Nasal Cavity Dimensions and Pharyngeal Airway Space in Simple Snoring: A Cross-Sectional CT-Based Study.

Background and Objectives: The anatomical relationship between nasal cavity dimensions and the pharyngeal airway space (PAS) in simple snoring remains poorly defined. We investigated the association between nasal cavity dimensions and the PAS in adults with simple snoring using computed tomography (CT), focusing on anatomical correlations. Materials and Methods: This cross-sectional study included 83 adults with simple snoring and nasal obstruction and a confirmed apnea-hypopnea index (AHI) < 2, enrolled between 2007 and 2022. Polysomnography and CT were performed to measure nasal and pharyngeal airway dimensions. The minimum cross-sectional areas (mCSAs) of three nasal cavity segments and pharyngeal airway dimensions were measured on awake CT images. Multivariable linear regression, adjusted for age, sex, and BMI, was used to evaluate the association between the nasal and pharyngeal airway dimensions. Results: A larger bilateral narrowest nasal cross-sectional area was significantly associated with a larger PAS mCSA in the full cohort (standardized β = 0.26, p = 0.012), after adjustment for age, sex, and BMI. A 10-mm2 larger nasal area corresponded to a 3.6% larger PAS mCSA (95% CI, 0.8-6.5%), and the model explained a modest share of the variance (adjusted R2 = 0.17). The association did not differ by sex (interaction p = 0.25), indicating no evidence of effect modification. Conclusions: In individuals with simple snoring, smaller nasal cavity dimensions were associated with a narrower PAS on static CT imaging, although this association was modest and explained only a small fraction of the variation in pharyngeal calibre. These findings reflect anatomical associations and should not be interpreted as evidence of functional airway collapse or disease progression.