title: Lateral cephalometric analysis and the risks of moderate to severe obstructive sleep-disordered breathing in Thai patients.
abstract: OBJECTIVE
  This cross-sectional study was aimed to compare lateral cephalometric parameters among patients with different severities of obstructive sleep-disordered breathing and to determine if there are radiographic variables that increase risk of moderate to severe obstructive sleep apnea (OSA).
  
  
  METHODS
  Ten linear and 5 angular parameters of lateral cephalometry in 188 adult subjects which included 47 controls and 141 patients with OSA classified by apnea-hypopnea index (AHI) from level-I polysomnography, were analyzed. All radiographs were done under standardized processes and measured twice on separate occasions.
  
  
  RESULTS
  There were statistically significant differences between controls and patients with AHI ≥ 15 in parameters such as a distance from mandibular plane to hyoid (MP-H), posterior airway space (PAS), skull base angle (NSBA), a distance from posterior nasal spine to posterior pharyngeal wall (PNS-PP), and soft palate length (PNS-P), (p < 0.01). However, no significant difference was found between controls and mild OSA. Logistic regression analysis showed that only MP-H with cutoff point of ≥ 18 millimeters, NSBA ≤ 130°, and PAS ≤ 10 millimeters were independent cephalometric variables that increased risk of having AHI ≥ 15 compared to controls with adjusted odds ratio of 17.1, 8.3 and 4.2, respectively. Gender did not significantly associate with OSA severity in this analysis.
  
  
  CONCLUSIONS
  Patients who had longer MP-H, narrower PAS and narrower NSBA than specific cutoff points significantly increased risks of moderate to severe OSA. Treatments that effectively improve these parameters, particularly at tongue base level (MP-H and PAS), may decrease the severity of disease.
authors.affiliation: Department of Otorhinolaryngology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand, wishbanh@gmail.com.
authors.forename: Wish
authors.initials: W
authors.lastname: Banhiran
authors.forename: Pisit
authors.initials: P
authors.lastname: Wanichakorntrakul
authors.forename: Choakchai
authors.initials: C
authors.lastname: Metheetrairut
authors.forename: Pipat
authors.initials: P
authors.lastname: Chiewvit
authors.forename: Wandee
authors.initials: W
authors.lastname: Planuphap
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002508:Cephalometry / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011237:Predictive Value of Tests; D012016:Reference Values; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D013785:Thailand; D055815:Young Adult