Table 1.

Distribution of clinical and epidemiological risk-factors for BPD in our cohort:

Variable	Infants without BPD (n=375)	Infants with BPD (n=284)	Infants with severe BPD (n=135)
Gestational age (wk)	29 (28; 30)	26 (25; 28)*	26 (24; 27)*
Birth-weight (grams)	1190 (678; 1352)	876 (675; 1107)§	760 (635; 991)§
Race - Caucasians	68%	77.8%†	75.5%
African American	21.3%	10.2%	11.9%
Others	10.7%	12.0%	12.6%
Prenatal steroid use	85%	91.1%	91%
Male sex	48.8%	57.8%§§	63.0%§§
Clinical chorioamnionitis	7.5%	11.7%	10.3%
Patent ductus arteriosus	22.6%	58.3%**	65.9%**

Data is represented as median ± interquartile range or as raw numbers with percentages.

^*P<0.001 (no BPD vs. BPD; severe BPD vs. others),

^§P=0.001 (no BPD vs. BPD; severe BPD vs. others),

^†P=0.006 (% CAU infants, no BPD vs. BPD),

^§§P<0.02 (no BPD vs. BPD; severe BPD vs. others),

^**P<0.001 (no BPD vs. BPD; severe BPD vs. others).

Clinical chorioamnionitis was diagnosed in the presence of maternal fever >38°C plus one additional criteria (uterine tenderness, malodorous vaginal discharge, maternal leukocytes >15,000 cells/mm³ or fetal heart-rate of >160/min)