Heart disease tends to develop about 10 years later in women than in men, but the gender gap decreases with age, and women face a higher risk as they get older.
Why are younger women at lower risk of heart disease than men? What protects them?
“Evidence indicates that sex hormones, namely estrogens, provide a cardioprotective effect to women before menopause, which may explain the lower incidence rates observed in younger women compared to men or postmenopausal women of the same age,” explains the Public Health Agency of Canada.
However, this protective effect disappears shortly after menopause, when these sex hormones decrease. The risk of coronary heart disease then rises sharply. Risk factors in postmenopausal women, such as increased cholesterol levels and a high prevalence of hypertension and diabetes, make these individuals more vulnerable to heart disease. Although mortality rates associated with heart disease are decreasing overall, the decline has been slower in women.
In addition, because heart disease in women generally affects the small blood vessels of the heart rather than the large coronary arteries, the symptoms women experience may differ from the typical ones experienced by men. Because the signs of a heart attack are harder to recognize, women have been found to wait longer before taking action. These delays may lead to poorer outcomes for women than men, including higher hospital mortality rates, the agency adds.
An alarming portrait
Heart disease is consequently the leading cause of premature death among women in Canada, and 78% of women missed the early signs of an impending heart attack. A woman dies of heart disease in Canada every 20 minutes. Women are five times more likely to die from heart disease than from breast cancer.
"Women are more likely than men to die or have a second heart attack within the first six months of a cardiac event," the Heart and Stroke Foundation of Canada (HSFC) said in a 2018 newsletter.
What’s more, after a heart attack, women are less likely to be prescribed medications such as drugs to regulate their blood pressure or lower their cholesterol levels. About 90% all people affected by spontaneous coronary artery dissection (SCAD) are women. Women who have had a heart attack are also half as likely as men to undergo cardiac rehabilitation, which is essential to avoid a recurrence.
From drugs to adverse effects
To make matters worse, some heart medications have been found to cause more adverse effects in women than in men, and these effects may even be more severe. Women are at greater risk of developing drug-induced heart rhythm disorders, and the risk of bleeding complications associated with many common treatments, such as angioplasty, is twice as high for women.
Another aggravating factor is that women are under-represented in cardiology research. Two-thirds of clinical studies of heart disease involve men only. Because many of the tests used to diagnose a heart attack were created by and tested on men, the HSFC is concerned that they may not be able to detect heart disease or a heart attack in women.
"In the case of heart disease," Dr. Quoc Dinh Nguyen, professor at the Faculty of Medicine of the Université de Montréal and geriatrician explains, "the most significant under-representation of women and older people is in coronary artery disease (CAD) and heart failure. Although, 54.6% of people with CAD in the United States are women, only 27.4% of participants in clinical trials for CAD are women.”
A study conducted by Nguyen published in Circulation: Cardiovascular Quality and Outcomes finds that researchers continue to test new interventions on people with an average age of 63, who are mostly male (71%), even though the majority of people affected by heart disease are women, and the average age of people with the two most common heart disease is between 68 and 69.
Because signs of a heart attack are different for women (nausea, sudden fatigue, shortness of breath) than men (chest pain, left shoulder pain, sweating), women are more likely to visit the emergency department and are therefore less likely to receive prompt treatment for their condition. Time undoubtedly plays a crucial role in reducing mortality and morbidity.
