Amy Millen

University of Buffalo, School of Public Health and Health Professions, Department of Social and Preventative Mendicine

PLCO (Learn more about this study)

2006-0240

Jul 1, 2006

Colorectal Adenoma -Dietary Factors Fruits and Vegetables

Background: Large case-control and longitudinal studies suggest a protective effect of fruit and vegetable intake on colorectal adenoma risk, although a randomized clinical trial showed no protective effect. Objective: To determine if fruit and vegetable intake protects against prevalent colorectal adenoma. Design: In subjects screened for colorectal cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (1993-2001) we compared 3,707 cases with histologically-verified adenoma of the distal large bowel to 34,853 subjects endoscopy-negative for colorectal polyps. Using a food frequency questionnaire, we quantified energy adjusted intake of fruits and vegetables in pyramid servings/day (ps/d). Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression. Results: Risk for distal adenoma was significantly reduced among subjects in high (~5.8 ps/d) versus low (~1.2 ps/d) quintiles of total fruit intake (OR=0.77, 95% CI=0.68, 0.86, ptrend<0.001). Inverse associations between adenoma and total fruit intake were observed regardless of adenoma type or location, and not explained by dietary fiber intake. Total vegetable intake was not associated with reduced risk for adenoma (OR comparing extreme quintiles=0.94, 95% CI=0.84, 1.05, ptrend=0.13), but after removal of potatoes, a modest, albeit not statistically significant reduced risk for adenoma (OR=0.90, 95% CI=0.80, 1.00, ptrend=0.05) was observed. High versus low intake of deep yellow and dark green vegetables was statistically significantly related to decreased risk of adenoma (OR comparing extreme quintiles=0.82, 95% CI=0.73, 0.92, ptrend<0.001 and 0.88, 95% CI=0.79, 0.99, ptrend=0.12, respectively).