title: Implications for Social Support on Prolonged Sleep Difficulties among a Disaster-Affected Population: Second Report from a Cross-Sectional Survey in Ishinomaki, Japan.
abstract: OBJECTIVE
  This study aimed to investigate the role of social factors, especially social support for sleep, among victims living at home around 1-2 years after the Great East Japan Earthquake and tsunami.
  
  
  METHODS
  A cross-sectional household survey was conducted between May and December 2012 (14-21 months after the disaster) in the Ishinomaki area, Japan. Univariate and multivariate logistic regression models were used to examine the association between social factors, including social support, and prolonged sleep difficulties (persisting over 1 month). Social support was divided into three functions: emotional, informational, and instrumental support.
  
  
  METHODS
  Data were obtained on 2,593 individuals who were living at home after the disaster.
  
  
  RESULTS
  The prevalence of prolonged sleep difficulties was 6.9% (5.8% male, 7.7% female). This study showed that lack of social support has a stronger association with prolonged sleep difficulties than non-modifiable or hardly modifiable consequences caused directly by the disaster, i.e., severity of home damage, change in family structure and income. Among the three dimensions of social support, lack of emotional support showed the strongest association with prolonged sleep difficulties.
  
  
  CONCLUSIONS
  Social support, especially emotional support, may positively affect sleep among victims living at home around 1-2 years after a disaster.
authors.affiliation: Graduate School of Public Health, Teikyo University, Tokyo, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Matsumoto
authors.affiliation: Graduate School of Public Health, Teikyo University, Tokyo, Japan.
authors.forename: Kazue
authors.initials: K
authors.lastname: Yamaoka
authors.affiliation: Department of Family and Community Medicine, Hamamatsu University School of Medicine, Shizuoka, Japan.
authors.forename: Machiko
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Graduate School of Public Health, Teikyo University, Tokyo, Japan; Department of Hygiene and Public Health, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Health and Life Revival Council in the Ishinomaki District (RCI), Miyagi, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Muto
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004190:Disasters; D055866:Earthquakes; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000523:psychology*; D012944:Social Support; D057192:Tsunamis