Spirometric lung function data expressed as z scores from 10 to 25 years of age for 83 subjects born EP with and without neonatal BPD and 81 term-born control subjects
| 1991–1992 cohort Development from childhood to adolescence | 1982–1985 cohort Development from adolescence to adulthood | |||||
|---|---|---|---|---|---|---|
| Examination Mean (SD) age (years) | First | Second | First | Second | ||
| 10.5 (0.4) | 17.8 (0.4) | 17.7 (1.2) | 24.9 (1.2) | |||
| z Score | z Score | Difference ΔZ | z Score | z Score | Difference ΔZ | |
| FEV1 mean (95% CI) | ||||||
| Control | −0.054 (−0.31 to 0.20) | −0.028 (−0.34 to 0.29) | 0.026 (−0.19 to 0.24) | 0.22 (−0.16 to 0.60) | −0.009 (−0.37 to 0.35) | −0.23 (−0.41 to −0.04) |
| EP non-BPD | −0.25 (−0.75 to 0.24) | −0.12 (−0.74 to 0.50) | 0.14 (−0.29 to 0.56) | −0.41 (−1.19 to 0.38) | −0.52 (−1.25 to 0.20) | −0.12 (−0.48 to 0.25) |
| EP mild BPD | −0.75 (−1.15 to −0.35) | −0.63 (−1.12 to −0.14) | 0.12 (−0.20 to 0.45) | −1.24 (−1.76 to −0.71) | −1.03 (−1.53 to −0.53) | 0.21 (−0.04 to 0.45) |
| EP m/s BPD | −1.41 (−1.84 to −0.98) | −1.29 (−1.80 to −0.78) | 0.12 (−0.21 to 0.44) | −1.36 (−2.08 to −0.64) | −1.36 (−2.03 to −0.68) | 0.001 (−0.35 to 0.35) |
| Control vs EP no BPD† | 0.20 (−0.35 to 0.76) | 0.09 (−0.61 to 0.78) | p=0.929 | 0.62 (−0.25 to 1.50) | 0.52 (−0.30 to 1.33) | p=0.050 |
| Control vs EP mild BPD† | 0.70 (0.23 to 1.17) | 0.60 (0.02 to 1.17) | 1.46 (0.81 to 2.10) | 1.02 (0.41 to 1.64) | ||
| Control vs EP m/s BPD† | 1.35 (0.86 to 1.85) | 1.26 (0.66 to 1.86) | 1.58 (0.76 to 2.39) | 1.35 (0.58 to 2.11) | ||
| FVC mean (95% CI) | ||||||
| Control | −0.12 (−0.38 to 0.14) | −0.072 (−0.38 to 0.24) | 0.05 (−0.18 to 0.27) | −0.16 (−0.58 to 0.27) | 0.005 (−0.40 to 0.41) | 0.16 (−0.05 to 0.37) |
| EP non-BPD | −0.38 (−0.89 to 0.14) | −0.047 (−0.66 to 0.57) | 0.33 (−0.13 to 0.79) | −0.043 (−0.92 to 0.84) | 0.29 (−0.52 to 1.10) | 0.33 (−0.13 to 0.79) |
| EP mild BPD | −0.63 (−1.04 to −0.22) | −0.59 (−1.08 to −0.11) | 0.03 (−0.32 to 0.38) | −1.30 (−1.89 to −0.71) | −0.66 (−1.21 to −0.10) | 0.64 (0.37 to 0.92) |
| EP m/s BPD | −0.61 (−1.05 to −0.16) | −0.15 (−0.66 to 0.35) | 0.46 (0.10, 0.81) | −1.07 (−1.87 to −0.25) | −0.68 (−1.43 to 0.072) | 0.38 (−0.01 to 0.77) |
| Control vs EP no BPD† | 0.26 (−0.32 to 0.83) | −0.03 (−0.72 to 0.66) | p=0.190 | −0.11 (−1.09 to 0.87) | −0.28 (−1.19 to 0.62) | p=0.058 |
| Control vs EP mild BPD† | 0.51 (0.02 to 0.99) | 0.52 (−0.05 to 1.10) | 1.14 (0.42 to 1.87) | 0.66 (−0.02 to 1.35) | ||
| Control vs EP m/s BPD† | 0.49 (−0.02 to 1.00) | 0.08 (−0.51 to 0.67) | 0.90 (−0.01 to 1.82) | 0.68 (−0.17 to 1.54) | ||
| FEV1/FVC mean (95% CI) | ||||||
| Control | 0.009 (−0.32 to 0.33) | 0.018 (−0.37 to 0.41) | 0.01 ( to 0.24 to 0.26) | 0.53 (0.21 to 0.85) | −0.018 (−0.30 to 0.27) | −0.55 (−0.77 to −0.32) |
