Proportions with expiratory airflows at 25 years of age <5th centile contrasted between EP/ELBW and control groups and between BPD and no BPD groups within the EP/ELBW cohort
| Flow variable | EP/ELBW n=164 | Control n=130 | OR (95% CI), P value* | BPD n=65 | No BPD n=99 | OR (95% CI), P value* |
| FEV1 | 26 (42) | 2 (3) | 13.8 (4.14 to 46.1), <0.001 | 34 (22) | 20 (20) | 2.24 (1.07 to 4.63), 0.03 |
| FVC | 7 (11) | 2 (3) | 3.08 (0.84 to 11.4), 0.09 | 9 (6) | 5 (5) | 1.92 (0.56 to 6.53), 0.30 |
| FEV1:FVC | 38 (63) | 10 (13) | 5.26 (2.71 to 10.2), <0.001 | 49 (32) | 31 (31) | 1.94 (1.10 to 3.44), 0.022 |
| FEF25%−75% | 46 (76) | 8 (11) | 9.06 (4.52 to 18.1), <0.001 | 58 (38) | 38 (38) | 2.37 (1.27 to 4.41), 0.006 |
Data are % (n), unless otherwise specified.
*From regression models using generalised estimating equations to allow for multiple births.
BPD, bronchopulmonary dysplasia; EP/ELBW, extremely preterm/extremely low birth weight; FEF25%−75%, airflow between 25% and 75% of the vital capacity.