Craniofacial profile in Asian and white subjects with obstructive sleep apnoea
1University of Hong Kong, Hong Kong SAR, China
2 Department of Medicine, University of British Columbia, Vancouver,
BC, Canada
Correspondence to:
Dr C F Ryan
UBC Respiratory Clinic, Vancouver General Hospital, 2775 Heather
Street, Vancouver, BC, V5Z 3J5, Canada; fryan@interchange.ubc.ca
Background: Clinical detection of structural narrowing of the
upper airway may facilitate early recognition of obstructive
sleep apnoea (OSA). To determine whether the craniofacial profile
predicts the presence of OSA, the upper airway and craniofacial
structure of 239 consecutive patients (164 Asian and 75 white
subjects) referred to two sleep centres (Hong Kong and Vancouver)
were prospectively examined for suspected sleep disordered
breathing.
Methods: All subjects underwent a history and physical examination
with measurements of anthropometric parameters and craniofacial
structure including neck circumference, thyromental distance,
thyromental angle, and Mallampati oropharyngeal score. OSA
was defined as an apnoea-hypopnoea index (AHI) of 5/hour on
full overnight polysomnography.
Results: Discriminant function analysis indicated that the
Mallampati score (F = 0.70), thyromental angle (F = 0.60),
neck circumference (F = 0.54), body mass index (F = 0.53),
and age (F = 0.53) were the best predictors of OSA. After controlling
for ethnicity, body mass index and neck circumference, patients
with OSA were older, had larger thyromental angles, and higher
Mallampati scores than non-apnoeic subjects. These variables
remained significantly different between OSA patients and controls
across a range of cut-off values of AHI from 5 to 30/hour.
Conclusions: A crowded posterior oropharynx and a steep thyromental
plane predict OSA across two different ethnic groups and varying
degrees of obesity.
Abbreviations: AHI, apnoea-hypopnoea index; BMI, body mass
index; MS, Mallampati score; NC, neck circumference; OSA, obstructive
sleep apnoea; OSAHS, obstructive sleep apnoea-hypoponea syndrome;
TMA, thyromental angle; TMD, thyromental distance
From Thorax 2005;60:504-510.
This article is important as it links dental malocclusions
and obstructive sleep apnea. More specifically it links
the narrow structure of the posterior mouth region, usually
found in many malocclusions with the findings of examinations
in patients with confirmed diagnoses of obstructive sleep apnea. Though
not a definitive study, it is consistent with many people’s
beliefs and other published papers that orthopedic/orthodontic
treatment of children may have very long term health benefits
other than just straight teeth. - DFB
