Stroke more than doubles risk of dementia

The link between stroke and dementia is stronger than many Canadians realize, the Heart and Stroke Foundation says, while stressing risk factors for both may be reduced with preventive action.

Link between stroke and dementia stronger than many Canadians realize, and prevention is key

After Susan Robertson suffered a stroke in 2011, her short-term memory continues to be affected. She also faces increased risk of dementia. A Heart and Stroke Foundation report stresses the importance of preventing stroke to reduce the risk of dementia. (Facebook/Heart and Stroke Foundation)

When Susan Robertson's fingers and left arm felt funny while she was Christmas shopping, they were signs of a stroke she experienced at age 36. The stroke survivor is now concerned about her increased risk of dementia.

The link between stroke and dementia is stronger than many Canadians realize, the Heart and Stroke Foundation says.

The group's annual report, released Thursday, is titled "Mind the connection: preventing stroke and dementia."

Stroke happens when blood stops flowing to parts of the brain.

Robertson, 41, of Windsor, Ont., said her short-term memory, word-finding and organizational skills were impaired after her 2011 stroke. She's extremely grateful to have recovered the ability to speak and walk after doctors found clots had damaged her brain's left parietal lobe.

"I knew what was happening, but I couldn't say it," the occupational nurse recalled.

Dementia risk

A stroke more than doubles the risk of dementia, said Dr. Rick Swartz, a spokesman for the foundation and a stroke neurologist in Toronto.

Raising awareness about the link is not to scare people, but to show how controlling blood pressure, not smoking or quitting if you do, eating a balanced diet and being physically active reduce the risk to individuals and could make a difference at a society level, Swartz said.

While aging is a common risk factor in stroke and dementia, evidence in Canada and other developed countries shows younger people are also increasingly affected.

"Stroke in young adults 18 to 44 [is] more common than MS [multiple sclerosis] in that population," Swartz said.

Yet a poll commissioned by the foundation suggested less than half of Canadians know what a stroke is and less than a third understand what dementia is.

The foundation urges people to remember to act fast when the signs of stroke occur, such as:

  • Face drooping?
  • Arms — can you raise both?
  • Speech — is it slurred or jumbled?
  • Time — call 911 right away.

Both obvious strokes and covert strokes, which happen when a small blood vessel becomes permanently blocked without outward physical damage, can lead to dementia. The changes from covert strokes can only be seen on a brain scan after the fact and often involve weakening the white matter connecting different parts of the brain, Swartz said.

Prevention pays off

Dementia usually affects memory, and by definition is a decline in mental ability severe enough to interfere with daily life. 

High blood pressure is the most important risk factor for stroke that Canadians can change, and there is also a link between high blood pressure in middle age and cognitive decline, according to the report.

"Prevention is often hard work," Swartz said. "It may have tremendous impact if we figure out how to do it well and broadly."

The report reaffirms advice from the Alzheimer Society of Canada.

One of the best ways to cut the risk of vascular dementia later in life is to take better care of cardiovascular health, said Dr. Larry Chambers, scientific adviser at the Alzheimer Society of Canada.

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