Researchers have found a link between high exposure to statins and a reduced Alzheimer's risk.
Published in JAMA Neurology, the study identifies a link between high statin use and a lower risk of Alzheimer's disease, though the reduced risk is dependent on sex, race/ethnicity, and the type of statin used.
While the study is purely observational, the research team - including Julie M. Zissimopoulos, Ph.D., of the University of Southern California in Los Angeles - and colleagues say that the findings should be further investigated in clinical trials.
Alzheimer's disease is the most common form of dementia, with around 5.2 million people in the United States aged 65 and older living with the disease. By 2050, this number could reach 13.8 million, unless new prevention or treatment strategies are found.
While great strides have been made in the search for ways to halt the development and progression of Alzheimer's in recent years, researchers are yet to jump the final hurdle.
Just last month, hopes of the first medication to slow Alzheimer's were dashed, after drug giant Eli Lilly announced that their promising drug candidate solanezumab had failed to reduce cognitive decline in a phase III trial of patients with the disease.
In the new study, Zissimopoulos and team suggest it might be worth investigating the feasibility of existing drugs for the prevention of Alzheimer's, after finding a link between high exposure to statins and reduced Alzheimer's risk.
Statins and Alzheimer's
According to Zissimopoulos and colleagues, previous studies have shown that high cholesterol levels may be associated with the buildup of beta-amyloid plaques in the brain, which are considered to be a hallmark of Alzheimer's disease.
As such, the researchers hypothesized that cholesterol-lowering medications might influence the onset of Alzheimer's and its subsequent progression.
To investigate their theory, the team analyzed 2006-2013 Medicare data of 399,979 adults aged 65 and older who had used statins.
The researchers looked at how low and high statin use might be associated with risk of an Alzheimer's diagnosis between 2009-2013. High statin exposure was defined as "at least the 50th percentile of days of filled prescriptions in a given year for at least 2 years during 2006, 2007, and 2008."
Each year between 2009-2013, around 1.72 percent of women and 1.32 percent of men were diagnosed with Alzheimer's, with diagnosis lowest among white men, at 1.23 percent.
Overall, men and women with high exposure to statins were 15 percent and 12 percent less likely to be diagnosed with Alzheimer's, respectively, compared with men and women with low exposure to the drugs.
However, on closer investigation, the team found that the link between high statin use and lower Alzheimer's risk was dependent on sex, race/ethnicity, and the type of statin used.
Alzheimer's risk dependent on statin type, sex, race/ethnicity
High exposure to statins overall was only associated with a reduced risk of Alzheimer's for Hispanic men, black women, and white men and women, compared with low exposure to the drugs.
Breaking the data down further by statin type, the researchers found that:
- High atorvastatin exposure was linked to reduced Alzheimer's risk for white and black women, as well as for Hispanic men and women
- White, Hispanic, and black women had a lower Alzheimer's risk with high use of simvastatin, as did white and Hispanic men
- Pravastatin and rosuvastatin were linked to a reduced risk of Alzheimer's for white women.
For black men, the team identified no significant reduction in Alzheimer's risk with the use of any statin.
The researchers stress that their study is unable to prove cause and effect, so clinical trials are required - involving all racial and ethnic groups - to confirm their results.
Still, they believe their findings indicate that certain statins could be a feasible strategy to combat Alzheimer's disease:
"Our study identified the associations between AD [Alzheimer's disease] incidence and statin use by statin type, sex, and race/ethnicity. This suggests that certain patients, facing multiple, otherwise equal statin alternatives for hyperlipidemia treatment, may reduce AD risk by using a particular statin.
The right statin type for the right person at the right time may provide a relatively inexpensive means to lessen the burden of AD."