Nitric oxide-releasing medications and colorectal cancer risk: The Framingham study

Background: The major sources of human exposure to nitric oxide (NO) are medicinal nitrovasodilators that release NO into the vasculature. Experimental NO-donating aspirin also releases NO in a similar manner, and is a potent in vitro inhibitor of colon cancer. Materials and Methods: The effects of nitrovasodilators on the risk of colorectal cancer was studied in the Framingham Heart and Offspring studies among 145 cases of colorectal cancer and 433 matched controls. Results: Eleven percent of controls reported currently using nitroglycerine or other long-lasting nitrates. In conditional logistic regression analysis, the odds ratio (OR) for colorectal cancer associated with nitrovasodilator use was 1.2 (95% confidence interval [CI] 0.6, 2.2). In subgroup analysis, the OR was 0.7 (95% CI 0.2, 2.2) in aspirin users and 1.6 (95% CI 0.8, 3.2) in subjects not taking aspirin. Conclusion: These data indicate that NO does not change the risk of colorectal cancer.