| Healthy | COPD | p-value | |
| Subjects | 40 | 20 | |
| Age years | 40.7±10.3 | 66.2±10.3 | <0.001 |
| Males/females | 12:28 | 16:04 | |
| Weight kg | 69.0±13.8 | 79.1±16.7 | <0.05 |
| Height cm | 169±8 | 173±9 | 0.068 |
| BMI kg·m−2 | 24.1±3.50 | 26.3±4.1 | <0.05 |
| FVC % pred | 102.2±12.1 | 83.7±13.9 | <0.001 |
| Z-score | 0.18±0.99 | −0.93±0.91 | <0.001 |
| FEV1 % pred | 101.0±11.5 | 55.2±13.9 | <0.001 |
| Z-score | 0.06±0.92 | −2.60±0.80 | <0.001 |
| MMEF % pred | 97.2±18.2 | 26.6±11.0 | <0.001 |
| Z-score | −0.14±0.69 | −2.46±0.64 | <0.001 |
| DLCO % pred | ND | 57.5±19.4 | |
| FRCMBW L | 3.21±0.81 | 4.19±1.27 | <0.05 |
| LCI | 6.94±0.61 | 12.23±2.67 | <0.001 |
| Scond L−1 | 0.028±0.026 | 0.045±0.034 | <0.05 |
| Scond×VT | 0.029±0.029 | 0.046±0.034 | 0.061 |
| Sacin L−1 | 0.058±0.028 | 0.343±0.139 | <0.001 |
| Sacin×VT | 0.060±0.034 | 0.355±0.150 | <0.001 |
| dN2 % N2 per L | 0.99±0.42 | 7.43±5.38 | <0.001 |
| dN2×VC % N2 | 3.82±1.36 | 20.60±6.84 | <0.001 |
| SIIIDTG g·mol−1·L−1 | −0.206±0.108 | −0.653±0.428 | <0.001 |
| SIIIDTG×VT g·mol−1 | −0.204±0.091 | −0.635±0.344 | <0.001 |
| AUC g·%·mol−1 | 16.39±5.37 | 33.04±18.59 | <0.001 |
| AUC60–90 g·%·mol−1 | 2.69±1.52 | 6.62±4.92 | <0.05 |
| Peak g·mol−1 | 0.59±0.15 | 0.77±0.30 | <0.001 |
| Peak volume % | 19.00±3.08 | 23.86±5.09 | <0.001 |
| FWHM % | 19.54±7.82 | 36.71±11.64 | <0.001 |
Data are presented as n or mean±sd. p-values derived from two-sample t-test. BMI: body mass index; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; MMEF: maximal midexpiratory flow; DLCO: diffusing capacity of the lung for carbon monoxide; FRCMBW: functional residual capacity measured by nitrogen multiple-breath washout; LCI: lung clearance index; Scond: index of conductive ventilation inhomogeneity; VT: tidal volume; Sacin: index of acinar ventilation inhomogeneity; dN2: phase III slope of nitrogen single-breath washout; VC: vital capacity; SIIIDTG: phase III slope of double tracer gas single-breath washout; AUC: area under the curve for double tracer gas single-breathe washout; AUC60–90: area under the curve between 60% and 90% of expired volume for double tracer gas single-breath washout; peak: absolute peak concentration of the double tracer gas single-breath washout signal; peak volume: proportion of exhaled volume at peak; FWHM: full width at half maximum of double tracer gas single-breath washout; ND: not done.