Lobar Mucus Plugging Identifies Regions of Air Trapping in Smokers With Preserved Lung Function (BEACON) and COPD Patients

In both BEACON and COPD participants, lobes containing CT-visible mucus plugs exhibited significantly greater air trapping, whereas this association was not observed in healthy never-smokers. Despite a similar prevalence of mucus plugging, BEACON participantsshowed greater lobar air trapping than healthy controls, consistent with early smoking-related small airway abnormalities. These findings suggest that CT-visible mucus plugs in larger airways likely reflect more extensive disease in the peripheral/small airways, rather than directly causing local airflow obstruction. Mucus plugs and peripheral functional abnormalities may develop in parallel, or mucus plugging may arise secondarily to pre-existing small airway disease. Overall, mucus plugs serve as a marker of greater functional impairment in young adult smokers and COPD patients.