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Thorax 68:544-550 doi:10.1136/thoraxjnl-2012-202658
  • Epidemiology
  • Original article

Impact of the Tohoku earthquake and tsunami on pneumonia hospitalisations and mortality among adults in northern Miyagi, Japan: a multicentre observational study

Open Access
  1. Shoji Okinaga1,9
  1. 1Kesennuma City Hospital, Kesennuma, Japan
  2. 2Department of Respiratory Medicine, Saitama Medical University, Saitama, Japan
  3. 3Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
  4. 4Wayne State University, Detroit, Michigan, USA
  5. 5Ohtomo Hospital, Kesennuma, Japan
  6. 6Kesennuma City Medical Association, Kesennuma, Japan
  7. 7Department of Virology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
  8. 8Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
  9. 9Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
  1. Correspondence to Dr Motoi Suzuki, Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Sakamoto 1-12-4, Nagasaki 852-8523, Japan; mosuzuki{at}nagasaki-u.ac.jp
  • Received 30 August 2012
  • Revised 25 January 2013
  • Accepted 29 January 2013
  • Published Online First 19 February 2013

Abstract

Background On 11 March 2011, the Tohoku earthquake and tsunami struck off the coast of northeastern Japan. Within 3 weeks, an increased number of pneumonia admissions and deaths occurred in local hospitals.

Methods A multicentre survey was conducted at three hospitals in Kesennuma City (population 74 000), northern Miyagi Prefecture. All adults aged ≥18 years hospitalised between March 2010 and June 2011 with community-acquired pneumonia were identified using hospital databases and medical records. Segmented regression analyses were used to quantify changes in the incidence of pneumonia.

Results A total of 550 pneumonia hospitalisations were identified, including 325 during the pre-disaster period and 225 cases during the post-disaster period. The majority (90%) of the post-disaster pneumonia patients were aged ≥65 years, and only eight cases (3.6%) were associated with near-drowning in the tsunami waters. The clinical pattern and causative pathogens were almost identical among the pre-disaster and post-disaster pneumonia patients. A marked increase in the incidence of pneumonia was observed during the 3-month period following the disaster; the weekly incidence rates of pneumonia hospitalisations and pneumonia-associated deaths increased by 5.7 times (95% CI 3.9 to 8.4) and 8.9 times (95% CI 4.4 to 17.8), respectively. The increases were largest among residents in nursing homes followed by those in evacuation shelters.

Conclusions A substantial increase in the pneumonia burden was observed among adults after the Tohoku earthquake and tsunami. Although the exact cause remains unresolved, multiple factors including population aging and stressful living conditions likely contributed to this pneumonia outbreak.

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