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Could cholesterol-lowering drugs reduce the risk of developing Alzheimer’s disease?

Maybe they can, but it’s too soon to be sure.

(April 2001)

Two articles in the Fall of 2000 suggest that those taking cholesterol-lowering drugs have a 60 to 70 percent reduced risk of Alzheimer's disease. If true, that would be extraordinary. One study involved three hospitals in the United States and compared men and women receiving powerful cholesterol-lowering drugs called statins (such as Pravachol, Lipitor, etc) with other groups of hospitalized patients and found that those on statins much less frequently carried a diagnosis of probable Alzheimer's. The other study, based on data collected in the United Kingdom, compared 284 men and women ages 50 to 89 years with a diagnosis of dementia with 1,080 controls and also found those on statins were less likely to have a diagnosis of dementia.

The authors of the latter study concluded that their study "suggests that the use of statins could substantially reduce the risk of dementia in the elderly".

Commentary: These are preliminary studies that could be correct, but there are major methodologic problems. In the UK study, there was no distinction made between Alzheimer's and other forms of dementia. In the American study, there were substantial differences among the three hospitals studied and, inexplicably, there was no reduced risk among those taking one of the newest statins, a finding that makes no sense because all the statins act similarly. One possible explanation is that there was shorter duration of exposure to the newer statin, and that the results would be similar to other statins if the individual were treated for a longer period of time.

There is some rationale for these drugs reducing risk of Alzheimer's because cholesterol and a protein in the blood that binds cholesterol can get into the brain and appear to be related to the development of Alzheimer's - so lowering the blood cholesterol level by a lot, as statins do, might indeed protect against Alzheimer's. But, the drugs may work in some way other than reducing cholesterol levels. A recent (May 2001) paper presented at the American Geriatric Society meeting from Harvard Medical School concludes that whatever the mechanism is, it has nothing to do with the blood cholesterol level. Furthermore, a report in the American Journal of Epidemiology in January 2001 showed a similar reduction in risk of Alzheimer's in patients given medications for high blood pressure. How cholesterol-lowering or blood pressure-lowering drugs reduce the risk of Alzheimer's is not known.

but, many more studies are needed, including prospective studies in which people placed on statins and proper control groups are followed for years to analyze the occurrence of Alzheimer's. For now, no conclusion, even a preliminary conclusion, is possible. Interestingly, two of the authors of one of the papers have already applied for a patent on the use of statins in treating Alzheimer's - a commentary on the state of research or perhaps on the state of American society in the early 21st century.

Wolozin, B., et al. Decreased prevalence of Alzheimer disease associated with 3 hydroxy 3 methyl glutaryl coenzyme A reductase inhibitors [statins]. Archives of Neurology. Vol 57. (October) Pgs 1479-1493. 2000.

Jick, H., et al. Statins and risk of dementia. Lancet. Vol 356. (Nov 11). Pgs 1627-1631. 2000.