Abstract
This systematic review/meta-analysis aims to highlight the effect of vitamin D supplementation in deficient children suffering from obesity. Published clinical studies on vitamin D supplementation in obese children and adolescents with vitamin D deficiency were identified through a comprehensive MEDLINE/PubMed search (from July 1966 to November 2017). Outcomes intended after vitamin D supplementation were improvements in vitamin D status, BMI alterations and appetite changes. The inclusion criteria were children aged 2 to 18 years of both sexes in clinical trials that specified the oral and/or intramuscular dose of vitamin D supplementation. Ten studies were retrieved, but only 6 were relevant. First, supplemented obese children and adolescents were compared to non-obese controls; thereafter, supplemented obese children and adolescents were compared to matching obese peers given placebo. Pooled risks from the 2 studies that evaluated the number of obese and non-obese children and adolescents who improved upon vitamin D supplementation revealed that obesity poses a risk for not benefiting from the vitamin D supplementation regardless of the dose and the duration of supplementation. Pooled results from the 6 retrieved studies that compared supplemented obese children and adolescents to matching non-obese or obese peers given placebo revealed significantly lower vitamin D levels in obese participants than in non-obese peers. Vitamin D levels are significantly lower in obese children and adolescents with obesity, posing a risk for not benefiting from vitamin D supplementation regardless of the dose and duration of supplementation.