Exploring the Interplay Between Vitamin D and Metabolic Parameters in Pediatric Obesity: Toward Early Biomarker Detection

Introduction It is still uncertain whether vitamin D deficiency is a cause, effect, or contributing element in childhood obesity and metabolic imbalance. This study combines univariate and multivariate analyses to investigate associations between vitamin D levels, metabolic parameters, and adiposity indices, with the goal of identifying potential patterns and biomarkers among highly interrelated variables. Patients and Methods We retrospectively analyzed data from 285 children with obesity (mean age of 10.71 ± 2.69 years). Clinical, anthropometric, metabolic, and endocrinological parameters and vitamin D levels were assessed. A control group of 55 normal-weight children, comparable in age, was included. Both univariate and multivariate statistical approaches were applied. Results Univariate analysis revealed significant differences between weight classes in multiple clinical and biochemical parameters, including atherogenic markers, adiposity indices, and insulin-resistance indicators (p < 0.001 for most). In comparisons based on vitamin D status, differences were particularly marked in body mass index (BMI), insulin, triglycerides, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and Triglyceride-Glucose (TyG) Index. Multivariate analysis identified weak but significant negative correlations between vitamin D and some clinical parameters (atherogenic coefficient, Triglyceride-Cholesterol Body Index, and HOMA-IR), with correlation coefficients ranging from −0.14 to −0.28. Principal component analysis (PCA) showed that vitamin D and BMI are often positioned on opposite axes in biplots, supporting a negative correlation. Notably, the principal component (PC) 2, dominated by BMI and vitamin D, effectively distinguished weight groups based on insulin resistance and adiposity variables. No consistent associations were observed with sex or traditional atherogenic markers. Conclusions Vitamin D levels are significantly associated with key metabolic parameters, especially those related to insulin resistance and adiposity. Although no direct relationship was observed with classical atherogenic markers, multivariate analysis suggests possible indirect links mediated by excess adiposity. These findings support the potential role of vitamin D as a marker of metabolic health. Longitudinal studies are needed to determine whether improving vitamin D status can enhance insulin sensitivity and reduce metabolic risk in children with obesity.