Abstract
OBJECTIVES: Irregular sleep, frequently resulting from night shifts, is associated with various mental health issues. However, the specific associations among these factors remain unclear. This study aimed to investigate the associations of night shift frequency with depressive, anxiety, and comorbid depressive-anxiety symptoms and to estimate the indirect associations through sleep quality and sleep duration. METHODS: A cross-sectional study was conducted among nurses in seven hospitals in Zhejiang Province in 2023. A self-administered questionnaire was utilized to collect sociodemographic, work-related, lifestyle, and mental health information. Multivariable logistic regression models were used to examine the associations of night shift frequency, sleep duration, sleep quality, and mental health outcomes. Additionally, we used a mediation analysis to estimate indirect effects through sleep quality and sleep duration. RESULTS: A total of 2037 nurses were included in the study. Compared to low-frequency night shifts, high-frequency night shifts were significantly associated with higher odds of depressive symptoms (odds ratio [OR] = 1.46, 95% confidence interval [CI] = 1.20-1.77), anxiety symptoms (OR = 1.29, 95% CI = 1.06-1.58), and comorbid depressive-anxiety symptoms (OR = 1.34, 95% CI = 1.09-1.65). The statistical indirect association via sleep quality accounted for 19.5%, 25.9%, and 19.0% of the total association for depressive, anxiety, and comorbid depressive-anxiety symptoms, respectively. The indirect effect through sleep duration was not statistically significant. CONCLUSIONS: In this cross-sectional study, a higher frequency of night shifts was significantly associated with poorer mental health outcomes among Chinese nurses, with sleep quality serving as a statistical mediator. These findings suggest that optimizing shift scheduling, enhancing institutional support for sleep recovery, and integrating sleep quality monitoring into occupational health policies may be effective strategies to promote nurse well-being. This study provides empirical evidence to inform nursing management practices and health workforce policy.