Risk factors you can’t change include:
Age: The chance of having a stroke approximately doubles for each decade of life after age 55. While stroke is common among the elderly, a lot of people under 65 also have strokes.
Heredity (family history): Your stroke risk may be greater if a parent, grandparent, sister or brother has had a stroke.
Race: African-Americans have a much higher risk of death from a stroke than Caucasians do. This is partly because blacks have higher risks of high blood pressure, diabetes and obesity.
Sex (gender): Each year, women have more strokes than men, and stroke kills more women than men. Use of birth control pills, pregnancy, history of preeclampsia/eclampsia or gestational diabetes, oral contraceptive use, smoking and post-menopausal hormone therapy may pose special stroke risks for women. Also, women may experience unique symptoms when having a stroke.
Prior stroke, TIA or heart attack: The risk of stroke for someone who has already had one is many times that of a person who has not. Transient ischemic attacks (TIAs) are warning strokes that produce stroke-like symptoms but no lasting damage. If you've had a heart attack, you're at higher risk of having a stroke, too.
Risk factors you can influence include:
High blood pressure: High blood pressure is the leading cause of stroke and the most important controllable risk factor for stroke. Many people believe the effective treatment of high blood pressure is a key reason for the accelerated decline in the death rates for stroke.
Cigarette smoking: In recent years, studies have shown cigarette smoking to be an important risk factor for stroke. The use of oral contraceptives combined with cigarette smoking greatly increases stroke risk.
Diabetes: Diabetes is an independent risk factor for stroke. Many people with diabetes also have high blood pressure, high blood cholesterol and are overweight. This increases their risk even more.
Carotid or other artery disease: The carotid arteries in your neck supply blood to your brain. A carotid artery narrowed by fatty deposits from atherosclerosis (plaque buildups in artery walls) may become blocked by a blood clot.
Peripheral artery disease: This narrowing of blood vessels carrying blood to leg and arm muscles is caused by fatty buildups of plaque in artery walls. People with peripheral artery disease have a higher risk of carotid artery disease, which raises their risk of stroke.
Atrial fibrillation: This heart rhythm disorder raises the risk for stroke. The heart's upper chambers quiver instead of beating effectively, which can let the blood pool and clot. If a clot breaks off, enters the bloodstream and lodges in an artery leading to the brain, a stroke results.
Other heart disease: People with coronary heart disease or heart failure have a higher risk of stroke than those with hearts that work normally. Dilated cardiomyopathy (an enlarged heart), heart valve disease and some types of congenital heart defects also raise the risk of stroke.
Sickle cell disease (also called sickle cell anemia): This is a genetic disorder that mainly affects African-American and Hispanic children. "Sickled" red blood cells are less able to carry oxygen to the body's tissues and organs. These cells also tend to stick to blood vessel walls, which can block arteries to the brain and cause a stroke.
High blood cholesterol: People with high blood cholesterol have an increased risk for stroke. Also, it appears that low HDL (“good”) cholesterol is a risk factor for stroke in men, but more data are needed to verify its effect in women.
Poor diet: Diets high in saturated fat, trans fat and cholesterol can raise blood cholesterol levels. Also, a diet containing five or more servings of fruits and vegetables per day may reduce the risk of stroke.
Physical inactivity and obesity: Being inactive, obese or both can increase your risk of high blood pressure, high blood cholesterol, diabetes, heart disease and stroke.
Source: American Stroke Association