| Groups | H-N | S-N | S-COPD | ES-COPD |
| Subjects n | 17 | 15 | 17 | 15 |
| Age* yrs | 49 (20–68) | 46 (30–65) | 60 (46–69) | 61 (53–69) |
| Female/male | 11/6 | 4/11 | 7/10 | 5/10 |
| Pack-yrs smoking | 0 | 35 (11–57) | 44 (18–82) | 50 (18–151) |
| FEV1/FVC#% | 82 (71–88) | 78 (70–96) | 59 (46–68) | 62 (38–68) |
| FEV1% pred | 107 (86–140) | 93 (78–125) | 79 (55–100) | 83 (55–112) |
| ΔFEV1% | 8 (0–30) | 10 (2–17) |
Data are presented as median (range), unless otherwise stated. H-N: healthy and nonsmoking controls; S-N: smokers with normal lung function; S-COPD: smokers with chronic obstructive pulmonary disease; ES-COPD: ex-smokers with COPD; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; % pred: % predicted. #: post-bronchodilator values. *: p<0.05 (nonparametric ANOVA).