Objectives: Although pharyngeal airway length has been implicated in an increased male predisposition for obstructive sleep apnea (OSA) in adults, data in obese children and adolescents are lacking. Our objective was to determine the influence of gender on pharyngeal airway length in obese adolescents, and to apply computational simulations to better understand the effect of pharyngeal airway length on the airway's predisposition to collapse in this select group.
Methods: Obese subjects without OSA were recruited from our Sleep Center. Their pharyngeal airway length was measured on midline sagittal magnetic resonance images as the distance between the hard palate and the base of the epiglottis. Computational fluid dynamics analysis was used to study the effect of pharyngeal airway length on airflow characteristics. The gender groups were compared for anthropometric measurements and pharyngeal airway length by an unpaired Student's t-test.
Results: Our study group included 18 female and 16 male obese adolescents with a mean (+/-SD) age of 14.7 +/- 2.3 years and a mean body mass index of 38.9 +/- 6.9 kg/m2. The groups did not differ in age, body weight, or normalized pharyngeal airway length (0.44 +/- 0.08 mm/cm in girls versus 0.44 +/- 0.11 mm/cm in boys; p = 0.9). The computational fluid dynamics simulation indicated that the 3-dimensional flow field and airway wall pressures were not significantly affected by pharyngeal airway lengthening of up to 10 mm.
Conclusions: Our results indicate that in obese adolescents, there is no influence of gender on pharyngeal airway length, and pharyngeal airway length alone does not significantly affect the airway's predisposition to collapse. These findings suggest that pharyngeal airway length may not explain the increased male gender predisposition for OSA in this select group.