Subject characteristics
| Subject group | Subjects n | Sex M:F | Age yrs | Smoking history pack yrs | FEV1 % pred | FEV1/FVC % | FEV1 post β2 % from baseline |
| Control nonsmokers | 12 | 6:6 | 61±12 | 0 | 111±14 | 85±5 | |
| Control smokers | 17 | 14:3 | 60±7 | 39±23 | 107±15 | 82±7 | |
| COPD patients | 14 | 11:3 | 64±8 | 45±28 | 59±15* | 56±7* | 4±4 |
Data are presented as mean±sd unless otherwise stated
FEV1: forced expiratory volume in one second
FVC: forced vital capacity
COPD: chronic obstructive pulmonary disease
*p<0.05 compared with control smokers and nonsmokers with normal lung function