TABLE 6

Percentage of explained variance of existing reference equations on our datasets

MalesFemales
TrainingInternal validationExternal validationTrainingInternal validationExternal validation
Quanjer [12]
 FEF25 L·s−18.4910.17.0114.515.611.2
 FEF50 L·s−119.119.318.026.727.427.6
 FEF75 L·s−143.443.055.150.951.356.3
 FEF25–75 L·s−132.330.637.241.942.342.1
GLI [13]
 FEF75 L·s−147.446.355.153.053.658.3
 FEF25–75 L·s−132.832.038.242.542.742.9

Data are presented as %. FEFx: forced expiratory flow at 25%, 50%, 75% and 25–75% of forced vital capacity.