By Wendy Haaf
Simply put, cardiovascular disease threatens women more than it does men
In early 2022, Mafaz Ismail, then 54, began feeling as if her body had been sapped of energy. Her customary long walks with her daughter along the Vancouver shoreline left her feeling short of breath. “It was as if I’d run a mile,” she says. It was a stark contrast to when she was able to work 14-hour days as an assistant to the former UAE health minister in Dubai despite living with type 1 diabetes (T1D). Nevertheless, she simply blamed the problem on such things as a recent heavy meal, aging, or being out of shape.
That lack of concern, along with her not having a family doctor at the time, nearly proved fatal. By the time she was diagnosed almost a year later with 90 per cent blockages in three of her coronary arteries, her condition was so critical that it was touch and go whether she’d make it through bypass surgery.
Ismail’s story illustrates some unfortunate truths about women and cardiovascular health. Many Canadians still don’t understand that not only are heart disease and stroke at least as big a problem for women as they are for men but some traditional risk factors affect them more powerfully. Take T1D, for instance. The autoimmune disorder quadruples heart-disease risk in women versus doubling it for men.
Ismail says she was never informed of this fact, even though she was diagnosed with T1D in early adulthood.
Women are also more likely to experience symptoms such as extreme fatigue and jaw pain, which both medical professionals and women themselves may not recognize as potentially urgent. For example, while Ismail’s endocrinologist recognized that her symptoms could be heart-related and arranged for a referral to a cardiologist, she then waited 10 months for an appointment. And not all women in Canada have equal access to the medical services needed for timely diagnosis and treatment. An estimated 20 per cent of Canadians don’t have a family physician, and the rate is as high as 75 per cent in some regions.
Understanding your individual risk factors and taking steps to manage those under your control can go a long way towards protecting your heart health and quality of life. The results of an international study called INTERHEART hint at just how much: it found that nine potentially modifiable risk factors accounted for 90 per cent of heart-attack risk in women: smoking, hypertension, diabetes, waist-to-hip ratio, dietary pattern, physical activity, alcohol consumption, blood cholesterol and related substances, and psychological factors such as depression.
Here’s what you should know about the aspects of heart disease that are unique to women.
Greater Impact
First, “smoking, blood pressure, diabetes, obesity, physical inactivity, and depression have a greater impact on women,” says Dr. Sherryn Rambihar, a staff cardiologist at Mackenzie Health and an adjunct assistant professor in the Department of Medicine at the University of Toronto.
For one thing, both the prevalence (total number of cases) and incidence (new cases) of high blood pressure are greater among women aged 60 or older compared to men in the same age bracket, and their hypertension is less likely to be well controlled. And in women, type 2 diabetes is linked with up to a 50 per cent greater increase in heart-disease risk compared to men.
Obesity is equally common among both sexes in Canada, but women who have it face a 64 per cent increase in cardiovascular-disease (CVD) risk, versus just 46 per cent for men. And according to a 2022 review published in the American Heart Association journal Circulation, not only are rates of depression and anxiety—both of which carry an increased risk of CVD—at least twice as high among women but “adverse cardiovascular outcomes in this context are more frequent in women than men, particularly at younger ages.”
While elevated LDL (“bad”) cholesterol raises CVD risk in both sexes, low levels of HDL (“healthy”) cholesterol are a stronger predictor of death from ischemic heart disease (weakening of the heart due to reduced blood flow) for women than for men, especially after age 65.
Women are also disproportionately affected by a group of more than 100 conditions, many of which come with a hefty increase in heart-attack risk— approximately 80 per cent of people diagnosed with autoimmune disorders, such as rheumatoid arthritis and lupus, are women.
In recent years, it’s become clear that on top of these more familiar risk factors, “women have unique and specific risk factors, especially regarding life stages that men don’t have,” notes Christine Faubert, vice-president of Health Equity and Mission Impact with the Heart and Stroke Foundation.
Polycystic ovarian syndrome, for example, is linked with higher CVD risk, as is a history of pregnancy complications such as gestational diabetes, hypertensive disorders of pregnancy, and giving birth to a low-birth-weight baby.
Another life passage that occurs only in women affects their hearts in ways scientists are only just beginning to understand. One example comes from research conducted in the laboratory of Glen Pyle, a professor of Molecular Cardiology from the IMPART Network at Dalhousie Medicine in Halifax and the Women’s Health Research Institute at BC Women’s Hospital.
“A former grad student of ours looked at perimenopause—the transition phase before menopause—in a mouse model, and she found two things that I think are particularly important,” Pyle says.