| EP non-BPD | 0.22 (−0.42 to 0.86) | −0.18 (−0.96 to 0.59) | −0.40 (−0.90 to 0.10) | −0.55 (−1.21 to 0.12) | −1.13 (−1.69 to −0.57) | −0.59 (−1.04 to −0.31) |
| EP mild BPD | −0.18 (−0.70 to 0.33) | −0.031 (−0.64 to 0.58) | 0.15 (−0.23 to 0.54) | 0.037 (−0.40 to 0.48) | −0.62 (−1.01 to −0.24) | −0.66 (−0.96 to −0.35) |
| EP m/s BPD | −1.34 (−1.89 to −0.78) | −1.44 (−2.08 to −0.79) | −0.10 (−0.48 to 0.29) | −0.42 (−1.04 to 0.19) | −0.78 (−1.31 to −0.25) | −0.35 (−0.79 to 0.07) |
| Control vs EP no BPD† | −0.21 (−0.93 to 0.51) | 0.20 (−0.67 to 1.07) | p=0.354 | 1.08 (0.34, 1.81) | 1.12 (0.49 to 1.74) | p=0.721 |
| Control vs EP mild BPD† | 0.19 (−0.42 to 0.80) | 0.05 (−0.68 to 0.77) | 0.50 (−0.05 to 1.04) | 0.60 (0.12 to 1.09) | ||
| Control vs EP m/s BPD† | 1.35 (0.70 to 1.99) | 1.45 (0.70 to 2.21) | 0.95 (0.27 to 1.64) | 0.80 (0.16 to 1.36) | ||
| FEF25–75 mean (95% CI) | ||||||
| Control | −0.16 (−0.46 to 0.14) | −0.12 (−0.46 to 0.23) | 0.04 (−0.17 to 0.26) | 0.47 (0.18 to 0.77) | 0.012 (−0.30 to 0.33) | −0.46 (−0.64 to −0.28) |
| EP non-BPD | −0.36 (−0.95 to 0.23) | −0.25 (−0.94 to 0.44) | 0.11 (−0.31 to 0.53) | −0.63 (−1.25 to −0.01) | −1.19 (−1.83 to −0.55) | −0.56 (−0.93 to −0.19) |
| EP mild BPD | −0.84 (−1.31 to −0.37) | −0.40 (−0.94 to 0.14) | 0.44 (0.12 to 0.76) | −0.76 (−1.17 to −0.34) | −1.07 (−1.50 to −0.64) | −0.31 (−0.55 to −0.07) |
| EP m/s BPD | −1.84 (−2.35 to −1.33) | −1.67 (−2.25 to −1.10) | 0.17 (−0.15 to 0.49) | −1.19 (−1.76 to −0.62) | −1.34 (−1.93 to −0.76) | −0.16 (−0.49 to 0.18) |
| Control vs EP no BPD† | 0.19 (−0.47 to 0.85) | 0.13 (−0.64 to 0.90) | p=0.244 | 1.10 (0.41 to 1.79) | 1.20 (0.49 to 1.91) | p=0.275 |
| Control vs EP mild BPD† | 0.68 (0.12 to 1.24) | 0.28 (−0.36 to 0.93) | 1.23 (0.72 to 1.74) | 1.08 (0.55 to 1.61) | ||
| Control vs EP m/s BPD† | 1.68 (1.09 to 2.27) | 1.56 (0.89 to 2.23) | 1.66 (1.02 to 2.31) | 1.35 (0.69 to 2.02) | ||
Figures are group mean z scores with 95% CIs or group mean differences with 95% CI, except for age (mean value with SDs). p Values assess differences between the three subgroups with respect to development from the first to the second examination (mixed linear model of SPSS, tests of group vs examination interaction). ΔZ denotes mean change in z score from first to second examination.
†Denotes differences between the control groups and the respective BPD subgroups.
BPD, bronchopulmonary dysplasia; EP, subjects born extreme preterm (ie, gestational age ≤28 weeks or birth weight ≤1000 g); FEF25–75, forced expiratory flow at 25–75% of FVC; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; m/s BPD, moderate/severe BPD (ie, oxygen supplement at gestational age 36 weeks); mild BPD, oxygen supplement at 28 postnatal days; z Score, (observed value − expected value)/(SE of the expected value), calculated with the all-age reference equation.17