Electronic cigarette use and its association with asthma, chronic obstructive pulmonary disease (COPD) and asthma COPD overlap syndrome among never cigarette smokers Smoking E Cigarettes May Up Risk of Asthma and Other Respiratory Allergies: Study E Cigarette Use Linked to Earlier Asthma Onset in Adults Respiratory Therapy Estimation of Health Risks Caused by Metals Contained in E Cigarette Aerosol through Passive Vaping