Mia Gaudet

American Cancer Society

PLCO (Learn more about this study)

2006-0100

Jul 1, 2006

Colorectal Adenoma -Dietary Factors Dietary Supplements

Background: Vitamin supplement use may protect from colorectal cancer by reducing the occurrence of nonmalignant cancer precursor polyps in the colon. Methods: In a large multi-center cancer screening trial, we compared vitamin supplement use among 4,273 participants with colorectal polyps of the distal colon (descending colon, sigmoid colon, and rectum) with use patterns in 33,971 sigmoidoscopy negative controls. Cases had either a hyperplastic polyp (n=1,479), adenoma (n=2,286), or both types of polyps (n=495). Assessment of vitamin supplement use was based on questions about use, duration, and dosage of nine multiple and single vitamin supplements. Results: Compared with non-users, daily use of one or more pills of one-a-day type supplements, the most commonly used supplement in the study population, was associated with a reduced risk for adenomas (OR=0.91, 95% CI 0.82 1.00; p-trend= 0.02), hyperplastic polyps (OR=0.88, 95% CI 0.78 0.99; p-trend= 0.01), and both poly types (OR=0.73, 95% CI 0.59 0.90; p-trend<0.01). One or more pills per day of vitamin C preparations was associated with the lowest odds for both poly types (OR=0.76, 95% CI 0.54-1.07; p-trend=0.04) and for hyperplastic polyps (OR=0.82, 95% CI 0.68-0.99; p-trend=0.01), but not associated with adenomatous polyps (OR=0.98, 95% CI 0.84-1.14; p-trend=0.38). Conclusion: Vitamin supplements may be associated with colorectal polyp formation, with more pronounced effects for hyperplastic than adenomatous polyps.