Airway Injury in Swine Confinement Workers

piratory symptoms are indicative of underlying lung disease among swine confinement workers and, if so, to identify whether respiratory changes were more indicative of airway or of interstitial lung injury. • Design: Nested case-control study within a popula-tion-based longitudinal study. • Setting: University hospital. • Participants: Study participants were randomly se-lected from a group of 207 swine confinement workers followed longitudinally. Of these, 43 workers with res-piratory symptoms were identified, and 31 were ran-domly selected for inclusion in this study. Three control groups (swine confinement workers, neighbor farmers, and blue collar workers) without work-related respira-tory symptoms were frequency-matched by age, sex