Purpose: To examine cross-sectional and longitudinal relationships between body mass index (BMI)-derived metrics for measuring severe obesity (SO) using the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) references and cardiometabolic risk factors in children and adolescents.
Methods: In this cohort study completed from 2013 to 2021, we examined data from 3- to 18-year-olds enrolled in the CANadian Pediatric Weight management Registry. Anthropometric data were used to create nine BMI-derived metrics based on the CDC and WHO references. Cardiometabolic risk factors were examined, including dysglycemia, dyslipidemia, and elevated blood pressure. Analyses included intraclass correlation coefficients (ICC) and receiver operator characteristic area-under-the-curve (ROC AUC).
Results: Our sample included 1,288 participants (n=666 [51.7%] girls; n=874 [67.9%] white), with SO of 59.9–67.0%. ICCs revealed high tracking (0.90–0.94) for most BMI-derived metrics. ROC AUC analyses showed CDC and WHO metrics discriminated the presence of cardiometabolic risk factors, which improved with increasing numbers of risk factors. Overall, most BMI-derived metrics rated poorly in identifying presence of cardiometabolic risk factors.
Conclusion: CDC BMI percent of the 95th percentile and WHO BMIz performed similarly as measures of SO, suggesting both can be used for clinical care and research in pediatrics. The latter definition may be particularly useful for clinicians and researchers from countries that recommend using the WHO growth reference.