Table 2.

Baseline demographic and clinical characteristics of all subjects.

	Mean (SD) or n (%)	Missing Data (N)
Infancy
Duration of neonatal antibiotic exposure (NABE) in the center of birth, days, mean (SD)	9 (7)	0
No NABE, n (%) NABE for max. 4 days, n (%) NABE 5–13 days, n (%) NABE ≥ 14 days (of which with confirmed disease), n (%)	10 (3) 102 (29) 103 (30) 38 (23)
First gravidity, n (%)	186 (54)	0
First parity, n (%)	228 (66)	0
Invasive ventilation first 28 d of life, n (%)	172 (50)	0
Intraventricular hemorrhage/periventricular leukomalacia grade III-IV, n (%)	21 (6)	1
>20% formula milk in first 28 d, n (%)	61 (21)	55
Neonatal necrotizing enterocolitis, sepsis or meningitis, n (%) Of which non-CoNS sepsis b, NEC, meningitis, n (%)	96 (28) 35 (10)	0
Exposure to mother’s milk ≥ 6 months	18 (5)	8
Moderate to severe bronchopulmonary dysplasia, n (%)	81 (24)	7
Palivizumab administration, n (%)	261 (88)	49
Childhood
Age at questionnaire, years, mean (SD)	4.6 (0.9)	0
Weight at ca. 24 months’ CA, mean (SD)	11.9 (1.6)	45
Stature at ca. 24 months’ CA, mean (SD)	86.7 (4.6)	50
Ever received medical feeding at home (oral or tube), n (%)	18 (5)	8
Weekly fastfood or ready-made food, n (%)	47 (14)	18
Family history
Maternal education, university level, n (%)	182 (55)	18
Ethnicity mother, non-Dutch/Belgian, n (%)	62 (19)	16
Ethnicity father, non-Dutch/Belgian, n (%)	51 (15)	14
Both parents’ mother tongue other than Dutch, n (%)	34 (10)	13
At least monthly exposure to nicotine smoke, n (%)	12 (5)	96
Atopic disease parents or siblings, n (%)	150 (44)	7

^b sepsis caused by other pathogens than coagulase negative Staphylococci. CA corrected age; N, total number of missing subjects per specific variable; n (%), number and percentage of subtotal number of participants per item; NABE, neonatal antibiotic exposure; SD, standard deviation.