TABLE 1

Lung functional characteristics of nonobstructed and obstructed subjects

NonobstructedObstructed
FEV1 % pred103±1564±17
FVC % pred106±1283±17
FEV1/FVC0.77±0.40.60±0.8
FEF25% % pred81±2332±18
FEF50% % pred100±4129±11
FEF75% % pred84±3641±18
FEF25–75% % pred61±527±10

Data are presented as mean±sd. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; FEFx%: forced expiratory flow at 25%, 50% and 75% of FVC. p<0.0001 for all comparisons.