Estimation of percentage of body fat in field studies – a method based on relative elbow breadth (Frame Index) and BMI

Abstract

Background
 Over the last 20 years, a decreasing trend in external skeletal robusticity and an increasing trend in overweight and obesity was observed worldwide in adults and children as modern lifestyles in nutritional and activity behavior have changed. However, body mass index (BMI) as a measure for overweight is not an ideal predictor of % body fat (%BF) either in children and adolescents or in adults. On the contrary, it disguises a phenomenon called “hidden obesity”.
 Objectives
 We aim to approximate %BF by combining skeletal robusticity and BMI and develop an estimation-based tool to identify normal weight obese children and adolescents.
 Sample and Methods
 We analyzed cross-sectional data on height, weight, elbow breadth, and skinfold thickness (triceps and subscapular) of German children aged 6 to 18 years (N=15,034). We used modified Hattori charts and multiple linear regression to develop a tool, the “%BF estimator”, to estimate %BF by using BMI and skeletal robusticity measured as Frame Index.
 Results
 Independent of sex and age an increase in BMI is associated with an increase in %BF, an increase in Frame Index is associated with a decrease in %BF. The developed tool “%BF estimator” allows the estimation of %BF per sex and age group after calculation of BMI and Frame Index.
 Conclusion
 The “%BF estimator” is an easily applicable tool for the estimation of %BF in respect of body composition for clinical practice, screening, and public health research. It is non-invasive and has high accuracy. Further, it allows the identification of normal weight obese children and adolescents.

Anthropometric parameters to estimate body frame size in children and adolescents: A systematic review

“…In 25 studies, the design was cross-sectional, in one it was longitudinal. The region of origin was European in 11 studies (42%) (Godina et al, 2016;Hesse et al, 2016;Mumm et al, 2018Mumm et al, , 2021Mus alek et al, 2018;Rietsch, Eccard, & Scheffler, 2013;Rietsch, Godina, & Scheffler, 2013;Scheffler, 2011;Scheffler & Hermanussen, 2014;Stolzenberg et al, 2007;Woronkowicz et al, 2016), Latin American in 7 (27%) (Avila Chaurand et al, 2007;Avila Chaurand et al, 2007;Baya Botti et al, 2009;Guzm an de la Garza et al, 2019;Guzm an-de la Garza et al, 2017;Lizana & Hormazabal-Peralta, 2020;Navazo et al, 2020), Asian in 6 (23%) (Asif et al, 2021;Fazeli et al, 2019;Kelishadi et al, 2016;Khadilkar et al, 2018;Kryst et al, 2021;Öztürk et al, 2017), multinational in 2 (8%) (Mumm et al, 2018;Rietsch, Godina, & Scheffler, 2013), and North American in 1 (4%) (Hetherington-Rauth et al, 2018).…”

“…Therefore, the determination of bone complexion adds information to the BMI optimizing the assessment of nutritional status. (Bemjumea et al, 2002; Lizana & Hormazabal‐Peralta, 2020; Mumm et al, 2021; Musálek et al, 2018).…”

Comparison of frame index reference percentiles in Argentine and European boys and girls

“…These changes in nutritional status and body composition have been interpreted as a consequence of the nutritional transition process, in which diets rich in flour, sugars and fats but poor in protein predominate (Garraza & Oyhenart 2020; Oyhenart et al, 2019). In this sense, it is important to consider that although fat mass is a component of body mass and contributes to skeletal loading, lean mass is the main determinant of bone strength in the extremities, especially in the upper extremities (Mumm et al, 2021). Therefore, further analysis of FI variability and its correlation with nutritional status and body composition in the Argentine population is encouraged.…”

Percentiles de referencia del índice de robustez esquelética humeral de niñas y niños (4-14 años). Un estudio antropométrico transversal en tres provincias argentinas

“…Asimismo, estudios recientes han dado cuenta de la importancia que posee el IRE para el monitoreo de posibles casos de obesidad oculta. Según Mumm et al (2021) las interacciones dadas entre IMC, porcentaje de grasa corporal (%G) y robustez esquelética del húmero permitirían combinar información sobre las masas grasa y magra. Así, dichas autoras plantean que, en niños y adolescentes, serían indicadores de riesgo de presencia de obesidad oculta valores de IRE bajos, de IMC menores al percentil 90 y de %G mayores al percentil 85 de la referencia de Slaughter et al (1988).…”