Preventing Stroke: Know the Risk Factors

What are Risk Factors for a Stroke?
Do You Know Your Stroke Risk?

Some conditions as well as some lifestyle factors can put people at a higher risk for stroke. The most important risk factors for stroke are high blood pressure, heart disease, diabetes, and cigarette smoking. Persons who have already had a stroke need to control the risk factors in order to lower their risk of having another stroke. All persons can take steps to lower their risk for stroke.

High Blood Pressure
High blood pressure, or hypertension, is a major risk factor for stroke. It is a condition where the pressure of the blood in the arteries is too high. There are often no symptoms to signal high blood pressure. About 60 million people in the United States have high blood pressure. Lowering blood pressure can lower the risk of stroke. Medicines to lower blood pressure can decrease the risk of stroke among those with high blood pressure.

Click here for more information on High Blood Pressure.

Heart Disease
Common heart disorders such as coronary artery disease can also increase a person's risk for stroke. Coronary artery disease (CAD) occurs when the arteries that supply blood to the heart muscle become hardened and narrowed due to the buildup of plaque. Plaque (a mixture of fatty substances, including cholesterol and other lipids) and blood clots can build up inside the artery walls, causing thickening, hardening, and loss of elasticity. They can result in decreased or blocked blood flow and lead to a heart attack. Also, heart problems such as valve defects, irregular heart beat, and enlargement of one of the heart's chambers can result in blood clots that may break loose and cause a stroke. Persons with heart disease may be given medicines such as aspirin to help prevent clots from forming. See the heart disease fact sheet.

You can also view the 'Brain Basics' information and scoring tables at http://www.ninds.nih.gov/disorders/stroke/preventing_stroke.htm.

Atrial Fibrillation
A heart condition known as atrial fibrillation is a major concern. Atrial fibrillation is irregular beating of the upper chambers, or atria, of the heart. When the atria quivers instead of beating in a regular pattern, blood is not fully pumped out of them and may pool and clot. The clots can then leave the heart and travel to the brain, causing a stroke. Atrial fibrillation affects as many as 2.2 million Americans. About 15 percent of stroke patients have had atrial fibrillation before they experience a stroke. See the fact sheet on this condition.

Diabetes
Diabetes is another disease that increases a person's risk for stroke. With diabetes, the body does not make enough insulin, cannot use its own insulin as well as it should, or both. This causes sugars to be unavailable to the body tissues and to build up in the blood. People with diabetes have 2 to 4 times the risk of stroke compared to people without diabetes. Further, having diabetes can worsen the outcome of stroke.

Click here for more information about Diabetes.

Tobacco Use
Smoking almost doubles a person's risk for ischemic stroke, independently of other risk factors. Cigarette smoking increases the risk of stroke by promoting atherosclerosis and increasing the levels of blood clotting factors, such as fibrinogen. Also, nicotine raises blood pressure, and carbon monoxide reduces the amount of oxygen that blood can carry to the brain.

Click here for more information on Tobacco Use Quitting Smoking.

OTHER FACTORS
Blood Cholesterol Levels Some strokes can be caused by a narrowing of the arteries through the buildup of plaque, a mixture of fatty substances, including cholesterol and other lipids. This is called atherosclerosis. Plaque and blood clots build up inside the artery walls, causing thickening, hardening, and loss of elasticity. These can lead to decreased blood flow and to stroke if they occur in the arteries to the brain.

Cholesterol is a waxy substance produced by the liver. It is needed by the body, and the liver makes enough cholesterol for the body's needs. Excess cholesterol-usually from eating foods that contain high levels of cholesterol and saturated fats-contributes to atherosclerosis.

There are two major kinds of cholesterol, one that is good, and one that is bad when there is too much of it. A higher level of high-density lipoprotein cholesterol, or HDL, is considered good. However, higher levels of low-density lipoprotein, or LDL, can lead to atherosclerosis and stroke. A lipoprotein profile can be done to measure several different kinds of cholesterol as well as triglycerides (another kind of fat found in the blood). See the cholesterol fact sheet.

Alcohol
Generally, excessive alcohol use can lead to an increase in blood pressure, which increases the risk for stroke. More information on alcohol can be found at CDC's alcohol and public health Web site.

Genetic Risk Factors
Stroke can run in families. Genes play a role in stroke risk factors such as high blood pressure, heart disease, diabetes, and vascular conditions. It is also possible that an increased risk for stroke within a family is due to factors such as a common sedentary lifestyle or poor eating habits, rather than hereditary factors. Find out more about genetics and diseases on CDC's genomics and disease prevention Web site.

Some of the most important risk factors for stroke can be determined during a physical exam at your doctor's office. If you are over 55 years old, a worksheet in a pamphlet available from the NINDS can help you estimate your risk of stroke and show the benefit of risk-factor control.

The worksheet was developed from NINDS-supported work in the well-known Framingham Study. Working with your doctor, you can develop a strategy to lower your risk to average or even below average for your age.

Many risk factors for stroke can be managed, some very successfully. Although risk is never zero at any age, by starting early and controlling your risk factors you can lower your risk of death or disability from stroke. With good control, the risk of stroke in most age groups can be kept below that for accidental injury or death.

To obtain a copy of the worksheet, write or telephone requesting the pamphlet Brain Basics: Preventing Stroke from the NINDS Brain Resources and Information Network (BRAIN) at:

BRAIN
P.O. Box 13050
Silver Spring, Maryland 20911
(800) 352-9424

Americans have shown that stroke is preventable and treatable. A better understanding of the causes of stroke has helped Americans make lifestyle changes that have cut the stroke death rate nearly in half in the last two decades.

More than a million stroke survivors suffer little or no long-lasting disability from their strokes. Another two million, however, live with the crippling and lifelong disabilities of paralysis, loss of speech, and poor memory. Scientists at the NINDS predict that, with continued attention to reducing the risks of stroke and by using currently available therapies and developing new ones, Americans should be able to prevent 80 percent of all strokes by the end of the decade.

For more information check these outside links:

• CDC's Cardiovascular Health Program
• Medlineplus: Stroke
• ahrq.gov - What you should know about stroke prevention

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