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NOVEMBER / DECEMBER 2003

AROUND HARVARD

This article originally appeared in the October 2003 Harvard Men’s Health Watch and is provided courtesy of Harvard Health Publications.

Preventing strokes: Understanding stroke and evaluating your risk — The first of two parts

On average, someone in the United States will have a stroke within the next 45 seconds. In all, about 730,000 Americans will have strokes this year — and nearly 60% of them will be men. About 30% of stroke victims die within a year of their attack, making stroke the third leading cause of death in the United States. While many survivors recover wonderfully well, many others suffer prolonged, even permanent disabilities; nearly a third, in fact, require assistance in caring for themselves. And stroke is also a financial burden, draining more than $51 billion from the economy every year.

Stroke is a worry for every man, but older gents have the most cause for concern since the risk doubles in each decade beyond age 55: Some 70% of stroke patients are 65 or older.

Stroke is a major threat, but it should cause concern, not panic. The treatment of stroke has improved greatly, and neurologists are making more progress every year (see Harvard Men’s Health Watch, July 2001). But treatment and rehabilitation are arduous, prolonged, and expensive. In the last analysis, the best treatment is prevention.

Prevent strokes? It seems too good to be true, but it’s not. In fact, the incidence of stroke in the United States has declined by 70% since 1950. It’s proof that prevention can work — but you have to work at it to make it a reality.

Different strokes
Any preventive program must encompass the two major types of stroke, ischemic and hemorrhagic (see figure). Ischemic (is-KEE-mic) strokes are far more common, accounting for 80% of the total. They occur when an artery in the brain is blocked by a blood clot, depriving the tissue of its vital supply of oxygen-rich blood. It’s a process much like a heart attack, but unlike the arteries in the heart, vessels in the brain can become blocked in either of two ways. In a thrombotic stroke, the clot forms in a diseased artery within the brain itself, much as clots that form in coronary arteries cause heart attacks. But in an embolic stroke, the clot forms outside the brain, then breaks away and is carried by the blood to the brain, where it lodges in a normal artery. Most emboli originate from the heart itself or from cholesterol-laden atherosclerotic plaques on the aorta or carotid arteries, the main vessels that carry blood to the brain. Three of every four ischemic strokes are caused by emboli; it’s why heart disease and atherosclerosis are major risk factors for stroke and why many of the measures that prevent heart attacks will also protect against strokes.

Although hemorrhagic (hem-or-AG-ic) strokes are less common, they are more cataclysmic. They occur when an artery in the brain bursts, spilling blood into the brain itself (an intracerebral hemorrhage) or into the fluid that surrounds the brain (a subarachnoid hemorrhage). The rupture typically occurs in an aneurysm, a tiny area of the artery wall that has ballooned out and is weak. Some aneurysms are caused by an inborn abnormality of the artery wall, but many are caused by vascular damage due to high blood pressure and other factors that can respond to a program of prevention.

Types of stroke

Hemorrhagic stroke	Ischemic stroke
• 20% of strokes • caused by ruptured blood vessels followed by blood leaking into tissue • usually more serious than ischemic stroke	• 80% of strokes • caused by blockages in brain blood vessels • brain tissue dies when blood flow is blocked
Subarachnoid hemorrhage	Embolic stroke
• bleeding into the space between the brain and the skull • develops most often from an aneurysm, a weakened, ballooned area in the wall of an artery • severe headache is often the first symptom	• caused by emboli, blood clots that travel from elsewhere in the body to blood vessels in the brain • 60% of all strokes in Americans are embolic strokes; 25% of embolic strokes are related to atrial fibrillation (an irregular heart rhythm)
Intracerebral hemorrhage	Thrombotic stroke
• bleeding from a blood vessel inside the brain • often caused by high blood pressure and the damage it does to arteries	• caused by thrombi, blood clots that form where an artery has been narrowed by atherosclerosis • also known as atherothrombotic stroke

Evaluating your risk
Every man is at risk for stroke — but some have a much higher risk than others. To find out where you stand, use the simple evaluation scale (below) developed by the Framingham Heart Study.

Other risks
The Framingham risk calculator considers age, blood pressure, diabetes, smoking, and heart disease — the major stroke risk factors. But there are others. The list includes familiar heart disease risk factors such as unhealthy cholesterol levels, obesity, stress and depression, and lack of exercise. It also includes emerging risk factors such as elevated levels of homocysteine (an amino acid in the blood; see HMHW, January 2001) and C-reactive protein (a marker of vascular inflammation; see HMHW, January 2002).

It’s a long list, and it’s getting longer each year as scientists learn more about stroke. But if the risk factors are a worry, they are also an opportunity: A comprehensive program to reduce risk can protect you from stroke (see HMHW, November 2003). In most cases, prevention includes long-term lifestyle modification, medication, or both. But in men with warning symptoms, the time scale is altogether different. For them, prevention is urgent.

More about strokes
Recognizing strokes
Stroke is a medical emergency. If you think you are having a stroke or if you spot symptoms in another person, call 911 first, then call your doctor.

It’s straightforward advice — but how can you recognize a stroke? It’s tough: The symptoms vary, and many less urgent conditions can mimic stroke. And some strokes can be clinically silent, but a 2003 study reported that even symptomless strokes can add up to increase a person’s risk of cognitive impairment (dementia) later in life. Silent strokes can elude even the best neurologists, but ordinary folks can learn to spot ordinary strokes. Here are some warning signs:

• sudden, unexplained confusion or loss of consciousness
• a sudden, severe headache
• weakness, numbness, or lack of coordination on one side of the body (face, arm, and/or leg)
• sudden loss of vision
• slurred speech or sudden loss of ability to speak or understand spoken words
• severe dizziness and loss of balance or coordination.

It’s a long list, but you can use a simple three-step test modified from the Cincinnati Prehospital Stroke Scale to see if a stroke is likely. Ask the victim to smile, to raise both arms and keep them up, and to speak a simple sentence clearly. If you detect facial weakness, arm weakness, or impaired speech, you may well be witnessing a stroke.

Flu shots and strokes
Influenza kills up to 35,000 Americans each year, and it makes countless others ill. That’s reason enough to get a flu shot each fall. But if you need any extra motivation, consider a French study that linked the vaccinations with a 50% reduction in the risk of stroke during the subsequent year. A 2003 American study is a bit less optimistic, reporting an 18%–23% reduction in strokes among vaccine recipients, but it also linked vaccinations with a 49% reduction in total deaths. It’s an unexpected finding that will have scientists rolling up their sleeves to do more research. While they’re at it, roll up your sleeve for a flu shot this autumn.

Unusual risk factors
Advancing age, high blood pressure, diabetes, smoking, unhealthy cholesterol levels, and heart disease are the main stroke risk factors. Others include lack of exercise, high levels of homocysteine or C-reactive protein, and personality factors. But research has identified other possible risk markers; here are some of them.

Height. A study of 10,059 Israeli civil servants found that short men have the highest risk of stroke. For men who are 5 feet 3 inches or less, the risk is 22.7 per 10,000 person-years. The risk declines progressively with increasing height; men 5 feet 7 inches or taller have a risk of only 13.6 per 10,000 person-years.

Abdominal obesity. Extra fat is never good, and extra fat around the midsection is particularly dangerous. Researchers at Columbia University reported that men with waist–hip ratios above .95 had almost three times more strokes than men with svelte profiles.
Education. In evaluating 22,392 volunteers, a team of researchers from Buffalo found that people with 12 or fewer years of education were one and a half times more likely to have strokes than people who had attended college.

Dental disease. In a 2003 study of 41,380 men, Harvard scientists linked periodontal disease and other dental problems severe enough to cause tooth loss with a 57% increase in the risk of stroke.

Family stress. An Israeli study reported that men with problems at home are more likely to die from strokes than men with happy family lives. Financial stress had a similar impact.

More studies are needed to learn if these minor risk factors add up to real trouble. In the meantime, it certainly won’t hurt to study hard, stay lean, take good care of your teeth, and smile a lot, especially at home. You may not get any taller, but your health prospects will look up.

Viagra and stroke
Viagra (sildenafil) is famous for its ability to improve the function of one part of a man’s body by increasing blood flow. But can it also help another part of the body when it needs more blood? Might Viagra help stroke patients recover by increasing blood flow to the injured brain?

Perhaps — at least if the patient is a rat. Researchers in Michigan produced ischemic strokes in rats by temporarily blocking blood vessels. During their recovery, the animals were divided into three groups. One received no treatment, another low-dose Viagra, and the third high-dose Viagra. The animals who got Viagra recovered better, with the highest doses producing the best results. The scientists concluded that Viagra actually stimulated the growth of new nerve cells in brain tissue next to the stroke damage.

It’s far too early to know whether Viagra may someday help people with strokes. Stay tuned for the results of additional research.

Warning signals
Everyone should take steps to reduce his risk of stroke, but those steps are most pressing for men at the highest risk. And men with warning symptoms are at the highest risk of all.

Warning symptoms mandate urgent medical evaluation and prompt treatment to prevent a stroke. Despite their importance, only 39% of Americans understand those symptoms.

The term “stroke” is derived from a Middle English word meaning “blow” or “sudden attack”; the popular synonym “shock” also implies that most strokes are unexpected. Even so, many are preceded by warning symptoms called transient ischemic attacks (TIAs).

The symptoms of TIAs resemble those of strokes, but they resolve completely within 24 hours because blood flow is restored before brain cells die. But since many patients with TIAs go on to have strokes, it is essential for people who experience warning symptoms to get medical attention. TIAs can produce abrupt, painless loss of vision in one eye, slurred speech, or an inability to understand or use words. They may also produce clumsiness, weakness, or numbness of the face, arm, or leg on one side of the body. Less often, TIAs can cause abrupt but temporary dizziness, usually accompanied by loss of balance, double vision, or slurred speech. A typical TIA lasts just 2–15 minutes, and half of all patients are back to normal in less than an hour.

A TIA is a call for prompt diagnosis and aggressive preventive measures. But men don’t have to wait for TIAs to take steps to reduce their risk of stroke; in fact, the best time to start is now.

The November 2003 issue of Harvard Men’s Health Watch reviews a comprehensive program of prevention.

Personality and stroke
Several studies suggest that mental factors may contribute to stroke risk. Anger appears to play a role. When researchers in Michigan evaluated more than 2,000 men over seven years, they found that the men who scored high on the Spielberger Anger Scale were two times more likely to have strokes than their calmer peers. The results were not explained by other risk factors. But a 2003 Harvard study of 23,527 men shows that men who express their anger are 58% less likely to suffer strokes than men who hold their anger in.

A Swedish study implicated stress. Researchers administered a mentally stressful test to 238 men with high blood pressure. After the scientists observed the men for 10 years, they found that the volunteers who had become flustered and stressed during the test were three times more likely to suffer strokes than those who had remained calm and collected. Similarly, an 11-year study of 2,303 Finnish men found that the men whose blood pressures soared in response to the mental stress of an upcoming medical test were 72% more likely to suffer strokes than those who did not get so worked up.

Depression is the third personality factor that has been linked to stroke. Researchers administered a personality test to 2,478 people in North Carolina; all the volunteers were older than 65 when the study began. Over the next six years, the people who displayed depression were 25% more likely to have strokes than those who exhibited emotional well-being and optimism. And a study of 1,703 people in Maryland reported an even stronger link between depression and stroke; over a 13-year period, depressed people were 2.6 times more likely to suffer strokes than individuals who were not depressed. In both studies other risk factors did not account for the results.

More research is needed to know whether reducing anger, stress, or sorrow can lower stroke risk. But it’s certainly wise to try to stay cool and lift your spirits without blowing your top.