Table 1: Demographic characteristics of population studied by cases and controls.

All infantsBPD
CasesControlsP
𝑛 = 2 1 2 𝑛 = 6 4 𝑛 = 1 4 8

Maternal age, y, mean ± (SD)27.2 (6.5)26.1 (6.0)27.3 (6.6)0.205
Male (%)108 (50.9)34 (53.1)74 (50.0)0.676
Gestational age at birth, wPMA, mean ± (SD)29.2 (1.3)28.6 (1.2)29.3 (1.3)0.001
Birth weight, grams, mean ± (SD)1271.2 (283.3)1155.3 (263.0)1306.5 (284.2)0.000
SGA, 𝑛 (%)12 (5.7)3 (4.7)9 (6.1)0.688
APGAR score 5 min, median (IR)9 (8-9)9 (8-9)9 (8-9)0.228
SNAP-II, score, mean ± (SD)5.7 (9)7.6 (10.5)5.4 (8.6)0.102

BPD: bronchopulmonary dysplasia, wPMA: weeks postmenstrual age, SGA: small for gestational age, SNAP-II: score for neonatal acute physiology, SD: standard deviation, IR: Interquartile range (difference between the value at 75% of cases, and the value at 25% of cases).