title: Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea.
abstract: OBJECTIVE
  To compare the differences in craniofacial morphology in Chinese patients with and without obstructive sleep apnoea (OSA).
  
  
  METHODS
  We performed lateral cephalometric radiographs on 94 consecutive patients (77 males) referred with snoring or other symptoms suggestive of OSA for polysomnography (PSG). Significant OSA was defined as an apneoa-hypopnoea index (AHI) > or = 10/h of sleep on overnight PSG. The cephalometric data were compared between those with and without significant OSA.
  
  
  RESULTS
  (mean +/- SD) There were 69 (56 males) with significant OSA with mean age 53 +/- 12 years, body mass index (BMI) 28.6 +/- 5.0 kg/m2, AHI 36.5 +/- 20.6/h, and minimum SaO2 76 +/- 14%. There were 25 controls (21 males) without significant OSA with similar age and BMI. The mandibular plane to hyoid bone distance (MPH) and the perpendicular distance from hyoid bone to the line connecting C3 vertebra and retrognathion (HHI) were significantly longer in the OSA patients. The angle measurement from sella to nasion to point A (SNA) was smaller in the OSA group. MPH distance was the only independent variable for significant OSA with an odds ratio of 3.47 (95% CI 1.39-8.66). Abnormalities of the MPH and SNA were more marked in the OSA patients with BMI > or = 30 kg/m2.
  
  
  CONCLUSIONS
  Significant differences in craniofacial morphology are noted between OSA patients and non-apnoeic controls. An inferiorly positioned hyoid bone and a retropositioned maxilla may predispose obese patients to more severe OSA.
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong. dschui@cuhk.edu.hk
authors.forename: D S C
authors.initials: DS
authors.lastname: Hui
authors.forename: F W S
authors.initials: FW
authors.lastname: Ko
authors.forename: A S Y
authors.initials: AS
authors.lastname: Chu
authors.forename: J P C
authors.initials: JP
authors.lastname: Fok
authors.forename: M C H
authors.initials: MC
authors.lastname: Chan
authors.forename: T S T
authors.initials: TS
authors.lastname: Li
authors.forename: D K L
authors.initials: DK
authors.lastname: Choy
authors.forename: C K W
authors.initials: CK
authors.lastname: Lai
authors.forename: A
authors.initials: A
authors.lastname: Ahuja
authors.forename: A S C
authors.initials: AS
authors.lastname: Ching
mesh_terms: D000704:Analysis of Variance; D015992:Body Mass Index; D002508:Cephalometry / Q000379:methods*; D002681:China / Q000208:ethnology; D005147:Facial Bones / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000208:ethnology / Q000473:pathology*; D012913:Snoring / Q000208:ethnology / Q000473:pathology