Scientists Identify Ways to Lower Risk for Stroke

0 Comments | Insight on the News, Jan 24, 2000 | by Karen Goldberg Goff

Although strokes can occur without warning, studies show that exercise and diets high in potassium can reduce risk. Lowering high blood pressure and high cholesterol also helps.

About 600,000 Americans suffer a first stroke or recurring strokes every year, according to the American Heart Association, or AHA. Stroke is the third-leading cause of death (about 160,000 annually) in the United States, ranking behind heart disease and cancer. A majority of stroke victims who survive have some form of permanent disability, and the American Stroke Association estimates that stroke rehabilitation is a $45.3 billion business.

Though the risk more than doubles each decade for those older than 55, strokes do occur in younger persons -- even in children as a complication from other conditions. Scientists are just beginning to look at genetic links and vitamin B deficiencies as contributors to stroke incidents in younger people.

Because a stroke can occur without warning, it can be difficult to pinpoint who is at risk. Several conditions are red flags, however, and need to be controlled, says Jerold Mikszewski, a neurologist and a spokesman for the AHA.

If a person has high blood pressure, he or she should "work fastidiously" to reduce it, says Mikszewski. That means taking medication, if necessary, to keep blood pressure below 135/80.

Diabetes, which affects the circulatory system, also can put one at high risk of stroke. Diabetics should be extra cautious about their blood pressure and control their blood sugar with diet and medication, says Mikszewski.

High cholesterol can be a risk factor, one that increasingly is highlighted as the use of cholesterol-lowering drugs becomes more popular. "For a long time, the relationship between stroke and high cholesterol was unclear," says Mikszewski. "But it is a risk factor, particularly if you have LDL cholesterol" -- bad cholesterol -- "that is over 130. Some studies have put a patient with heart disease on a cholesterol-lowering agent, such as pravastatin, and the incidence of stroke has decreased dramatically, even more so than heart attack." Researchers at Wake Forest University in North Carolina recently discovered that in patients who already have heart disease, cholesterol-lowering medication can decrease the risk of stroke by 22 percent.

Changes in lifestyle can impact stroke risk, too. Most important is quitting cigarettes. "Smoking is one of the worst risk factors for stroke," says Mikszewski. "The risk factors are multiplicative."

As with many conditions, diet and exercise play an important role. The high-potassium content of a diet rich in fruits, vegetables and whole-grain cereals may reduce the risk of stroke, particularly if one has high blood pressure.

A 1998 Harvard Medical School study published in Circulation: The Journal of the American Heart Association, followed 44,000 men for eight years and found that individuals who consumed diets high in potassium had a 38 percent lower risk of stroke than those who didn't. The diets high in potassium included about nine servings daffy of high-potassium foods such as tomatoes, spinach, bananas and oranges. In the same study, 8,500 men who had high blood pressure and took potassium supplements of about 1 gram per day had a 60 percent reduced risk of stroke when compared with those with high blood pressure who were not taking supplements.

Another 1998 Harvard study of 11,130 alumni found that one hour of moderate exercise five days a week can lower stroke risk by 46 percent compared with little or no exercise. A half-hour of exercise five days a week showed a 24 percent reduction in stroke risk. Exercise helps reduce common risk factors such as high blood pressure, high cholesterol and diabetes, notes the study's lead author, I-Min Lee.

"This finding provides additional support for the surgeon general's report on physical activity, which calls for at least 30 minutes of moderate physical activity on most days of the week," says Lee. "We found that doubling that effort showed an even greater reduction in risk."

It is more important than ever for people -- particularly those in high-risk groups -- to get immediate help if they suspect they are having or have had a stroke, says Steven Kittner, professor of neurology, epidemiology and preventive medicine at the University of Maryland School of Medicine. New drug therapies have worked very well on stroke patients, but they must be administered within three hours of the attack.

"Stroke symptoms might show up as weakness, particularly on one side; trouble communicating; vision problems; sudden, severe headaches; and problems with coordination," says Kittner. "It all depends on where the site of the blockage or blood is. It is very important to recognize the symptoms and call your doctor. Every minute counts."