title: Evaluation of Bone Mineral Density by Computed Tomography in Patients with Obstructive Sleep Apnea.
abstract: OBJECTIVE
  Clinical studies have investigated whether obstructive sleep apnea (OSA) can modulate bone metabolism but data are conflicting. Bone mineral density (BMD) measured by dual-energy x-ray absorptiometry is the standard technique for quantifying bone strength but has limitations in overweight patients (body mass index [BMI] ≥ 25 kg/m(2)). The aim of this study was to examine the association between OSA and BMD by examining CT images that allow true volumetric measurements of the bone regardless of BMI.
  
  
  METHODS
  Lumbar vertebrae BMD was evaluated in 234 persons (180 males and 54 females) by CT scan. The method was calibrated by a phantom containing a known concentration of hydroxyapatite.
  
  
  RESULTS
  BMD was lower in male patients with severe OSA (apnea-hypopnea index [AHI] ≥ 30/h) than non OSA (AHI < 5; p < 0.05), while OSA and BMD had no association in females. Linear and multiple regression analyses revealed that age (p < 0.0001, β = -0.52), hypertension (p = 0.0068, β = -0.17), and the alveolar-arterial oxygen pressure difference (A-aDO2) (p = 0.012, β = -0.15) in males were associated with BMD, while only age (p < 0.0001, β = -0.68) was associated with BMD in females.
  
  
  CONCLUSIONS
  Males with severe OSA had a significantly lower BMD than non OSA participants. Age, hypertension, and elevation of A-aDO2 were significant factors for BMD by CT imaging. The usefulness of measuring BMD in OSA patients by CT scanning should be studied in future.
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamada
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Ikezoe
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Hirai
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Oguma
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Tanizawa
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Morito
authors.initials: M
authors.lastname: Inouchi
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Handa
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Oga
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University; Kyoto, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications*; D012307:Risk Factors; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: bone mineral density; computed tomography; daytime oxygenation; hypertension; obstructive sleep apnea