Women need to be more aware of their heart disease risk and symptoms, and more gender-specific clinical studies are being called for. CLAIRE O'CONNELLinvestigates
WHAT IMAGE springs to mind when you hear the term “heart attack” – a middle-aged or older man clutching his chest while pain shoots down his left arm?
Think again: cardiovascular disease (including stroke) remains one of the major killers of women worldwide, accounting for more female deaths than all cancers, TB, HIV/Aids and malaria combined, according to the World Heart Federation.
But despite the scale of the problem in women, studies on cardiovascular disease have generally focused on men, and a European campaign is calling for more research into gender-specific risks and treatments.
A key difference between the sexes is that women tend to have heart attacks later in life than men, and seem to be protected before the menopause, explains Dr Blaithnead Murtagh, a consultant cardiologist at the Galway Clinic.
“Women don’t have a lowered risk of heart disease, they have a delayed risk of heart disease,” she says. “So their risk is going to come 10 years later and that has got to do with the menopausal hormones – once the ovarian hormones decrease, your blood pressure is going to start to increase, the ratio of your good cholesterol to bad cholesterol tends to change and women tend to put on more weight around the menopause.”
But while pre-menopausal women could be somehow protected by their hormones, women need to pay keen attention to other risk factors at any age, adds Murtagh, who addressed the Irish Menopause Society Symposium at the Royal Hibernian Academy on Saturday.
“Diabetes is a much more powerful risk factor for heart disease in women than it is in men. Diabetes will increase a woman’s risk of heart disease three to seven fold but it will only increase a man’s risk two to three fold,” she says. “And before menopause, it will negate the protective effect of oestrogen in pre-menopausal women.”
Women also seem to fare particularly badly in the face of risk factors like family history or smoking, adds Murtagh. “Smoking is a much more potent cardiac risk factor for a woman than it is for a man; it actually increases a woman’s risk of dying from a heart attack by about 2.2 fold, where it increases a man’s risk 1.4 fold,” she says.
“This is important because around 80 per cent of women less than 40 years old who get heart attacks are smokers, and 60 per cent of women less than 50 years old who have heart attacks are smokers.”
She adds that mortality rates from heart attack are higher among younger women – if a woman and a man under age 50 each have a heart attack, the woman is twice as likely to die from it.
Heart disease can be more difficult to diagnose in women using standard tests, explains Murtagh, and patients themselves may not even recognise the warning signs quickly – over a third of women having a heart attack won’t have chest pain, but rather more vague symptoms.
“Women will often just have severe fatigue, difficulty sleeping, shortness of breath, indigestion, nausea, vomiting, anxiety or a lot of things that are attributed to stress like shoulder, back or jaw pain, or palpitations,” she says.
“The problem is that the sooner you treat people the better, but if women have got vague symptoms, they are not presenting to the doctor as early and the doctors aren’t sending them into the emergency room as early.”
Awareness is increasing among women, but there’s still a need to emphasise that heart disease is not just for men, says Dr Kathleen McGarry, who chairs the Irish Heart Foundation’s Council on Women and Cardiovascular Disease.
“For a woman the risk of dying from heart disease is actually 10 times greater than dying from breast cancer, yet there’s much more of an awareness of breast cancer among women,” she says.
Earlier this month McGarry attended the Red Alert for Women’s Hearts conference in Nice, which highlighted that women account for only one-third of patients enrolled in European cardiovascular trials since 2006.
The European Heart Network and the European Society of Cardiology are now calling for more inclusion and analysis of women in clinical research and trials.
“If you look at all the major trials, women are very under-represented and the disadvantage there is not only efficacy but the risk profile of a lot of these drugs,” says McGarry, noting that cholesterol-lowering statin drugs in particular need more gender-specific study.
Why do women not sign up? It could be down to social factors like having to look after dependants, she suggests. “If you are on a drug trial it means you have to come to more visits.”
Women may also not be recruited because their disease presents later in life, suggests cardiologist Dermot Kenny, professor of cardiovascular science at the Royal College of Surgeons in Ireland.
“In the last two years we would have entered at least 700 patients in clinical research projects on heart disease and it’s predominantly men, but that’s because the disease predominantly affects men,” says Kenny.
But this means that globally the bulk of clinical cardiac research to date has been on men, so clinical recommendations are generally male specific, he adds.
Kenny and his team have been looking at gender differences in blood platelets, which can increase the risk of heart attack or stroke if they become activated or “sticky”, and are the target of treatments like aspirin.
Even at that cellular level of heart attack risk, men and women are very different, says Kenny, and several questions remain to be answered.
“If we take platelets from a man and platelets from a woman and we study them in the test tube they behave very differently. We can’t attribute it all to hormone effects, there’s some intrinsic difference. We have chased that and we still don’t understand it.”
- For more information on heart health, see www.irishheart.ie
