Post-nuclear disaster evacuation and survival amongst elderly people in Fukushima: A comparative analysis between evacuees and non-evacuees

- After the 2011 Fukushima nuclear incident, it was evacuation, not the disaster, that had the significant mortality impact.
- Initial evacuation (vs. non-evacuation) had a substantial impact on mortality.
- Second/subsequent evacuations, which were pre-planned and carefully executed, did not show a significant mortality impact.
- Relevant authorities should support facilities so that they can shelter in place for sufficient time to prepare evacuation.
- Relevant authorities should support care facilities so that, during/following a disaster residents can shelter in place for at least sufficient time to adequately prepare initial evacuation.

BackgroundConsidering the health impacts of evacuation is fundamental to disaster planning especially for vulnerable elderly populations; however, evacuation-related mortality risks have not been well-investigated. We conducted an analysis to compare survival of evacuated and non-evacuated residents of elderly care facilities, following the Great East Japan Earthquake and subsequent Fukushima Dai-ichi nuclear power plant incident on 11th March 2011.ObjectiveTo assess associations between evacuation and mortality after the Fukushima nuclear incident; and to present discussion points on disaster planning, with reference to vulnerable elderly populations.MethodsThe study population comprised 1,215 residents admitted to seven elderly care facilities located 20-40 km from the nuclear plant in the five years before the incident. Demographic and clinical characteristics were obtained from medical records. Evacuation histories were tracked until mid 2013. Main outcome measures are hazard ratios in evacuees versus non-evacuees using random-effects Cox proportional hazards models, and pre- and post-disaster survival probabilities and relative mortality incidence.ResultsExperiencing the disasters did not have a significant influence on mortality (hazard ratio 1.10, 95% confidence interval: 0.84-1.43). Evacuation was associated with 1.82 times higher mortality (95% confidence interval: 1.22-2.70) after adjusting for confounders, with the initial evacuation from the original facility associated with 3.37 times higher mortality risk (95% confidence interval: 1.66-6.81) than non evacuation.ConclusionsThe government should consider updating its requirements for emergency planning for elderly facilities and ensure that, in a disaster setting, these facilities have the capacity and support to shelter in place for at least sufficient time to adequately prepare initial evacuation.