Does salivary cortisol secretion mediate the association of work-related stressors with workers' depression?

ABSTRACT

PURPOSE: The purpose of this study was to verify the mediating role salivary cortisol intensity plays between work organization conditions and depression. This study simultaneously considered psychological and physiological (salivary cortisol) stress indicators on workers' depression in a single model. METHODS: We relied on cluster sampling of 341 workers in 34 Quebec establishments. Five saliva samples (on awakening, 30 min after awakening, at 200 p.m., 400 p.m., and bedtime) were collected per day. The weekly collection period spanned a period of 3 days (1 day off and 2 work days). We evaluated the main effects of work organization conditions on salivary cortisol intensity and depression, as well as the mediation effect of salivary cortisol intensity between work organization conditions and depression. To adjust for design effects, the direct and indirect (mediation) associations between the variables were evaluated while accounting for the non-independence of the data. RESULTS: Skill utilization and job insecurity were associated with salivary cortisol intensity, while psychological demands and job insecurity were associated with higher depression levels. Work-related variables were not found to have an indirect effect on depression via worker's salivary cortisol (AUC) intensity. CONCLUSION: Work-related stressors examined in this study did not indirectly affect worker's depression levels. Additional studies are necessary to be able to identify all work-related stressors that could potentially increase worker's depression levels through salivary cortisol.