title: Obstructive sleep apnea in older adults is a distinctly different physiological phenotype.
abstract: OBJECTIVE
  Current evidence suggests that the pathological mechanisms underlying obstructive sleep apnea (OSA) are altered with age. However, previous studies examining individual physiological traits known to contribute to OSA pathogenesis have been assessed in isolation, primarily in healthy individuals.
  
  
  METHODS
  We assessed the four physiological traits responsible for OSA in a group of young and old patients with OSA.
  
  
  METHODS
  Sleep research laboratory.
  
  
  METHODS
  Ten young (20-40 y) and old (60 y and older) patients with OSA matched by body mass index and sex.
  
  
  RESULTS
  Pharyngeal anatomy/collapsibility, loop gain (LG), upper airway muscle responsiveness/gain (UAG) and the respiratory arousal threshold were determined using multiple 2- to 3-min decreases or drops in continuous positive airway pressure (CPAP). Passive pharyngeal anatomy/collapsibility was quantified as the ventilation at CPAP = 0 cmH2O immediately after the CPAP drop. LG was defined as the ratio of the ventilatory overshoot to the preceding reduction in ventilation. UAG was taken as the ratio of the increase in ventilation to the increase in ventilatory drive across the pressure drop. Arousal threshold was estimated as the ventilatory drive that caused arousal. Veupnea was quantified as the mean ventilation prior to the pressure drop. In comparison with younger patients with OSA, older patients had a more collapsible airway (ventilation at 0 cmH2O = 3.4 ± 0.9 versus 1.5 ± 0.7 L/min; P = 0.05) but lower Veupnea (8.2 ± 0.5 versus 6.1 ± 0.4 L/min; P < 0.01) and a lower LG (5.0 ± 0.7 versus 2.9 ± 0.5; P < 0.05). The remaining traits were similar between groups.
  
  
  CONCLUSIONS
  Our data suggest that airway anatomy/collapsibility plays a relatively greater pathogenic role in older adults, whereas a sensitive ventilatory control system is a more prominent trait in younger adults with obstructive sleep apnea.
  
  
  BACKGROUND
  Edwards BA, Wellman A, Sands SA, Owens RL, Eckert DJ, White DP, Malhotra A. Obstructive sleep apnea in older adults is a distinctly different physiological phenotype.
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors: Bradley A
authors: BA
authors: Edwards
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors: Andrew
authors: A
authors: Wellman
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors: Scott A
authors: SA
authors: Sands
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors: Robert L
authors: RL
authors: Owens
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA ; Neuroscience Research Australia (NeuRA) and the University of New South Wales, Randwick, Sydney, New South Wales, Australia.
authors: Danny J
authors: DJ
authors: Eckert
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors: David P
authors: DP
authors: White
authors: Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA ; Division of Pulmonary and Critical Care Medicine, University of California San Diego, San Diego, CA.
authors: Atul
authors: A
authors: Malhotra
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001143:Arousal / Q000502:physiology; D015992:Body Mass Index; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000503:physiopathology; D010641:Phenotype; D011312:Pressure; D012119:Respiration; D012137:Respiratory System / Q000503:physiopathology; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000473:pathology* / Q000503:physiopathology*; D055815:Young Adult
keywords: aging; loop gain; lung; obstructive sleep apnea; sleep disordered breathing; upper airway collapsibility