Upper Airway Collapsibility Is Associated With Obesity and Hyoid Position

Study Questions:

What is the association between obesity, as measured by body mass index (BMI), neck and waist circumferences, and variables associated with hyoid position (pharyngeal length, upper airway volume, and tongue dimensions) with passive pharyngeal critical closing pressure (Pcrit)?


This was a cross-sectional study at an academic hospital of 34 Japanese-Brazilian males ages 21-70 years. The investigators performed computed tomography scans of the upper airway, overnight polysomnography, and Pcrit measurements in all subjects. Continuous variables were compared according to the median value of Pcrit using nonpaired Student t-test or Mann-Whitney U test.


On average, subjects were overweight (BMI = 28 ± 4 kg/m2) and obstructive sleep apnea (OSA) was moderately severe (apnea-hypopnea index = 29 [13–51], range 1–90 events/hour). Factor analysis identified two factors among the studied variables: obesity (extracted from BMI, neck and waist circumferences) and hyoid position (mandibular plane to hyoid distance [MPH], pharyngeal length, tongue length, tongue volume, and upper airway volume). Both obesity and hyoid position correlated with Pcrit (r = 0.470 and 0.630, respectively) (p < 0.01). In addition, tongue volume, tongue length, pharyngeal length, and MPH correlated with waist and neck circumferences (p < 0.05).


The authors concluded that pharyngeal critical closing pressure is associated with obesity and hyoid position.


This study reports that upper airway collapsibility (Pcrit) is associated with obesity (BMI, neck and abdominal circumferences) and hyoid position (and most of its related variables: MPH, tongue length, tongue volume, and pharyngeal length). Moreover, tongue dimensions, pharyngeal length, and MPH are associated with obesity variables. These findings provide novel insight into the potential factors mediating upper airway collapse in OSA. Given the many factors underlying OSA and their complex interactions, further work investigating the relationship between obesity, upper airway structures, and function is required.

Clinical Topics: Noninvasive Imaging, Sleep Apnea

Keywords: Waist Circumference, Body Mass Index, Brazil, Polysomnography, Overweight, Tomography, Factor Analysis, Statistical, Obesity, Hyoid Bone, Sleep Apnea, Obstructive

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