Validating the waist-height ratio and developing centiles for use amongst children and adolescents.

ABSTRACT

AIM: To assess the statistical validity of the waist-height ratio (WHtR) as an appropriate method of adjusting waist circumference (WC) for height in children and adolescents. INTRODUCTION: Recently, WHtR has been proposed to be of greater value than body mass index (BMI), in predicting obesity-related cardiovascular co-morbidities in children. This index, however, is yet to be extensively validated within the paediatric population. METHODS: Height and WC in centimetres, were measured in 3597 children from grades 1 (5-7 years), 5 (9-11 years) and 10 (15-17 years). Log regression analyses using WC and height were performed to determine appropriate powers (p) to raise height, to completely adjust the index for height, by sex and grade. Correlations between WHtR and height were assessed. RESULTS: Statistically, the WHtR is only valid for use among grade 1 boys and girls (p = 1.09 [95%CI 0.95-1.23] and p = 1.07 [95%CI 0.92-1.22], respectively) and grade 10 girls p = 0.85 (95%CI 0.62-1.08). However, the error (0.25%-1.85%), associated with the use of this index, in all ages and both sexes is clinically and biologically acceptable. CONCLUSION: The WHtR is a clinically and biologically valid index to use among Australian children and adolescents.