Effects of stable and changing demand-control histories on worker health

Objectives The present study examined effects of stability and change in exposure to job demands and job control (demand-control histories) in relation to the strain hypothesis of Karasek's demand-control model. Methods The hypotheses [(i) high (low) levels of ill health were expected for workers exposed to stable I levels of high (low) job demands and low (high) job control; (ii) decreases (increases) in strain-related health outcomes were expected for workers with positive (negative) changes in job demands and job control; (iii) workers reporting major changes in job demands or control were expected to report more "objective" job changes] were tested with a group-by-time analysis of variance using data from a four-phase Dutch cohort study on musculoskeletal disorders, absenteeism, stress, and health. Associations between demand-control histories and job changes were tested in a log-linear analysis. Results The hypotheses for the stable exposure groups were supported for depression and job satisfaction. Those for positive and negative changes were partially supported. There was no relation, however, between the level of stability or changes in exposure to demands and control for the registered duration and frequency of sickness absence. Finally, the results showed that workers reporting major changes in demand-control histories overtime had more job changes, and those reporting job changes towards high strain jobs evaluated the changes as more distressful. Conclusions This longitudinal study supports the strain hypothesis of the demand-control model and shows a significant association between major changes in demand-control histories and job changes.