title: Autonomic dysfunction in obstructive sleep apnea is associated with impaired glucose regulation.
abstract: BACKGROUND
  Autonomic dysfunction has been theorized to be responsible for the increased risk of cardiovascular disease in obstructive sleep apnea (OSA). Previous studies did not control for the presence of impaired glucose regulation (IGR, comprising impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes) which is also associated with abnormalities in autonomic function.
  
  
  METHODS
  Thirty-two patients were recruited for the study. Patients underwent autonomic testing consisting of heart rate response to deep breathing, valsalva maneuver, tilt-up, and quantitative sudomotor axon reflex testing. Polysomnography (PSG) and a 2-h oral glucose tolerance test were performed. Results were analyzed with logistic regression, with age, race, body mass index (BMI), and gender as covariates.
  
  
  RESULTS
  Nineteen of 24 patients with OSA had abnormal glucose (79%, p=0.04) compared to two of nine patients without OSA. The correlation between IGR, OSA and total autonomic dysfunction was similar (p=.10 for IGR, p=0.06 for OSA). However, cardiac autonomic function was more strongly associated with IGR than OSA (p=.10 vs. 0.50). Age was a significant confounder, as glucose correlated with adrenergic autonomic dysfunction significantly when age was removed from the model (p=0.006).
  
  
  CONCLUSIONS
  The presence of IGR may be a confounding factor in studies of autonomic function in OSA. Larger studies are needed to delineate whether OSA is directly associated with autonomic dysfunction or whether the previously described association between dysautonomia and OSA may have been due to glucose dysregulation.
authors.affiliation: Department of Neurology, University of Michigan, Ann Arbor, MI, USA. Amanda.peltier@vanderbilt.edu
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Peltier
authors.forename: Flavia B
authors.initials: FB
authors.lastname: Consens
authors.forename: Kiran
authors.initials: K
authors.lastname: Sheikh
authors.forename: Lily
authors.initials: L
authors.lastname: Wang
authors.forename: Yanna
authors.initials: Y
authors.lastname: Song
authors.forename: James W
authors.initials: JW
authors.lastname: Russell
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology*; D001369:Axons / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005951:Glucose Tolerance Test; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012018:Reflex / Q000502:physiology; D012119:Respiration; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D013546:Sweating / Q000502:physiology; D018667:Tilt-Table Test; D014636:Valsalva Maneuver / Q000502:physiology
chemical_list: D001786:Blood Glucose