Table 1.

Comparison of demographic and perinatal characteristics of the surviving VLBW cohort who were assessed on MRI with those not assessed and with controls.

Measure	VLBW assessed on MRI (N = 150)	VLBW not assessed on MRI (N = 173)	Pa	Controls (N = 50)	Pb
Mean (SD) age at scan	28.5 (1.2)	–	–	27.7 (0.5)	<0.001
% (n) Male	41.3 (62)	52.0 (90)	0.055	40.0 (20)	0.87
% (n) Māori/Pacific Island ethnicity	28.7 (43)	34.7 (60)	0.25	18.0 (9)	0.14
Mean (SD) birthweight (g)	1077 (238)	1213 (215)	<0.001
% (n) < 1000 g	38.0 (57)	15.6 (27)	<0.001
Mean (SD) gestation (weeks)	28.8 (2.6)	29.6 (2.3)	0.002
% (n) < 28 weeks gestation	35.3 (53)	15.6 (27)	<0.001
Mean (SD) Apgar 5 min	7.8 (1.9)	8.0 (1.7)	0.51
% (n) SGA	30.7 (46)	27.2 (47)	0.49
% (n) Vaginal delivery	43.8 (64)	40.1 (69)	0.5
% (n) Sepsis	20.7 (31)	26.7 (46)	0.2
% (n) ANS	54.7 (82)	59.5 (103)	0.38
% (n) RDS	56.7 (85)	56.1 (97)	0.91
% (n) BPD	20.7 (31)	21.4 (37)	0.87
% (n) ROP	25.0 (36)	17.4 (27)	0.11
% (n) Any neurosensory disability (age 7–8 years)	16.6 (24)	33.1 (50)	0.001
% (n) Mod/severe disability (age 7–8 years)	4.1 (6)	13.9 (21)	0.004

SGA: small for gestational age (birthweight <10% centile), RDS: respiratory distress syndrome, BPD: bronchopulmonary dysplasia (oxygen requirement at 36 weeks post-menstrual age), ANS: antenatal corticosteroids, ROP: retinopathy of prematurity. Moderate or severe disability at 7–8 years of age was defined as cerebral palsy in non-ambulant children or in ambulant children causing considerable limitation of movement; bilateral sensorineural deafness requiring hearing aids; bilateral blindness; or an IQ score of >2 SD below the test mean (<70) on the Revised Wechsler Intelligence Scale for Children (WISC-R). Any neurosensory disability at 7–8 years of age also included cerebral palsy with only minor limitation of movement and mild cognitive impairment (IQ 1-2 SD below the mean).

^aComparisons of VLBW assessed and not assessed by t-test or chi square.

^bComparisons of VLBW assessed and Controls by t-test or chi square.