Clinical implications of airway obstruction with normal or low FEV in childhood and adolescence.

Background: Airway obstruction is defined by spirometry as a low forced expiratory volume in 1 s (FEV) to forced vital capacity (FVC) ratio. This impaired ratio may originate from a low FEV (classic) or a normal FEV in combination with a large FVC (dysanaptic). The clinical implications of dysanaptic obstruction during childhood and adolescence in the general population remain unclear.