Cholesterol Levels Linked to Stroke

High levels of 'good' cholesterol cut risk by 47 percent, study says

SATURDAY, July 21, 2001 (HealthDayNews) -- Doctors have long known that cholesterol and heart disease go hand in hand, but now it appears the same can be said for stroke.

High levels of HDL, or "good cholesterol," may reduce by almost half the risk of stroke among the elderly, blacks and Hispanics, a recent study from Columbia University shows.

Stroke is one of the nation's leading causes of death, ranking third behind heart disease and cancer. Someone in United States suffers a stroke every 53 seconds, and someone dies from the condition every three minutes, according to the American Stroke Association. Stroke is most common among elderly and minority populations, the fastest-growing segments of American society.

Doctors have long suspected that high cholesterol is a key risk factor for stroke, the death of brain tissue due to a lack of blood flow. But not all cholesterol is created equal. High levels of LDL, or "bad cholesterol," can lead to the buildup of fatty deposits in the bloodstream. HDL, or "good cholesterol," is thought to limit LDL cholesterol in the blood and prevent it from clogging arteries.

Results of the Columbia study, published in a recent issue of the Journal of the American Medical Association, were based on a review of the ongoing Northern Manhattan Stroke Study. The researchers looked at the effect of HDL on stroke in 1,444 elderly whites, black and Hispanic volunteers from 1993 to 1997.

"There have been conflicting studies about cholesterol and stroke," says study author Dr. Ralph Sacco, who is associate chairman of neurology at Columbia University's College of Physicians and Surgeons. "But our study showed conclusively that as good cholesterol went up, stroke risk went down."

The researchers found people with high HDL levels had a 47 percent lower risk for developing the most common type of stroke, ischemic, which occurs when a blood vessel is blocked by fatty deposits or a blood clot. The study also found that high levels of HDL were associated with an 80 percent reduced risk for strokes resulting from atherosclerosis.

Factors that increase the risk of stroke include high blood pressure, diabetes, physical inactivity and smoking. Your chance of having a stroke doubles with each decade after 50, and blacks and Hispanics are twice as likely as whites to suffer a stroke, says Sacco.

"Our data suggest that risk factors like blood pressure and diabetes are more frequent and uncontrolled in these populations," he says.

But it's more difficult to elevate HDL levels than to lower LDL levels, says Dr. Stanley Tuhrim, director of the stroke program at Mount Sinai School of Medicine in New York City.

"Your HDL levels seem to be a little more hard-wired," he says. "But there are things you can do -- such as getting a lot of exercise, drinking modest amounts of alcohol, and quitting smoking -- that may elevate those levels."

Drugs such as statins have also been shown to lower cholesterol and reduce the risk of stroke. However, they mainly affect LDL levels, Sacco says.

"It is sometimes hard to get HDL levels up with drugs, so we need to be thinking about more ways to prevent stroke through behavior modification," he says. "But if we can get it up even a little, that translates into a big reduction in stroke."

What to Do: You can find out more about stroke from the National Stroke Association, the American Heart Association or the National Institute of Neurological Disorders and Stroke.

SOURCES: Interviews with Ralph Sacco, M.D., associate chairman, neurology, Columbia University's College of Physicians and Surgeons, New York City; Stanley Tuhrim, M.D., director, stroke program, Mount Sinai School of Medicine, New York City; June 6, 2001 Journal of the American Medical Association
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