It is well known that more women than men die of stroke even though men are more at risk.
Experts have in the past suggested this is because women live longer than men, giving them a greater likelihood of stroke.
Scientists at the University of Toronto are now suggesting however that other factors are involved.
In a new study it has been found that the mortality gap has grown steadily to the point where 45 per cent more women now die of stroke than men.
Moira Kapral, an associate professor of medicine at the university says while aging is part of the explanation it fails to explain why the gap has grown over time and something else appears to be going on.
Three decades ago in 1973, there were 8,523 female deaths from stroke, compared to 7,702 male deaths - a 10 per cent gap.
When Dr. Kapral conducted an analysis of newly published mortality data she found that in 2004, 8,667 women and 5,959 men died of stroke in Canada - a 45 per cent difference.
There are two main kinds of stroke, an ischemic stroke where a clot blocks blood flow to the brain and a hemorrhagic stroke which results from a burst vessel in the brain.
For both men and women the main risk factors for stroke - high blood pressure, smoking, diabetes, inactivity and high cholesterol - are the same.
But some risk factors are more common to women such as migraines which 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, increases the risk of stroke by about 40 per cent;
Oral contraceptives slightly increase the risk of blood clots and stroke, but are a particular problem for women who smoke or suffer migraines.
Dr. Kapral says while these factors increase the risk for stroke they still do not explain the higher number of deaths.
Dr. Kapral found one area worthy of further examination - the fact that many older women, those most likely to suffer a stroke, live in isolation.
Dr. Kapral says when a man suffers a stroke, he usually has a wife caring for him 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 neurologists say 'time is brain."
The symptoms of a stroke, dizziness, numbness, trouble speaking, sudden confusion, vision loss must be taken seriously and acted on as treatment within 3 hours can mean a full recovery.
About 50,000 Canadians a year suffer a stroke.