Lung function in healthy children and preterm children during mid-childhood
| Term controls (reference) | Preterm | Mean difference (95% CI) | |
|---|---|---|---|
| Forced flows and volumes (spirometry) | |||
| n successful | 48 | 131 | |
| FEV1 z-score | 0.04 (0.90) | −0.72 (1.13) | −0.76 (−1.12 to −0.40)** |
| FEV1/FVC z-score | −0.27 (0.92) | −1.25 (1.01) | −0.98 (−1.33 to −0.63)** |
| FEF25–75 z-score | −0.42 (0.90) | −1.46 (1.11) | −1.04 (−1.42 to −0.67)** |
| FVC z-score | 0.17 (0.95) | 0.13 (1.04) | −0.04 (−0.40 to 0.33) |
| Lung volume and ventilation distribution (multiple breath washout) | |||
| n successful | 50 | 140 | |
| LCI | 6.14 (0.58) | 6.33 (0.82) | 0.19 (−0.06 to 0.44) |
| FRC z-score | −0.09 (0.96) | 0.42 (1.32) | 0.51 (0.10 to 0.91)* |
| TLC z-score | −0.16 (0.85) | −0.05 (1.02) | 0.11 (−0.21 to 0.42) |
| RV z-score | −0.45 (1.10) | −0.16 (1.23) | 0.28 (−0.11 to 0.68) |
| FRC/TLC (%) | 50.36 (6.65) | 52.80 (7.49) | 2.44 (0.07 to 4.81)* |
| RV/TLC (%) | 21.29 (6.18) | 22.79 (7.02) | 1.50 (−0.73 to 3.72) |
| Gas exchange (DLCO) | |||
| n successful | 38 | 74 | |
| DLCO z-score | 0.10 (0.97) | 0.28 (1.27) | 0.17 (−0.29 to 0.64) |
| VA z-score | −0.72 (1.16) | −0.50 (1.33) | 0.24 (−0.27 to 0.74) |
| KCO z-score | −0.56 (0.86) | −0.57 (0.98) | −0.02 (−0.39 to 0.36) |
| Respiratory system mechanics (forced oscillation technique) | |||
| n successful | 31 | 132 | |
| Rrs8 z-score | 0.00 (0.94) | 0.33 (1.04) | 0.32 (−0.08 to 0.72) |
| Xrs8 z-score | 0.14 (0.53) | −0.43 (0.99) | −0.57 (−0.94 to −0.21)* |
| AX z-score | −0.44 (0.85) | 0.29 (1.15) | 0.72 (0.29 to 1.16)** |
| Fres z-score | −0.18 (1.26) | 0.64 (1.23) | 0.82 (0.31 to 1.33)* |
Data are presented as mean (SD) and unadjusted mean difference (95% CI) except for the number of successful tests.
*p<0.05; **p<0.001.
DLCO, diffusing capacity of the lung for carbon monoxide; FRC, functional residual capacity.