New Insights into Preventing Deadly Strokes

Subarachnoid hemorrhages often strike young and middle-aged adults

THURSDAY, May 22, 2003 (HealthDayNews) -- They're called subarachnoid strokes, and they're about as deadly as strokes come.

They also tend to strike young and middle-aged adults. Yet, new research shows they can be prevented.

Fifty-five thousand to 60,000 Americans suffer a subarachnoid hemorrhage each year, and 40 percent to 50 percent of them die, half within two days of the attack.

"Most subarachnoid hemorrhages in young and middle-aged people are preventable," says Dr. Joseph P. Broderick, chairman of the department of neurology at the University of Cincinnati. He's also leader of the study that appears in the May 23 issue of Stroke.

The key to prevention: "People have to change their behavior," Broderick says.

To determine which behavior changes are most important, Broderick and his colleagues questioned 312 young and middle-aged men and women who had suffered these hemorrhages between 1994 and 1999. They asked about lifestyle and other factors that could be related to the risk of such strokes. Then the researchers compared the answers with those of 618 similar people who had not had such strokes.

One risk factor that stood out was family history. The risk was 3.8 times higher for people with a close relative who had had a subarachnoid stroke, compared to those without such a family history.

Another culprit, to no one's surprise, was smoking. Two-thirds of the stroke patients were smokers, compared to 30 percent of the healthy people.

"It should be emphasized that current cigarette smoking is the most important modifiable risk factor," says Dr. Thomas Brott, a professor of medicine at the Mayo Medical School in Jacksonville, Fla., and a member of the research team.

Another common risk factor was one that's behind most cardiovascular disease: high blood pressure. People with the condition had 2.39 times the normal risk of subarachnoid hemorrhage.

Diabetes and high blood cholesterol, two other familiar cardiovascular risk factors, don't seem to play a role in subarachnoid hemorrhage, the study indicates.

But drug use might. The numbers are small, but it's significant that three of the stroke patients reported cocaine use, while none of the healthy people did, Broderick says.

One unexpected finding was that the stroke risk was higher for thin people -- a low body mass index (23 or lower) was associated with a 50 percent higher risk of subarachnoid hemorrhage. "The association was strongest among four-pack-a-day smokers, so this might be an indirect effect of smoking," says Brott, noting that heavy smoking can keep people thin.

You can't change family history, the leading risk factor, Broderick says. So for those with such a history, he says, "it becomes more critical and more important to make lifestyle changes."

Those changes should include controlling blood pressure, Brott says. Just last week, the American Heart Association issued new guidelines that say any reading between 120/80 and 139/89 is now considered "prehypertensive;" previously that was considered within the normal range.

Broderick says a genetic-based effort to identify people who might be at especially high risk of subarachnoid stroke has begun. "We're trying to identify genes that are related to high risk," he says. "Any results are probably a couple of years away."

More information

To learn more about preventing a stroke, visit the American Heart Association or the National Institute of Neurological Disorders and Stroke.

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