title: Impaired endothelial function in persons with obstructive sleep apnoea: impact of obesity.
abstract: OBJECTIVE
  Obstructive sleep apnoea (OSA) and obesity are both associated with endothelial dysfunction, which precedes the development of atherosclerosis. As obesity is highly prevalent in OSA, we wanted to test the hypothesis that OSA is associated with endothelial dysfunction independently of obesity.
  
  
  METHODS
  Cross-sectional, population-based study.
  
  
  METHODS
  Norwegian university hospital.
  
  
  METHODS
  Seventy-one subjects (median age 44 years, 35% female) were recruited from a population-based study in Norway. Participants were categorised as obese (body mass index (BMI) ≥30 kg/m(2)), non-obese (BMI<30 kg/m(2)) with OSA (apnoea-hypopnoea index (AHI)≥10), or non-obese without OSA (AHI<5).
  
  
  METHODS
  None.
  
  
  METHODS
  Endothelial function measured by brachial artery ultrasound and expressed as percentage of flow-mediated dilation (FMD%).
  
  
  RESULTS
  When non-obese subjects without OSA were used as the reference (FMD% (mean±SD) 10.1±6.3), endothelial function was found to be impaired in subjects with OSA (FMD% 6.4±3.2) (p=0.003). FMD% did not differ between obese (6.0±3.4) and non-obese (6.7±3.1) OSA subjects (p=0.3). By univariate linear regression analysis, AHI, BMI, gender and baseline brachial artery diameter were significantly associated with FMD%. When these variables were entered into a multivariate model, only AHI was significantly associated with FMD%.
  
  
  CONCLUSIONS
  OSA is associated with endothelial dysfunction independently of obesity and conventional risk factors.
authors.affiliation: Department of Internal Medicine, Division of Medicine, Akershus University Hospital, Lorenskog, Norway.
authors.forename: Silje K
authors.initials: SK
authors.lastname: Namtvedt
authors.forename: Jonny
authors.initials: J
authors.lastname: Hisdal
authors.forename: Anna
authors.initials: A
authors.lastname: Randby
authors.forename: Stefan
authors.initials: S
authors.lastname: Agewall
authors.forename: Einar
authors.initials: E
authors.lastname: Stranden
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
authors.forename: Helge
authors.initials: H
authors.lastname: Røsjø
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Omland
mesh_terms: D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D015992:Body Mass Index; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D017286:Polysomnography; D011159:Population Surveillance; D011379:Prognosis; D012039:Regional Blood Flow; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology*