title: Nocturnal intermittent hypoxia is independently associated with pain in subjects suffering from sleep-disordered breathing.
abstract: BACKGROUND
  On the basis of experimental and clinical evidence, the authors hypothesized that nocturnal hypoxemia would be associated with pain reports in subjects suffering from sleep-disordered breathing, independently of sleep fragmentation and inflammation.
  
  
  METHODS
  After obtaining institutional approval and access to the Cleveland Family Study phenotype and genotype data, the authors used proportional odds regression to examine the association between arterial desaturation and four different types of pain, as well as their composite measure, sequentially adjusted for: (1) clinical characteristics and (2) sleep fragmentation and inflammation. The authors also examined the association of selected candidate single-nucleotide polymorphisms with pain reports.
  
  
  RESULTS
  Decreased minimum nocturnal arterial saturation increased the odds for morning headache (adjusted odds ratio per SD=1.36; 95% CI [1.08-1.71]; P=0.009), headache disrupting sleep (1.29 [1.10-1.51]; P=0.002), and chest pain while in bed (1.37 [1.10-1.70]; P=0.004). A decrease in the minimum nocturnal saturation from 92 to 75% approximately doubled the odds for pain. One single-nucleotide polymorphism for the α 1 chain of collagen type XI (COL11A1-rs1676486) gene was significantly associated with headache disrupting sleep (odds ratio=1.72 [1.01-2.94]; P=0.038), pain disrupting sleep (odds ratio=1.85 [1.04-3.28]; P=0.018), and pain composite (odds ratio=1.89 [1.14-3.14]; P=0.001).
  
  
  CONCLUSIONS
  Nocturnal arterial desaturation may be associated with an increased pain in subjects with sleep-disordered breathing, independently of sleep fragmentation and inflammation.
authors.affiliation: * Associate Professor, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, California, and Outcomes Research Consortium, Cleveland, Ohio. † Assistant Professor, Department of Health Research and Policy, ‡ Director of Faculty Development, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine. § Postdoctoral Research Fellow, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, and Stanford Center for Sleep Sciences and Medicine.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Doufas
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.forename: Margaret Frances
authors.initials: MF
authors.lastname: Davies
authors.forename: Simon C
authors.initials: SC
authors.lastname: Warby
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D006801:Humans; D000860:Hypoxia / Q000150:complications* / Q000235:genetics; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D010146:Pain / Q000150:complications* / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017286:Polysomnography; D012044:Regression Analysis; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000235:genetics; D012894:Sleep Stages; D018746:Systemic Inflammatory Response Syndrome / Q000503:physiopathology; D016896:Treatment Outcome; D055815:Young Adult