MICRONUTRIENTS AND THE RISK OF COLORECTAL ADENOMAS

Recent studies suggest that micronutrients, especially folate, calcium , iron, and antioxidant vitamins, affect the risk of colorectal neopla sia. The objective of this case-control study was to examine the assoc iation between these micronutrients and the risk of colorectal adenoma s. The study was based on 236 cases with adenomatous polyps or cancer and 409 controls, all colonoscopy patients at University of North Caro lina Hospitals between July 1988 and March 1991. After colonoscopy, su bjects were interviewed using a semiquantitative food frequency questi onnaire, and average daily nutrient intakes were calculated. Sex-speci fic odds ratios relative to the lowest quartile of intake for each mic ronutrient were determined using unconditional logistic regression whi le adjusting for a number of potential confounders. In women, folate, iron, and vitamin C were inversely related to the risk of adenomas. Fo late appeared to be most protective, with women in the highest quartil e only 40% as likely to develop adenomas compared with women in the lo west (odds ratio = 0.39, 95% confidence interval 0.15-1.01). In men, g reater vitamin E and calcium intakes were associated with reduced risk of adenomas, with vitamin E showing the strongest inverse association . Men in the highest vitamin E quartile had a risk of 0.35 (95% confid ence interval 0.14-0.92) relative to those in the lowest. These study results support previous research findings that selected micronutrient s protect against colorectal neoplasia.