Exercise-induced bronchoconstriction (EIB) is a symptom shared by 90% of individuals diagnosed with asthma, and is typically caused by the inhalation of cold and/or dry air. Since respiratory heat and moisture exchange occurs primarily in the nasal passages, EIB ultimately arises from nasal insufficient air-conditioning. However, there is a paucity of research exploring whether certain aspects of nasal morphology predispose an individual to exhibit this potentially fatal response to cold/dry air. To investigate the relationship between internal nasal form variation and airflow physiology, computed tomography-derived 3D models of nasal passages were collected from an ancestrally diverse, mixed-sex sample (N = 20). Fifteen linear measurements encompassing dimensions throughout the nasal passage were collected on each model, and computation fluid dynamics (CFD) analysis performed to assess intranasal humidity and temperature transfers during the inspiration of cold, dry air (-5°C, RH = 0%). Two-block partial least squares (2BPLS) analysis was used to assess potential associations between nasal passage morphology and airflow physiology, and found significant covariation between nasal anatomy and respiratory physiology (RV = 0.19, P < 0.05). The first PLS axis explained 97.5% of covariation, and denotes a consistent pattern in which individuals with shorter, wider, and shallower nasal passages are associated with diminished air-conditioning capabilities. Thus, individuals with shorter, wider, and shallower nasal passages may be more vulnerable when breathing in cold, dry air and predisposed to EIB. These findings highlight the need for further research into potential anatomical etiologies of asthma. (Sponsored by Grant #RF00241 from the Texas Center for Health Disparities via NIMHD 5U54MD006882-10).
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