Stroke: Causes & Risk Factors

Blood clots or plaque-lined arteries are the primary causes of ischemic strokes. A ruptured blood vessel in the brain causes a hemorrhagic stroke. Different factors—from harmful habits to things you can't control—can contribute to the development of either type.

Common risk factors for stroke include:

  • Age: Your risk of having a stroke more than doubles each decade after age 55. Most strokes occur in people over age 65, and they face a higher risk of dying from stroke.
  • Gender: Men have a higher risk for stroke than women. But women face a higher risk of dying from stroke than men. Oral contraceptives, fluctuating hormones during pregnancy, at childbirth and around menopause may increase a woman's stroke risk. Migraine headaches, which are much more common in women than in men, are also a risk factor for stroke.
  • Ethnicity: African Americans have almost twice as many strokes as white Americans—they are also more likely to die from a stroke.
  • Weight: If you are overweight or obese, you are also likely to have stroke risk factors, such as high blood pressure, high cholesterol and/or diabetes.
  • Family history: You may inherit a tendency for health conditions (like high blood pressure) that increase stroke risk. You also may share lifestyle behaviors with other family members, such as overeating or smoking, that increase stroke risk. Congenital diseases that result in abnormally formed blood vessels and genetic disorders such as sickle cell disease also increase stroke risk in some individuals.
  • Cigarette smoking: Smoking nearly doubles your risk for ischemic stroke. Fortunately, your risk for stroke begins to decrease as soon as you quit.
  • Heavy alcohol consumption: Heavy alcohol consumption or binge drinking can result in thicker blood, higher blood pressure and lower numbers of platelets that can increase your stroke risk. (On the other hand, recent studies suggest that light drinking may help to thin the blood and decrease your stroke risk.)
  • Transient ischemic attacks (TIAs): TIAs, often called "mini strokes," are episodes that start just like a stroke, usually last as little as a few minutes to an hour, and leave no lasting symptoms. TIAs are a warning sign that a major stroke may be looming. They offer a chance to get healthier and prevent stroke.
  • Previous stroke: One out of four people who recover from their first stroke will have another within 5 years. The risk of disability or death increases with each stroke recurrence.
  • Other diseases/conditions: If you have high blood pressure, high cholesterol, diabetes, sickle cell disease, heart disease or migraine headaches, you face a higher risk for stroke. People with diabetes have three times the risk for stroke compared to people without the disease. People with migraine headaches have more than twice the risk for stroke compared to people without the disease. And women with migraines who also take birth control pills have 8 times the risk of stroke
  • Drug use: People who use cocaine or crack cocaine face a higher risk for stroke. Smoking marijuana and using drugs like heroin, amphetamines and anabolic steroids may also increase stroke risk.
  • Head and neck injuries: Trauma to the head or neck that results in bleeding in the brain can lead to stroke. Neck injuries caused by severely and abruptly extending or rotating the neck may result in ischemic stroke.
  • Infections: Recent viral and bacterial infections, in combination with other risk factors, are thought to increase your chances of having a stroke.