title: Population-based incidence of sudden cardiac and unexpected death before and after the 2011 earthquake and tsunami in Iwate, northeast Japan.
abstract: BACKGROUND
  The aim of this study was to evaluate the temporal impact of the 2011 Japan earthquake and tsunami on the incidence of sudden cardiac and unexpected death (SCUD).
  
  
  RESULTS
  We surveyed the impact of the disaster on the incidence and clinical characteristics of SCUD in Iwate. To perform complete identification of SCUD for 8 weeks before and 40 weeks after the disaster, medical records and death certificates relevant to SCUD were surveyed in the study area. Compared with the previous year's rate, the incidence (per 10 000 person-year) of SCUD for the initial 4 weeks after the disaster (acute phase) was double (33.5 vs 18.9), and thereafter the rate returned to the previous level. Significant relationships were found between weekly numbers of SCUD and seismic activity (intensity, r=0.43; P<0.005: frequency, r=0.46; P<0.002). The standardized incidence ratio (SIR) of SCUD in the acute phase was significantly increased compared with that of previous years (1.71, 95% CI 1.33 to 2.16). Increased SIRs were predominantly found in female subjects (1.73, 95% CI 1.22 to 2.37), the elderly (1.73, 95% CI 1.29 to 2.27), and residents living in the tsunami-stricken area (1.83, 95% CI 1.33 to 2.46). In addition, SIRs for weekdays (1.71, 95% CI 1.28 to 2.24) and nights-mornings (2.09, 95% CI 1.48 to 2.86) were amplified.
  
  
  CONCLUSIONS
  The present results suggest that the magnitude of a disaster, related stress, and population aging may cause a temporary increase in the incidence of SCUD with amplification of ordinary weekly and circadian variations.
authors.affiliation: Department of Internal Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, 020-8505, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Niiyama
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Tanaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakajima
authors.forename: Tomonori
authors.initials: T
authors.lastname: Itoh
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Mikio
authors.initials: M
authors.lastname: Kawakami
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Naganuma
authors.forename: Shinichi
authors.initials: S
authors.lastname: Omama
authors.forename: Takashi
authors.initials: T
authors.lastname: Komatsu
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Onoda
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Sakata
authors.forename: Takashi
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003645:Death, Sudden / Q000453:epidemiology* / Q000209:etiology; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology; D004190:Disasters; D055866:Earthquakes / Q000401:mortality*; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D012737:Sex Factors; D057192:Tsunamis
keywords: disaster; general population; incidence; sudden death