The Natural History of Small Airways Physiology in Diseased and Healthy States

Background The main objective of this study is to measure the damage of the small airways in lung disease exploring the "silent zone" with methods that have not been used before together in the same patients. Furthermore, because this is a 4 year longitudinal study, the study team will investigate the time related changes of small airway function in lung disease and normal healthy subjects. The study will also investigate the relationship between small airway resistance and inflammation.