Table 1.

Sample characteristics (clinical and socio-demographic variables)

	Mean	Mean	p value
	(SD)	(SD)
	95 % CI	95 % CI
Total enrolled infants	VLBW	FTI	χ 2 = 0.0275; n.s.
Gender	n = 150	n = 145
Female (%)	52.0	51.0
Male (%)	48.0	48.9
Birth weight (grams)	1,132	3,297	t = 59.86; p < 0.0005
	(232.6)	(374.4)
	1,094−1,169	3,236−3,357
Gestational age at birth (weeks)	29.1	38.3	t = 49.13; p < 0.0005
	(2.2)	(1.1)
	28.7−29.5	38.1−38.5
NICU length of stay (days)	59.7	0	t = 31.55; p < 0.0005
	(21.6)	0
	56.2−63.2
Mother:
Socio-economic status (%)	n = 148	n = 143
Education (years)	12.5	12.7	t = −0.14; n.s.
	(3.8)	(3.7)
	11.9−13.1	12.1−13.3
Father:
Socio-economic status (%)	n = 146	n = 142
Education (years)	12.5	11.5	t = −0.83; n.s.
	(4.0)	(3.4)
	11.9−13.1	10.9−12.1
Parents’ socio-economic status score	n = 123	n = 116
	51.6	54.8	t = −0.48; n.s.
	(19.9)	(20.5)
	48.1−55.1	51.1−58.5