Growth of primary school children: a validation of the 1990 references and their use in growth monitoring.

AIMS To determine whether the British 1990 growth charts are valid for cross sectional and longitudinal use in primary school children. METHODS A total of 694 children aged 7-10 years from 10 Leeds primary schools were weighed and measured annually over three years by an expert auxologist. SD scores were calculated using both the Tanner-Whitehouse (TW) and the revised British 1990 growth references. RESULTS The growth of this sample of children approximated the 1990 growth reference, with mean (SD) scores for height 0.12 (1.01), weight 0.20 (1.07), and body mass index (BMI) 0. 19 (1.12). By comparison, the TW standards exaggerated the height and weight centiles. There was minimal channel crossing for height in either direction with 1.0% crossing up at least one channel width (0.67 SD scores), and 0.2% down for height. However, there was clear evidence of weight and particularly BMI increasing with age between and within subjects, at rates of up to 0.1 SD scores per year. CONCLUSIONS This study supports the adoption of the new growth references, and their use longitudinally for height monitoring. It also highlights the increasing weight of the school age population as a public health issue.