| COPD case–control study | ICGN family study | |||
| Cases | Controls | Probands | Siblings | |
| Subjects | 953 | 956 | 610 | 1300 |
| Age yrs | 65.5±10.1 | 55.5±9.7 | 58.4±5.5 | 58.1±9.8 |
| Females | 370 (38.8) | 477 (49.9) | 247 (40.5) | 648 (49.80) |
| Post-bronchodilator FEV1 L | 1.58±0.71 | 3.24±0.74 | 1.11±0.44 | 2.36±0.98 |
| Post-bronchodilator FEV1 % pred | 50.3±17.5 | 94.1±9.2 | 36.3±12.9 | 77.5±25.9 |
| Post-bronchodilator FEV1/FVC# | 0.51±0.13 | 0.79±0.04 | 0.37±0.12 | 0.61±0.15 |
| Smoking exposure pack-yrs | 32.0±18.6 | 19.1±13.2 | 51.5±26.8 | 40.6±24.9 |
| Current smokers | 457 (48.1) | 407 (42.6) | 207 (33.9) | 661 (50.8) |
Data are presented as n, mean±sd or n (%). COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity. #: FEV1/vital capacity (VC) was used for the ICGN family study, with VC determined as the higher of FVC and synchronised VC.