Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: Impact of ethnicity

Authors

  • KATE SUTHERLAND,

    1. Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital, Sydney
    2. NHMRC Centre for Sleep Health (CIRUS), Woolcock Institute of Medical Research, University of Sydney, Sydney
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  • RICHARD W.W. LEE,

    1. Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital, Sydney
    2. NHMRC Centre for Sleep Health (CIRUS), Woolcock Institute of Medical Research, University of Sydney, Sydney
    3. Department of Respiratory Medicine, Gosford Hospital, Gosford
    4. School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia
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  • PETER A. CISTULLI

    Corresponding author
    1. Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital, Sydney
    2. NHMRC Centre for Sleep Health (CIRUS), Woolcock Institute of Medical Research, University of Sydney, Sydney
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  • The Authors: Kate Sutherland, PhD, is a Postdoctoral Research Fellow at the Woolcock Institute of Medical Research and Royal North Shore Hospital, with research interests in craniofacial and upper airway imaging in OSA. Richard Wai Wing Lee, MD PhD, is a Research Fellow at the Woolcock Institute of Medical Research and a Staff Specialist at Gosford Hospital, with research interests in craniofacial and upper airway imaging in OSA. Peter Cistulli, MD PhD, is a Professor of Respiratory Medicine and Head of the Discipline of Sleep Medicine at the University of Sydney, and Head of Respiratory and Sleep Medicine at Royal North Shore Hospital, with research interests in the pathophysiology of OSA and novel treatments for OSA.

  • SERIES EDITOR: AMANDA J. PIPER

Peter Cistulli, Centre for Sleep Health and Research, Department of Respiratory Medicine, Level 8, Main Block, Royal North Shore Hospital, Pacific Highway, St Leonards, NSW 2065, Australia. Email: peter.cistulli@sydney.edu.au

ABSTRACT

OSA is the result of structural and functional abnormalities that promote the repetitive collapse of the upper airway during sleep. This common disorder is estimated to occur in approximately 4% of men and 2% of women, with prevalence studies from North America, Australia, Europe and Asia indicating that occurrence is relatively similar across the globe. Anatomical factors, such as obesity and craniofacial morphology, are key determinants of the predisposition to airway collapse; however, their relative importance for OSA risk likely varies between ethnicities. Direct inter-ethnic studies comparing craniofacial phenotypes in OSA are limited. However, available data suggest that Asian OSA populations primarily display features of craniofacial skeletal restriction, African Americans display more obesity and enlarged upper airway soft tissues, while Caucasians show evidence of both bony and soft tissue abnormalities. Our recent comparison of Chinese and Caucasian OSA patients found for the same degree of OSA severity. Caucasians were more obese, and Chinese had more skeletal restriction. However, the ratio of obesity to craniofacial bony size (or anatomical balance, an important determinant of upper airway volume and OSA risk) was similar between Caucasians and Chinese OSA patients. Ethnicity appears to influence OSA craniofacial phenotype but furthermore the relative contribution of the anatomical factors underlying OSA risk. The skeletal restriction craniofacial phenotype may be particularly vulnerable to increasing obesity rates. Better understanding of craniofacial phenotypes encompassing ethnicity may help improve OSA recognition and treatment; however, further studies are needed to elucidate ethnic differences in OSA anatomical risk factors.

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