COPD is a progressive, largely irreversible airflow limitation characterized by chronic cough, sputum production, and dyspneamost commonly due to smoking. Spirometry (FEV FVC < 0.7) confirms diagnosis; smoking cessation is the most effective Chronic Bronchitis: A Review Journal of the COPD Foundation Vaping' Increases Odds of Asthma and COPD Johns Hopkins Medicine Will chronic e cigarette use cause lung disease? Thoracic and Sleep Group Queensland