Stroke prevention

# Prevention
Prevention of stroke can work at various levels including:
- primary prevention - the reduction of risk factors across the board, by public health measures such as reducing smoking and the other behaviours that increase risk;
- secondary prevention - actions taken to reduce the risk in those who already have disease or risk factors that may have been identified through screening; and
- tertiary prevention - actions taken to reduce the risk of complications (including further strokes) in people who have already had a stroke.
The most important modifiable risk factors for stroke are hypertension, heart disease, diabetes, and cigarette smoking. Other risks include heavy alcohol consumption (see Alcohol consumption and health), high blood cholesterol levels, illicit drug use, and genetic or congenital conditions. Family members may have a genetic tendency for stroke or share a lifestyle that contributes to stroke. Higher levels of Von Willebrand factor are more common amongst people who have had ischemic stroke for the first time. The results of this study found that the only significant genetic factor was the person's blood type. Having had a stroke in the past greatly increases one's risk of future strokes.
One of the most significant stroke risk factors is advanced age. 95% of strokes occur in people age 45 and older, and two-thirds of strokes occur in those over the age of 65. A person's risk of dying if he or she does have a stroke also increases with age. However, stroke can occur at any age, including in fetuses.
Sickle cell anemia, which can cause blood cells to clump up and block blood vessels, also increases stroke risk. Stroke is the second leading killer of people under 20 who suffer from sickle-cell anemia.
Men are 1.25 times more likely to suffer strokes than women, yet 60% of deaths from stroke occur in women. Since women live longer, they are older on average when they have their strokes and thus more often killed (NIMH 2002). Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, menopause and the treatment thereof (HRT).
Prevention is an important public health concern. Identification of patients with treatable risk factors for stroke is paramount. Treatment of risk factors in patients who have already had strokes (secondary prevention) is also very important as they are at high risk of subsequent events compared with those who have never had a stroke. Medication or drug therapy is the most common method of stroke prevention. Aspirin (usually at a low dose of 75 mg) is recommended for the primary and secondary prevention of stroke.  Also see Antiplatelet drug treatment.  Treating hypertension, diabetes mellitus, smoking cessation, control of  hypercholesterolemia, physical exercise, and avoidance of illicit drugs and excessive alcohol consumption are all recommended ways of reducing the risk of stroke.
In patients who have strokes due to abnormalities of the heart, such as atrial fibrillation, anticoagulation with medications such as warfarin is often necessary for stroke prevention.
Procedures such as carotid endarterectomy or carotid angioplasty can be used to remove significant atherosclerotic narrowing (stenosis) of the carotid artery, which supplies blood to the brain. These procedures have been shown to prevent stroke in certain patients, especially where carotid stenosis leads to ischemic events such as transient ischemic attack. (The value and role of carotid artery ultrasound scanning in screening has yet to be established.)
A meta-analysis concluded that lowering homocysteine with folic acid and other supplements may reduce stroke. However, the two largest randomized controlled trials included in the meta-analysis had conflicting results. Lonn reported positve results; whereas the trial by Toole was negative.