A stroke occurs when a blood clot or bleeding suddenly interrupts the flow of blood to an area of the brain. When deprived of blood, brain cells lose their ability to function and, if deprived for too long, die. Because brain cells and groups of brain cells have highly specialized functions, the location of stroke damage determines what loss of neurological and bodily function occurs as a result of stroke. Impairment may be temporary or permanent.
As is true of coronary artery disease (CAD), a number of factors can increase your risk of having a stroke. Some factors, such as age and heredity, are out of your hands, but you can do much to control risk factors that are related to lifestyle choices.
Risk factors you can't change
Although you can't change the risk factors in the following list, understanding them may increase your awareness and help you make better choices about the risk factors you can control.
- Age: Although many people younger than 65 have strokes, the risk of stroke doubles with each decade after age 55.
- Heredity and family history: Your risk of having a stroke is higher if a parent, grandparent, or sibling has had a stroke. Certain inherited genetic traits, such as blood-clotting disorders, and family lifestyle patterns likely contribute to this elevated risk.
- Gender: Although men and women have about the same overall risk of having a stroke, women are more likely to die from stroke. Taking birth control pills also slightly increases the risk of stroke particularly when combined with other risk factors like smoking or high blood pressure.
- Previous stroke: Having had one stroke greatly increases your risk of having another stroke. For this reason, preventing recurrent stroke is an important goal in the long-term health-care plan for stroke survivors.
Risk factors you can control
Controlling one or more of these risk factors can significantly lower your risk of stroke. Having one of these risk factors will raise your risk of stroke. Having a cluster or two or three factors, which is a fairly common circumstance, dramatically raises your risk of stroke.
- High blood pressure: Having high blood pressure is perhaps the greatest risk factor for stroke. In fact, the higher your blood pressure, the greater the risk. Controlling blood pressure within normal ranges can lower this risk.
- Smoking: Because smoking damages the cardiovascular system all over the body, and not just in the heart, it damages vessels in the brain and the carotid arteries leading to the brain and contributes to the narrowing of these vessels.
- Heart disease: People with heart disease and people who've had heart attacks are at higher risk of stroke. Having atrial fibrillation is a particularly significant risk factor because embolitic clots often form during atrial fibrillation.
- Diabetes: Not only is having diabetes an independent risk factor for stroke, but people with diabetes often have high blood pressure, high cholesterol, and weight problems, all of which are additional factors that increase stroke risk.
- Substance abuse: Binge drinking or even drinking beyond recommended moderate levels (no more than one drink daily for women and two for men) raises the risk of stroke. Intravenous drug abuse can lead to cerebral embolisms; cocaine abuse also has been linked to stroke.