Undetected strokes increase risk
Everyday, 1,000 people in Canada turn 65, entering a stage of life that has increasing risk of stroke and Alzheimer's disease.
"Recent national and international imaging studies on the brains of people aged 65 and older show that 95 per cent have brain small vessel disease seen as white spots and patches on magnetic resonance images," says Dr. Sandra Black, director of the Brain Sciences Research Program at Sunnybrook Research Institute at the University of Toronto.
These studies also show that a quarter of healthy senior volunteers, average age 70, living in the community, have evidence of small silent strokes. Even in younger people (average age 60), this number may be as high as 14 per cent, according to preliminary results of the Canadian PURE MIND study, presented at the Canadian Stroke Congress in Ottawa, where Dr. Black addressed more than 900 researchers and clinicians.
"Microbleeds, another type of small vessel disease, are associated with high blood pressure and with Alzheimer's disease," she says. Unlike major stroke events, these types of small vessel disease gradually build up and increase the risk of clinical stroke events, depression, falls and Alzheimer's dementia.
"Alzheimer's and small vessel disease often live together in the brains of the elderly in a way that is very disabling," says Dr. Black. "People become depressed, off balance when walking, have trouble thinking and often cannot live on their own. Unfortunately, so far there is no cure for either disease but there are actions we can all take to delay onset or progression."
The time is now for the brain to be the top priority for Canada's health research community, says Dr. Black. In the next 20 years the number of people with dementia and Alzheimer's disease is expected to reach more than one million in Canada alone, increasing ten-fold the current health care costs of$15 billion/year, she says.
"Stroke is adding to the increasing incidence of dementia: 65 per cent of stroke patients experience difficulty with thinking, memory, goal setting and motivation after a stroke and 20 to 30 per cent become clinically demented within three months post-stroke," says Dr. Black.
Research for a cure is being actively pursued but, in the meantime, there are important counter measures people can take to delay and prevent these devastating diseases. This is because stroke and Alzheimer's share the same vascular risk factors, such as high blood pressure, obesity, diabetes, high cholesterol, smoking and a lifestyle of physical inactivity.
"It turns out protecting the blood vessels in your heart and body also helps to protect your brain and its blood vessels. This can delay the onset of dementia," says Dr. Black."For example, regular aerobic exercise throughout the lifespan can help delay the onset of late life dementia, even more so in people who may be genetically prone to dementia."
"Researchers from all fields are going to need to work together," says Dr. Antoine Hakim, CEO and Scientific Director of the Canadian Stroke Network
"Lifestyle choices will have the biggest impact in protecting the hearts and brains of our aging population," says Heart and Stroke Foundation spokesperson Dr. Michael Hill.