“The first was that during that transition, the heart actually remodels—it changes—so that by the time of menopause, it’s fundamentally different. And by the end of that transition, how the heart responds to estrogens is very different.” (In younger women, estrogen appears to have a protective effect on heart health—for instance, it relaxes the arteries and promotes a healthy balance of cholesterol.)
“This leads in two directions,” he adds. “The first is the idea that maybe estrogen therapies should be started before menopause to stop or slow that change and allow women to retain some of the cardiovascular benefits for longer. It also potentially explains why after menopause, estrogen therapy doesn’t seem to have a clear benefit for cardiovascular disease.” (Estrogen therapy isn’t intended to protect against heart disease—it’s prescribed to ease perimenopausal symptoms such as hot flashes and night sweats.)
“We generally know that up to age 60, menopausal hormone therapy is safe for most women, and there are benefits,” Pyle says. “Beyond 60, it starts to become a little cloudy. But there was a study in 2024 that found it’s safe up to age 65 for most women.”
In fact, in the trial, “they did see cardiovascular benefits up to age 65, specifically a reduction in heart-attack mortality.” While a single study is far from enough to change current guidelines based on earlier research that failed to find clear cardiovascular benefits, “it is trending in a positive direction,” he says.
Finally, Faubert says that there’s evidence that a history of treatment for breast cancer also appears to increase CVD.
Greater Prevalence
In addition to differences in the influence and types of risk factors between women and men, women are more prone to certain heart conditions.
First, among women experiencing angina (chest pain caused by a shortage of oxygen to the heart), the cause is three times as likely to be a kind of heart disease that doesn’t involve
blockage of the large coronary arteries as it is for men. Called INOCA (ischemia with no obstructive coronary disease), this condition involves damage to the lining of small vessels that branch off of the main coronary arteries. Heart attacks resulting from INOCA are twice as common in women as they are in men and typically occur at a younger age than the more classic type.
The prevalence of atrial fibrillation, an irregular-heart-rhythm disorder that substantially increases stroke risk, is higher among women than among men, too. In particular, “older women are more likely to have atrial fibrillation,” Rambihar says. In fact, a 2022 US study found that the risk for the condition was 50 per cent higher among women. Age is one risk factor; others include high blood pressure, alcohol consumption, smoking, sleep apnea, physical inactivity, family history, and chronic conditions such as type 2 diabetes.
Women are also more susceptible than men to a specific type of heart failure. “There are two kinds of heart failure,” Rambihar explains. “Women tend to have something called heart failure with preserved ejection fraction (HFpEF).” In essence, the heart muscle stiffens and thickens due to age or hypertension and consequently “doesn’t relax well,” she says, so it doesn’t fill properly. This leads to an accumulation of blood/fluid in the lungs, legs, veins, and tissues, which can cause symptoms such as shortness of breath, decreased ability to exercise, and fatigue. An estimated 64 per cent of cases of HFpEF in women are attributable to eight risk factors, the two strongest being high blood pressure and high cholesterol.
Until recently, the outlook for patients with this form of heart failure was poor, since “there are no medical therapies that reduce mortality,” according to a 2022 expert analysis from the American College of Cardiology. Thankfully, this seems to be changing. Two classes of drugs initially used to treat diabetes are proving to benefit people with this condition. SGLT2 inhibitors (such as dapagliflozin and empagliflozin) have been shown to reduce the risk of hospitalization for heart failure and death from cardiovascular disease regardless of diabetes status. These have become the first therapies for heart failure with preserved ejection fraction.
Additionally, “there is solid cardiac data on Ozempic [semaglutide],” Rambihar says. Used to treat diabetes (and off-label in Canada for treating obesity), “it’s actually almost more of a heart-failure drug.” While more research is needed, according to studies thus far, “it has benefit,” she adds.
While heart disease may affect men and women differently, one thing we know is that detecting and managing risk factors reduces the odds of bad outcomes. And, in fact, thanks to the outsized effect of certain risk factors on them, women arguably reap greater benefits from heart-healthy behaviours such as regular exercise and a reduced-salt Mediterranean-style diet.
“The majority of heart disease and stroke is preventable,” Faubert stresses. “It’s important for women to get assessed so that they have a good understanding of their own personal risk and get the support they need to manage, reduce, or prevent those risks.”
That’s a message Ismail has taken to heart. Following her bypass surgery, she faithfully attended cardiac rehabilitation sessions and changed her eating habits, experimenting with foods such as plant-based cheese. She has shared her story publicly on behalf of Diabetes Canada and been able to resume her regular activities. She is walking more and has even managed to lose some weight.
“I’m much better—90 per cent, which is amazing,” she says.
Ismail’s health crisis also led to her daughter being identified as having a genetic risk factor for heart disease. Consequently, she “can start preventing heart disease early in her life, and that will put her in a position better than mine,” Ismail says.
