Job stress linked to type of stroke

People who have demanding jobs and job strain are more likely to suffer one type of stroke, a review of previous studies suggests.

Job strain has been linked to heart-attack risk in the past, but not necessarily to stroke.

“Previous studies on the association between job strain and stroke have showed mixed results, with some studies showing an association and others not,” said lead author Eleonor I. Fransson, of the School of Health Sciences at Jonkoping University in Sweden, said in an email.

In this new analysis, which pooled the results of 14 earlier studies from Europe, people with job strain had an increased risk of ischemic stroke. It happens when the brain doesn’t get enough oxygen — when, for example, the arteries are clogged.

Fransson, senior author Mika Kivimaki of University College London and their co-authors used data from 14 European studies between 1985 and 2008. Altogether, almost 200,000 adults filled out questionnaires about job strain. The studies lasted nine years on average.

Those with a demanding job and little control over their work environments were categorized as having high “job strain.” This accounted for 13 to 22 percent of people, depending on the original study.

In general, out of every 100,000 people in Europe, each year 115 men and 75 women have an ischemic stroke, earlier research has shown.

In the new study, the risk of ischemic stroke was about 24 percent higher for people in the job-strain group.

There was no difference in risk of hemorrhagic stroke, another common type in which a blood vessel ruptures and leaks blood into the brain.

High blood pressure, diabetes, high cholesterol and family history of stroke all are important risk factors, but this data was not available for most people in the new study.

Some strokes might have a genetic component, which may be why the researchers did not find an association with hemorrhagic stroke, Toivanen said.

“The classification is not so exact, and they don’t discuss these different types of hemorrhagic stroke,” she said.

This and other studies do not necessarily prove that stressful jobs cause strokes, Fransson noted.

“However, the association is plausible because stress might cause release of stress-related hormones, which in turn affect the metabolic, immunological and cardiovascular systems,” she said. Ischemic stroke, like heart attack, is closely linked to atherosclerosis, the “hardening of the arteries,” she said.

The researchers said the risk of ischemic stroke was 24 percent higher for people with high job strain.