Electronic cigarette use and its association with asthma chronic obstructive pulmonary disease (COPD) and asthma COPD overlap sy E Cigarette use linked to COPD and hypertension in large study Frontiers More to Explore: Further Definition of Risk Factors for COPD Differential Gender Difference, Modest Elevation in PM2.5, and e Cigarette Use E Cigarettes Have No Benefit for COPD Patients Trying to Quit Smoking