowest quintile: cadmium OR=1.81; 95% CI: 01.12, 2.95; P-trend = 0.03; molybdenum OR=0.50; 95% CI: 0.32, 0.80; P-trend = 0.02]. The inverse molybdenum association was only observed among ever smokers (OR=0.31, 95% CI: 0.17, 0.58, P-trend= 0.003, P-interaction=0.03) with no association in never smokers. Lead, arsenic, and other trace elements were not associated with PDAC. Our results support that increasing prediagnostic whole blood cadmium increases while molybdenum reduces PDAC risk.