TUESDAY, April 16, 2002 (HealthDayNews) -- New research adds to a growing body of evidence that suggests people who take the cholesterol-lowering drugs called statins have a much lower risk of Alzheimer's disease.
However, that's still not convincing enough to justify the use of statins to ward off the condition, experts say.
Two studies conducted in 2000 found a 70 percent reduction of Alzheimer's risk and other dementias in people taking statins, which are prescribed to help prevent heart disease. The same reduction was found in the new study, which was reported today at the American Academy of Neurology annual meeting in Denver.
"This adds a couple of things," says study author Dr. Robert C. Green, an associate professor of neurology at Boston University School of Medicine. "This study had a larger number of patients, and it is the first one to include African-Americans and to consider the role of APO-E4."
Both factors are important in studying Alzheimer's disease, Green says. Blacks have a higher incidence of the condition than whites, and APO-E4 is a gene variant that has been associated with an increased risk of Alzheimer's.
Green and his colleagues compared 912 people with probable or definite Alzheimer's disease and 1,669 unaffected members of their families, and found roughly the same risk reduction of the previous two studies.
The link between statins and lower Alzheimer's risk is especially strong in the new study because of its design, Green says.
"This is the first to include well-characterized patients," he says. "One of the earlier studies looked at any diagnosis of dementia, and so there was a potential for misdiagnosis, and the other relied on clinicians in general practice. All our cases were confirmed over the last four years by specialists at 15 medical centers."
However, the new study did have the same basic weakness as the others, Green says -- it was "observational," meaning that it looked backward to show only that taking statins was associated with a decreased risk, rather than demonstrating a cause-and-effect relationship. Real proof would have to come from a prospective trial, which would follow a large number of people for several years to see whether those taking statins are less likely to develop Alzheimer's disease, Green says.
"Our study adds weight to the observational evidence," Green says. "It further suggests that something is there, and that we ought to be looking at it in prospective trials."
Two such trials are under way or in the planning stage, he says. Both involve people who have been diagnosed with Alzheimer's disease and are designed to see whether statins can retard the progress of the disease or bring about mental improvement. Results are not expected for some time.
"The real question is whether the evidence to date warrants taking a statin to prevent Alzheimer's disease," Green says. "I don't think people should take it as a result of this study. I wouldn't suggest they should be taking it because of possible side effects."
Statins generally have a low incidence of side effects. About 1 percent or 2 percent of patients experience problems such as constipation or diarrhea, gas, dizziness, headache, heartburn or stomach pain.
The Alzheimer's Association is taking a guarded approach to the issue.
"This is the latest in a number of studies suggesting that statins may reduce the risk of Alzheimer's disease," says Bill Thies, vice president of medical and scientific affairs for the association. "It provides support for the clinical trials currently under way to resolve the issue."
What To Do
A decision about taking statins for any reason other than reducing blood cholesterol levels would have to be made following a discussion with your doctor about the possible benefits and risks of the drug.
You can check out the American Heart Association to learn more about statins. Meanwhile, learn about Alzheimer's disease from the Alzheimer's Association.
