Hudda M T, van Niekerk E, Sedumedi C M, Moeng-Mahlangu L, Whincup P H, Reilly J J, Kruger H S, Monyeki M A
Department of Population Health, Dasman Diabetes Institute, Kuwait City, Kuwait.
Physical Activity, Sport and Recreation Research Focus Area (PhASRec), Faculty of Health Sciences, North-West University, Potchefstroom, South Africa.
Diabetes Obes Metab. 2025 Dec;27(12):7275-7284. doi: 10.1111/dom.70129. Epub 2025 Sep 14.
BACKGROUND/AIMS: While several prediction equations which combine anthropometric, demographic, and/or bioelectrical impedance (BIA) variables to estimate childhood fat mass (FM) are available, comprehensive comparisons of their performance are lacking. We validated FM estimates for children from a range of published equations against reference-standard deuterium dilution observed FM.
This cross-sectional study was based on 323 children (42% male) from South Africa of Black African ethnic origins aged 5 to 8 years with information on age, sex, ethnicity, height, weight, deuterium dilution observed FM, triceps and subscapular skinfold thickness, and BIA observed FM, resistance, and impedance. We extracted all equations from three systematic reviews of childhood FM prediction equations that used the above available predictors and were developed on more than 100 males and females. FM estimates from each equation were calculated and the performance of each, as well as FM reported from the BIA manufacturer software, was compared with deuterium dilution observed FM using statistics of R, Calibration (slope and calibration-in-the-large), and root mean square error (RMSE).
Nineteen equations (1 based on basic anthropometry, 12 on skinfold thickness, 6 on BIA) were validated. R and RMSE values ranged between 58.3% (BIA manufacturer equation) and 89.0% (Britz et al. (2017) skinfold thickness equation), and between 1.1 kg (Wendel et al. (2016) skinfold thickness equation) and 3.4 kg (Horlick et al. (2002) BIA equation), respectively. Calibration varied considerably across the equations. From the basic anthropometry, skinfold thickness, and BIA categories, the best performing equations from each category were by: Hudda et al. (2019) (basic anthropometry), Wickramasinghe et al. (2008) (skinfold thickness), and Ramirez et al. (2012) (BIA).
The performance of published equations varied considerably upon external validation in this South African childhood population. Notably, the Hudda et al. (2019) equation, which relies solely on readily available information of weight, height, sex, age and ethnicity, produced one of the highest R values, was well calibrated, and produced a low RMSE value (1.4 kg). Alternative equations which also performed very well relied on additional measurements of skinfold thickness and/or BIA which require equipment, training, extra costs and additional time to obtain.
背景/目的：虽然有几种结合人体测量学、人口统计学和/或生物电阻抗（BIA）变量来估计儿童脂肪量（FM）的预测方程，但缺乏对它们性能的全面比较。我们根据参考标准氘稀释法观察到的FM，验证了一系列已发表方程对儿童FM的估计。
这项横断面研究基于323名来自南非的5至8岁非洲裔黑人儿童（42%为男性），他们提供了年龄、性别、种族、身高、体重、氘稀释法观察到的FM、肱三头肌和肩胛下皮褶厚度以及BIA观察到的FM、电阻和阻抗等信息。我们从三项关于儿童FM预测方程的系统评价中提取了所有方程，这些方程使用了上述可用预测因子，并在100多名男性和女性中开发。计算每个方程的FM估计值，并使用R、校准（斜率和总体校准）和均方根误差（RMSE）统计量，将每个方程的性能以及BIA制造商软件报告的FM与氘稀释法观察到的FM进行比较。
验证了19个方程（1个基于基本人体测量学，12个基于皮褶厚度，6个基于BIA）。R值和RMSE值分别在58.3%（BIA制造商方程）至89.0%（布里茨等人（2017年）皮褶厚度方程）之间，以及1.1千克（温德尔等人（2016年）皮褶厚度方程）至3.4千克（霍利克等人（2002年）BIA方程）之间。各方程的校准差异很大。从基本人体测量学、皮褶厚度和BIA类别来看，每个类别的最佳方程分别是：胡达等人（2019年）（基本人体测量学）、维克拉马辛哈等人（2008年）（皮褶厚度）和拉米雷斯等人（2012年）（BIA）。
在这个南非儿童群体中，经外部验证，已发表方程的性能差异很大。值得注意的是，胡达等人（2019年）的方程仅依赖于体重、身高、性别、年龄和种族等容易获得的信息，其R值是最高的之一，校准良好，RMSE值较低（1.4千克）。其他表现也非常好的方程则依赖于皮褶厚度和/或BIA的额外测量，而这些测量需要设备、培训、额外费用和额外时间才能获得。
