Risk Factors

Risk Factors

New or recurrent strokes affect about 700,000 Americans every year. 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. Women may have a higher risk for hemorrhagic strokes than men (although this risk is not consistent in all countries). It is not clear why women have a higher mortality rate from stroke. The arteries that lead to the brain may be more vulnerable to the effects of plaque build-up in women than in men.

Ethnicity

All minority groups, including Native Americans, Hispanics, and African Americans, face a significantly higher risk for stroke and stroke death than 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.

Geography

People in the southeastern U.S. have had the highest risk for stroke in the country for some years; those at particular risk live in North Carolina, South Carolina, and Georgia. This risk may be shifting westward. High stroke rates are also occurring in the lower Mississippi valley and in Southern California. Socioeconomic differences do not fully explain these higher-risk areas.

Heart Disease and Heart Attack

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, according to a major 2002 study, is 2.5% in the first 6 months and 5% per year thereafter. In the study, patients with a higher risk (about 4%) for stroke within 6 months of a heart attack tended 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. Most people at high risk have more than one of these problems.