Interactive effects of job stressor and chronotype on depressive symptoms in day shift and rotating shift workers

Abstract

Background: In working adults, higher work stressor is associated with depressive symptoms in adults. A later chronotype is linked with a higher self-perceived stress response. However, their interactive effect has not been studied. This study first examined the interactive effects on depressive symptoms in working adults. Methods: A cross-sectional study was conducted on Japanese nurses aged 20–59 years, using a self-reported questionnaire. Among them,1363 were day shift workers and 1959 were rotating shift workers. The Japanese versions of the Job Content Questionnaire and the Morningness-Eveningness Questionnaire (MEQ) were used, to measure job strain and to assess chronotype, respectively. The Center for Epidemiologic Studies-Depression Scale (CES-D) was used to determine the level of depressive symptoms. Results: Multiple linear regression analysis revealed that the interaction between job strain scores and MEQ scores was negatively associated with CES-D scores in overall participants, indicating that a later chronotype was associated with greater effects of job strain on depressive symptoms. The interactive effects were also confirmed in participants stratified by current work shift (day shift work and rotating shift work). Limitations: This study did not establish causal associations. Conclusions: The results indicate that psychological responses to stressors may be greater in working adults with later chronotypes. These findings may be important for developing novel strategies, focusing on chronotype, to prevent and improve poor mental health in both day shift and rotating shift workers.

Keywords

• Stress
• Eveningness
• Circadian rhythm
• Misalignment
• Mental health
• Depression