Importance: Some shift work arrangements allow for less than 11 hours off between shifts. The consequences of short daily rest periods are currently not well understood.
Objective: To determine the effect and cost-benefit of reducing the number of short daily rest periods on sickness-related absence among health care workers.
Design, setting, and participants: This 2-arm cluster-randomized clinical trial was conducted between January 11, 2021, and May 22, 2022, in hospital care units at Haukeland University Hospital in Bergen, Norway. Statistical analysis was performed from April to May 2025.
Intervention: The intervention group followed a 6-month shift schedule with reduced instances of short daily rest periods, whereas the control group adhered to a 6-month shift schedule maintaining the usual number of short daily rest periods.
Main outcomes and measures: Primary analyses followed intention-to-treat principles. The outcome was change in sickness-related absence days and absence spells (ie, each uninterrupted period of ≥1 consecutive sickness-related absence days) over the final 5 months of the intervention (allowing a 1-month stabilization period), compared with the same period in the preceding year and against a control group. The economic returns, measured as the increase in net present value of production from reduced sickness-related absence days due to the intervention, was [...]