Saying no to cigarettes and yes to blood pressure screenings is the bedrock of stroke prevention, according to an expert scientific panel of the American Stroke Association, a division of the American Heart Association, which has issued a statement to physicians on strategies to prevent stroke.

The scientific statement "Primary Prevention of Ischemic Stroke" is published in the January issue of Stroke: Journal of the American Heart Association and the combined January 2/9 issue of Circulation: Journal of the American Heart Association.

Hypertension (high blood pressure) increases the risk of stroke up to four-fold. Proper treatment can diminish that risk by 38 percent. Cigarette smoking nearly doubles stroke risk, but quitting can slash the risk in half within one year and decrease it to a level similar to non-smokers after five years, according to the statement.

Stroke is currently the third leading cause of death in the United States and a leading cause of serious, long-term disability. According to the association's 2001 Heart & Stroke Statistical Update, about 600,000 strokes occur annually, and the economic burden of stroke is more than $45 billion in direct and indirect expenses.

Despite new approaches to stroke treatment such as using the clot-dissolving drug tissue plasminogen activator (TPA) to treat stroke, prevention remains the primary goal, according to the expert writing group chaired by Larry B. Goldstein, M.D., executive committee member of the association's Stroke Council and director of the Center for Cerebrovascular Disease and Stroke Policy Program at Duke University Medical Center, Durham, N.C.

"For all the promise TPA has heralded in stroke treatment, it is only being given to about 2 percent of people who suffer a stroke because of its limited time window - which is within hours after stroke onset. The treatment has a great potential benefit to those who qualify, but from a public health standpoint effective prevention is the best way to fight stroke," says Goldstein.

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The association formed a panel of stroke experts to review evidence on established and potential risk factors for stroke. The compilation succinctly catalogs the best scientific evidence to date and identifies where there are gaps in knowledge.

Some risk factors for stroke cannot be controlled, but help identify those at high risk - increasing age, family history and being black. The risk of stroke more than doubles for each decade of life after age 55. African Americans have a much higher risk of death and disability from a stroke than whites, in part because blacks have a greater incidence of high blood pressure and diabetes. But many risk factors can be controlled, treated or modified by changes in lifestyle habits, medication or surgical intervention.

A significant portion of the population has undiagnosed or inadequately treated hypertension. The panel recommends all adults have their blood pressure checked at least once every two years and urges health care providers to encourage people with high blood pressure to follow a healthy lifestyle and take their medication.

"Hypertension is very prevalent and it can be treated, so its identification is an important component of stroke prevention," notes Goldstein. "Unless it's checked, you don't know you have high blood pressure. That's why it's called the silent killer."

Among other risk factors for stroke cited in the statement:

  • Atrial fibrillation, a disorder in which the upper heart chambers improperly contract, potentially leading to blood clots that can travel to the brain and cause stroke. This increases the stroke risk approximately three- to five-fold in those age 65 or older or with additional risk factors. Treating the condition can cut the risk of stroke by as much as 68 percent.
  • Clogged neck arteries, which double the risk. Surgery to unblock it (endarterectomy) performed by a highly skilled surgeon can halve the risk.
  • Sickle cell disease in children, which magnifies the stroke risk 200 to 400-times compared to children without it. Blood transfusions for high risk children can slash risk 91 percent.
  • High cholesterol levels, which increase the risk in men 1.8 to 2.6-fold. Medication can ease risk 20 percent to 30 percent in those who also have coronary heart disease.

The panel had less clear evidence on the risk reduction offered by other factors but made these lifestyle suggestions for limiting stroke risk:

  • avoid illicit drug use;
  • weight reductions in overweight persons;
  • a minimum of 30 minutes of moderate intensity activity daily;
  • a healthy diet with five servings of fruits and vegetables daily;
  • avoid secondhand tobacco smoke; and
  • limit alcoholic drinks to no more two per day for men and one per day for women.

Also, the panel suggests that physicians encourage tight control of diabetes; avoid prescribing oral contraceptives for women with risk factors such as smoking; and consider folic acid and B vitamins for patients with elevated homocysteine, pending results of ongoing studies.

Other authors are Robert Adams, M.D.; Kyra Becker, M.D., Curt D. Furberg M.D.; Philip Gorelick, M.D.; George Hademenos, Ph.D.; Martha Hill, Ph.D., R.N.; George Howard, Ph.D.; Virginia J. Howard, MSPH; Bradley Jacobs, M.D.; Steven R. Levine, M.D.; Lori Mosca, M.D.; Ralph L. Sacco, M.D.; David G. Sherman, M.D.; Philip A. Wolf, M.D.; and Gregory J. del Zoppo, M.D.