Why heart attacks are leading cause of death in women, and why many women are unaware of the higher risks they face
The deaths of film star Sridevi Kapoor and TV actress Emma Chambers are a reminder heart attacks kill far more women than breast cancer. Doctors explain the unique and aggravated risks women face, and precautions to take
Breast cancer is the biggest killer of women, right? The most prolific female cancer? Wrong.
In a week in which the world has lost two actresses, Bollywood superstar Sridevi Kapoor, 54, and British comic Emma Chambers, 53, we’re reminded that, in fact, heart disease is the leading cause of death among women globally.
According to the World Health Organisation, seven times more women die of heart disease than breast cancer. Healthcare provider Siemens Healthineers Global concludes that heart disease and stroke account for almost half of all female deaths in China: 43.9 per cent. The Singapore Heart Foundation warns that heart disease has no geographic, gender or socio-economic boundaries, and nine out of 10 women exhibit at least one risk factor for heart disease.
So why are women so susceptible to this silent killer? What are those risks? And how does it feel to suffer a heart attack?
Many heart attack risks are similar in men and women. Obesity and diabetes are universal risks, as is high blood pressure. When blood pressure rises, the heart must work harder, which puts it, and the blood vessels, under strain. This, says Dr Susan Jamieson, “roughs up the walls of the coronary arteries, making a small piece of clot or blood debris likely to stick there and block the artery”.
High blood cholesterol, while a risk in both men and women, has different systems in women and men.
Dr Susan Jamieson is an integrative medical specialist with her own clinic in Central, Hong Kong. She says: “Research suggests that women’s cholesterol is higher than men’s from age 55 onwards.”
Additionally, low levels of HDL (high-density lipoprotein) cholesterol – the “good” cholesterol, which helps lower the risk of heart disease by protecting the heart and arteries, as it helps to filter LDL (low-density lipoprotein) cholesterol away from the artery walls back to the liver to be processed – are a greater risk in women than men.
Dr DeLisa Fairweather, director of translational cardiovascular diseases research and associate professor of immunology at the Mayo Clinic in the US state of Florida, says the risk of heart attack in women is different from that in men.
“Women exhibit unique risks for heart attacks because of how hormones affect inflammation. Oestrogen increases antibody responses in women, which provides women with extra protection against infections, but increases the chance that antibodies may bind to vessels in the heart and increase the risk for a heart attack,” she says.
And talking of inflammation, high homocysteine levels have, Jamieson says, been linked to increased risk of premature heart disease, even among people who have normal cholesterol levels. “It’s the ‘new cholesterol’ and is also related to ageing, bowel cancer and Alzheimer’s. Homocysteine is an amino acid produced in the body as a by-product of metabolic processes. Many things contribute to high levels, but increasing age is one of them. Levels can, however, be controlled with sufficient folic acid and B vitamin intake,” she says.
While family history plays a role in heart-attack risk, there was no history of heart disease in Carolyn Thomas’ family. The Canadian had a heart attack at 58.
“I’d been a distance runner for decades, my cholesterol levels were normal and I was almost a vegetarian (except for bacon). In the week before my heart attack, I had two episodes of severe shortness of breath that stopped me in my tracks,” Thomas recounts. She had to stop walking to catch her breath, but didn’t register the significance of this until after her heart attack.
Thomas’ heart-attack symptoms came out of the blue. “Suddenly, [I had] central chest pain, nausea, sweating and pain down my left arm,” she says. Despite her obvious cardiac symptoms (some women experience vague, atypical heart attack symptoms like jaw pain or crushing fatigue), all Thomas’ diagnostic tests at the accident and emergency department were “normal”. She was sent home with a diagnosis for acid reflux, “feeling very embarrassed because I’d just made a big fuss over nothing”.
When her symptoms returned, she didn’t return to the accident and emergency department – “because I knew it was not my heart: a man with the letters M.D. after his name had clearly told me, ‘This is not your heart!’” Her symptoms worsened, and finally, desperate, she returned to A&E, where she was diagnosed with significant heart disease and myocardial infarction, a heart attack.
