Relationship between effort–reward imbalance and hair cortisol concentration in female kindergarten teachers

ObjectiveThe present study aims to investigate the relationship between effort–reward imbalance and hair cortisol concentration among teachers to examine whether hair cortisol can be a biomarker of chronic work stress.MethodsHair samples were collected from 39 female teachers from three kindergartens. Cortisol was extracted from the hair samples with methanol, and cortisol concentrations were measured with high performance liquid chromatography–tandem mass spectrometry. Work stress was measured using the effort–reward imbalance scale.ResultsThe ratio of effort to reward showed significantly positive association with hair cortisol concentration.ConclusionThe cortisol concentration in the system increases with the effort–reward imbalance. Measurement of hair cortisol can become a useful biomarker of chronic work stress.