Understanding potential associations between anatomic and other factors in OSA severity

The aim of this prospective study was to investigate associations between nasal/oropharyngeal structures and a range of factors including age, gender, daytime sleepiness, and body mass index (BMI).

Patients with OSA were prospectively selected as research participants in rhinomanometric analysis as well as for otolaryngological evaluation. Participants were grouped as follows according to their apnea/hypopnea index (AHI) scores: no OSA (AHI < 5), mild OSA (5 ≤ AHI ≤ 15), moderate OSA (15 ≤ AHI < 30), and severe OSA (AHI ≥ 30). One-way analysis of variance (ANOVA), Kruskal-Wallis H, and Mann-Whitney U tests were performed to assess OSA severity in terms of the relationships between nasal resistance (NR) and anthropometric indices (body mass index (BMI), Friedman tongue position (FTP)), age, and gender.

The study cohort of 177 men and 81 women ranged in age between 21 and 76 years, with BMI ranging from 23 to 45. In total, 37 patients were simple snorers (AHI < 5), and 221 patients were diagnosed with OSA. There was no significant difference among the AHI groups in terms of nasal volume (Vol05) (p = 0.952), mean flow (p = 0.778), and mean NR total (p = 0.723). A statistically significant difference was found between the AHI groups in terms of mean BMI and median FTP scores (p < 0.001).

This study provides evidence that that the oropharyngeal region (oropharynx, tongue, and vallecula) is a more important determinant of OSA severity than the nasal region.