Association between psychosocial job characteristics and insomnia: an investigation using two relevant job stress models--the demand-control-support (DCS) model and the effort-reward imbalance (ERI) model.

BACKGROUND AND
PURPOSE: The details of risky psychosocial job characteristics related to insomnia are unclear, although potential relationships between the two have been suggested. The study objective was to clarify these relationships by using the demand-control-support (DCS) model and the effort-reward imbalance (ERI) model. PATIENTS AND METHODS: A cross-sectional questionnaire survey was conducted with 1081 middle-aged (39 years and older) workers in a corporate group of electric products in Osaka, Japan. The study variables included insomnia symptoms (non-refreshing sleep, difficulty falling asleep, frequent sleep disruption, and early morning arousal) and psychosocial job characteristics which were evaluated using the DCS and ERI models, gender, age, disease, sleep-related factors, occupational status, and health practices.
RESULTS: ERI [odds ratio (95% confidence interval): 2.27 (1.43, 3.60)], overcommitment [1.86 (1.40, 2.47)], and high job strain [1.55 (1.12, 2.15)] were independently associated with insomnia. The odds ratio of insomnia for individuals with high job strain was increased by adding ERI or overcommitment.
CONCLUSIONS: The ERI and DCS models describe the adverse psychosocial job characteristics related to insomnia. Simultaneously employing these two models is more useful than employing a single model to identify workers at risk of insomnia. The conceptual framework derived from the job stress models assists in defining preventive measures for insomnia in workers.