High risk vs. "metabolically healthy" phenotype in juvenile obesity - neck subcutaneous adipose tissue and serum uric acid are clinically relevant.

BACKGROUND: Since obesity and its associated co-morbidities do not only have effect on the individual patient, but also on society and the health system, it is of great importance to investigate this lifestyle-disease. The rationale of this study was to distinguish metabolically healthy from unhealthy overweight/obese patients as compared to healthy normal weight children and adolescents by means of a comprehensive anthropometric, laboratory and sonomorphological vascular assessment.

MATERIALS AND METHODS: 299 study participants were derived from the prospective, observational study STYJOBS/EDECTA (STYrian Juvenile Obesity Study/Early DEteCTion of Arteriosclerosis). Standard anthropometric data were obtained for each subject. This study comprised different diagnostic steps: extended anthropometry (Lipometer®), carotid artery ultrasound, various laboratory measurements, blood pressure measurement, oral glucose tolerance test. Ow/ob juveniles were classified as "metabolically healthy" (no laboratory criteria of metabolic syndrome fulfilled) vs. "metabolically unhealthy" (≥ 3 criteria of metabolic syndrome). Results underwent statistical evaluation, including t-test or Mann-Whitney U-test, regression analysis and a p-value < 0.05 was considered statistically significant.

RESULTS AND DISCUSSION: In the study's central European cohort only about 16% (n=48/299) of the overweight/obese juveniles can be regarded as metabolically healthy. About 36% (n=108/299) of the overweight/obese patients fulfilled the criteria for metabolic syndrome. High visceral fat stores (p<0.001) and their clinical surrogate waist circumference (p<0.001) determine an adverse metabolic phenotype. Several parameters, including uric acid (p<0.001), adiponectin (p<0.05), insulin resistance (HOMA-Index, p<0.001), nuchal SAT thickness (p<0.001), arteriosclerosis of the carotids (p<0.001), and others are responsible for the distinction between -metabolically healthy and unhealthy juveniles. Nevertheless, "healthy obesity" only defines a sub-phenotype of a disease effecting rising numbers of young patients.

CONCLUSIONS: Since obesity in children and adolescents is not a consistent entity, it remains crucial to differ between metabolically healthy and unhealthy obese children in order to achieve appropriate intervention and prevention for our patients.