"Women who had high-strain jobs had a 40% higher likelihood of having a cardiovascular event compared to women who were in the low-strain category," says researcher Michelle A. Albert, MD, MPH, a cardiologist at Brigham and Women's Hospital and an associate professor of medicine at Harvard Medical School.
"High strain is defined as high demand and low control," she says. A factory job in which a worker is pressured to produce is an example.
Then came the surprise finding. Women in what she calls ''active strain'' jobs -- highly demanding, but with high control -- had the same increased risk as those in the high stress, low-control positions.
Job insecurity was not linked with a risk of heart attack, stroke, and other cardiovascular problems, Albert also found.
The study is published in PLoS ONE.
High-Stress Jobs & Women
The researchers followed more than 22,000 participants in the long-running Women's Health Study. The women's average age was 57.
The women were categorized into four job-strain groups. Job strain takes into account both the demands and the control a worker has. The groups are:
- Low strain: with low demand, high control
- Passive: with low demand, low control
- Active: with high demand, high control
- High strain: with high demand, low control
The researchers followed the women for 10 years, looking to see who had one of four types of events. They found:
- 170 heart attacks
- 163 strokes
- 440 heart procedures such as stents, bypass surgery, or angioplasty
- 52 deaths from cardiovascular disease
The researchers took into account other factors that could affect heart health, such as age, race, education, and income.
Even then, they found the nearly 40% increased risk of any of the four outcomes in the women in the active or high-strain groups.
When they looked just at nonfatal heart attacks, they found women in the high-strain group were 67% more likely than those in the low-strain jobs to have one.
Job insecurity did not appear to increase the risk of heart attack or stroke, she says.
High-Stress Jobs & Women: Perspective
The new findings differ from some previous research, says Mika Kivimaki, PhD, professor of social epidemiology, University College London. He reviewed the findings.
He has published reports on stress and cardiovascular disease. Researchers at University College London have led the long-running Whitehall Studies, also known as the Stress & Health Study, following more than 10,000 British men and women.
"It has been previously thought that high job demands increase cardiovascular disease risk only if an employee additionally has poor decision authority at work," Kivimaki says.
"This study of U.S. women is important because it suggests this might not be the case. Elevated cardiovascular risk was also seen among women who had demanding jobs combined with high job control."
However, he says the researchers just found a link between job stress and heart health, but cannot prove cause and effect.
It's difficult to take into account all the risk factors that may play in, says Peter Schnall, MD, MPH, clinical professor of medicine at the University of California, Irvine.
He is also director of the university's Center for Occupational and Environmental Health program in work organization and cardiovascular disease.
"The field of stress research is only now focusing on job strains, but in the past 10 years another dozen serious work-related risk factors have been documented," he tells WebMD.
Among the most heart-hazardous factors? Working long hours, making low wages, and facing threats of harm, he says. For example, a bus driver.
Advice for Women With High-Stress Jobs
Most important? "Find the thing that works for you to reduce stress," she says.