title: Association between loss of bone mass due to short sleep and leptin-sympathetic nervous system activity.
abstract: BACKGROUND
  Sleep has been reported to be an important factor in bone metabolism, and sympathetic nervous system activity has been reported to regulate bone metabolism. In this study, we evaluated the association between sleep, sympathetic nervous system activity, and bone mass.
  
  
  METHODS
  The study subjects were 221 individuals (108 males; 113 females; mean age: 55.1±7.0years) divided into two groups: those who slept for less than 6h a day (short sleep [SS] group), and those who slept 6h or longer (normal sleep [NS] group). The groups were compared with regard to lifestyle, cortical bone thickness, cancellous bone density, bone metabolism markers, blood leptin levels, and sympathetic nervous system activity as evaluated by heart rate variability analysis.
  
  
  RESULTS
  Significant differences were observed between the two groups in cortical bone thickness, blood TRACP-5b, and leptin levels. The L/H ratio (an index of sympathetic nervous system activity) was higher in the SS group than in the NS group. Significant negative correlations were observed between cortical bone thickness and both the L/H ratio and leptin levels, and a significant positive correlation was observed between the L/H ratio and leptin levels.
  
  
  CONCLUSIONS
  Short sleep was associated with a decline in cortical bone thickness due to the promotion of bone resorption and sympathetic nervous system hyperactivity in the middle-aged group. Leptin levels and cortical bone thickness were found to be closely related, suggesting that cortical bone mass may be regulated via interaction with the leptin-sympathetic nervous system.
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan; Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: nkuriyam@koto.kpu-m.ac.jp.
authors.forename: Nagato
authors.initials: N
authors.lastname: Kuriyama
authors.affiliation: Department of Metabolism, Endocrinology, and Molecular Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Ozaki
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Yoneda
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsui
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Hashiguchi
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Teruhide
authors.initials: T
authors.lastname: Koyama
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Komei
authors.initials: K
authors.lastname: Iwai
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Watanabe
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Omichi
authors.affiliation: Endoscopy Department, Kindai University Nara Hospital, Japan.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Mizuno
authors.affiliation: Department of Orthopaedics, Saiseikai Suita Hospital, Osaka, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Kurokawa
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Horii
authors.affiliation: Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Niwa
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Iwasa
authors.affiliation: Department of Metabolism, Endocrinology, and Molecular Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000502:physiology*; D000071538:Cortical Bone / Q000503:physiopathology*; D003720:Densitometry; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012893:Sleep Wake Disorders / Q000503:physiopathology*; D000071681:Tartrate-Resistant Acid Phosphatase / Q000097:blood
chemical_list: D015415:Biomarkers; D020738:Leptin; D000469:Alkaline Phosphatase; C000605510:ACP5 protein, human; D000071681:Tartrate-Resistant Acid Phosphatase
keywords: Bone metabolism; Cortical bone thickness; Leptin-sympathetic nervous system; Short sleep