Job Strain as a Risk Factor for Type 2 Diabetes: A Pooled Analysis of 124,808 Men and Women

  1. Mika Kivimäki1,12,29
  2. for the IPD-Work Consortium
  1. 1Finnish Institute of Occupational Health, Helsinki, Tampere, and Turku, Finland
  2. 2School of Health Sciences, Jönköping University, Jönköping, Sweden
  3. 3Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
  4. 4Stress Research Institute, Stockholm University, Stockholm, Sweden
  5. 5Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden
  6. 6National Research Centre for the Working Environment, Copenhagen, Denmark
  7. 7Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
  8. 8Federal Institute for Occupational Safety and Health (BAuA), Berlin, Germany
  9. 9Institute for Medical Sociology, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany
  10. 10Versailles-Saint Quentin University, Versailles, France
  11. 11Inserm U1018, Centre for Research in Epidemiology and Population Health, Villejuif, France
  12. 12Department of Epidemiology and Public Health, University College London, London, U.K.
  13. 13Institute of Behavioral Sciences, University of Helsinki, Helsinki, Finland
  14. 14Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
  15. 15Department of Public Health, University of Helsinki, Helsinki, Finland
  16. 16School of Sociology, Social Policy & Social Work, Queen's University Belfast, Belfast, U.K.
  17. 17UKCRC Centre of Excellence for Public Health Northern Ireland, Queen's University Belfast, Belfast, U.K.
  18. 18Department of Psychology, Umeå University, Umeå, Sweden
  19. 19The Danish National Centre for Social Research, Copenhagen, Denmark
  20. 20Department of Public Health and Department of Psychology, University of Copenhagen, Copenhagen, Denmark
  21. 21Department of Psychology, University of Turku, Turku, Finland
  22. 22Folkhälsan Research Center, Helsinki, Finland
  23. 23Nordic School of Public Health, Göteborg, Sweden
  24. 24Department of Public Health, University of Turku, Turku, Finland
  25. 25Turku University Hospital, Turku, Finland
  26. 26Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden
  27. 27Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, U.K.
  28. 28School of Community and Social Medicine, University of Bristol, Bristol, U.K.
  29. 29Hjelt Institute, Medical Faculty, University of Helsinki, Helsinki, Finland
  1. Corresponding authors: Solja T. Nyberg, solja.nyberg{at}ttl.fi, and Mika Kivimäki, m.kivimaki{at}ucl.ac.uk.

Abstract

OBJECTIVE The status of psychosocial stress at work as a risk factor for type 2 diabetes is unclear because existing evidence is based on small studies and is subject to confounding by lifestyle factors, such as obesity and physical inactivity. This collaborative study examined whether stress at work, defined as “job strain,” is associated with incident type 2 diabetes independent of lifestyle factors.

RESEARCH DESIGN AND METHODS We extracted individual-level data for 124,808 diabetes-free adults from 13 European cohort studies participating in the IPD-Work Consortium. We measured job strain with baseline questionnaires. Incident type 2 diabetes at follow-up was ascertained using national health registers, clinical screening, and self-reports. We analyzed data for each study using Cox regression and pooled the study-specific estimates in fixed-effect meta-analyses.

RESULTS There were 3,703 cases of incident diabetes during a mean follow-up of 10.3 years. After adjustment for age, sex, and socioeconomic status (SES), the hazard ratio (HR) for job strain compared with no job strain was 1.15 (95% CI 1.06–1.25) with no difference between men and women (1.19 [1.06–1.34] and 1.13 [1.00–1.28], respectively). In stratified analyses, job strain was associated with an increased risk of diabetes among those with healthy and unhealthy lifestyle habits. In a multivariable model adjusted for age, sex, SES, and lifestyle habits, the HR was 1.11 (1.00–1.23).

CONCLUSIONS Findings from a large pan-European dataset suggest that job strain is a risk factor for type 2 diabetes in men and women independent of lifestyle factors.

Footnotes

  • Received December 16, 2013.
  • Accepted April 18, 2014.
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