Persistent and changing job strain and risk of coronary heart disease. A population-based cohort study of 1.6 million employees in Denmark

• Main Authors: Reiner Rugulies (Author), Elisabeth Framke (Author), Jeppe Karl Sørensen (Author), Annemette Coop Svane-Petersen (Author), Kristina Alexanderson (Author), Jens Peter Bonde (Author), Kristin Farrants (Author), Esben Meulengracht Flachs (Author), Linda L Magnusson Hanson (Author), Solja T Nyberg (Author), Mika Kivimäki (Author), Ida EH Madsen (Author)
• Format: Book
• Published: Nordic Association of Occupational Safety and Health (NOROSH), 2020-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 0355-3140; 1795-990X; 10.5271/sjweh.3891
• Keywords: job strain; psychological demand; coronary heart disease; job control; denmark; psychosocial work environment; employee; strain; job exposure matrix; jem; chd; epidemiology; stress; cardiovascular disease; cohort study; work stress; Public aspects of medicine; RA1-1270
• Source: Scandinavian Journal of Work, Environment & Health, Vol 46, Iss 5, Pp 498-507 (2020)

OBJECTIVES: This study aimed to examine the association between job strain and incident coronary heart disease (CHD) in Denmark, while accounting for changes of job strain. METHODS: We included all employees residing in Denmark in 2000, aged 30-59 years with no prevalent CHD (N=1 660 150). We determined exposure to job strain from 1996-2009 using a job exposure matrix (JEM) with annual updates. Follow-up for incident CHD was from 2001-2010 via linkage to health records. We used Cox regression to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the association between job strain and incident CHD. RESULTS: During 16.1 million person-years, we identified 24 159 incident CHD cases (15.0 per 10 000 person-years). After adjustment for covariates, job strain in 2000 predicted onset of CHD during a mean follow-up of 9.71 years (HR 1.10, 95% CI 1.07-1.13). When analyzing changes in job strain from one year to the next and CHD in the subsequent year, persistent job strain (HR 1.07, 95% CI 1.03-1.10), onset of job strain (HR 1.20, 95% CI 1.12-1.29) and removal of strain (HR 1.20, 95% CI 1.12-1.28) were associated with higher CHD incidence compared to persistent no job strain. Associations were similar among men and women. CONCLUSIONS: Job strain is associated with a higher risk of incident CHD in Denmark. As we used a JEM, we can rule out reporting bias. However, under- or overestimation of associations is possible due to non-differential misclassification of job strain and residual confounding by socioeconomic position.