Clinical and functional characteristics of the population studied
| Never-smokers | Smokers with normal lung function | Smokers with COPD | |
| Subjects n | 26 | 24 | 26 |
| Age yrs | 57±2 | 58±2 | 61±1 |
| Sex male/female | 26/0 | 24/0 | 26/0 |
| Smoking history pack-yrs | 0±0 | 39±4# | 49±3# |
| FEV1 % reference | 106±3 | 94±2# | 48±4#,¶ |
| FEV1/FVC % | 80±1 | 82±3 | 52±2#,¶ |
Data are presented as mean±sem, unless otherwise stated. COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in one second; FVC: forced vital capacity. #: p<0.01 versus never-smokers; ¶: p<0.01 versus smokers with normal lung function.