| Subjects n | 845 |
| Males % | 49 |
| Age yrs (IQR) | 59 (52–64) |
| Occupational exposure | 50 |
| Mean FEV1 post-bronchodilator L | |
| Males | 3.19 |
| Females | 2.38 |
| Mean FEV1 post-bronchodilator % pred (95% CI) | 100.1 (99–101) |
| COPD | 10 |
| COPD ever smoked | 77 |
| Undiagnosed COPD | 6 |
Data are presented as %, unless otherwise stated. IQR: interquartile range; FEV1: force expiratory volume in 1 s; % pred: % predicted; COPD: chronic obstructive pulmonary disease.