Health

Myth: heart attacks and strokes are "men's diseases"

Fact: cardiovascular disease kills more women than men in Canada. To help you beat the odds, Linda Heller reports on the latest research

Lynn Lanigan, a petite and physically active 50-year-old, never smoked, rarely drank and followed a healthy low-fat diet for years. The assistant to the president of an Ottawa consulting firm had no idea that a time bomb was ticking inside her–until one night in June 1991.

“I went to sleep feeling perfectly fine but woke up at 2:30 in the morning dizzy and confused,” Lanigan recalls. “I had a tingly feeling in my left side and a terrible numbness in my leg. I knew something awful had happened.”

Still, she hoped the problem was temporary and put off seeing her family doctor for two days. He referred her immediately to a neurologist, and a CT scan (computerized X ray) of her brain showed that she had suffered a stroke. A clot had blocked the blood flow to a tiny part of the brain’s right side, which controls movement on the body’s left side.

Today, Lanigan’s left side remains weak, and she still has a pins-and-needles sensation in her hands, feet and around her mouth. She also experiences occasional forgetfulness, loss of balance and searing migraines. But she is able to work and lead an active life. In a sense, she is lucky. However, Lanigan might have avoided a stroke altogether if she had recognized early warning signs. “Looking back, I now recall having momentary periods of dizziness, tingling in my arms and legs, blurred vision and bad headaches. But I was too busy to bother about all of this and I certainly didn’t think I was at high risk for a stroke.”

Lanigan isn’t alone in her beliefs. According to a Heart and Stroke Foundation survey, only 9 percent of women are aware that cardiovascular disease is the number one killer of women in Canada, causing 41 percent of female deaths versus 37 percent of male deaths. Dr. Lorretta Daniel, a cardiologist at The Toronto Hospital and an assistant professor at the University of Toronto, says, “Contrary to popular belief, women are eight times more likely to die from heart disease and stroke than from breast cancer.” The year that Lanigan had her stroke, 8,159 women in Canada died from strokes, and another 24,874 from heart disease. Although the mortality rate actually dropped 50 percent over the past 40 years, doctors expect deaths to rise again as baby boomers age and as we see the fallout from a surge in women’s smoking during the 1970s.

Most premenopausal women’s chances of developing heart disease are seven times lower than men’s, although they may not be so well protected when it comes to a stroke; for unknown reasons, strokes are about 2.5 times more common than heart attacks among women under 44. When estrogen levels drop after menopause or ovary removal, a woman’s risk of developing cardiovascular disease soon equals a man’s.

But Dr. Daniel says it’s essential for all women to start protecting themselves before menopause because damage can begin early. A U.S. study recently found that some women and men in their 20s and 30s already had the beginnings of atherosclerosis, a gradual thickening and hardening of the arteries that can eventually block the flow of blood to the heart or brain.

One of the factors that particularly increases risk even before menopause is uncontrolled high blood pressure (hypertension), which occurs in about 40 percent of women, although at least one-third of them are unaware they have it since there are often no symptoms. Lanigan’s doctors suspect she had high blood pressure for years, although it was detected only a few months before her stroke. She may have inherited it and high cholesterol (despite her healthy diet) from her father, who died of a heart attack at age 69. As long as Lanigan keeps both conditions under control with the help of medication and a healthy lifestyle, she may never have another stroke, according to one of her physicians, Dr. Antoine Hakim, neurologist-in-chief at Ottawa General Hospital and chair of neurology at the University of Ottawa.

What can you do to reduce your chances of having a stroke or heart attack? Dr. Daniel urges all women to be aware of the risk factors and warning signs, which even doctors sometimes overlook.

How to spot the warning signs

Lanigan’s spells of dizziness, tingling in her arms and legs, and blurred vision were transient ischemic attacks (TIAs), also called mini-strokes, which precede about 10 percent of full-blown strokes. Other common symptoms include weakness or loss of feeling in the arm, leg or face on one side of the body, difficulty in speaking or understanding speech, unexplained unsteadiness or sudden falls. The symptoms usually last only a few minutes, and many people soon forget about them.

But Dr. Hakim says, “You should seek medical attention immediately because TIAs are a signal that part of the brain may soon become permanently damaged. With intervention [drugs or sometimes surgery], we can often prevent a catastrophic outcome.”

Although women’s and men’s TIA symptoms are the same, their symptoms of angina, which can precede or accompany a heart attack, are often different. In addition to the dull chest pain or pressure that men usually experience, many women have a sharp pain or temporary burning sensation in the back, shoulder, neck or arm, or such symptoms as nausea, fatigue, light-headedness, shortness of breath or sweating, which tend to subside with rest. Dr. Lynda Mickleborough, professor of cardiac surgery at the University of Toronto, says that women and even doctors sometimes dismiss the symptoms as a psychological problem, indigestion or the flu.

