Job strain linked to poor long-term prognosis after a first AMI
MedWire News: Work stress is associated with a poor prognosis in patients experiencing a first acute myocardial infarction (AMI), research from Sweden indicates.
The relationship does not appear to be explained by lifestyle, blood lipids, glucose, inflammatory, or hemostatic factors, refuting the “widely accepted hypothesis” that such factors mediate the association between job strain and coronary heart disease, the study authors report.
For the study Krisztina László (Karolinska Institute, Stockholm) and team followed up individuals enrolled in the Stockholm Heart Epidemiology Program, a population-based case–control study of incident AMI including all Swedish citizens living in Stockholm County, aged 45–70 years of age, who were free of previously diagnosed AMI.
The analysis included 676 participants who were aged younger than 65 years and were in paid employment at the time they suffered a first, nonfatal AMI between 1992 and 1994. The patients completed questionnaires on demographic, work-related, clinical, sleep, and lifestyle factors a few days after the AMI.
The patients’ job strain during the 5 years preceding the AMI was measured on two scales, the psychological demands scale (incorporating having to work fast, hard, and with too much effort, encountering conflicting demands, and having a lack of time to do the work) and the job control scale (incorporating the possibility to decide what and how to do the job, or “decision latitude,” the potential to learn new things and use high levels of skills and creativity, and for variety, together termed “skill discretion”).
During the 8.5-year follow-up, 155 patients died of cardiac causes or had a nonfatal AMI and 96 patients died, 52 of cardiac causes.
In multivariate analysis adjusting for age, gender, education, occupational status, overtime, shift and household work, and the interaction between shift and household work and age, patients with high job strain (both high demands and low control) had a 1.73-fold increased risk for death and nonfatal AMI relative to those with low job strain (low demands and high control).
Similar results were seen for the secondary outcomes of cardiac and total mortality, at hazard ratios of 2.81 and 1.65, respectively.
These associations remained essentially unchanged after further adjusting for a range of blood lipid, glucose, and inflammatory markers, and lifestyle factors including smoking, alcohol consumption, physical activity, and sleep difficulties.. Interestingly, adjustment for early morning awakenings strengthened the association between job strain and risk for cardiac death and nonfatal AMI, with a hazard ratio of 2.02 for high versus low job strain.
László and co-authors suggest: “Interventions reducing stressors at the workplace or improving coping with work stress in cardiac patients might improve their survival after AMI.”
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By Caroline Price