Table 2– Comparison of children who did and did not attend the respiratory laboratory at the Institute of Child Health (ICH; London, UK) for extended assessments
EP95% CI of difference (school–ICH)
School testedICH tested
Subjects (% males)140 (44)49 (37)-9–22
Gestational age weeks25.0±0.724.9±0.7-0.13–0.35
Birth weight kg0.749±0.1260.747±0.098-0.033–0.037
Birth weight Z-score#-0.17±0.78-0.05±0.73-0.36–0.13
Received ANS8086-16–8
History of chorioamnionitis2226-18–10
Wheeze in last 12 months2322-13–14
Current asthma2627-16–13
Ethnicity White8478-8–19
Smoking in pregnancy3922-31–2*
FEV1 Z-score+-1.4±1.2-1.6±1.1-0.3–0.5
FEF25–75% Z-score+-2.0±1.3-2.0±1.2-0.4–0.4
  • Data presented as mean±sd or %, unless otherwise stated. BPD: bronchopulmonary dysplasia, defined as oxygen given at or beyond 36 weeks post-menstrual age; ANS: antenatal steroid; FEV1: forced expiratory volume in 1 s; FEF25–75%: forced expiratory flow at 25–75% forced vital capacity. Comparison of FEV1 and FEF25–75% Z-scores was undertaken by using data obtained from both groups during school assessments. *: p<0.05. #: according to 22; : defined as currently symptomatic and/or with doctor-diagnosis of asthma and on medication during past 12 months; +: according to 20.