Treatment for Chronic Obstructive Pulmonary Disease (SOURCE Trial)

This is an observational study of 1000 participants to further define the nature of early chronic obstructive pulmonary disease (COPD) in younger, at-risk individuals. The study has three main goals: * To use CT scan imaging to identify which smokers will develop COPD. * To identify biomarkers predictive of smokers that will develop COPD. * To determine if sputum (phlegm) can be analyzed to predict which smokers will develop COPD. Procedures (methods): All participants will undergo study related questionnaires assessing medical history, smoke exposure and use, medication use, social and behavioral health, pulmonary symptoms, food frequency, and will provide nasal swab, blood, stool, and urine samples, pulmonary function testing to determine function, sputum induction to provide a sputum sample for airway biospecimen analysis, and CT imaging of the lungs.