| Variables | Nonsmokers | Smokers |
| Patients n | 8 | 8 |
| Age yrs | 65±11 | 55±8 |
| Male/female n | 1/7 | 7/1 |
| Tobacco pack-yrs | 37±11 | |
| FEV1 L | 2.47±0.49 | 2.81±0.55 |
| FEV1 % pred | 110±26 | 96±5 |
| FEV1/FVC % pred | 81±5 | 78±4 |
| Pa,O2 mmHg | 86±8 | 83±9 |
| Pa,CO2 mmHg | 36±4 | 39±4 |
Data are presented as mean±sem, unless otherwise stated. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; % pred: % predicted; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension.