Effort-reward imbalance and physical health among Japanese workers in a recently downzised corporation

Objectives: The present study investigated the effort-reward imbalance (ERI) model-related biological markers of disease risks in Japanese workers of a recently downsized manufacturing corporation. Methods: A total of 441 workers was examined to find whether situational effort-reward imbalance or personal over-commitment was associated with hematological and biochemical measurements, serum cortisol, and urine biopyrrins as oxidative metabolites of antioxidant bilirubin. Results: The effort-reward imbalance was positively associated with the values of red blood cells, hemoglobin, hematocrit, triglycerides and glutamic pyruvic transaminase (GPT), and negatively correlated with the high-density lipoprotein cholesterol level. Overcommitment was positively related to the values of hematocrit and glucose levels, but negatively associated with the total protein level. The relationships between effort-reward imbalance and GPT level, and that between overcommitment and glucose level, persisted when potential confounders were adjusted for. The ERI model was not significantly related to either cortisol or biopyrrins levels. Conclusions: The ERI model seems to have an impact on the physical health of the downized Japanese workers, although the results are mixed and are different from those in workers of Western countries.