Physiological characteristics of subjects
| Baseline characteristics | Median (quartiles) |
| Age (years) | 67.5 (60.5, 74.3) |
| M:F | 8:10 |
| Smoking history (pack years) | 35 (30, 55) |
| FEV1(l) | 0.53 (0.45, 0.76) |
| FEV1 (% predicted) | 26 (18.5, 35) |
| Tlco (mmol/min/kPa) | 2.49 (1.48, 3.54) |
| Tlco (% predicted) | 44 (29, 64) |
| BMI (kg/m2) | 23.3 (17.6, 26.9) |
| Oximetry at rest (%) | 94 (91, 95) |
FEV1 = forced expiratory volume in one second; Tlco = carbon monoxide transfer factor; BMI = body mass index.