Statin use and the incidence of dementia in the elderly: a nation-wide data survey

Abstract

Background: The objective of this study was to examine the association between the use of statins and the risk for new onset dementia (excluding vascular dementia) in an elderly population. Methods: The analysis included a random sample of 1,000,000 individuals covered by the National Health Insurance. Patients >65 years of age without a history of dementia in 1997 and 1998 were identified. New diagnoses of dementia including pre-senile and senile dementia were determined for elderly subjects. Cox regression analysis was used to evaluate the adjusted hazard ratio (HR) for all patients and subgroups. The study subjects were divided into tertiles according to mean daily dosage and total dosage of each statin and mean equivalent and total equivalent doses. Results: A total of 5516 new diagnoses of dementia occurred among 57669 patients during approximately 4.5 years of follow-up. The adjusted HRs for dementia were significantly inversely associated with increased total or daily equivalent statin dosage (total equivalent statin exposure: HRs = 0.773, 0.632, 0.332 from Q1 to Q3 vs. control, p < 0.001 for trend; mean equivalent daily dosage: HRs = 0.622, 0.697, 0.419 from Q1 to Q3 vs. control, p < 0.001 for trend). The protective effect of statins remained robust in different age, gender, cardiovascular risk subgroups with strong statistical trends. High potency statins such as atorvastatin and rosuvastatin showed a significant inverse association with developing dementia in a dose-response manner, whereas high mean daily dosage of lovastain was positively associated with the development of dementia. Conclusions: Independent of traditional risk factors, newly diagnosed cases of dementia decreased in elderly patients who had received statins in either higher daily or total dosage. Highly potent statins seemed to have an even stronger advantage in the prevention of dementia.