Comparison of the upper airway morphology between Dutch and Chinese adults with obstructive sleep apnea

Purpose: The pathogenesis of obstructive sleep apnea (OSA) is complex and may vary between different races. It has been suggested that the anatomical balance between skeletal tissues and soft tissues around the upper airway is a key pathophysiologic factor of OSA. Therefore, the aim of this study was to compare the anatomical balance of the upper airway between Dutch and Chinese patients with OSA based on cone beam computed tomography (CBCT) images. Methods: This was a cross-sectional study performed in two centers and included Dutch and Chinese adults with OSA. CBCT scans in the supine position were obtained for both Dutch and Chinese OSA groups. The primary outcome variable was the anatomical balance of the upper airway, defined as the ratio of the tongue area and the maxillomandibular enclosure area. Results: A total of 28 Dutch adults (mean age ± SD of 46.6 ± 14.1 years, body mass index [BMI] of 26.8 ± 3.5 kg/m², and apnea-hypopnea index [AHI] of 15.7 ± 7.1 events/h) and 24 Chinese adults (age 41.0 ± 12.4 years, BMI 26.5 ± 3.3 kg/m², and AHI 16.5 ± 7.8 events/h). There were no significant differences in AHI, age, BMI, and sex between the two groups (P = 0.14–0.76). The Dutch group had a significantly larger tongue area and tongue length compared to the Chinese group (P = 0.01 and P < 0.01). On the other hand, the Chinese group had a smaller maxilla length compared to the Dutch group (P < 0.01). However, the anatomical balance of the upper airway of both groups was not significantly different (P = 0.16). Conclusion: Within the limitations of this study, no significant difference was found in the anatomical balance of the upper airway between Dutch and Chinese patients with mild to moderate OSA. Trial registration: The present study was registered at the ClinicalTrials.gov identifier NCT03463785.