Estimation of internal abdominal fat from anthropometry measurements in children

Abstract

Introduction: Internal abdominal fat (IAF) measured by dual energy X-ray absorptiometry (DXA) has been proposed as subrogate of visceral adipose tissue, which is a cornerstone measurement for screening of metabolic syndrome1,2. However, measuring IAF is time-consuming, expensive and impractical for field studies with children. Since 1990, anthropometric models have been developed to estimate IAF in adults, but no models exist for children. Because of the high prevalence of childhood obesity, the assessment of IAF is a major factor in the evaluation metabolic risk. Therefore, the aim of this study was to develop an anthropometry-based model to estimate IAF in children. Methods: Forty-one (n=24 boys, n=17 girls) healthy Caucasian children (age 11.4±0.6 years, BMI 20.1±3.9 Kg/m2) were volunteers. Anthropometric measurements (waist and hip circumferences, abdominal sagittal diameter and skinfolds) were taken in accordance with ISAK guidelines. Total body and IAF (dependent variable) body composition were measured by DXA. Stepwise regression analysis was carried out to obtain the fittest variables and beta coefficients in order to develop the equation that predicts IAF with a high squared R and a low standard error of estimation. Results: The best-correlated variables with IAF were BMI, waist circumference, calf and subscapular skinfolds (r=0.900; r=0.946; r=0.901; r=0.900; respectively, all P<0.001). The best model for estimating the IAF included waist circumference and subscapular skinfold (R2=0.93 SEE=115.43; P<0.001). The estimated model was IAF (g) = -1332.89 + (18.515*WC) + (773.39*SubSKF). Conclusion: We developed a model, which accurately predict IAF in children, affording a practical tool to quantify this variable without expensive techniques such as DXA. However, external cross-validation must be performed in order to confirm the model validity. Additionally, construct validity should be carried out to determine the applicability of this measurement in children.

References: 1. Hill AM, La_Forgia J, Coates AM, Buckley JD, Howe PR. Estimating abdominal adipose tissue with DXA and anthropometry. Obesity. 2007 Feb;15(2):504-10. 2. Kaul S, Rothney MP, Peters DM, Wacker WK, Davis CE, Shapiro MD, et al. Dual-energy X-ray absorptiometry for quantification of visceral fat. Obesity. 2012 Jun; 20(6):1313-8.