Study
PLCO
(Learn more about this study)
Project ID
2008-0037
Initial CDAS Request Approval
Sep 11, 2008
Title
Flavonoid intake and the risk of colorectal carcinogenesis in the PLCO Cancer Screening Trial
Summary
Background: Colorectal cancer is an important public health problem annually leading in the United States to $6.5 billion treatment costs and over 50,0000 deaths. Screening is an effective prevention tool but has limited impact because of below 50% screening rates. Nutrition offers great promise for prevention because nutrition could, according to estimates, prevent 70-80% of all colorectal cancer cases. Flavonoids are a group of bioactive polyphenols that are especially enriched in fruits and vegetable and prevent colorectal carcinogenesis in cell culture and animal studies. Therefore, we propose that high dietary flavonoid and proanthocyanidin intake may inhibit colorectal carcinogenesis in humans. Method: Intakes of total flavonoids, 6 major flavonoid subgroups, 29 individual flavonoids, proanthocyanidins, 6 proanthocyanidin subgroups, and flavonoid-rich foods will be estimated from the baseline and follow-up dietary questionnaires of the control and intervention arm in the PLCO Cancer Screening Trial using the 2007 USDA Flavonoid database and the 2004 Proanthocyanidin database for foods. Hazard ratios and 95% confidence intervals of incident primary colorectal cancer will be estimated within quintiles of energy-adjusted flavonoid intakes at baseline in the control arm. Odds ratios and 95% confidence intervals of adenoma occurrence (any, advanced, multiple) will be estimated within quartiles of energy-adjusted flavonoid intakes at baseline and follow-up in the intervention arm. Odds ratios and 95% confidence intervals of adenoma recurrence (any, advanced, multiple) will be estimated within quartiles of energy-adjusted flavonoid intakes at baseline and follow-up in the intervention arm. Significance: The current study will grant sufficient power to examine prospectively the association between intakes of total, subgroups, and individual flavonoids and proanthocyanidins and incident colorectal cancer, adenoma occurrence, and adenoma recurrence and, combined with the results for other cohorts (PPT, NIH-AARP), would provide evidence for cancer-protective effects of flavonoids and/or proanthocyanidins that could be followed up by nutrition intervention studies.
Aims
1. Estimate the intakes of total flavonoids, the 6 major flavonoid subgroups, 29 individual flavonoids, proanthocyanidins, 6 proanthocyanidin subgroups, and flavonoid-rich foods from the baseline and the follow-up questionnaires in the PLCO Cancer Screening Trial. 2. Examine the association between dietary intakes of total flavonoids, the six major flavonoid subgroups, 29 individual flavonoids, proanthocyanidins, six proanthocyanidin subgroups, and flavonoid-rich foods and development of colorectal cancer in the control arm of the PLCO Cancer Screening Trial. 3. Examine the association between dietary intakes of total flavonoids, the 6 major flavonoid subgroups, 29 individual flavonoids, proanthocyanidins, 6 proanthocyanidin subgroups, and flavonoid-rich foods and development of colorectal adenomas in the intervention arm of the PLCO Cancer Screening Trial. 4. Examine the association between dietary intakes of total flavonoids, the 6 major flavonoid subgroups, 29 individual flavonoids, proanthocyanidins, 6 proanthocyanidin subgroups, and flavonoid-rich foods and development of colorectal adenoma recurrence (any, advanced, multiple) in the intervention arm of the PLCO Cancer Screening Trial.
Collaborators
Kevin Dodd (Biometry Research Group, DCP, NCI)
Wen-Yi Huang (OEEB, DCEG, NCI)
Rachael Stolzenberg-Solomon (NEB, DCEG, NCI)
Robert Schoen (University of Pittsburg, Pittsburg)
Amy Subar (Applied Research Program, DCCPS, NCI)
