Correlation between Upper Airway and Lower Airway Function in Current Smokers, Never Smokers and Former Smokers

This cross-sectional observational study evaluated whether the effects of smoking on the lower airways are also reflected in the nasal epithelium and upper-airway function. The study included 105 participants divided into current-smoker, former-smoker and never-smoker groups. Nasal mucociliary function, nasal airflow and nasal cytology were assessed using saccharin transit time, peak nasal inspiratory flow and ciliated-cell-to-goblet-cell measurements. Lower-airway function was evaluated using spirometry. The findings showed significantly prolonged saccharin transit time in current and former smokers compared with never smokers, indicating reduced nasal mucociliary function. The study was published in Volume 35, Issue 19 of the Journal of Advances in Medicine and Medical Research in 2023.