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 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 Jönköping University in Sweden, in email to
Reuters Health.
In this new analysis, which pooled the results of 14 earlier studies
from Europe, people with job strain had an increased risk of
so-called ischemic stroke. Ischemic strokes happen when the brain
doesn’t get enough oxygen – when, for example, the arteries are
clogged.
Fransson, senior author Mika Kivimäki of University College London,
and their coauthors 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 than for the others.
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 are all important risk factors, but this data was not
available for most people in the new study.
The researchers accounted for basic socioeconomic status, which they
used as a stand-in for other health risk factors, which lessened the
increase in ischemic stroke risk for those with stressful jobs.
“This present study is good contribution but of course the results
present more questions,” according to Susanna Toivanen, associate
professor of sociology at the Center for Health Equity Studies in
Stockholm, Sweden, who was not part of the new analysis.
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Some strokes may have a genetic component, which may be why the
researchers did not find an association with hemorrhagic stroke,
Toivanen told Reuters Health by phone.
“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.
In any case, Fransson and Tovianen agreed that job strain is hard
for an individual to change, even if it is increasing his risk for
stroke.
“Here we have a very big issue because it’s employers’
responsibility to see that working conditions are healthy,” Tovianen
said. “Individuals can’t control this.”
Stress is only one of the potential factors at play with stroke
risk, Fransson noted.
“The recommendations are to keep track of your blood pressure, do
not smoke, eat well, keep a healthy weight and exercise,” Fransson
said. “Along with that it may also be good to try to avoid long
periods of stress, but we do not currently have evidence from
interventions to prove this.”
SOURCE: http://bit.ly/1yrpfw0 Stroke, online January 6, 2015.
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