Exposure to environmental chemicals and heavy metals, and risk of pancreatic cancer

Samuel O. Antwi, Elizabeth C. Eckert, Corinna V. Sabaque, Emma R. Leof, Kieran M. Hawthorne, William R. Bamlet, Kari G. Chaffee, Ann L. Oberg, Gloria M. Petersen

Exposure to various chemicals and heavy metals has been associated with risk of different cancers; however, data on whether such exposures may increase the risk of pancreatic cancer (PC) are very limited and inconclusive. We examined PC risk with self-reported exposures to chemicals and heavy metals. The design was a clinic-based, case-control study of data collected from 2000 to 2014 at Mayo Clinic in Rochester, Minnesota, USA. Cases were rapidly ascertained patients diagnosed with pancreatic ductal adenocarcinoma (n = 2,092). Controls were cancer-free patients in primary care clinics (n = 2,353), frequency-matched to cases on age, race, sex, and state/region of residence. Cases and controls completed identical risk factor questionnaires, which included yes/no questions about regular exposure to pesticides, asbestos, benzene, chlorinated hydrocarbons, chromium, and nickel. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CI) comparing those who affirmed exposure to each of the chemicals/heavy metals to those who reported no regular exposure, adjusting for potential confounders. Self-reported regular exposure to pesticides was associated with increased odds of PC (OR 1.21, 95 % CI 1.02-1.44). Regular exposure to asbestos (OR 1.54, 95 % CI 1.23-1.92), benzene (OR 1.70, 95 % CI 1.23-2.35), and chlorinated hydrocarbons (OR 1.63, 95 % CI 1.32-2.02) also was associated with higher odds of PC. Chromium and nickel exposures were not significantly associated with PC. These findings add to the limited data suggesting that exposure to pesticides, asbestos, benzene, and chlorinated hydrocarbons may increase PC risk. They further support the importance of implementing strategies that reduce exposure to these substances.