1. Healthy subjects less than 45 years of age and BMI < 35
1. Age < 18 years
2. Pregnant or Breast-Feeding
3. Participation in a clinical trial of an investigational medicinal product within 30 days
4. Consent declined
5. History of asthma
6. Marijuana use or other inhaled products with or without nicotine in the last 3 months
7. Alcohol abuse, as defined by the Alcohol Use Disorders Identification Test (AUDIT)
The three groups in our cohort will be defined as follows and will be used as cohort specific criteria for inclusion into the study:
Electronic Cigarette Users: Subjects who use electronic cigarettes daily and have not used conventional cigarettes in the previous 3 months. Total pack years of smoking should be less than 20 for their smoking history, with normal lung function (FEV1 and FEV1/FVC) and no clinical symptoms of airway obstruction/inflammation (cough, dyspnea, sputum and wheeze).
Cigarette Smokers: Subjects who smoke at least ¼ pack cigarettes per day for the past 1 year, with no history of electronic cigarette use in the last 30 days.
Controls: Subjects with no history of prior conventional cigarette (< 100 cigarettes lifetime) or electronic cigarette use.