Objective: To compare and contrast proposed definitions of metabolic syndrome in pediatrics, and to determine prevalence of metabolic syndrome in preadolescent females when applying different criteria.

Study Design: A literature review on definitions of metabolic syndrome and cardiovascular "risk factor clustering" in children and adolescents published in the past decade. Pediatric definitions of metabolic syndrome were then applied to a community-based study of 261 black preadolescent females (Girls Health Enrichment MultiSite studies [GEMS]) and a school-based, cross-sectional study of 240 ethnically-diverse preadolescent females (Girls Activity, Movement and Environmental Strategy [GAMES]) who had a baseline physical examination and fasting morning blood sample.

Results: Agreement among pediatric definitions of metabolic syndrome was poor. The prevalence of MS and cardiovascular risk factor clustering ranged from 0.4% to 23.0% for GEMS and 2.0% to 24.6% for GAMES with definitions adapted from the National Cholesterol Education Program Adult Treatment Panel III, and 0% to 15.3% for GEMS and 0.4% to 15.8% for GAMES using modified criteria from the World Health Organization.

Conclusions: The prevalence of metabolic syndrome in preadolescent girls varies widely because of disagreement among proposed definitions of metabolic syndrome in pediatrics. Further investigation is needed to determine which metabolic factors and their respective cut points should be used to identify children at risk for development of clinical disease.