Isolated small airways obstruction predicts future chronic airflow obstruction: A multinational longitudinal study

This study evaluated whether the presence of isolated small airways obstruction was associated with progression to chronic airflow obstruction in 3957 individuals enrolled in a multinational observational cohort study (BOLD) and in 26,512 participants enrolled in the UK Biobank study. Baseline and follow-up spirometric testing (FEV1, FVC, FEF25–75, FEV3) in the UK Biobank study was measured using a calibrated Vitalograph Pneumotrac spirometer.