Healthy children# | Asthmatic children¶ | ||||||
Absolute values | z-scores | Intra-measure CV % | Inter-subject CV % | Absolute value | z-scores | Intra-measure CV % | |
FVC L | 1.84 (1.69–2.04) | 0.37 (−0.04–0.82) | 2.4 (1.5–3.6) | 13 | 1.92 (1.65–2.15) | 0.08 (−0.37–0.76) | 2.0 (1.3–2.7) |
FEV1 L | 1.62 (1.49–1.77) | 0.36 (−0.08–0.96) | 1.9 (1.4–3.2) | 11.8 | 1.57 (1.43–1.80) | −0.09 (−1.01–0.66)*** | 2.1 (1.4–2.9) |
FEV1/FVC | 0.88 (0.85–0.91) | −0.09 (−0.56–0.39) | 0.85 (0.79–0.90) | −0.68 (−1.27–0.24)** | |||
PEF L·s−1 | 3.69 (3.32–3.95) | NA | 4.2 (2.8–6.3) | 12.7 | 3.70 (3.14–4.26) | NA | 4.0 (2.6–5.2) |
FEF25–75% L·s−1 | 2.08 (1.87–2.37) | 0.33 (−0.06–0.80) | 4.1 (2.8–6.7) | 18.9 | 1.83 (1.51–2.28) | −0.21 (−1.04–0.65)*** | 4.3 (2.7–7.3) |
FEF50% L·s−1 | 2.28 (2.04–2.64) | NA | 3.8 (2.6–6.6) | 21 | 1.97 (1.69–2.50) | NA | 4.7 (2.7–7.8) |
FEF75% L·s−1 | 1.08 (0.92–1.24) | NA | 6.2 (3.9–10.4) | 22.4 | 0.97 (0.70–1.17) | NA | 8.5 (4.7–11.5) |
Data are presented as median (interquartile range), unless otherwise stated. FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; PEF: peak expiratory flow; FEF: forced expiratory flow at % of FVC; CV: coefficient of variation (i.e. standard deviation/mean); NA: not available. #: n=66; ¶: n=50. Asthmatic children at baseline were significantly different from healthy children. **: p=0.01; ***: p=0.001.