Flavonoids are the most common of the plant polyphenolics and are obtained from foods such as tea, citrus and other fruits. Laboratory and animal studies suggest that through anti-oxidant properties dietary flavonoids may reduce the risk of pancreatic cancer, and the few previous epidemiologic studies on flavonoid intake and pancreatic cancer risk have shown protective associations for specific types of flavonoids. We examined the association between total flavonoid intake, six flavonoid subgroups, flavonoid-rich foods and development of exocrine pancreatic cancer among 537,104 participants in the NIH-AARP Diet and Health Study with complete dietary data. Men and women aged 50 to 71 years completed a self-administered food frequency questionnaire at baseline (1995-1996) that ascertained diet and other lifestyle information. During follow-up through 2006 (median 10.6 years, max 11.2 years), 2379 incident pancreatic cancer cases were identified. Flavonoid intake was estimated from two databases developed from the USDA Nutrient Data laboratory. The distribution of flavonoid intake differed by sex (mean female intake 216 mg/day, range 0.41-9456; mean male intake 153 mg/day, range 0.95-6561); therefore, quintiles were based on sex specific cut-points. We used Cox proportional hazard models with age as the underlying time metric to calculate hazard ratios (HR) for pancreatic cancer. Models were adjusted for sex, smoking, diabetes, body mass index, alcohol use, and saturated fat and red meat intake. We found no association between total flavonoid intake (hazard ratio (HR)=1.09; 95% confidence interval (CI) 0.96-1.24) or the six flavonoid subgroups and risk of pancreatic cancer. Although there was no significant interaction by sex or smoking (p-interaction > 0.10), in stratified analyses we observed significant increased risks for total flavonoid intake among current smokers (Q5 versus Q1 HR=1.45, 95% CI 1.12-1.88, p-trend=0.002), while no such associations were evident among never (HR=1.01, 95% CI 1.00-1.03) or former smokers (HR=0.99, 95% CI 0.98-1.01). Among smokers flavonol and isoflavone intakes were positively associated with pancreatic cancer comparing extreme quintiles, with HRs =1.38 (95% CI 1.05-1.82, p trend=0.019) and 1.39 (95% CI 1.03-1.86, p trend=0.022) respectively. It is possible that exposures correlated to smoking but not accounted for in our analysis explain the observed associations. Our results do not support the hypothesis that flavonoid intake plays a protective role in pancreatic cancer carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 625. doi:1538-7445.AM2012-625