Statins & Memory Loss

Statins & Memory Loss

People who took cholesterol-lowering statins are half as likely to develop dementia as those who do not take statins, a new UM study shows.

The study consisted of older Mexican-Americans in Sacramento, California, many of whom suffered from Type-2 diabetes or obesity, which put them at higher risk for developing dementia, Alzheimer's or cognitive impairment without dementia, says Mary Haan, SPH professor of epidemiology and lead author of the study. Some of the risk factors for dementia include high cholesterol, Type-2 diabetes, obesity, and hypertension.

"The bottom line is that if a person took statins over a course of about five to seven years, it reduced the risk of dementia by half, and that's a really big change," says Haan, who notes that the study did not look at statins as a treatment for existing dementia, only as a preventative. Statins are drugs that specifically lower LDL or bad cholesterol.

The longitudinal study was originally funded in 1997 to look at metabolic and vascular conditions like hypertension and diabetes and their effect on the risk of dementia and Alzheimer's disease. Of 1,674 participants who were free of dementia at the start of the study, 27 percent, or 452 people, took statins at some point in the study. Over the five-year followup period, 130 participants developed dementia or cognitive impairment. Researchers adjusted for factors such as education, smoking status, the presence of a particular gene thought to predict dementia, and history of stroke or diabetes. The study appeared in the July 29 issue of Neurology.

It's not clear exactly how statins work to decrease the development of dementia. An emerging risk factor for dementia is high insulin, Haan says, and one theory is that statins may work on those insulin pathways in a way that lowers the high insulin levels in the brain that can lead to the classic Alzheimer's pathology.

"We aren't suggesting that people should take statins for purposes other than what they are indicated for, but hopefully this study and others will open the door to statin testing for dementia and other types of cognitive impairment," Haan says. The next step, she says, is to determine exactly how the statins work on the biochemical pathways involved in dementia.

By Laura Bailey

Send correspondence about this or any Findings article to the editor at sph.findings@umich.edu. You will be contacted if your letter is considered for publication.