Table 2

Demographic and perinatal sample characteristics of the studies included in the meta-analysis

YearAuthorGA, weeks
M (SD)
BW, grams
M (SD)
Age, years
M (SD)
% SGA% IVH I/II% IVH III/IV% PVL% BPD% NEC% Meningitis% Sepsis% PCS use% Mothers
<12 years education
% Male% Non-Caucasian
2003Assel et al2229.7 (2.5)1111 (264)8.0 (NA)NANANANANANA0.0NANANA54.079.0
2013Cheong et al3125.8 (1.1)897 (177)18.0 (NA)2.7NA6.84.138.5NANANA37.251.847.3NA
2015Clark and Woodward3227.9 (2.3)1071 (313)9.0 (NA)10.811.85.94.934.0NANA29.75.940.251.588.9
2009Frye et al2029.6 (2.1)1109 (205)12.7 (0.5)NA15.40.02.831.5NA0.0NANANA43.979.9
2013Hutchinson et al3326.5 (2.0)833 (164)8.5 (0.4)18.0NA3.73.238.15.0NANA37.050.352.9NA
2011Johnson et al2424.5 (0.7)745 (130)*10.9 (0.4)0.549.010.016.073.03.0NANANA76.046.018.0
2012Litt et al3426.4 (2.0)815 (124)14.7 (0.7)33.234.313.36.641.05.58.849.2NA39.038.760.0
2012Loe et al2328.8 (2.7)1226 (466)12.2 (1.8)5.612.55.69.79.7NANANANA35.047.028.0
2009Luu et al1628.0 (2.0)961 (174)12.2 (0.4)25.010.8NANA46.0NANANANA11.154.429.1
2014McNicholas et al3529.9 (2.8)1172 (219)11.6 (1.0)NA20.0NA8.9NANANANANANA51.1NA
2012Northam et al3627.0 (2.0)1081 (385)16.2 (1.4)14.334.022.04.1NANANANANANA38.0NA
2011Rose et al1729.7 (2.8)1165 (268)11.2 (0.4)27.343.20.0NANANANANANANA56.888.6
2015Sayeur et al3728.7 (1.8)1222 (238)7.6 (0.5)NA0.00.00.020.020.00.00.0NANA50.0NA
2003Short et al1828.3 (2.0)1085 (223)8.8 (0.6)NA22.510.4NA57.0NANANA16.2NA49.147.0
2015Simms et al3828.6 (2.0)1213 (365)9.7 (0.7)NANANANANANANANANA62.654.8NA
2011Taylor et al3925.9 (1.6)818 (174)6.0 (0.4)25.0NA10.1NA52.010.18.041.9NA13.545.961.5
2016Taylor et al4027.5 (1.9)962 (223)7.5 (0.3)8.6NA3.64.635.010.6NA44.4NANA52.5NA
  • The highest and lowest value for each factor is underlined.

  • *Estimated from median and IQR.

  • BPD, bronchopulmonary dysplasia; BW, birth weight; GA, gestational age; IVH I/II, III/IV, intraventricular haemorrhage grade I/II, III/IV; M, mean; NA, not available; NEC, necrotising enterocolitis; PCS, postnatal corticosteroids; PVL, periventricular leukomalacia; SGA, small for gestational age.