Body composition of healthy 7-and 8-year-old children and a comparison with the 'reference child'.

BACKGROUND: There are few longitudinal data on body composition in healthy children. This has prompted a reliance on notional standards such as the 'reference child', to validate new methods of determining body composition and comparing cross-sectional height, weight and fatness data.
OBJECTIVES: These were twofold-to provide normative longitudinal data on changes in body composition in healthy pre-pubertal children, and to compare measures of growth and body composition with the appropriate age-specific reference child.
DESIGN: A sample of healthy Scottish children aged 7-8y (n = 257) was recruited during 1991/1992. Data on height, weight, skinfold thickness and resistance from bioelectrical impedance analysis were collected twice, 12 months apart. Percentage body fat was estimated from both skinfolds and bioelectrical impedance.
RESULTS: Fat and fat-free mass, but not body mass index, differed between boys and girls. All measurements increased significantly over the 12 month period except percentage body fat from skinfolds in boys. The reference child comparison revealed that our sample was taller, heavier and fatter and gained weight and fat mass at a greater rate than the Fomon standards.
CONCLUSIONS: Data from the children in this study suggest that the reference child has a body composition which is now out of date. This may have important implications for body composition methodology. New references for height and weight may be required, but an upgrading of the body fat reference may conflict with public health aims to reduce obesity.