¹Department of Social Medicine, University of Bristol, Bristol, UK

Correspondence: MA Brion, Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol BS8 2 PR, UK. E-mail: Marie-Jo.Brion@bristol.ac.uk

Received 23 May 2006; Revised 16 November 2006; Accepted 21 November 2006; Published online 1 February 2007.

Abstract

Elevated blood pressure (BP) in children is an early risk factor for cardiovascular disease and is positively associated with body mass index (BMI). However, BMI does not distinguish between fat and lean masses, and the relationship of BP in children to different elements of body composition is not well established. BP, BMI and body composition were measured in 6863 children enrolled in the Avon Longitudinal Study of Parents and Children. Fat mass, lean mass and trunk fat were assessed using dual-energy X-ray absorptiometry. After full adjustment for confounders, total body fat and BMI were positively associated with systolic blood pressure (SBP) (=3.29, 95% confidence interval CI 3.02, 3.57 mm Hg/standard deviation (s.d.) and =3.97, 95% CI 3.73, 4.21 mm Hg/s.d., respectively) and diastolic blood pressure (DBP) (=1.26, 95% CI 1.05, 1.46 mm Hg/s.d. and =1.37, 95% CI 1.19, 1.54 mm Hg/s.d., respectively). SBP was also positively associated with lean mass (=3.38, 95% CI 2.95, 3.81 mm Hg/s.d.), and weakly associated with trunk fat (=1.42, 95% CI -0.06, 2.90 mm Hg/s.d., independent of total fat mass), which was robust in girls only. The association between lean mass and SBP remained even after accounting for fat mass. SBP in 9-year-old children is independently associated with fat mass and lean mass and, to a lesser extent, trunk fat in girls. In this analysis, because both fat and lean masses are associated with BP, BMI predicts BP at least as well as these components of body composition.