Vitamin D supplementation in individuals with type 1 diabetes mellitus (T1DM) in children: an updated systematic review and meta-analysis focusing

Background and Purpose: Type 1 Diabetes Mellitus (T1DM) in children is characterized by autoimmune destruction of pancreatic \beta-cells. Vitamin D has emerged as a potential adjunctive therapy due to its immunomodulatory effects and role in glucose homeostasis. However, clinical evidence regarding its efficacy in improving glycemic control and preserving \beta-cell function remains inconsistent. The purpose of this research is to provide an updated, rigorous synthesis of existing evidence to determine whether Vitamin D supplementation, as an adjunct to routine insulin therapy, improves clinical outcomes in the pediatric population (aged \le 18 years). Methodology (PICO Framework): This study will follow PRISMA guidelines to systematically identify and analyze randomized controlled trials (RCTs) and cohort studies. • Population (P): Children and adolescents (\le 18 years) diagnosed with T1DM. • Intervention (I): Vitamin D supplementation (including cholecalciferol, ergocalciferol, alfacalcidol, or calcitriol) as an adjunct to insulin. • Comparator (C): Placebo or no vitamin D supplementation (standard care). • Outcomes (O): The primary efficacy outcomes include mean change in HbA1c (%), C-peptide levels, and daily insulin dose (DID). Secondary outcomes focus on safety, including adverse events and tolerability. Expected Outcomes: We expect to clarify the therapeutic value of Vitamin D in pediatric T1DM. The results will likely provide a definitive estimate of its effect on glycemic control (HbA1c) and \beta-cell preservation (C-peptide). Furthermore, this meta-analysis will evaluate the safety profile of various Vitamin D analogs and dosages, potentially informing clinical guidelines for adjunctive T1DM management in children.