Vitamin D and Vascular Health in Children

Our primary objective is to determine, in obese and overweight children aged 10 to 18 years with vitamin D deficiency (defined as serum 25-hydroxyvitamin D \<20 ng/mL), the efficacy of enhanced vitamin D3 supplementation in improving vascular endothelial function, arterial stiffness, insulin sensitivity, and metabolic syndrome risk status; and to assess whether these effects are dose-dependent. As a secondary objective, we will examine the vitamin D supplementation-induced effect on adipokines and inflammatory markers relevant to CVD risk. In a double-masked, controlled trial, we will randomize 252 eligible children to receive either 600 IU (conventional supplementation), or 1000 IU or 2000 IU (enhanced supplementation) of vitamin D3 daily for 6 months. In terms of reporting of results, the following pre-specified outcomes are included in the primary manuscript (PubMed PMID:31950134 -- see Reference section for citation details) 1. Waist Circumference 2. Serum High Density Lipoprotein (HDL) Cholesterol 3. Serum Triglycerides 4. Inflammatory markers (Plasma TNF-alpha, high-sensitivity C-reactive protein, and IL-6) 5. Adiopkines (Plasma Leptin and Adiponectin) Plasma nitric oxide metabolites were not measured.