Job stress and mental health of permanent and fixed-term workers measured by effort-reward imbalance model, depressive complaints, and clinic utilization

The number of workers with precarious employment has increased globally; however, few studies have used validated measures to investigate the relationship of job status to stress and mental health. Thus, we conducted a study to compare differential job stress experienced by permanent and fixed-term workers using an effort- reward imbalance (ERI) model questionnaire, and by evaluating depressive complaints and clinic utilization. Methods: Subjects were permanent or fixed-term male workers at a Japanese research institute (n=756). Baseline data on job stress and depressive complaints were collected in 2007. We followed up with the same population over a 1-year period to assess their utilization of the company clinic for mental health concerns. Results: The ERI ratio was higher among permanent workers than among fixed-term workers. More permanent workers presented with more than two depressive complaints, which is the standard used for the diagnosis of depression. ERI scores indicated that the effort component of permanent work was associated with distress, whereas distress in fixed-term work was related to job promotion and job insecurity. Moreover, over the one-year follow-up period, fixed-term workers visited the on-site clinic for mental concerns 4.04 times more often than permanent workers even after adjusting for age, lifestyle, ERI, and depressive complaints. Conclusions: These contrasting findings reflect the differential workloads and working conditions encountered by permanent and fixed-term workers. The occupational setting where employment status was intermingled, may have contributed to the high numbers of mental health-related issues experienced by workers with different employment status.