Work related stressful life events and the risk of myocardial infarction. Case-control and case-crossover analyses within the Stockholm heart epidemiology programme (SHEEP)
- 1Department of Public Health Sciences, Division of Social Medicine, Karolinska Institutet, Stockholm, Sweden
- 2Swedish National Institute for Psychosocial Factors and Health, Stockholm, Sweden
- 3Institute of Environmental Medicine, Division of Cardiovascular Epidemiology, Karolinska Institutet
- 4Institute of Environmental Medicine, Division of Epidemiology, Karolinska Institutet
- Correspondence to: Mrs J Möller Karolinska Institutet, Department of Public Health Sciences, Division of Social Medicine, Norrbacka, SE-171 76 Stockholm, Sweden;
- Accepted 20 April 2004
Study objectives: Recent changes in labour market conditions and in the organisation of work in developed societies have increased exposure to work related stress. The question is whether this also implies an increased risk of myocardial infarction, either through the triggering effect of acute stress, or through accumulation of stress over several months.
Design: A case-control and a case-crossover study design was applied.
Setting: The Stockholm heart epidemiology programme (SHEEP), in Stockholm County during 1992 to 1994.
Participants: Patients with a first episode of non-fatal acute myocardial infarction, a total of 1381 men and women, responded to questionnaires and participated in interviews and health examinations.
Main results: The case-crossover analysis showed triggering effects of sudden, short term situations of increased work load or work competition. Having “had a high pressure deadline at work” entailed a sixfold increase in risk of myocardial infarction (OR = 6.0 95% CI (1.8 to 20.4)) during the next 24 hours. The importance of work related life events as risk factors for myocardial infarction was supported by the case-control analysis. However, no support was found for the hypothesis that an accumulation of stressful life events over a period of 12 months increases the risk of myocardial infarction.
Conclusion: Specific work related stressful life events seem to be potential triggers of the onset of myocardial infarction.
Funding: the study was supported by grants from the Swedish Council for Social Research, Sweden’s National Institute of Public Health, and the Swedish Council for Working Life and Social Research.
Conflicts of interest: none declared.
The ethics committee of Karolinska Institutet approved both the SHEEP study and the embedded onset study.