Lovastatin lowers the risk of breast cancer: a population-based study using logistic regression with a random effects model

Background: Laboratory studies have demonstrated statin-induced apoptosis of cancer cells, including breast cancer cells, and evidence is accumulating on the mechanism of statin-induced apoptosis. However, despite numerous epidemiological studies, no consensus has been reached regarding the relationship between statin use and breast cancer risk. Methods: This retrospective case–control study enrolled 4332 breast cancer patients and 21,660 age-matched controls registered in the National Health Insurance program of Taiwan, which covers approximately 99% of the population. The study cases were women for whom a diagnosis of breast cancer (ICD-9-CM code 174.X) had been recorded in LHID2005 between January 1, 2004 and December 31, 2010. A logistic regression model was adjusted for potential confounding factors, including the level of urbanization, and the Charlson Comorbidity Index was applied to assess potential comorbidities. We also considered possible bias caused by random urbanization, because nutrition and lifestyle factors are related to breast cancer incidence. Results: Our results showed that lovastatin was associated with a lower risk of breast cancer (adjusted OR 0.596; 95% CI 0.497–0.714; p < 0.001), and atorvastatin exhibited a protective tendency against breast cancer (adjusted OR 0.887; 95% CI 0.776–1.013; p < 0.077). Conclusions: Although no consensus has been established regarding the relationship between statin use and breast cancer risk, our study indicated that lovastatin is a potential chemopreventive agent against breast cancer. Further detailed research is warranted.