Preterm birth alters the normal sequence of lung development with lasting respiratory consequences. It is still unclear whether observed respiratory morbidities in preterm born individuals reflect sequelae from a non-progressive lung disease that occurred early in life or result from ongoing active disease that, if left undiagnosed and untreated, could increase the risk of a COPD-like phenotype. We propose to examine micro-structural abnormalities of the lung using innovative non-invasive imaging technologies in relation to pulmonary function and markers of inflammation and oxidative stress in young adults born preterm.