Evaluation of Alternative Body Mass Index (BMI) Metrics to Monitor Weight Status in Children and Adolescents With Extremely High BMI Using CDC BMI-for-age Growth Charts.

In the United States, obesity and severe obesity in children and adolescents are defined using threshold values from the 2000 Centers for Disease Control and Prevention (CDC) sex-specific body mass index (BMI)- for-age growth charts. BMI z-scores and percentiles from the 2000 CDC BMI-for-age growth charts are also used to monitor children's weight status over time and to evaluate obesity treatments. Parameters to calculate percentiles and corresponding z-scores (BMIz) were derived from selected percentiles between the 3rd and 97th. Use of the BMI-for-age growth charts for children and adolescents with extremely high BMI requires extrapolation beyond the 97th percentile, which leads to compression of BMIz values into a very narrow range and is not recommended. This report evaluates eight alternative BMI metrics for monitoring weight status in children and adolescents with extremely high BMI.