Table 1.

Main clinical characteristics of the two groups of the study population at birth and during the first 11 years of life.

	All preterms	Term controls	P-values
	(N = 55)	(N = 55)
Sex (M/F)	27/28	27/28
Neonatal characteristics
Mother age at birth (years)	30.8 ± 5.4	31.3 ± 4.7
Gestational age (weeks)	30.6 ± 1.6	38.4 ± 1.4
Cesarean section (Yes/No; %)	54/1 (98.2%)	18/37 (32.7%)
Birth weight (kg)	1.43 ± 0.4	3.12 ± 0.6
Birth length (cm)	41.6 ± 2.7	49.6 ± 2.1
Mechanical Ventilation (days)	1.2 ± 2.5
CPAP (days)	5.3 ± 6.8
Oxygen supplementation (days)	7.6 ± 9.6
Hospital stay (days)	45.5 ± 19.6	4.1 ± 5.8
Prenatal and postnatal risk factors
Family history of asthma (Yes/No; %)	11/44 (20.0%)	12/43 (21.8%)	0.86
Family history of allergy (Yes/No; %)	19/36 (34.5%)	18/37 (32.7%)	0.84
In utero smoke exposure (Yes/No; %)	7/48 (12.7%)	5/50 (9.1%)	0.76
Passive smoking (Yes/No; %)	23/32 (41.8%)	18/37 (32.7%)	0.43
Pet keeping (Yes/No; %)	28/27 (50.9%)	20/35 (36.4%)	0.18
Breastfeeding (months)	4.3 ± 5.3	10.2 ± 6.9	<0.001
Medical history
Atopic dermatitis (Yes/No; %)	8/47 (14.5%)	12/43 (21.8%)	0.46
Food allergy (Yes/No; %)	6/49 (10.9%)	4/51 (7.3%)	0.74
Bronchiolitis (Yes/No; %)	7/48 (12.7%)	5/50 (9.1%)	0.76
Allergic Rhinitis (Yes/No; %)	19/36 (34.5%)	23/32 (41.8%)	0.56
Pneumonia (Yes/No; %)	5/50 (9.1%)	6/49 (10.9%)	0.76
Urticaria (Yes/No; %)	6/49 (10.9%)	9/46 (16.4%)	0.58
Preschool wheezing (Yes/No; %)	15/40 (27.3%)	4/51 (7.3%)	0.01
School aged asthma (Yes/No; %)	6/49 (10.9%)	4/51 (7.3%)	0.74
Current asthma (Yes/No; %)	3/52 (5.5%)	4/51 (7.3%)	0.86

Values are absolute numbers (percentages) for categorical data and mean ± standard deviation for continuous variables.

N, numbers; CPAP, continuous positive airway pressure.

The statistical significance level is p < 0.05 and it is indicated in bold.