| Group A (n = 182) | Group B (n = 264) | Group C (n = 60) | |
| Sex (M/F) | 109/73 | 160/104 | 44/16 |
| Age (years) | 52.6 (14.9) (18–84) | 52.3 (14.5) (18–85) | 51.3 (12.3) (24–73) |
| FEV1 (% pred) | 59.4 (23.5) (16–115) | 61.8 (23.5) (16–118) | 62.4 (25.2) (21–115) |
| FEV1/FVC (%) | 73.1 (13.1) (33–98) | 73.4 (12.8) (33–98) | 72.9 (15.4) (21–95) |
| VC (% pred) | 66.1 (23.5) (16–118) | 68.0 (23.4) (16–143) | 68.9 (23.1) (23–118) |
| ΔVC (%) (n = 101) | 22.1 (16.5) (0–71) | 20.1 (14.2) (0–71) | 23.8 (14.9) (0–71) |
Values presented as mean (SD) (minimum – maximum).
FEV1 (% pred), forced expiratory volume in 1 s as percentage of predicted value; VC (% pred), vital capacity as percentage of predicted value; ΔVC, fall in vital capacity when changing position from sitting to supine.