Trans-fatty acids and colon cancer

Trans fatty acids have been hypothesized to be carcinogenic, although there are limited data in humans testing this hypothesis. In this study, we exam ine the association between trans fatty acids and colon cancer using data f rom a case (n = 1,993)-control (n = 2,410) study conducted in Utah, Norther n California, and Minnesota. Dietary data were collected using a detailed d iet history questionnaire, and nutrient values were generated from the Nutr ition Coordinating Center nutrient database. After adjustment for other var iables, including age at diagnosis, body size, physical activity, aspirin a nd/or nonsteroidal anti-inflammatory drug (referred to collectively as NSAI Ds) use, energy intake, and dietary fiber and calcium, we found a weak asso ciation in women [odds ratio (OR)=1.5, 95% confidence interval (CI)=1.1-2.0 ] but not in men (OR=1.2, 95% CI=0.9-1.7); no increased risk was observed f or the cis form of the fatty acids. For men and women, slightly stronger as sociations were observed in those greater than or equal to 67 years of age (OR=1.4, 95% CI=0.9-2.1 for men; OR=1.6, 95% CI=1.0-2.4 for women). Those w ho did not use NSAIDs were at a 50% greater risk of developing colon cancer when they consumed high levels of trans-fatty acids. Women who were estrog en negative, i.e., postmenopausal not taking hormone replace therapy, had a twofold increase in risk from high levels of trans fatty acids in the diet , while women who were estrogen positive did not experience an increased ri sk of colon cancer, regardless of level of trans fatty acids consumed. We b elieve that these data have important public health implications. It seems prudent to avoid consuming partially hydrogenated fats, since no increased risk was observed for the cis form of fatty acids, while suggestions of inc reased risk from trans fatty acids exist for subsets of the population.