Linda Sykes, 43, of Jerseyville, Ont., experienced symptoms off and on for months but thought they resulted from being out of shape and allergies. After she finally went to a doctor, she was shocked to learn that she was at high risk for a heart attack. She had a total blockage in one artery, a 90-percent blockage in a second and a 50- to 60-percent blockage in a third.

Diagnostic delays

Tests are sometimes less accurate in women, according to Dr. Daniel. An angiogram, an X ray of blood vessels, may not reveal the narrowing of the tiniest vessels leading to the heart, which occurs more in women than men. In a thallium stress test, which traces blood flow through the heart, women’s breast tissue can interfere with readings. A treadmill stress test is less accurate in women too.

Studies have shown that women are twice as likely as men to die within weeks after their first heart attack and are at greater risk for a second attack within a year, perhaps because their disease tends to be more advanced by the time it’s diagnosed or they are older.

But diagnosing a heart attack may become easier with a new blood test that, within minutes, can detect proteins released when a lack of oxygen damages heart tissue. Clinical trials so far indicate that it is equally effective for women and men, according to its developer, Spectral Diagnostics of Toronto. The test may become available this year.

What increases your risk

High blood pressure
It is the leading risk factor for strokes and increases the risk of heart disease up to four times. Although the exact cause in most cases is unknown, certain factors appear to play a role, such as obesity, heredity and, in some people, a high salt intake and/or low intake of calcium. Some cases are also associated with pregnancy.

Smoking
It more than doubles the risk of a heart attack and stroke because, among other problems, it increases blood pressure, decreases the flow of oxygen to the heart and brain and causes blood vessels to constrict. Research shows that smokers who use oral contraceptives are at particular risk. Health Canada does not recommend the Pill for smokers over 35. Dr. Daniel also warns that smoking can lead to an early menopause.

Some studies indicate that passive smoking is harmful too and may raise the risk of death due to heart disease 20 to 70 percent.

High lipids
A high level of either cholesterol or triglycerides increases risk and, according to recent research, so can a high level of lipoprotein (a). These lipid levels tend to be genetically determined, although cholesterol and triglyceride levels often improve with dietary changes and exercise.

Diabetes
It accelerates hardening of the arteries, tends to raise triglyceride levels and reduces levels of protective high-density lipoproteins.

Other significant factors

Obesity
Excess weight (more than 20 percent above what’s desirable for your height, body frame and age) intensifies the strain on the heart and blood vessels, particularly if the fat concentrates around your abdomen. It also increases the risk of high blood pressure, cholesterol, triglycerides and diabetes.

Physical inactivity
Mainly because it contributes to high blood pressure and obesity, a sedentary lifestyle almost doubles the chances of getting heart disease.

Family history
Some research suggests that, while men are at greater risk only if a parent developed cardiovascular disease before age 55, women are at increased risk even if it occurred later. But Dr. Daniel says risk is highest when there’s a family history of the disease before menopause.

Special risk factors for stroke

People with heart disease or other heart problems, such as atrial fibrillation (a common heartbeat irregularity), are at twice the risk for stroke.

Small preliminary studies in France suggest that women under age 45 with a history of migraines have a higher stroke risk, especially if they smoke or take oral contraceptives. Dr. Hakim advises women who get migraines to avoid smoking and the Pill.

Strokes are more common after frequent episodes of having more than two drinks at one sitting. Excessive alcohol dehydrates the body, causing blood to course so sluggishly through the arteries that it may be unable to reach the brain if there is even just a partial blockage. Dr. Hakim says that more than two drinks a day can also increase the risk of hypertension, heart disease and other defects, such as an irregular heartbeat.

But doctors disagree on the effects of moderate drinking. Some studies have suggested that those who have one drink a day have lower rates of heart disease and cerebral thrombosis, a blood clot in an artery leading to the brain; researchers theorize that a moderate amount of alcohol may improve cholesterol levels and inhibit blood clot formation. But other doctors believe the lower disease rates are actually related to drinkers’ diets or other health habits. And some research suggests that even one drink a day increases the risk for breast cancer.

Treatments and gender differences

Drugs
Some medications commonly used to reduce the risk of heart attacks and strokes may be less effective for women than men. Beta-blockers can reduce the amount of oxygen required by the heart, but some research suggests that at least one type, propranolol, may be ineffective in some women, possibly due to hormonal fluctuations. Calcium channel blockers can improve blood flow through the arteries, but side effects may be more pronounced in women; some studies suggest women may need smaller doses.

