title: Association between osteoporosis and sleep duration in healthy middle-aged and elderly adults: a large-scale, cross-sectional study in Japan.
abstract: OBJECTIVE
  This study aims to explore the association between osteoporosis and nightly sleep duration among adult outpatients.
  
  
  METHODS
  This is a large-scale, retrospective cross-sectional study.
  
  
  METHODS
  The setting was in a preventive medicine health center at a general community hospital in Tokyo, Japan.
  
  
  METHODS
  There were 19,321 healthy individuals (≥50 years old) who underwent annual general health checkup between January and December 2008.
  
  
  METHODS
  The participants were divided into four groups according to their self-reported average nightly sleep duration (<6, 6-6.9, 7-7.9, and >8 h). Radial bone mineral density was measured using dual-energy X-ray absorptiometry, and T-score was compared to young adult mean to diagnose osteoporosis. Multivariate logistic regression was used to explore the association between sleep duration and osteoporosis.
  
  
  RESULTS
  The mean age of the participants was 60.9 years (standard deviation [SD], 7.9) and 48.0% were female. The prevalence of osteoporosis was 8.0% (95% confidence interval [CI] = 7.6-8.4%). Those with sleep duration of >8 h were more likely to have osteoporosis (odds ratio [OR] = 1.35; 95% CI = 1.06-1.73) than those with short sleep duration (<6 h).
  
  
  CONCLUSIONS
  Those individuals with self-reported sleep duration of more than 8 h (long sleepers) appear to have higher odds of osteoporosis compared to the progressively shorter sleepers.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, St. Luke's International Hospital, Tokyo, Japan. daikoba@luke.or.jp
authors.forename: Daiki
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Osamu
authors.initials: O
authors.lastname: Takahashi
authors.forename: Gautam A
authors.initials: GA
authors.lastname: Deshpande
authors.forename: Takuro
authors.initials: T
authors.lastname: Shimbo
authors.forename: Tsuguya
authors.initials: T
authors.lastname: Fukui
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010024:Osteoporosis / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D012016:Reference Values; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology*