Stress Management

Stroke

Risks for Stroke

Risks Factors for Stroke That Can Be Changed

High Alcohol Consumption

Generally, an increase in alcohol consumption leads to an increase in blood pressure. Heavy drinking increases the risk for both hemorrhagic and ischemic stroke. Moderate alcohol consumption, however, may lower the risks for stroke.

Studies have shown that consumption of smaller amounts of alcohol may have a protective effect against ischemic stroke. It is possible that alcohol decreases the clotting ability of platelets in the blood, just like aspirin.

For example, in a study, reported in the Nov. 18, 2000 issue of The New England Journal of Medicine, 22,000 men were followed for an average of 12 years as part of the Physicians Health Study. Researchers found that drinking as little as one alcoholic beverage a day significantly reduced the overall risk of stroke. Klaus Berger, M.D., of Brigham and Women's Hospital in Boston, and colleagues found that the benefit was apparent with as little as one drink per week. Greater consumption did not increase the observed benefit.

The researchers analyzed the medical records of male doctors, most of them white, who were between the ages of 40 and 84. Over about 12 years, 679 men experienced first strokes. Most of the first strokes were ischemic strokes, while fewer than 15 percent were hemorrhagic strokes. Compared with other study participants, the group of men who consumed at least one drink per week had a 21 percent lower risk of having any type of stroke. The same group had a 23 percent lower risk of ischemic stroke. Drinking alcohol had neither a positive nor a negative effect on the risk of hemorrhagic stroke. The authors concluded that "light-to-moderate consumption of alcohol (one to seven drinks per week) reduced the risks of total stroke and ischemic stroke." Other studies have shown the benefit of drinking small amount of alcohol on the heart diseases, a phenomenon called French Paradox.

Heavy alcohol consumption, however, may seriously deplete platelet numbers and compromise blood clotting and blood viscosity, leading to hemorrhage. In addition, heavy drinking or binge drinking can lead to a rebound effect after the alcohol is purged from the body. The consequences of this rebound effect are that blood viscosity (thickness) and platelet levels skyrocket after heavy drinking, increasing the risk for ischemic stroke.

Use of Illicit Drugs

The use of illicit drugs, such as cocaine and crack cocaine, can cause stroke. Cocaine may act on other risk factors, such as hypertension, heart disease, and vascular disease, to trigger a stroke. It decreases relative cerebrovascular blood flow by up to 30 percent, causes vascular constriction, and inhibits vascular relaxation, leading to narrowing of the arteries. Cocaine also affects the heart, causing arrhythmias and rapid heart rate that can lead to the formation of blood clots.

Marijuana decreases blood pressure and may interact with other risk factors, such as hypertension and cigarette smoking, to cause rapidly fluctuating blood pressure levels, damaging blood vessels.

Head and Neck Injuries

Injuries to the head or neck can cause a small number of strokes. Head injury or traumatic brain injury may cause bleeding within the brain leading to damage akin to that caused by a hemorrhagic stroke. Neck injury, when associated with spontaneous tearing of the vertebral or carotid arteries caused by sudden and severe extension of the neck, neck rotation, or pressure on the artery, is a contributing cause of stroke, especially in young adults.

Infections

Recent viral and bacterial infections may act with other risk factors to add a small risk for stroke. The immune system responds to infection by increasing inflammation and increasing the infection-fighting properties of the blood. Unfortunately, this immune response increases the number of clotting factors in the blood, leading to an increased risk of embolic-ischemic stroke.

Source: National Institutes of Health

Caution: If you suspect a stroke, seek emergency medical treatment immediately. Time is of essence.

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