Table 3

Body mass indices, z scores (standard deviation scores), and mean percentages >91st centile at baseline and 12 months

CharacteristicControl clusters (n=14)Intervention clusters (n=15)Mean difference (95% CI)
Baseline*:
Mean (SD) body mass index17.6 (0.7)17.4 (0.6)0.0 (−0.5 to 0.5)
Mean (SDS) z score0.47 (0.2)0.50 (0.23)−0.03 (−0.2 to 0.13)
Mean percentage >91 st centile (z score >1.34)19.4 (8.4)20.3 (6.3)−0.9 (−6.6 to 4.8)
12 months*:
Mean (SD) body mass index18.3 (0.8)17.9 (0.7)0.4 (−0.2 to 1.0)
Mean (SDS) z score0.60 (0.19)0.48 (0.23)0.12 (−0.04 to 0.28)
Mean percentage >91 st centile (z score >1.34)26.9 (12.3)20.1 (6.7)6.8 (−0.7 to 14.3)
Change over 12 months:
Mean (SD) body mass index0.8 (0.3)0.7 (0.2)0.1 (−0.1 to 0.3)
Mean z score0.08 (0.13)0.04 (0.07)0.04 (−0.04 to 0.12)
Mean percentage >91 st centile7.5 (8.0)−0.2 (6.3)7.7 (2.2 to 13.1)
  • * Based on maximum number of children in each cluster.

  • Age and sex specific body mass index converted to standard deviation score using revised 1990 reference standards.

  • Based on children with data at baseline and 12 months.