| BPD | Non-BPD | Full-term | BPD versus non-BPD | BPD versus non-BPD# | BPD versus full-term | Non-BPD versus full-term | |
| Subjects n | 56 | 40 | 55 | ||||
| FEV1 z-score | -1.41±1.25 | -0.19±1.16 | 0.14±0.96 | -1.22 (-1.72− -0.72)*** | -1.83 (-2.76− -0.90)*** | -1.55 (-1.97− -1.13)*** | -0.33 (-0.76–0.11) |
| FEV1 % pred | 81.89±15.90 | 96.98±15.22 | 101.16±11.40 | -15.08 (-21.50− -8.66)*** | -22.63 (-34.34− -10.91)*** | -19.27 (-24.48− -14.06)*** | -4.19 (-9.61–1.23) |
| FVC z-score | -0.79±1.14 | 0.17±0.98 | 0.12±0.94 | -0.96 (-1.40− -0.52)*** | -1.53 (-2.22− -0.84)*** | -0.91 (-1.30− -0.52)*** | 0.05 (-0.35–0.44) |
| FVC % pred | 90.11±14.46 | 101.85±12.60 | 101.67±0.83 | -11.74 (-17.38− -6.10)*** | -19.25 (-27.99− -10.50)*** | -11.57 (-16.38− -6.75)*** | 0.18 (-4.61–4.97) |
| FEV1/FVC z-score | -0.68±0.22 | -0.13±1.22 | 0.34±0.89 | -0.55 (-1.16− -0.06) | -0.36 (-1.51–0.79) | -1.02 (-1.52− -0.53)* | -0.47 (-0.90− -0.40)* |
| FEV1/FVC % pred | 94.32±13.41 | 98.45±10.32 | 102.67±7.18 | -4.13 (-9.15–0.89) | -3.00 (-12.56–6.56) | -8.35 (-12.41− -4.29)* | -4.22 (-7.79− -0.66)* |
| FEF25–75% z-score | -1.80±1.10 | -1.13±1.02 | -0.56±1.45 | -0.67 (-1.11–0.23)** | -0.90 (-1.72–0.26)** | -1.24 (-1.73− -0.769)*** | -0.57 (-1.10− -0.43)* |
| FEF25–75% % pred | 61.63±23.59 | 74.93±22.06 | 90.96±21.55 | -13.30 (-22.74− -3.86)** | -20.99 (-36.78− -5.40)** | -29.34 (-37.84− -20.84)*** | -16.04 (-25.02− -7.06)*** |
Data are presented as mean±sd or unadjusted mean difference (95% CI), unless otherwise stated. BPD: bronchopulmonary dysplasia; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; FEF25–75%: forced expiratory flow at 25–75% of FVC. #: adjusted for maternal smoking, having ever smoked, birth weight and gestational age. *: p<0.05; **: p<0.01; ***: p<0.001.