For as long as statistics have been kept, more women than men have died of stroke.
The standard explanation is that women live longer than men, giving them a greater likelihood of stroke (a condition associated with aging) and leaving women more vulnerable to the potentially deadly effects of interrupting blood flow to the brain.
But new research is calling this theory into question, suggesting that there are other factors. A new study shows that the mortality gap has grown steadily to the point where 45 per cent more women now die of stroke than men.
"Aging is part of the explanation for the gap but it doesn't explain why the gap is growing over time," said Moira Kapral, an associate professor of medicine at the University of Toronto and spokeswoman for the Heart and Stroke Foundation.
"There appears to be something else going on, but we don't know what that 'something else' is," she said.
About 50,000 Canadians a year suffer a stroke. An analysis of newly published mortality data, conducted by Dr. Kapral, shows that in 2004, 8,667 women and 5,959 men died of stroke in Canada - a 45 per cent difference.
Three decades earlier, in 1973, there were 8,523 female deaths from stroke, compared to 7,702 male deaths - a 10 per cent gap.
There are two principal kinds of stroke: An ischemic stroke occurs when a clot blocks blood flow to the brain; a hemorrhagic stroke results from a burst vessel in the brain. The main risk factors for stroke - high blood pressure, smoking, diabetes, inactivity and high cholesterol - are the same for women and men.
But there are some risk factors that are more specific to women:
Migraines: Having them doubles the risk of stroke, and women suffer in far greater numbers;
Pre-eclampsia: Pregnancy-related high blood pressure increases the risk of stroke by about 60 per cent;
Hormone replacement therapy: the treatment for the symptoms of menopause was once believed to lower the risk of heart disease, but actually increases the risk of stroke by about 40 per cent;
Oral contraceptives: Taking the Pill slightly increases the risk of blood clots and stroke, but contraceptives are problematic especially for women who smoke or suffer migraines.
But while these factors could increase stroke risk, they don't explain the higher number of deaths, Dr. Kapral noted.
She said one area that warrants further examination is the fact that many older women - those most likely to suffer a stroke - live in isolation.
"When a man suffers a stroke, he usually has a spouse to provide care," Dr. Kapral said. "But women are less likely to have social supports."
Women are also less likely to seek help promptly when they suffer a stroke and that is important because, as neurologists say, "time is brain."
Stephanie Bertossi, a Halifax restaurateur, was trying to book an airline ticket when she found herself suddenly confused and unable to dial the number. She also had trouble speaking, but convinced her husband to dial her sister's cellphone number.
"It's weird. I knew I was having a stroke because my symptoms were identical to my dad's when he had a stroke," Ms. Bertossi said. "But I wanted confirmation. I didn't want to waste people's time at the hospital,"
Luckily, she said, her sister "started screaming at me to call 9-1-1 and get to the hospital quickly."
Ms. Bertossi got clot-busting drugs (which have to be administered within three hours to be effective) and has recovered fully. Follow-up tests showed that she had a small hole in her heart, which was the likely cause of her stroke at the young age of 45.
"Strokes don't just happen to men, and they don't just happen to the elderly," she said.
"We should all know the signs of a stroke [dizziness, numbness, trouble speaking, sudden confusion, vision loss] and take the symptoms seriously."
