Abstract
BACKGROUND: Oxidative stress causes damage to many components of human cells (ie, proteins, lipids, and DNA) and is involved in carcinogenesis. Nutrients with antioxidant properties may protect against oxidative stress. In this study, the authors examined the intake of antioxidants from diet and supplements in relation to pancreatic cancer risk among participants of the Vitamins and Lifestyle (VITAL) Study. METHODS: The participants included 77,446 men and women ages 50 to 76 years who were residents of western Washington State and who completed a baseline questionnaire between 2000 and 2002. Participants reported usual diet over the past year and use of supplements over the past 10 years in addition to demographic and lifestyle factors. During a median follow-up of 7.1 years, 184 participants developed pancreatic adenocarcinoma. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for 7 antioxidants: β-carotene, lutein plus zeaxanthin, lycopene, vitamin C, vitamin E, selenium, and zinc. RESULTS: An inverse association was observed between dietary selenium and the risk of pancreatic cancer (medium vs low intake: HR, 0.58; 95% CI, 0.35-0.94; high vs low intake: HR, 0.44; 95% CI, 0.23-0.85; Ptrend = .01); however, when supplemental and dietary exposures were combined, the association was no longer statistically significant. CONCLUSIONS: Dietary selenium intake was inversely associated with the risk of pancreatic cancer, and the observed association was attenuated by selenium supplementation.