Abstract 4820: Habitual intake of total flavonoids and flavonoid subclasses and risk of colorectal cancer in men and women.

Abstract

Abstract Background: Flavonoids inhibit the growth of colon cancer cells in vitro. In a recent randomized controlled trial, the Polyp Prevention Trial, a higher intake of one sub-class, flavonols, was significantly associated with a 76% reduced risk of recurrent advanced adenoma. Cohort studies that have examined the association between flavonoid intake and risk of colorectal cancer (CRC) have yielded inconsistent results, but most previous studies only evaluated habitual intake of a limited number of subclasses and there is growing evidence for differential effects depending on subtle difference in structure between the sub-classes Objective: To examine whether higher habitual dietary intake of total flavonoids and their subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones and polymers) are associated with lower risk of CRC. Methods: Using data from validated food frequency questionnaires administered every four years and an updated USDA flavonoid food composition database flavonoid intakes were calculated for 73,666 participants from the Nurses’ Health Study I, and for 32,059 participants from the Health Professionals Follow-up Study. Results: During 16 years of follow-up, 1,405 colorectal cancer cases (652 in men, 753 in women) were identified. Intakes of total flavonoids and subclasses were not associated with risk of CRC (hazard ratios (95% confidence interval) multivariable adjusted for age, smoking before age 30, family history of colorectal cancer, history of endoscopy, aspirin use, body mass index, physical activity, postmenopausal hormone use in women, alcohol consumption, intake of total energy, calcium and vitamin D; highest vs. lowest quintile: total flavonoids, men: 0.97 (0.75-1.26), women: 1.00 (0.80-1.26); flavonols, men: 0.98 (0.76-1.26), women: 1.21 (0.96-1.52); flavones, men: 0.86 (0.67-1.11), women: 0.90 (0.72-1.13); flavanones, men: 0.98 (0.75-1.28), women: 1.00 (0.80-1.26); flavan-3-ols, men: 1.00 (0.78-1.29), women: 0.96 (0.76-1.21); anthocyanins, men: 0.89 (0.69-1.15), women: 1.25 (0.98-1.60); polymers, men: 0.92 (0.71-1.18), women: 0.88 (0.69-1.11)). Conclusion: Our findings do not provide support for the hypothesis that a higher intake of flavonoids or any specific sub-class decrease risk of CRC. Citation Format: Katharina Nimptsch, Xuehong Zhang, Edward Giovannucci, Aedin Cassidy, Éilis J. O'Reilly, Tobias Pischon, Eric B. Rimm, Jennifer Lin, Walter C. Willett, Charles S. Fuchs, Kana Wu. Habitual intake of total flavonoids and flavonoid subclasses and risk of colorectal cancer in men and women. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4820. doi:10.1158/1538-7445.AM2013-4820