title: Reducing depressive symptoms after the Great East Japan Earthquake in older survivors through group exercise participation and regular walking: a prospective observational study.
abstract: Survivors of the 2011 Great East Japan Earthquake have an increased risk of depressive symptoms. We sought to examine whether participation in group exercise and regular walking could mitigate the worsening of depressive symptoms among older survivors.
  
  
  
  Prospective observational study.
  
  
  
  Our baseline survey was conducted in August 2010, ∼7 months prior to the Great East Japan Earthquake and tsunami, among people aged 65 or older residing in Iwanuma City, Japan, which suffered significant damage in the disaster. A 3-year follow-up survey was conducted in 2013.
  
  
  
  3567 older survivors responded to the questionnaires predisaster and postdisaster.
  
  
  
  Change in depressive symptoms was assessed using the 15-item Geriatric Depression Scale (GDS).
  
  
  
  From predisaster to postdisaster, the mean change in GDS score increased by 0.1 point (95% CI -0.003 to 0.207). During the same interval, the frequency of group exercise participation and daily walking time also increased by 1.9 days/year and 1.3 min/day, respectively. After adjusting for all covariates, including personal experiences of disaster, we found that increases in the frequency of group exercise participation (B=-0.139,β=-0.049, p=0.003) and daily walking time (B=-0.087,β=-0.034, p=0.054) were associated with lower GDS scores. Interactions between housing damage and changes in group exercise participation (B=0.103,β=0.034, p=0.063) and changes in walking habit (B=0.095,β=0.033, p=0.070) were marginally significant, meaning that the protective effects tended to be attenuated among survivors reporting more extensive housing damage.
  
  
  
  Participation in group exercises or regular walking may mitigate the worsening of depressive symptoms among older survivors who have experienced natural disaster.
authors.affiliation: Center for Preventive Medical Sciences, Chiba University, Chiba, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Tsuji
authors.affiliation: Center for Preventive Medical Sciences, Chiba University, Chiba, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Matsuyama
authors.affiliation: Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Aida
authors.affiliation: Center for Preventive Medical Sciences, Chiba University, Chiba, Japan.|Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Kondo
authors.affiliation: Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D000368:Aged; D003863:Depression / Q000523:psychology / Q000628:therapy*; D055866:Earthquakes; D005081:Exercise Therapy / Q000379:methods* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D017741:Survivors / Q000523:psychology*; D016138:Walking / Q000523:psychology* / Q000706:statistics & numerical data
keywords: geriatric depression scale; multiple imputation; natural disaster; older adults; the JAGES project