Correlations among adiposity measures in school-aged children.

Caroline E Boeke,Ken P Kleinman,Emily Oken,Elsie M Taveras,Matthew W Gillman,Sheryl L Rifas-Shiman

doi:10.1186/1471-2431-13-99

Caroline E Boeke, Ken P Kleinman + Show 4 more

Open Access

https://doi.org/10.1186/1471-2431-13-99

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Abstract

BackgroundGiven that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives. Therefore, we sought to determine the extent to which other adiposity measures were correlated with DXA fat mass in school-aged children.MethodsIn 1110 children aged 6.5-10.9 years in the pre-birth cohort Project Viva, we calculated Spearman correlation coefficients between DXA (n=875) and other adiposity measures including body mass index (BMI), skinfold thickness, circumferences, and bioimpedance. We also computed correlations between lean body mass measures.Results50.0% of the children were female and 36.5% were non-white. Mean (SD) BMI was 17.2 (3.1) and total fat mass by DXA was 7.5 (3.9) kg. DXA total fat mass was highly correlated with BMI (rs=0.83), bioimpedance total fat (rs=0.87), and sum of skinfolds (rs=0.90), and DXA trunk fat was highly correlated with waist circumference (rs=0.79). Correlations of BMI with other adiposity indices were high, e.g., with waist circumference (rs=0.86) and sum of subscapular plus triceps skinfolds (rs=0.79). DXA fat-free mass and bioimpedance fat-free mass were highly correlated (rs=0.94).ConclusionsIn school-aged children, BMI, sum of skinfolds, and other adiposity measures were strongly correlated with DXA fat mass. Although these measurement methods have limitations, BMI and skinfolds are adequate surrogate measures of relative adiposity in children when DXA is not practical.

Highlights

Given that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives
To assess how well body mass index (BMI)-defined obesity detects elevated DXA fat mass, we identified the children with BMI ≥95th age- and sex-specific percentile (“obesity”) and ≥85th percentile (“overweight plus obesity”) according to reference data from the Centers for Disease Control and Prevention [20]
DXA total fat mass was highly correlated with BMI [Spearman r=0.83; Pearson r=0.88], sum of skinfolds, and bioelectrical impedance body fat

Summary

Introduction

Given that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives. BMI does not explicitly distinguish between fat and lean mass, so there are still concerns about its use in pediatric studies Another low cost and safe option for measuring adiposity is skinfold thickness. If not accompanied by rigorous training, intraand inter-rater reliability can be low [14,15] Bioelectrical impedance is another option that was well-correlated with DXA in previous studies in children (r>0.7), but it requires expensive equipment and may underestimate fat mass and overestimate fat-free mass [4,16,17,18]

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