Background: The increasing prevalence of severe obesity among children and adolescents poses
a significant challenge for pediatricians and general practitioners. This study aimed to investigate
the relationships between biochemical results, anthropometry, blood pressure measurements and
bioimpedance analysis (BIA)-derived parameters, to identify potential cardiometabolic
complications associated with severe obesity. Methods: The study included 347 children (162
boys, 185 girls) aged 0-19 years, meeting criteria for severe obesity based on BMI thresholds for
different age groups. Patients were recruited in four pediatric endocrinology centers in Poland
(Zabrze, Cracow, Rzeszow, Szczecin). Each participant underwent anthropometric
measurements, pubertal stage assessment, blood pressure measurement, biochemical and
hormonal tests and BIA. Results: BMI showed significant associations with fat mass percentage
(FM%) and waist-to-height ratio (WHtR), but not waist-to-hip ratio (WHR). The relationship
between BMI and FM% was stronger in girls and prepubertal children. Metabolic syndrome (MetS)
Z-score showed a strong positive correlation with BMI in pubertal children. Negative correlation
between HDL and triglycerides was observed only in boys. Prepubertal children exhibited more
significant correlations despite a smaller sample size and shorter duration of obesity.
Conclusions: Considering multiple parameters beyond BMI alone provides a better
understanding of cardiometabolic risks associated with severe obesity in children. MetS Z-score
was not a reliable indicator of increased cardiometabolic risk in younger children. Early-onset
severe obesity was associated with a higher risk of metabolic complications. Early intervention is
crucial to mitigate metabolic complications in this population.