Prospective Analysis of Association Between Use of Statins or Other Lipid-Lowering Agents and Colorectal Cancer Risk

PURPOSE: To determine whether 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) are associated with a decreased risk of colorectal cancer. METHODS: The population included 159,219 postmenopausal women enrolled in the Women's Health Initiative in which 2000 pathologically confirmed cases of colorectal cancer were identified during an average of 10.7 (S.D. 2.9) years. Information on statins was collected at baseline and years 1, 3, 6, and 9. Self- and interviewer-administered questionnaires were used to collect information on other risk factors. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by the use of Cox proportional hazards regression to evaluate the relationship between statin use and risk. Statistical tests were two-sided. RESULTS: Statins were used by 12,030 (7.6%) women at baseline. The annualized colorectal cancer rate was 0.13% among users and 0.12% among nonusers. The multivariable adjusted HR for users versus nonusers was 0.99 (95% confidence interval [CI], 0.83-1.20, p = .95), and 0.79 (95% CI, 0.56-1.11) for users of >= 3 years. In the multivariable adjusted time-dependent model, the HR for lovastatin was 0.62 (95% CI, 0.39-0.99). There was no effect of tumor location, stage or grade. CONCLUSIONS: There was a reduction in colorectal cancer risk associated with lovastatin and a nonsignificant association with longer duration of use. Ann Epidemiol 2012;22:17-27. (C) 2012 Elsevier Inc. All rights reserved.