Mean and SD of z-scores of lung function measures adjusted for age, gender and height at age 14–17 years, with CIs for the difference of means (premature − term), unadjusted and adjusted for maternal smoking in pregnancy and social status
| 25–32 weeks (n=42) | Term (n=4105) | Difference (95% CI) (unadjusted) | Difference (95% CI) (adjusted) | p Value for adjusted analysis | |||
| Mean | SD | Mean | SD | ||||
| FEV1 | −0.186 | 0.850 | 0.001 | 1.004 | −0.186 (−0.494 to 0.121) | −0.145 (−0.534 to 0.244) | 0.464 |
| FVC | −0.151 | 1.034 | −0.004 | 1.002 | −0.148 (−0.452 to 0.156) | −0.041 (−0.427 to 0.346) | 0.836 |
| FEF25–75 | −0.438 | 0.899 | 0.011 | 1.001 | −0.449 (−0.753 to −0.145) | −0.382 (−0.768 to 0.005) | 0.053 |
| FEV1/FVC | −0.195 | 1.117 | 0.010 | 0.995 | −0.205 (−0.517 to 0.106) | −0.150 (−0.535 to 0.236) | 0.446 |
| FEF25–75/FVC | −0.260 | 1.006 | 0.013 | 1.000 | −0.274 (−0.581 to 0.034) | −0.338 (−0.723 to 0.046) | 0.084 |
| 33–34 weeks (n=49) | Term (n=4105) | Difference and 95% CI (unadjusted) | Difference and 95% CI (adjusted) | p Value for adjusted analysis | |||
| Mean | SD | Mean | SD | ||||
| FEV1 | −0.022 | 1.135 | 0.001 | 1.004 | −0.023 (−0.304 to 0.259) | −0.059 (−0.348 to 0.231) | 0.691 |
| FVC | 0.169 | 0.905 | −0.004 | 1.002 | 0.173 (−0.109 to 0.454) | 0.127 (−0.161 to 0.415) | 0.386 |
| FEF25–75 | −0.279 | 1.143 | 0.011 | 1.001 | −0.290 (−0.572 to −0.009) | −0.289 (−0.577 to −0.001) | 0.049 |
| FEV1/FVC | −0.401 | 1.104 | 0.010 | 0.995 | −0.411 (−0.693 to −0.130) | −0.379 (−0.666 to −0.092) | 0.010 |
| FEF25–75/FVC | −0.415 | 0.984 | 0.013 | 1.000 | −0.428 (−0.709 to −0.147) | −0.397 (−0.683 to −0.110) | 0.007 |
| 35–36 weeks (n=129) | Term (n=4105) | Difference and 95% CI (unadjusted) | Difference and 95% CI (adjusted) | p Value for adjusted analysis | |||
| Mean | SD | Mean | SD | ||||
| FEV1 | 0.057 | 0.859 | 0.001 | 1.004 | 0.057 (−0.120 to 0.234) | 0.094 (−0.089 to 0.276) | 0.315 |
| FVC | 0.095 | 0.956 | −0.004 | 1.002 | 0.099 (−0.077 to 0.274) | 0.119 (−0.060 to 0.299) | 0.191 |
| FEF25–75 | −0.077 | 0.877 | 0.011 | 1.001 | −0.088 (−0.263 to 0.087) | −0.056 (−0.235 to 0.124) | 0.543 |
| FEV1/FVC | −0.079 | 1.047 | 0.010 | 0.995 | −0.089 (−0.267 to 0.088) | −0.062 (−0.243 to 0.119) | 0.502 |
| FEF25–75/FVC | −0.137 | 0.957 | 0.013 | 1.000 | −0.151 (−0.326 to 0.024) | −0.133 (−0.311 to 0.045) | 0.143 |
FEF25–75, forced expiratory volume at 25–75% of FVC; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.