Correlation between retroglossal airway size and body mass index in OSA and non-OSA patients using cone beam CT imaging

Most obstructive sleep apnea (OSA) patients are overweight, and OSA is substantially more common in obese individuals. In morbidly obese patients, at least 70% suffer from OSA. However, the exact mechanism by which obesity causes OSA is unclear. The aim of this study is to evaluate the retroglossal airway configuration quantitatively and to make clear the relationship between Body mass index (BMI) and airway configuration. This retrospective study included 15 OSA patients (male = 11; female = 4) and 14 normal controls (male = 8; female = 6). We studied the airway configuration on an axial slice at the level of the anterior–inferior corner of the second cervical vertebra. Maximum anterior–posterior diameter (AP) and lateral width (LW) of the airway were measured, and the square area (SA) was calculated. The airway cross-section area (AWA) was also measured, and then the AWA/SA ratio was calculated. AP, LW, and AWA were not statistically significantly different between controls and OSA patients. On the other hand, the AWA/SA ratio in OSA patients was 8.8% statistically significantly smaller than in controls after adjusting for sex, age, and BMI. In this sample, there was a negative correlation between age and the AWA/SA ratio but only in the OSA group. The AWA/SA ratio was significantly negatively correlated with OSA status (R = −0.5; p = 0.008) after adjusting for BMI and age. In this present study, we could evaluate the retroglossal airway configuration quantitatively. The AWA/SA ratio was correlated with OSA status after adjusting for BMI and age.