- Immune system disorders, pulmonary diseases (e.g., asthma within the prior 5 years, acute bronchitis within 1 year, chronic obstructive pulmonary disease [COPD], chronic bronchitis, and restrictive lung disease), clinically diagnosed kidney or liver diseases, or any other medical disorders that will increase the risk from bronchoscopy, affect biomarker data, or increase risk of an adverse effect from e-cig use; all subjects are screened by a pulmonologist obtaining a medical history and a physical examination (heart, lungs and oral cavity) to ensure no increased risk from bronchoscopy or e-cig use