The newly published results of a major long-term study (J Neurol NeuroSurg Psychiatry Oct. 17, 2008) now provides powerful new evidence that taking statins substantially reduces the risk of alzheimer’s disease (AD).  In this comprehensive study, researchers in The Netherlands found that older men and women who took statin drugs during the multi-year study had a 43% lower risk of AD. No such reduction in AD risk was found for non-statin cholesterol lowering medication.

The study was part of the Rotterdam Study, a highly respected long term prospective study of factors that determine the occurrence of common diseases of the elderly, such as heart disease and Alzheimer’s disease. Researchers followed 6,992 men and women recruited at age 55 years or older from baseline (1990-1993) until January 2005 for incident AD. During this period, participants were screened periodically for signs of dementia and those with suspected cognitive decline were referred for exhaustive in-depth evaluation for dementia and AD diagnosis. They were also continuously monitored for incident dementia through access to medical records databases. The researchers had complete access to the participants’ prescription medication records, including statins, thus eliminating a potential source of error compared to earlier studies that relied on self-reported drug use.

The 47% reduction in AD risk for people taking statins was similar in size to the positive effect for statins found in some earlier large scale observational or prospective studies: 67% reduction in the risk of AD (Current Alzheimer Research 2008; 5: 416-421); 48% reduction in risk of dementia or cognitive impairment for statin users (Neurology 2008; 71; 344-350); 74% unadjusted lower risk of AD for statin users (Arch Neurol 2002; 59: 223-227); 69.6% lower prevalence of AD for statin users (Arch Neurol 2000; 57: 1439-1443); 71% lower relative risk of AD for statin users (Lancet 2000; 356:1627-1631).

Statins are widely used cholesterol-lowering drugs with a well-established track record of safety. They have an estimated global market over $25 billion and represent a potential new way of treating or preventing AD. AD is the leading cause of dementia in the elderly, afflicting an estimated 4.5 million people in the U.S.