Other drugs often used to treat heart disease include ASA, which can help prevent clot formation by reducing the ability of blood platelets to stick together, and anticoagulants, such as warfarin, which reduce the activity of certain blood-clotting factors. Studies show that these medications can also help prevent strokes in high-risk patients, according to Dr. John Norris, chair of the Canadian Stroke Consortium, a research network.

But doctors aren’t certain that women who do not yet have coronary disease reap the same benefits. Also, in some people, excessive ASA use may increase the risk of bleeding in the brain, which can cause a stroke. Dr. Hakim does not advise starting a daily ASA regimen without consulting your doctor first.

Thrombolytic drugs, such as tissue plasminogen activator or streptokinase, can break up blood clots and limit damage to the heart when administered within the first six hours after a heart attack. According to Dr. Daniel, they are equally effective in women and men, but a few women are more likely to experience bleeding complications. Doctors are now testing the drugs on stroke patients to try to limit neurological impairment.

Heart surgery
If drugs don’t work or a vessel is badly clogged, surgery can often help. But a U.S. study of 3,975 women and men, ages 45 to 65, found that doctors referred about half as many women as men for surgery; not surprisingly, a greater number of women than men (6.9 percent versus 2.5 percent) subsequently suffered heart attacks or cardiac deaths within two years. Other studies, however, have shown that, even when women have surgery, they are more likely to die, possibly because they’re older and sicker by the time they are diagnosed.

But Dr. Mickleborough says, “Provided all risk factors are comparable, surgery can be just as successful in women as in men.”

Obstructions can often be cleared by an angioplasty. Inserting a miniature catheter with a small balloon in the artery, the cardiologist inflates the balloon to flatten the obstruction against the artery walls, then removes the deflated device. But in at least 25 percent of cases, the artery narrows again, often within the first six months (new research suggests a virus may be partly responsible). The patient then requires another angioplasty or bypass surgery, which constructs a detour around the artery blockage, using a blood vessel from another part of the body.

Endarterectomy
This surgery can correct the most common cause of strokes, a blockage in the carotid arteries, which run through the neck to the brain. A recent study shows that the procedure, removing part of the artery lining damaged by atherosclerosis, is as successful in women as in men.

Sykes has had no angina attacks since she had an angioplasty two years ago, quit smoking, started walking about five kilometers a day and reduced the fat in her diet. She wishes she had paid more attention to her health sooner: “I tell my friends, if you’re not feeling well, go to the doctor–don’t put it off.”

How to protect yourself

Dr. Daniel and other specialists recommend:

·Get your blood pressure checked at least once a year. Your doctor may recommend more frequent checks if you have known risk factors or already have high blood pressure.

·Don’t smoke. Once smokers kick the habit, the risk of death from heart disease and stroke gradually decreases.

·Reduce your fat intake to 30 percent or less of your daily calories.

·Limit your cholesterol intake and have a cholesterol test at least every five years. If you have a family history of high cholesterol, heart disease or stroke, or if you’re postmenopausal, a test every two years is prudent.

·Keep your weight healthy and be physically active. Do 20 to 60 minutes of aerobic exercise–e.g., brisk walking, swimming, cycling–three to four times a week.

·Eat at least five servings of fruits and vegetables a day. Several studies have shown that antioxidant vitamins (C, E and beta-carotene) in fruits and vegetables protect against the oxidation of low-density lipoproteins, the process that turns the lipids into an artery-clogging form of cholesterol, according to Jeffrey Blumberg, chief of the antioxidant research laboratory at the U.S. Human Nutrition Research Center on Aging.

·Consult your doctor about a multivitamin supplement. Harvard University researchers found lower rates of heart disease among women who took vitamin E supplements. Although a Finnish study last year suggested that death rates from heart attack and stroke were slightly higher among men who took beta-carotene or vitamin E supplements, Blumberg says the study didn’t look at prevention because it was conducted on high-risk older smokers. In addition to a well-balanced diet, he recommends a daily supplement with 250 to 1,000 milligrams of vitamin C, 100 to 400 international units of vitamin E, six to 20 milligrams of beta-carotene and about 400 micrograms of folic acid (which may help decrease levels of an amino acid that can contribute to atherosclerosis).

·Consider hormonal replacement therapy after menopause. The Society of Obstetricians and Gynecologists of Canada issued new guidelines last year endorsing hormonal replacement therapy to reduce the risk of cardiovascular disease. Several preliminary studies show that estrogen lowers the risk of coronary heart disease as much as 50 percent, and preliminary studies indicate it may also decrease stroke risk. Since estrogen alone increases the risk of uterine cancer and possibly breast cancer, it’s usually combined with progestin, which protects against the risk of uterine cancer (but not breast). According to Dr. Daniel, the benefits may outweigh the risks for most women, but you should discuss the pros and cons in your case with your doctor.