July 11, 2005
Statin drugs, the popular cholesterol-lowering medications taken by millions of older Americans to ward off heart attacks, may not be beneficial against Alzheimer's disease, a new study reports. Earlier studies suggested that these medicines, which go by brand names such as Lipitor and Zocor, might have benefits not just for the heart but for the brain as well. This large new study calls into question whether these drugs have benefits for keeping the memory sharp, although further studies are needed.
Researchers at the University of Washington in Seattle analyzed data from 2,798 senior citizens, aged 65 and up. All were members of the Cardiovascular Health Study and underwent sophisticated magnetic resonance imaging (MRI), brain scans, as well as a standardized mental testing at the start of the study to establish that they were free of Alzheimer's.
The study participants were then given exams and memory tests annually for the next five years, on average. During this time, 480 of the men and women developed Alzheimer's disease and other forms of dementia. After controlling for other known or suspected risk factors for dementia, such as smoking and diseases like high blood pressure and diabetes, the researchers found that those who had taken statin drugs had no reduction in their risk of developing Alzheimer's.
"Several factors may explain why statin use was not associated with a lower risk of dementia," the authors write. "Participants were on average 75 years of age, and statin use was assessed for a median of five years. Statin exposure may need to occur earlier in adulthood or for longer periods to prevent dementia." It's also likely that those people using statins did so because of high cholesterol or cardiovascular disease. These conditions increase the risk for developing Alzheimer's. So, even if statins had lowered their risk for Alzheimer's, the benefit may have been erased by the increased risk associated with cardiovascular disease.
Anyone whose doctor has prescribed a cholesterol-lowering medication should certainly continue taking it. These drugs have proven benefits for heart health, as they help to lower "bad" LDL cholesterol, a known risk factor for heart attacks, and keep blood vessels open and clear. Statin drugs may also reduce inflammation, which has been linked to heart disease as well as Alzheimer's disease.
It remains uncertain, however, whether cholesterol-lowering statin drugs may help to lower the risk of developing Alzheimer's or other forms of dementia. A study earlier this year, for example, found that among younger people aged 20 to 40, keeping cholesterol in a healthy range and avoiding other risk factors for heart disease may help to keep the brain young as we age. (See the story, "Be Good to Your Heart and Your Brain May Thank You.")
Other research has hinted at benefits as well. A small study from 2004 found that statin drugs may slow the progression of Alzheimer's disease. (See "Cholesterol Pill May Slow Alzheimer's Progression.")
More studies will need to be done to determine whether, and if so, who might derive brain benefits from the use of cholesterol-lowering drugs. In the meantime, experts advise that everyone follow a heart-healthy diet and get plenty of exercise, lifestyle factors that appear to benefit both heart and mind. The current study appeared in the Archives of Neurology, a medical journal published by the American Medical Association.
Thomas D. Rea, M.D., MPH, John C. Breitner, M.D., Bruce M. Psaty, M.D., Ph.D., et al: "Statin Use and the Risk of Incident Dementia." Archives of Neurology Volume 62, July 2005, pages 1047-1051.