Fatigue in Different Groups of Disaster Responders after the 2024 Noto Peninsula Earthquake: Group-Specific Associations and Priorities for Intervention

Objective To compare fatigue in the external supporters and local public officers who responded to the January 1, 2024 Noto Peninsula Earthquake, identify group-specific factors associated with fatigue, and estimate population-level differences under hypothetical scenarios. Methods A repeated-measures observational study was conducted using responder health surveillance data collected between January and March 2024. Generalized estimating equations were used to compare fatigue levels and examine group-specific associations with operational and health-related factors. G-computation was used to estimate model-based population-level differences in fatigue under hypothetical scenarios in which each factor was set to zero. Results There were 23,865 observations from 7,135 responders. Local public officers reported greater fatigue than external supporters (β = 2.32, 95% CI: 2.22–2.43). The inability to take meals and breaks and unclear command/task structure were associated with greater fatigue in both groups. Sleep disturbance and irritability had stronger associations with fatigue in external supporters. G-computation showed larger model-based population-level differences under the hypothetical scenarios in local public officers, primarily because operational and health-related problems were more prevalent in this group. Conclusions Operational factors and health problems were associated with fatigue in disaster responders, and the model-based population-level differences under hypothetical scenarios depended on their prevalence. Increasing the number of responders, provision of rest periods, improving command clarity, and monitoring the health of responders may reduce fatigue and improve disaster responses.