The male predisposition to pharyngeal collapse: importance of airway length.
Obstructive sleep apnea is an important disorder because of both its prevalence and its cardiovascular and neurocognitive sequelae. Despite the fact that male sex is a major risk factor for this disorder, the mechanisms underlying this predisposition are unclear. To understand the pathophysiologic basis of the male predisposition for pharyngeal collapse, we performed a detailed analysis of the anatomic and physiologic features of the upper airway in a cohort of normal and near-normal subjects (equal number of men and women). Although no important physiologic (genioglossal electromyogram, airflow resistance) differences were observed between sexes, a number of anatomic differences were apparent. The pharyngeal airway length was substantially longer in men compared with women. There was also an increased cross-sectional area of the soft palate and an increased airway volume in men compared with women. Using signal-averaged anatomic data from male and female subjects, we developed representative male and female finite element airway models. This model demonstrated the male airway to be substantially more collapsible than the female airway, solely on the basis of anatomic differences. This study suggests that the male predisposition to pharyngeal collapse is anatomically based, primarily as the result of an increased length of vulnerable airway as well as increased soft palate size.
Malhotra
Atul
A
Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA. amalhotra1@partners.org
Huang
Yaqi
Y
Fogel
Robert B
RB
Pillar
Giora
G
Edwards
Jill K
JK
Kikinis
Ron
R
Loring
Stephen H
SH
White
David P
DP
D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000150:complications / Q000235:genetics / Q000503:physiopathology; D000403:Airway Resistance / Q000502:physiology; D005260:Female; D020342:Finite Element Analysis; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010608:Pharyngeal Diseases / Q000150:complications / Q000235:genetics* / Q000503:physiopathology; D010609:Pharyngeal Muscles / Q000473:pathology / Q000502:physiology; D015203:Reproducibility of Results; D012137:Respiratory System / Q000473:pathology; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000235:genetics / Q000503:physiopathology