Citation

Kawano T, Nishiyama K, Morita H, Yamamura O, Hiraide A, Hasegawa K. BMJ Open 2016; 6(1): e009711.

Affiliation

Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Copyright

(Copyright © 2016, BMJ Publishing Group)

DOI

10.1136/bmjopen-2015-009711

PMID

26769785

Abstract

OBJECTIVES: We determined whether crowding at emergency shelters is associated with a higher incidence of sleep disturbance among disaster evacuees and identified the minimum required personal space at shelters.

DESIGN: Retrospective review of medical charts. SETTING: 30 shelter-based medical clinics in Ishinomaki, Japan, during the 46 days following the Great Eastern Japan Earthquake and Tsunami in 2011. PARTICIPANTS: Shelter residents who visited eligible clinics. OUTCOME MEASURES: Based on the result of a locally weighted scatter-plot smoothing technique assessing the relationship between the mean space per evacuee and cumulative incidence of sleep disturbance at the shelter, eligible shelters were classified into crowded and non-crowded shelters. The cumulative incidence per 1000 evacuees was compared between groups, using a Mann-Whitney U test. To assess the association between shelter crowding and the daily incidence of sleep disturbance per 1000 evacuees, quasi-least squares method adjusting for potential confounders was used.

RESULTS: The 30 shelters were categorised as crowded (mean space per evacuee <5.0 m(2), 9 shelters) or non-crowded (≥5.0 m(2), 21 shelters). The study included 9031 patients. Among the eligible patients, 1079 patients (11.9%) were diagnosed with sleep disturbance. Mean space per evacuee during the study period was 3.3 m(2) (SD, 0.8 m(2)) at crowded shelters and 8.6 m(2) (SD, 4.3 m(2)) at non-crowded shelters. The median cumulative incidence of sleep disturbance did not differ between the crowded shelters (2.3/1000 person-days (IQR, 1.6-5.4)) and non-crowded shelters (1.9/1000 person-days (IQR, 1.0-2.8); p=0.20). In contrast, after adjusting for potential confounders, crowded shelters had an increased daily incidence of sleep disturbance (2.6 per 1000 person-days; 95% CI 0.2 to 5.0/1000 person-days, p=0.03) compared to that at non-crowded shelters.

CONCLUSIONS: Crowding at shelters may exacerbate sleep disruptions in disaster evacuees; therefore, appropriate evacuation space requirements should be considered.

Language: en