Table 2 Percentages of children classified as underweight, poor infant weight gain, or obese according to the WHO Growth Standard (WHO) and the British 1990 Growth Reference (UK1990)
ALSPACGMSCombined:RR (95% CI)
WHOUK1990WHOUK1990
Underweight
    6–8 weeks3.62.91.12 (0.87 to 1.43)
    4 months2.02.42.12.40.86 (0.55 to 1.33)
    8 months0.72.60.71.80.30 (0.17 to 0.56)
    1 year0.32.40.42.50.15 (0.07 to 0.32)
    1.5 years0.62.90.22 (0.10 to 0.48)
Poor infant weight gain
    Birth to 1 year1.77.11.65.40.24 (0.16 to 0.36)
    6–8 weeks to 1 year0.45.40.08 (0.03 to 0.24)
Obese (%)
    1 year8.72.73.26 (2.21 to 4.83)
    1.5 years8.02.63.11 (2.06 to 4.71)
    2 years7.54.31.74 (1.20 to 2.51)
    4–5 years7.25.010.18.41.35 (1.02 to 1.78)
  • ALSPAC, Children in Focus sub-cohort of Avon Longitudinal Study of Parents and Children; GMS, Gateshead Millennium Baby Study; RR, relative risk for each outcome using the WHO standard, compared with the UK 1990 reference; Underweight, weight <2nd centile; Poor infant weight gain, conditional weight gain <−1.33 SD, equivalent to downward crossing through two major centile lines on each growth chart; Obese, body mass index >98th centile.