The National Institute of Neurological Disorders and Stroke has identified five treatable risk factors associated with stroke. Agency officials emphasize that having a risk factor doesn't mean you'll have a stroke. And not having a risk factor doesn't mean you'll avoid a stroke. But your likelihood of having a stroke grows as the number and severity of risk factors increase. Risk factors that can be controlled by medical treatment include:

• High blood pressure. This is by far the most important risk factor. Have your blood pressure checked by a qualified professional, and if it is high, seek medical attention to bring it into the normal range. Some over-the-counter (OTC) drugs may cause high blood pressure. For example, phenylpropanolamine (PPA), a widely used ingredient in OTC cough, cold, and weight-loss drugs, is under review because of concerns that the compound, especially in doses beyond those recommended, may elevate blood pressure and increase the risk of stroke. The Nonprescription Drug Manufacturers Association, at FDA's request, is sponsoring a study of PPA in OTC drugs and its possible relationship to an increased risk of stroke.
• Cigarette smoking. Studies have linked smoking to the buildup of fatty substances in the carotid artery, the main neck artery supplying blood to the brain. Blockage of this artery is the main cause of strokes in Americans. Nicotine in cigarettes can raise blood pressure, and smoke can make blood thicker and more likely to clot.
• Heart disease. Disorders such as coronary artery disease, valve defects, irregular heartbeat, and enlargement of one of the heart's chambers can create clots that may break loose and cause a stroke. Regular physicals will pinpoint treatable problems.
• History of stroke. If you experience a "mini-stroke," or transient ischemic attack (TIA), with symptoms that quickly subside, seek emergency help. If you have had a stroke, consult with your doctor about what you can do to avoid a second stroke.
• Diabetes. This causes destructive changes in blood vessels throughout the body, including the brain. If blood glucose levels are high at the time of a stroke, brain damage is usually more severe than when glucose is well controlled. Treating diabetes can delay complications that increase stroke risk.