Men with cardiometabolic disease — specifically, heart disease, type 2 diabetes or a history of stroke — who are working in a psychologically demanding job over which they have little control are at increased risk of dying early, according to a large European study.
The risk is almost as great as smoking and higher than that associated with being obese, not exercising, drinking too much alcohol and having high cholesterol, the study also found.
The study did not observe, however, a similar link between a demanding job and premature death among women, whether or not they had cardiometabolic disease.
And it found only a slightly heightened risk of early death among men without cardiometabolic disease who have a high-demand, low-control job.
These findings suggest, say the study’s authors, that controlling high blood pressure, high blood cholesterol or other elements of cardiometabolic disease may not be enough to reduce the risk of premature death among men who are also experiencing job strain.
Improving the health of those men may also require reducing their work-related stress.
The study was published earlier this month in The Lancet Diabetes & Endocrinology journal.
What the study involved
For the study, researchers pooled data from seven cohort studies involving 102,633 men and women living in Finland, France, Sweden and the United Kingdom. The studies are some of the original studies in the IPD-Work Consortium, whose purpose is to create a large collective database that can be used to study the long-term associations between working conditions and chronic disease.
The participants in the seven cohort studies filled out detailed questionnaires about their health and lifestyle between 1985 and 2002. Those questionnaires revealed that 3,441 of them had heart disease, diabetes or a history of stroke. The medical records of all the participants were then tracked for an average of almost 14 years. During that period, 3,841 of the participants died.
The authors of the current study used the questionnaires to identify two types of work stress among the participants: job strain (having a job that is psychologically demanding, but over which the worker has little control) and effort-reward imbalance (having a job that requires lots of effort but offers little reward in return).
The researchers then looked to see if either type of work stress was associated with a greater risk of premature death.
The data revealed that among men with cardiometabolic disease, those who were experiencing job strain were 68 percent more likely to die over the course of the study than those without job strain.
By comparison, the increased risk of premature death among men with cardiometabolic disease who smoked in the study was 78 percent — only 10 percentage points higher than the risk linked with job strain.
The association between job strain and early death came after the researchers adjusted for various socioeconomic factors linked with an increased risk of cardiometabolic disease, such as income and education levels, as well as a long list of conventional risk factors, including smoking, obesity, high blood pressure, physical inactivity and high alcohol consumption.
An increased risk was found even among those men in the study who had reached their treatment targets for cardiometabolic disease — in other words, those who were eating healthy foods and exercising regularly and who had lowered their blood pressure and cholesterol counts to healthy levels.
Job strain was not associated, however, with a significant increase in risk among men without cardiometabolic disease or in women.
The study also found no association between early death and the other type of work-related stress, effort-reward imbalance, among men with cardiometabolic disease. But, interestingly, men without cardiometabolic disease did have a slightly higher risk associated with this type of work stress.
One possible explanation for that finding, according to the study’s authors, is that men with cardiometabolic disease whose jobs are pscyhologically demanding may be more likely to cut back their work hours and thus reduce some of their work-related stress.
Needed: workplace interventions
This study is observational, so it can’t prove a relationship between job strain and an increased risk of early death among men with heart disease, type 2 diabetes or a history of stroke. Furthermore, the study measured work-related stress only once, at the start of the study. The participants’ job situations may have changed significantly over the course of the study.
Still, as the study’s authors point out in their paper, the associations uncovered in this study are biologically plausible.
“The stress hormone cortisol stimulates glucose production in the liver and antagonizes the action of insulin in peripheral tissues — both process have the potential to contribute to worse prognoses in people with diabetes,” they point out.
By raising blood pressure, stress can also increase the risk of a heart disease or stroke in people who already have hardened arteries (atherosclerosis), they add.
The researchers say their study points to a need for more research into effective workplace interventions for the treatment and management of cardiometabolic disease.
“These findings suggest that controlling blood pressure and cholesterol levels alone are unlikely to eliminate the excess risk associated with job strain in men with cardiometabolic disease,” said Mika Kivmaki, the study’s lead author and a social epidemiologist at University College London, in a released statement. “Other interventions might be needed at least for some patients — possibly including stress management as part of cardiovascular disease rehabilitation job redesign, or reducing working hours.”
FMI: You’ll find an abstract of the study on The Lancet Diabetes & Endocrinology website, but the full study is, unfortunately, behind a paywall.