Clinical and lung function data of all participants
| Nonsmokers | Smokers | ||
| Normal lung function | COPD | ||
| Subjects n | 9 | 14 | 18 |
| Age yrs | 56±7 | 60±2 | 64±2 |
| Pack-yrs | 0 | 36±5* | 46±3* |
| FEV1 % pred | 100±7 | 95±3 | 59±2*,# |
| FEV1/FVC % | 75±2 | 77±1 | 57±2*,# |
Data presented as mean±sem, unless otherwise stated. COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in one second; FVC: forced vital capacity. *: p<0.05 versus nonsmokers; #: p<0.05 versus smokers with normal lung function. Spirometric reference values were taken from a Mediterranean population 29.