Intake of dietary flavonoids and risk of epithelial ovarian cancer

• Published in: The American journal of clinical nutrition Vol. 100; no. 5; pp. 1344 - 1351
• Main Authors: Cassidy, Aedín, Huang, Tianyi, Rice, Megan S, Rimm, Eric B, Tworoger, Shelley S
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Nutrition 01.11.2014; American Society for Clinical Nutrition, Inc; American Society for Nutrition
• Subjects: Adult; animal ovaries; anthocyanins; Anthocyanins - administration & dosage; Black tea; Cancer; Carcinoma, Ovarian Epithelial; clinical nutrition; Correlation analysis; Diet; Female; flavanols; flavanones; Flavanones - administration & dosage; Flavones - administration & dosage; Flavonoids; Flavonoids - administration & dosage; flavonols; Flavonols - administration & dosage; Follow-Up Studies; food frequency questionnaires; food intake; Health risks; Heterogeneity; Humans; Middle Aged; Multivariate Analysis; Neoplasms, Glandular and Epithelial - prevention & control; nurses; Nutrition; Ovarian cancer; ovarian neoplasms; Ovarian Neoplasms - prevention & control; Proportional Hazards Models; Prospective Studies; risk; Risk assessment; Risk Factors; Surveys and Questionnaires; Tea; Tumors
• ISSN: 0002-9165; 1938-3207; 1938-3207
• DOI: 10.3945/ajcn.114.088708

Background: The impact of different dietary flavonoid subclasses on risk of epithelial ovarian cancer is unclear, with limited previous studies that have focused on only a few compounds.Objective: We prospectively examined associations between habitual flavonoid subclass intake and risk of ovarian cancer.Design: We followed 171,940 Nurses’ Health Study and Nurses’ Health Study II participants to examine associations between intakes of total flavonoids and their subclasses (flavanones, flavonols, anthocyanins, flavan-3-ols, flavones, and polymeric flavonoids) and risk of ovarian cancer by using Cox proportional hazards models. Intake was calculated from validated food-frequency questionnaires collected every 4 y.Results: During 16–22 y of follow-up, 723 cases of ovarian cancer were confirmed through medical records. In pooled multivariate-adjusted analyses, total flavonoids were not statistically significantly associated with ovarian cancer risk (HR for the top compared with the bottom quintile: 0.85; 95% CI: 0.66, 1.09; P-trend = 0.17). However, participants in the highest quintiles of flavonol and flavanone intakes had modestly lower risk of ovarian cancer than did participants in the lowest quintile, although the P-trend was not significant [HRs: 0.76 (95% CI: 0.59, 0.98; P-trend = 0.11) and 0.79 (95% CI: 0.63,1.00; P-trend = 0.26), respectively]. The association for flavanone intake was stronger for serous invasive and poorly differentiated tumors (comparable HR: 0.68; 95% CI: 0.50, 0.92; P-heterogeneity = 0.10, P-trend = 0.07) compared with nonserous and less-aggressive tumors. Intakes of other subclasses were not significantly associated with risk. In food-based analyses used to compare subjects who consumed >1 and ≤1 cup black tea/d, the HR was 0.68 (95% CI: 0.51, 0.90; P < 0.01).Conclusions: Higher intakes of flavonols and flavanones as well as black tea consumption may be associated with lower risk of ovarian cancer. Additional prospective studies are required to confirm these findings.