STUDY OBJECTIVES: Despite persistent nursing shortages, newly hired nurses inevitably engage in shift work, which harms their sleep and mental health, accelerating their early-career turnover. This study examined whether pre-shift work chronotype is associated with post-shift work sleep/mental health outcomes and whether resilience mediates these relationships.
METHODS: A prospective cohort of 595 newly hired nurses, of whom 331 were included in the final analysis, was recruited from two national tertiary hospitals. Participants provided baseline and 6-12 months follow-up data after SW exposure. Chronotype, resilience, sleep outcomes (sleep quality and daytime sleepiness), and mental health outcomes (depression, anxiety, and stress scales) were assessed at both baseline and follow-up using validated self-report questionnaires. Structural equation modeling examined direct and indirect pathways linking baseline chronotype to follow-up resilience and sleep/mental health outcomes.
RESULTS: Among 331 nurses (age: 23.4 ± 1.2 years, 293 females, 26 morningness, 186 intermediate, 119 eveningness), the morningness group exhibited the highest resilience at both baseline (p = .0206) and follow-up (p = .0002). Baseline chronotype was significantly associated with resilience following SW (β = 0.259, p < .01). Baseline chronotype further indirectly affected both excessive daytime sleepiness (β = -0.013, 95% CI: [-0.025, -0.001]) and mental health (β = -0.045, 95% CI [-0.066, -0.009]) via resilience.
CONCLUSION: Pre-shift work chronotype significantly influenced post-shift work sleep and mental health outcomes, with resilience serving as a key mediator. These findings highlight the potential for targeted interventions-such as resilience training or chronotype-based scheduling-to mitigate early shift work-related mental health challenges and reduce nurse turnover. Statement of Significance Previous studies examining the interaction between chronotype and shift work (SW) schedules among nurses have yielded inconsistent results, primarily because SW schedules transiently influence chronotype, and most research has focused on nurses already exposed to SW. Although chronotype is generally stable and tends to revert once an intervention (e.g. altered light exposure) ceases-highlighting its trait-like characteristic-it can still be temporarily influenced by SW exposure. Consequently, prior studies often assessed chronotypes after participants had already been exposed to SW, potentially affecting the reliability of their assessments. In our study, baseline chronotypes measured before SW exposure influenced sleep and mental health during the initial adaptation period, with resilience acting as a mediator between chronotype and these outcomes. Although we did not examine long-term outcomes following SW exposure, our findings suggest that baseline chronotype may serve as a predictive biomarker for early SW outcomes.
