The role of cholesterol and statins in Alzheimer's disease.

OBJECTIVE: To briefly discuss the impact of elevated total and low-density-lipoprotein cholesterol levels, as well as the potential relationship of hydroxymethylglutaryl coenzyme A reductase inhibitor (statin) use, on the development of Alzheimer's disease (AD). DATA SOURCES: Biomedical literature was accessed through MEDLINE and International Pharmaceutical Abstracts (1966-June 2003). The authors independently reviewed literature for possible inclusion in this article. STUDY SELECTION AND DATA EXTRACTION: Clinical studies were selected and reviewed from the data sources, with special emphasis on those dealing with statin use and AD. DATA SYNTHESIS: The impact of AD is significant, as it is rapidly becoming one of our country's most debilitating and costly diseases. Data from epidemiologic trials indicate that statins may have some protective effect against the development of AD. These trials also allude to theories regarding possible mechanisms of action for this use, data implicating possible superiority of one statin over another, and their lack in certain populations, specifically the very old elderly population.
CONCLUSIONS: Preliminary evidence suggests that statins may offer a protective effect against the development of AD. However, review of the literature does not lend credence to the use of statins in the general nondemented population without hyperlipidemia. Potential confounding variables have not been considered in the majority of trials. Placebo-controlled clinical trials are ongoing and should yield more definitive results.