Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Children's Health, Dallas, Texas, USA.
Obesity (Silver Spring). 2020 Aug;28(8):1512-1518. doi: 10.1002/oby.22858. Epub 2020 Jul 6.
This study aimed to examine the relation between change in different BMI metrics and change in adiposity over a 12-month weight management intervention.
Baseline and 12-month weights and heights from 399 children aged 2 to 12 years with BMI ≥ 85th percentile were used to calculate BMI, %BMI, %BMI, BMI z-score (BMIz), and modified BMI z-score (BMImz). Changes (Δ) in these measures were compared with changes in body fat percent (Δfat%) from bioelectrical impedance assessment. Correlation and regression models predicting associations between ΔBMI metrics and Δfat% were examined.
A total of 89% of the cohort was Hispanic, and 34% had class 2 or 3 obesity. In models predicting Δfat% adjusting for age, sex, and weight category, R for ΔBMI, ΔBMIz, BMImz, Δ%BMI, and Δ%BMI were 0.53, 0.38, 0.45, 0.53, and 0.54, respectively (all P < 0.001). Only the ΔBMIz model had an interaction with weight status. Among the models with the highest R, age group and sex interacted with the Δ%BMI model but not ΔBMI or ΔBMI models.
Longitudinal analyses demonstrate the utility of several BMI metrics other than z-score in capturing adiposity change consistently across a range of obesity severity. Characteristics of studied groups and interpretability could influence metric choice.
本研究旨在探讨在为期 12 个月的体重管理干预中，不同 BMI 指标的变化与体脂变化之间的关系。
使用 399 名年龄在 2 至 12 岁、BMI≥第 85 百分位数的儿童的基线和 12 个月体重及身高，计算 BMI、%BMI、%BMI、BMIz 评分和改良 BMIz 评分。将这些指标的变化（Δ）与生物电阻抗评估得出的体脂百分比变化（Δfat%）进行比较。检验了预测 BMI 指标变化与 fat%变化之间关联的相关和回归模型。
该队列中 89%为西班牙裔，34%为 2 类或 3 类肥胖。在调整年龄、性别和体重类别后预测Δfat%的模型中，ΔBMI、ΔBMIz、BMImz、Δ%BMI 和 Δ%BMI 的 R 值分别为 0.53、0.38、0.45、0.53 和 0.54（均 P<0.001）。仅 BMIz 模型的变化与体重状况存在交互作用。在 R 值最高的模型中，年龄组和性别与Δ%BMI 模型存在交互作用，但与ΔBMI 或ΔBMI 模型不存在交互作用。
纵向分析表明，除 z 评分外，其他几种 BMI 指标在捕捉肥胖严重程度不同的体脂变化方面具有一致性。研究人群的特点和可解释性可能会影响指标的选择。
