Risk Factors

New or recurrent strokes affect about 780,000 Americans every year. On average, someone in the United States has a stroke every 40 seconds. Although incidence of stroke has increased, more people are surviving stroke, and the death rate is declining. While age is the major risk factor, people with stroke are likely to have more than one risk factor.

Age

Older Adults. People most at risk for stroke are older adults, particularly those with high blood pressure, who are sedentary, overweight, smoke, or have diabetes. Older age is also linked with higher rates of post-stroke dementia.

Younger Adults. Younger people are not immune, however. About 28% of stroke victims are under age 65.

Gender

In most age groups except older adults, stroke is more common in men than in women. However, it kills more women than men, regardless of ethnic groups. This may be partly due to the fact that women tend to live longer than men, and stroke is more common among older adults. Women account for about 6 in 10 stroke deaths.

Ethnicity

All minority groups, including Native Americans, Hispanics, and African-Americans, face a significantly higher risk for stroke and death from stroke than Caucasians. African-Americans have twice the risk for first-time stroke as Caucasians. The risk is also higher in Asian Americans, although stroke rates appear to be declining in this group. The differences in risk among all groups diminish as people age.

The greatest disparity in risk occurs in young adults. Younger African-Americans are two to three times more likely to experience a stroke than their Caucasian peers and four times more likely to die from one. They also face a higher risk for death from heart disease. African-Americans have a higher prevalence of diabetes and hypertension than other groups. However, studies suggest that socioeconomic factors also affect these differences.

Presence of Other Vascular Disease

Heart disease and stroke are closely tied for many reasons:

• Patients with one condition often have risk factors for the other, such as high blood pressure, atherosclerosis (hardening of the arteries), and diabetes.
• The risk of stroke increases during surgical procedures involving the coronary arteries, including coronary bypass operations and angioplasty. Coronary bypass poses the greater risk -- about 2 - 5%.
• Anti-clotting drugs used for treatment of heart disease and heart attacks slightly increase the risk for hemorrhagic stroke.
• A heart attack itself poses a high risk for stroke, which is about 2.5% in the first 6 months and 5% per year thereafter. Patients with a higher risk (about 4%) for stroke within 6 months of a heart attack tend to be older (over age 75), African-American, or to have a history of a previous stroke, atrial fibrillation, hypertension, diabetes, or peripheral artery disease.

Abnormal Blood Pressure

High Blood Pressure (Hypertension). High blood pressure (known medically as hypertension) contributes to 70% of all strokes. Researchers have estimated that controlling blood pressure can prevent nearly 40% of strokes.