Table 3

 Neurological disabilities at 8 years of age in birthweight subgroups in regional ELBW cohorts compared over three distinct eras

Neurosensory disability, n (%)
NilMildModerateSevere
Comparisons of severity of disabilities between eras are as follows:
500–999 g birthweight group: 1979–80 compared with 1985–87: χ2trend = 5.0, p = 0.025; 1979–80 compared with 1991–92: χ2trend = 4.0, p = 0.046; 1985–87 compared with 1991–92: χ2trend = 0.8, p = 0.78, NS.
500–749 g birthweight group: 1979–80 compared with 1985–87: χ2trend = 5.7, p = 0.017; 1979–80 compared with 1991–92: χ2trend = 2.5, p = 0.11, NS; 1985–87 compared with 1991–92: χ2trend = 2.1, p = 0.14, NS.
750–999 g birthweight group: 1979–80 compared with 1985–87: χ2trend = 2.4, p = 0.12, NS; 1979–80 compared with 1991–92: χ2trend = 4.0, p = 0.044; 1985–87 compared with 1991–92: χ2trend = 0.4, p = 0.52, NS.
NS, not significant.
500–999 g birthweight group
    1979–80, n = 8737 (42.5)28 (32.2)10 (11.5)12 (13.8)
    1985–87, n = 206113 (54.9)59 (28.6)19 (9.2)15 (7.3)
    1991–92, n = 224126 (56.2)56 (25.0)22 (9.8)20 (8.9)
500–749 g birthweight group
    1979–80, n = 82 (25.0)2 (25.0)1 (12.5)3 (37.5)
    1985–87, n = 2111 (52.4)7 (33.3)3 (14.3)0 (0.0)
    1991–92, n = 5221 (40.4)17 (32.7)8 (15.4)6 (11.5)
750–999 g birthweight group
    1979–80, n = 7935 (44.3)26 (32.9)9 (11.4)9 (11.4)
    1985–87, n = 185102 (55.1)52 (28.1)16 (8.6)15 (8.1)
    1991–92, n = 172105 (61.0)39 (22.7)14 (8.1)14 (8.1)