title: Computed tomographic evaluation of the role of craniofacial and upper airway morphology in obstructive sleep apnea in Chinese.
abstract: OBJECTIVE
  To evaluate the relationship between cephalometric parameters, upper airway morphological factors and obstructive sleep apnea (OSA) in Chinese subjects.
  
  
  METHODS
  Polysomnogram (PSG) were performed and scored using standard criteria. Supine lateral cephalometric parameters and pharyngeal cross-sectional areas at the level of velopharynx (VA) and hypopharynx (HA) were measured from computed tomographic scans. The roles of these parameters and other anthropometric/demographic characteristics in OSA (apnea hypopnea index, AHI > or = 5) and their relationship with severity of OSA were explored by multiple logistic and multinominal regression analysis.
  
  
  RESULTS
  Ninety-two subjects, ranging from normal (n = 36), mild/moderate OSA (n = 34) to severe OSA (n = 22), were evaluated. Compared with normal subjects, OSA subjects were heavier (body mass index 27 vs. 24 kg/m2) and older (47 vs. 42 years of age); had smaller VA size and VA to HA ratio, lower positioned hyoid bone, longer and thicker soft palate, and more retropositioned mandible relative to maxilla. After controlling for body mass index and age, subjects with severe OSA (AHI > 30) had more retropositioned mandible relative to maxilla (odds ratio, OR 1.31, P = 0.044) and longer soft palate (OR 1.16, P = 0.01), while those with mild/moderate OSA had larger VA to HA ratio (OR 0.17, P = 0.018).
  
  
  CONCLUSIONS
  Craniofacial factors and upper airway morphology contributed to severity of OSA in Chinese subjects. Having controlled for obesity, more retropositioned mandible was associated with more severe OSA.
authors.affiliation: University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Porfulam, Hong Kong SAR, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Lam
authors.forename: Clara G C
authors.initials: CG
authors.lastname: Ooi
authors.forename: Wilfred C G
authors.initials: WC
authors.lastname: Peh
authors.forename: I
authors.initials: I
authors.lastname: Lauder
authors.forename: Kenneth W T
authors.initials: KW
authors.lastname: Tsang
authors.forename: Wah-Kit
authors.initials: WK
authors.lastname: Lam
authors.forename: Mary S M
authors.initials: MS
authors.lastname: Ip
mesh_terms: D002508:Cephalometry; D002681:China / Q000208:ethnology; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D010608:Pharyngeal Diseases / Q000000981:diagnostic imaging / Q000208:ethnology / Q000473:pathology*; D010614:Pharynx / Q000473:pathology*; D017286:Polysomnography; D012044:Regression Analysis; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000208:ethnology / Q000473:pathology*; D014057:Tomography, X-Ray Computed