Trajectory of preserved ratio impaired spirometry: Natural history and long-term prognosis

This study evaluated the natural history and long-term prognosis of 1160 individuals aged 20–40 years with varying trajectories of preserved ratio impaired spirometry (ie FEV1/FVC ≥ 0.7 [or ≥ the lower limit of normal] and FEV1 <80% predicted). Included participants were enrolled in the Copenhagen City Heart Study, with lung function trajectories based on data from surveys undertaken from 1976–1983 to 2001–2003. In the 2001–2003 survey, lung function testing was undertaken using a calibrated Vitalograph dry wedge spirometer.