Her major coronary artery was 95 per cent blocked – a “widow maker” level; patients who experience a major blockage of this severity in the left main or the left anterior descending artery do not survive without emergency medical assistance.
That the phenomenon is nicknamed “widow maker” reflects the fact that almost all cardiac research has been done on (white, middle-aged) men. This gender gap in cardiology, Thomas says, “is also why diagnostic tests are more accurate in identifying men’s heart disease compared to women’s”.
It also sustains a myth that lulls many women into a false sense of security. As Jamieson says: “They think it’s a male problem, especially as they tend to exhibit more subtle symptoms.”
Dr Jason Ko Kwok-chun, consultant cardiologist at Hong Kong’s Adventist Hospital, says that the age at which women suffer a first heart attack has fallen. He agrees that “women who present with a heart attack more frequently present without chest pain. According to the national registry of myocardial infarction in the United States, a significantly higher proportion of women had a silent [heart attack] than men.”
Women also tend to have a higher risk of developing spontaneous coronary artery dissection, or SCAD, Ko says.
“This can occur during pregnancy, or during extreme stress when a layer of the vessel suddenly tears due to sudden stress on the vessel wall. Women are also more likely to suffer from what is referred to as ‘broken heart syndrome’ – the sudden release of stress hormones during stressful events which causes acute heart failure, or stunning of the heart.”
Ko echoes Fairweather. “After menopause, women’s vessel-protective female hormone – oestrogen – declines. Vessels lose elasticity and blood pressure rises. Cholesterol levels also increase. All these cardiovascular risk factors increase the possibility of a heart attack.”
Ko elaborates on further risks that women face. “Diabetic female patients tend to have a higher heart-attack risk than diabetic men, probably due to associated risk factors that are more prevalent among diabetic female patients such as obesity, hypertension, and a high cholesterol level, together called the metabolic syndrome; diabetes also affects smaller vessels worse, and women tend already to have smaller heart vessels than men.”
The latter, as Fairweather observes, is an omnipresent risk in women. “Heart disease in women,” she reminds us, “often involves hypertension or an increase in blood pressure that is due in part to the simple fact that women have smaller vessels than men do”.
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Other cardiovascular risk factors peculiar to women include premature menarche, pre-eclampsia – high blood pressure in pregnancy – and premature birth.
Thomas, who began her blog Heart Sisters in 2009 to raise awareness of heart disease in women and published A Woman’s Guide to Living with Heart Disease in November 2017, had no idea that the pregnancy complication pre-eclampsia, which she suffered during her first pregnancy, was a serious risk factor for future heart attack, raising the risk by two to three times.
Fairweather adds that a type of hypertension, pulmonary arterial hypertension, occurs around four times more often in women than men, “but women with autoimmune diseases like lupus, rheumatoid arthritis or systemic sclerosis – which in themselves increase the risk of heart disease – are nine times more likely to develop this form of hypertension”.
Clearly, then, there are a number of heart attack risk factors specific to women. So what can they do to protect themselves?
“After menopause,” Jamieson says, “have yearly check-ups of blood pressure, cholesterol and glucose. Women often say so to me, ‘Oh my cholesterol is really low, I don’t need it checked’. Sadly, they do: it rises with age.”
Whatever you do, Ko warns, do not smoke. “For some unknown reason, female smokers are more likely to suffer a heart attack than male smokers. They are also less successful at quitting.”
Like all doctors, he encourages moderate intensity exercise for at least 30 minutes five days a week, and advocates the DASH – dietary approaches to stop hypertension – diet. It is rich in fruit, vegetables, whole grains, and low-fat dairy foods; it includes meat, fish, poultry, nuts, and beans, but limits sugar-sweetened foods and beverages, red meat, and added fats.
Keep a close eye on those all-important numbers: your blood pressure, your weight, your glucose levels, your body mass index (BMI), derived from your weight and height, and your waist measurement.