Table 1– Group characteristics of extreme pre-term (EP) children with and without prior bronchopulmonary dysplasia (BPD) compared to classmate controls
EP with BPDEP without BPDAll EPControl95% CI of difference
Neonatal characteristics
 Subjects n34154952
 Gestational age weeks24.8±0.825.0±0.624.9±0.740.1±1.6-15.7–14.7***
 Birth weight kg0.740±0.1010.762±0.0930.747±0.0983.361±0.450-2.75–2.48***
 Birth weight Z-score#-0.06±0.71-0.03±0.80-0.05±0.74-0.24±1.14-0.57–0.20
 Post-natal steroids706769
Maternal/family details
 Antenatal steroids858786
 Smoking in pregnancy25142222-16–17
 Current smoking exposure1871526-27–4
 Maternal asthma120812-16–9
 FH of asthma38333733-14–22
 Maternal ethnicity White74877894-30–3*
 Maternal education after age 16 yrs52575373-38–0*
 Non-manual occupation74797669-10–29
  • Data presented as % or mean±sd, unless otherwise indicated. BPD is defined as oxygen given at or beyond 36 weeks post-menstrual age. PROM: prolonged rupture of membranes (>24 h). *: p<0.05; **: p<0.01; ***: p<0.0001. #: according to Child Growth Foundation algorithms 22; : classification based on either parent with a non-manual occupation.