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Impaired endothelial function in persons with obstructive sleep apnoea: impact of obesity
  1. Silje K Namtvedt1,2,3,
  2. Jonny Hisdal4,
  3. Anna Randby1,2,3,
  4. Stefan Agewall3,5,
  5. Einar Stranden3,4,
  6. Virend K Somers6,
  7. Helge Røsjø1,2,3,
  8. Torbjørn Omland1,2,3
  1. 1Department of Internal Medicine, Division of Medicine, Akershus University Hospital, Lorenskog, Norway
  2. 2KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
  3. 3University of Oslo, Oslo, Norway
  4. 4Section for Vascular Investigations, Oslo Vascular Centre, Oslo University Hospital Aker, Oslo, Norway
  5. 5Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway
  6. 6Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, Minnesota, USA
  1. Correspondence to Professor Torbjørn Omland, Department of Internal Medicine, Division of Medicine, Akershus University Hospital, Sykehusveien 27, Lørenskog 1478, Norway; torbjorn.omland{at}


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.

Design Cross-sectional, population-based study.

Setting Norwegian university hospital.

Patients 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/m2), non-obese (BMI<30 kg/m2) with OSA (apnoea–hypopnoea index (AHI)≥10), or non-obese without OSA (AHI<5).

Interventions None.

Main outcome measures 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.

  • Endothelium

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