Strong link found between strokes, stress

Stress and psychological angst may be as deadly to the brain as they are to the heart, a large new study suggests.

Researchers who followed nearly 69,000 British men and women over eight years found that psychological distress was associated with an increased risk of death from stroke.

Until now, there has been a "paucity" of evidence linking mental stress with stroke, the team reports in last week's issue of the Canadian Medical Association Journal.

"What you find in the literature is that most of the work is on heart disease -- and there's very, very little work on cerebrovascular disease," said lead author Dr. Mark Hamer of the department of epidemiology and public health at University College London.

For their study, the team analyzed data from a study of 68,652 adults participating in the Health Survey for England, who had no known history of cardiovascular disease at the outset. The researchers pooled data for 10 different survey years: 1994-2004.

During a home visit, interviewers measured psychological distress using a widely used 12-item questionnaire that taps into overall mental health, including anxiety, depression, social dysfunction and loss of confidence. Questions included, "Do you lose sleep due to worry?"

Overall, nearly 15 per cent of participants showed signs of psychological distress. Those reporting stress were younger and were more likely to be women. They were also more likely to come from lower socioeconomic classes, smoke and to be taking medication for high blood pressure.

The researchers followed participants for an average of eight years. According to death certificates, there were 2,367 deaths from cardiovascular disease -- 1,010 from heart disease, 562 from cerebrovascular disease (essentially, stroke) and 795 other cardiovascular-related deaths.

Compared to people with no symptoms of stress, people with psychological distress had a 66 per cent increased risk of dying from stroke, and the association was similar in size to the link between stress and heart disease in the same group. Overall, the chronically stressed were 59 per cent more likely to die from ischemic heart disease -- a reduced blood supply to the heart causing angina and heart attacks.

The results remained largely unchanged after the researchers took smoking and other risk factors into account.

Smokers have about a 70-per-cent increased risk of death from stroke, Hamer said -- suggesting that mental stress is as risky as smoking, in terms of the size of the effect.

Stress activates the body's sympathetic nervous system. Evidence suggests that people exposed to chronic stress tend to have higher levels of markers of inflammation throughout the body.

It's well known that stress contributes to illness, said Dr. Michael Hill, co-chairman of the Canadian Stroke Congress and director of the acute stroke unit at Foothills Medical Centre in Calgary. Stress-related hypertension is a known biological phenomenon.

"I see this a lot in the clinic where something is happening -- the job is going crazy or there's breakdown in the marriage, and the blood pressure goes up, and it stays up until the social situation resolves," Hill said.

"There is no doubt that the things that happen in people's environment -- their life, their ability to manage and interact with their life -- results in changes in their biology which puts them potentially at risk," Hill said.

Psychological distress manifests in things such as a suppressed immune system, hypertension and other biological changes that either expose an underlying illness or disease, or speed up its progression, he said.

"Not everyone who has stress has stroke," he said. "But is it a contributor? Absolutely."

About 50,000 strokes occur in Canada each year, and are the third-leading cause of death. An estimated 315,000 Canadians are living with disability due to stroke, according to the Canadian Stroke Network and the Heart and Stroke Foundation. About half of stroke victims are never able to return to work.

Signs of a stroke include sudden weakness or numbness in the face, arm or a leg, trouble speaking, sudden trouble with vision, headaches and dizziness.

-- Postmedia News

Republished from the Winnipeg Free Press print edition June 25, 2012 D1