Childhood Nutrition Research Centre, Population, Policy and Practice Programme, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
Eur J Clin Nutr. 2019 Jun;73(6):887-895. doi: 10.1038/s41430-018-0292-x. Epub 2018 Aug 30.
BACKGROUND/OBJECTIVES: Bio-electrical impedance (BI) analysis is a simple body composition method ideal for children. However, its utility in sick or malnourished children is complicated by variability in hydration. BI vector analysis (BIVA) potentially resolves this, using a theoretical model that differentiates hydration from cell mass. We tested this model against reference methods in healthy children varying widely in age and nutritional status.
SUBJECTS/METHODS: We compiled body composition data from 291 children and adolescents (50% male) aged 4-20 years of European ancestry. Measurements included anthropometry, BIVA outcomes (height-adjusted resistance (R/H) and reactance (Xc/H); phase angle (PA)), and fat-free mass (FFM), fat mass (FM) and FFM-hydration (H) by the criterion 4-component model. All outcomes were converted to age- and sex-standardised standard deviation scores (SDS). Graphic analysis and regression analysis were used to evaluate the BIVA model.
R/H and Xc/H declined with age in curvilinear manner, whereas PA increased linearly with age. R/H-SDS and Xc-SDS were negatively correlated with FFM-SDS, H-SDS. and FM-SDS. PA was positively correlated with FFM-SDS but unrelated to H-SDS and FM-SDS.
While previous studies of adults with major fluid perturbations support the BIVA model, it is less successful in predicting variability in FFM in healthy children and adolescents. BIVA outcomes varied as predicted by the model with H, but not as predicted with FFM. Variability in adiposity also explains some of the variability in BIVA traits. Further work is needed to develop a theoretical BIVA model for application in paediatric patients without major fluid disturbances.
背景/目的：生物电阻抗（BI）分析是一种简单的身体成分方法，非常适合儿童。然而，在患有疾病或营养不良的儿童中，其应用受到水合作用变异性的影响。BI 向量分析（BIVA）使用区分水合作用和细胞质量的理论模型，可能解决这个问题。我们在年龄和营养状况差异很大的健康儿童中对该模型进行了测试，与参考方法进行了比较。
受试者/方法：我们汇编了 291 名欧洲裔儿童和青少年（50%为男性）的身体成分数据，年龄在 4-20 岁之间。测量包括人体测量学、BIVA 结果（身高调整电阻（R/H）和电抗（Xc/H）；相位角（PA））以及通过 4 成分模型标准的无脂肪质量（FFM）、脂肪质量（FM）和 FFM-水合作用（H）。所有结果均转换为年龄和性别标准化标准偏差评分（SDS）。图形分析和回归分析用于评估 BIVA 模型。
R/H 和 Xc/H 以曲线方式随年龄下降，而 PA 则以线性方式随年龄增加。R/H-SDS 和 Xc-SDS 与 FFM-SDS、H-SDS 和 FM-SDS 呈负相关。PA 与 FFM-SDS 呈正相关，但与 H-SDS 和 FM-SDS 无关。
虽然以前对有重大液体波动的成年人的研究支持 BIVA 模型，但它在预测健康儿童和青少年 FFM 的变异性方面不太成功。BIVA 结果与模型预测的 H 变化一致，但与 FFM 变化不一致。肥胖程度的变异性也解释了 BIVA 特征的一些变异性。需要进一步的工作来开发适用于没有重大液体干扰的儿科患者的理论 BIVA 模型。
