Comparison of metabolic syndrome prevalence using eight different definitions: a critical approach

Objective: Multiple definitions of the metabolic syndrome (MS) have been proposed for children, adolescents and adults. The aim of this study was to analyse the variations in the MS prevalence using different definitions and to examine which factors influence the frequency of the MS in childhood and adolescence. Methods and design: The prevalence of the MS according to eight proposed definitions was studied in 1205 Caucasian overweight children and adolescents aged 4-16 years (mean body mass index (BMI) 27.3 kg/m(2), mean age 11.8 years, 46% males, 39% prepubertal). Blood pressure, waist circumference and fasting triglycerides, HDL-cholesterol, total cholesterol, insulin and glucose concentrations were determined. Overweight was defined according to the International Task Force of Obesity in Childhood. Degree of overweight was calculated as standard deviation score of BMI (SDS-BMI). Insulin resistance was estimated based on the HOMA model. Results: The prevalence of the MS varied significantly (p<0.001), being between 6% and 39% depending on the different definitions. Only 2% of the children fulfilled the criteria of the MS in all definitions. Insulin resistance and degree of overweight were associated with the MS. In most definitions, pubertal stage did not influence the occurrence of the MS. In a principal component analysis, total cholesterol, triglycerides and waist circumference showed high final communality estimates. Conclusions: Since the prevalence of the MS varied widely in overweight children and adolescents depending on the proposed definition used, an internationally accepted uniform definition of the MS is necessary to compare different populations and studies.