TUESDAY, Oct. 9, 2007 (HealthDay News) -- Chronic on-the-job stress doubles the risk that someone who has had a heart attack will have another major coronary event, a Canadian study finds.
Other studies have shown that workplace stress boosts heart woes, but this is the first to link job anxieties with recurrent heart attacks and other major events, the report's authors said.
The study, published in the Oct. 10 Journal of the American Medical Association, provides "very solid scientific evidence" on how job strain might contribute to coronary trouble, said Dr. Paul J. Rosch, president of the American Institute of Stress.
In their study, a group led by Dr. Corine Aboa-Eboule, professor of psychology at the Universite Laval in Quebec, gathered information on 972 men and women ages 35 to 59, all of whom had returned to work after a heart attack.
The participants were interviewed an average of six weeks after returning to work and were followed for an average of almost 6 years.
Job stress, or "strain" as the researchers called it, was defined as workplace environments with high psychological demands but low worker control of decisions made on the job.
During the follow-up period, 82 of the participants suffered unstable angina (chest pain), 111 had nonfatal heart attacks, and 13 had fatal heart attacks.
After adjusting for risk factors for heart disease, as well as lifestyle, sociodemographic and work-environment characteristics, workplace stress doubled the odds of such heart troubles, the team found.
One striking finding: There was no association between the social support workers got and their increase in heart risk, Rosch said. "The most powerful buffer we know against stress is strong social support," he said. However, "in this study, it did not have that effect, which is sort of counterintuitive," Rosch added.
For that and other reasons, the new study provides "many more questions than answers," Rosch said. People who feel that job stress might be affecting their health could try changing jobs, he said, but "you never know whether you're going from the frying pan into the fire."
"Further studies are needed to establish optimal interventions," the researchers wrote. But, they said, "information about the results of this study should be disseminated in cardiac practice and in occupational health services with the aim of reducing job strain for workers returning to work" after a heart attack.
A review of the scientific literature on the relationship between stress and disease, published in the same issue of the journal, finds that stress contributes to illness from depression, cardiovascular disease and HIV/AIDS.
The review is based on a paper commissioned by the U.S. Institute of Medicine to consider the behavioral and biological mechanisms by which stress contributes to disease. Sheldon Cohen, professor of psychology at Carnegie Mellon University, is the principal author.
His team found the strongest evidence for a link between stress and depression, although studies such as the one just done in Canada also show stress boosts heart risks, too. Recent studies have shown links between stress and progression of HIV/AIDS, the review found.
One possible mechanism for the effect is behavioral, with people under stress sleeping poorly, eating badly, not exercising and not complying with medical orders, the review authors said. Stress might also have adverse effects on the body's immune and inflammatory systems.
Stress' role in cancer remains unclear, since there are many forms of cancer, some of which take a long time to develop. For that reason, progression is often difficult to measure, the authors said.
There's more on stress' impact on sickness and health at the American Institute of Stress.