Objective: This study aimed to examine the relation between change in different BMI metrics and change in adiposity over a 12-month weight management intervention. Methods: Baseline and 12-month weights and heights from 399 children aged 2 to 12 years with BMI ≥ 85th percentile were used to calculate BMI, %BMIp95, %BMIp50, 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. Results: 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, R2 for ΔBMI, ΔBMIz, BMImz, Δ%BMIp95, and Δ%BMIp50 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 R2, age group and sex interacted with the Δ%BMIp95 model but not ΔBMI or ΔBMIp50 models. Conclusions: 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.
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Endocrinology, Diabetes and Metabolism
- Nutrition and Dietetics