Elevated cholesterol levels can cause cognitive decline; drugs may help
(HealthDay News) – The evidence that high cholesterol levels can cause heart problems has accumulated to a point that there is little dispute in the medical community.
And it could be that damage isn't confined to the heart.
Research in 2002, followed by a four year clinical trial, may help determine whether high cholesterol levels also cause brain damage, specifically, cognitive decline.
The research came from a long-running study of older women. It said that postmenopausal women with the highest blood readings of low-density lipoprotein (LDL) cholesterol, the "bad kind" that clogs the arteries, did much worse on tests of memory, language, orientation, and other kinds of brain function than women with low cholesterol levels.
That report, published in the journal Archives of Neurology, also adds evidence that statins, the cholesterol-lowering drugs, might be able to reduce the risk of Alzheimer's disease and other brain-robbing conditions.
The case is far from proven, but the clues were strong enough to impel the National Institute on Aging to sponsor a major trial to determine whether statin therapy can help keep old minds young.
The new report uses data from a hormone replacement therapy trial for post-menopausal women. Women in the study had their cholesterol levels tested periodically and took a test of mental ability at the end of the four-year trial.
Women with the highest LDL cholesterol levels did significantly worse on the tests, says the report by a group led by Dr. Kristine Yaffe, who was an assistant professor of psychology at the University of California in San Diego when the research was done. But women whose blood cholesterol levels decreased over the four years of the study had better scores than those whose cholesterol levels increased. And taking a statin drug appeared to improve performance on the mental tests.
"These results fit with other studies showing that statins may help to prevent Alzheimer's disease," says Yaffe, who is now a researcher of psychopathology/epidemiology in the department of psychiatry at the University of California in San Francisco .
The report cites two such studies that were published in November 2000.
"There has always been a debate about whether elevated serum cholesterol is related to cognitive decline," says Bill Thies, vice president of medical and scientific relations at the Alzheimer's Association. "This is a solid study, with good methodology, that offers excellent evidence. I suspect it will be the first of a number of studies showing that elevated cholesterol is associated with cognitive decline."
But Yaffe added, "Until we see the results of a randomized clinical trial, people shouldn't be taking statins for that purpose."
The NIA-sponsored statin trial, headquartered at the University of California at San Diego , began in 2000 and was completed in 2004, but the data is still being analyzed. It was a randomized trial, in which the incidence of mental decline was compared in people who take a statin or a placebo, an inactive substance.
The American Heart Association recommendations for cardiovascular health are equally applicable to mental function, says Thies.
"The rules for healthy living are pretty simple. They are not a guarantee, but they give the best chance of getting good results," he says. "Don't smoke, watch your blood pressure, don't get too big, exercise regularly. Those are as good a set of rules as you can get."
On the Web
Learn more about cholesterol and its effect on your body from the American Heart Association.
SOURCES:
Bill Thies, Ph.D., vice president, medical and scientific relations, Alzheimer's Association, Chicago; Kristine Yaffe, M.D., researcher of psychopathology/epidemiology, Department of Psychiatry, University of California, San Francisco; March 2002 Archives of Neurology
Author:
Ed Edelson, HealthDay Reporter
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