Table 2

Ascertainment problems and incidence of disability at 6 years (1983 population based cohort of babies born before 32 weeks of gestation)

Follow upBabies surviving to discharge n=Intelligence quotient less than 752-150 n=Severe sensorimotor disability n=Severe sensorimotor or cognitive disability
n=%(95% CI)
Child reviewed without difficulty at 2 and 6 years2031012178.45.0  to  13.1
Child only traced at 2 with difficulty (family mobility, etc)1403321.44.7 to  50.8
Assessment at 2 only arranged with difficulty after the child was traced2-152 1235541.715.2 to  72.3
Died after discharge from hospital but before the age of six722-151 28.63.7 to  71.0
Total2362711.47.4 to  15.5
  • 2-150 More than 3 standard deviations below average for all the children without severe sensorimotor disability at 6 years.

  • 2-151 As in table 1.

  • 2-152 Family mobility also added to the difficulty of maintaining contact with two of these 12 families in the first 2 years.