Dietary total antioxidant capacity and pancreatic cancer risk: an Italian case-control study

Background: Pancreatic cancer is one of the leading causes of cancer mortality. Diet may be associated with pancreatic cancer, but it is unknown whether specific dietary components contribute to its risk. The potential differential role of dietary antioxidants warrants further investigation. Methods: We analysed data from a case-control study of 326 pancreatic cancer cases and 652 controls conducted between 1991 and 2008 in Northern Italy. Subjects' usual diet was assessed through a validated and reproducible food frequency questionnaire. Using this information and an Italian food composition database, we calculated three indices of dietary total antioxidant capacity (TAC): Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric-reducing antioxidant power (FRAP). We estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for pancreatic cancer using multiple logistic regression models conditioned on study centre, sex and age, and adjusted for major known pancreatic cancer risk factors. Results: Significant inverse associations were found for the highest tertile of TAC compared with the lowest tertile for both TEAC and FRAP. The ORs were 0.61 (95% CI 0.39-0.94, P-value for trend 0.03) and 0.63 (95% CI 0.41-0.99, P-value for trend 0.05), respectively. Total radical-trapping antioxidant parameter was inversely, but not significantly, associated with pancreatic cancer risk, with an OR of 0.78 (95% CI 0.49-1.24, P-value for trend 0.27). Conclusions: Diet high in TAC, as measured by TEAC and FRAP, is inversely associated with pancreatic cancer risk.