Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
Department of Paediatrics and Child Health, School of Medicine College of Health Sciences, Makerere University, Kampala, Uganda.
J Nutr. 2023 Feb;153(2):426-434. doi: 10.1016/j.tjnut.2022.12.028. Epub 2022 Dec 29.
BIA represents an important tool in body composition (BC) assessment, especially in low-income settings in which simple and affordable options are preferred. There is a particular need to measure BC in stunted children, in which cases population-specific BIA estimating equations are lacking.
We calibrated an equation to estimate body composition from BIA using deuterium dilution (H) as the criterion method in stunted children.
We measured BC with H and performed BIA in stunted Ugandan children (n = 50). Multiple linear regression models were constructed to predict H-derived FFM from BIA-derived whole-body impedance and other relevant predictors. Model performance was expressed as adjusted R and RMSE. Prediction errors were also calculated.
Participants were aged 16-59 mo, of whom 46% were girls, and their median (IQR) height-for-age z-score (HAZ) was -2.58 (-2.92 to -2.37) according to the WHO growth standards. Impedance index (height/impedance measured at 50 kHz) alone explained 89.2% variation in FFM and had an RMSE of 583 g (precision error 6.5%). The final model contained age, sex, impedance index, and height-for-age z-score as predictors and explained 94.5% variation in FFM with an RMSE of 402 g (precision error 4.5%).
We present a BIA calibration equation for a group of stunted children with a relatively low prediction error. This may help evaluate the efficacy of nutritional supplementation in large-scale trials in the same population. J Nutr 20XX;xxx:xx.
生物电阻抗分析（BIA）是身体成分（BC）评估的重要工具，尤其在首选简单且经济实惠方法的低收入环境中。在身材矮小的儿童中特别需要测量 BC，而针对这些人群，目前还缺乏特定的 BIA 估算方程。
我们使用氘稀释（H）作为标准方法，针对身材矮小的儿童，对 BIA 估算身体成分的方程进行了校准。
我们使用 H 测量 BC，并对来自乌干达的身材矮小儿童（n=50）进行 BIA 测量。构建了多个线性回归模型，以预测 BIA 衍生的全身阻抗和其他相关预测因子得出的 H 衍生去脂体重（FFM）。通过调整 R 和 RMSE 来表示模型性能。同时还计算了预测误差。
参与者年龄为 16-59 月龄，其中 46%为女孩，根据世卫组织生长标准，其身高年龄 z 评分（HAZ）中位数（IQR）为-2.58（-2.92 至-2.37）。仅阻抗指数（50 kHz 处测量的身高/阻抗）就能解释 FFM 变异的 89.2%，RMSE 为 583 g（精密度误差为 6.5%）。最终模型包含年龄、性别、阻抗指数和 HAZ 作为预测因子，可解释 FFM 变异的 94.5%，RMSE 为 402 g（精密度误差为 4.5%）。
我们提出了一个针对身材矮小儿童的 BIA 校准方程，其预测误差相对较低。这可能有助于评估在同一人群的大规模试验中营养补充的效果。
