Hair cortisol in relation to job stress and depressive symptoms

Measurement of hair cortisol concentration (HCC) may be used as a biomarker for chronic stress. However, the association between stress and HCC has rarely been investigated in a working population. To explore associations between (i) HCC and various stress measures and (ii) HCC and symptoms of depression in Belgian workers. Hair samples were collected from workers in two production companies and cortisol content was determined by liquid chromatography tandem mass spectrometry. Participants completed a questionnaire including socio-demographics, health behaviours and standardized measures for assessing stress. After excluding those workers suffering from a psychiatric or neuroendocrine disease and those treated with glucocorticoids, there were a total of 102 workers with both questionnaire, cortisol results and anthropometric measures. Median HCC was 5.73 pg/mg hair (interquartile range = 4.52-9.06). No significant associations were found between cortisol and the standardized measures related to several work psychosocial risk factors. A significantly lower mean HCC was found in shift workers compared with dayworkers, adjusted for age. Additionally, a significant higher mean HCC was found in workers with symptoms of depression compared with those without symptoms of depression, after adjustment for age. HCC showed a limited applicability as a biomarker for job stress in this sample, although the results suggest this method may be a suitable marker for detecting early symptoms of depression. Further research is needed to investigate the applicability of HCC in the working environment and within job stress research.