Which metric of relative weight best captures body fatness in children?

Autor: Field AE; Division of Adolescent Medicine, Department of Medicine, Children's Hospital Boston and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. Alison.Field@TCH.harvard.edu, Laird N, Steinberg E, Fallon E, Semega-Janneh M, Yanovski JA
Jazyk: angličtina
Zdroj: Obesity research [Obes Res] 2003 Nov; Vol. 11 (11), pp. 1345-52.
DOI: 10.1038/oby.2003.182
Abstrakt: Objective: To evaluate the relative merits of BMI (kilograms per meter squared) and age- and gender-adjusted BMI, age- and gender-specific z score of BMI, and age- and gender-specific percentiles of BMI as surrogate measures of body fatness among a sample of youth.
Research Methods and Procedures: The sample comprised 596 children and adolescents 5 to 18.7 years old and was 40% male and 55% white. Height and weight were measured by trained research staff. DXA was used to determine body fat mass. BMI, age- and gender-specific percentile of BMI, and age- and gender-specific z scores of BMI were computed, and these metrics were compared with measured body fatness.
Results: The BMI values in the sample ranged from 12.9 to 55.0 kg/m(2), with a mean of 24.9 kg/m(2). The Spearman correlations with percentage body fat were similar for all of the BMI metrics (r = 0.82 to 0.88). Linear regression models with age- and gender-specific percentiles of BMI explained significantly less of the variance (65%) than models with log-transformed BMI (81%) or age- and gender-specific z scores of BMI (75% to 79%). z scores were the most accurate at classifying children who were overfat (sensitivity = 0.84, specificity = 0.96 for z score > or = 1). However, using a BMI > or = 85th percentile or a BMI > or = 20 kg/m(2) was also accurate at classifying youth.
Discussion: The BMI metrics had similar correlations with body fatness, but age- and gender-specific percentiles of BMI were the least accurate proxy measure of body fatness. However, a BMI z score > or = 1, BMI percentile > or = 85, and BMI> or = 20 kg/m(2) are all useful for identifying children who may be overfat.
Databáze: MEDLINE
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