Association Between Vitamin D Deficiency and Cardiovascular Risk Factors in Children and Adolescents: A Systematic Review.

CONTEXT: Vitamin D deficiency is prevalent among children and adolescents and has emerged as a potential contributor to early cardiometabolic dysfunction. Growing evidence suggests links between low serum 25-hydroxyvitamin D (25[OH]D) concentrations and adverse cardiovascular risk profiles; however, the magnitude, independence, and clinical relevance of these associations in pediatric populations remain controversial. OBJECTIVE: This review aimed to critically evaluate evidence regarding the relationship between vitamin D deficiency and cardiovascular risk factors in pediatric populations. DATA SOURCES: This review was conducted in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO). A comprehensive electronic search of PubMed, SciELO, and Embase was performed up to September 10, 2025. DATA EXTRACTION: Studies assessing serum (25[OH]D) levels in relation to established cardiovascular risk factors in pediatric populations were included. DATA ANALYSIS: Risks of bias and overall quality of evidence were evaluated. Findings were synthesized through a structured qualitative narrative approach. In observational studies, a consistent inverse association was observed with markers of adiposity, with lower circulating 25(OH)D concentrations repeatedly reported in study participants with overweight or obesity. Associations with dyslipidemia, insulin resistance, and elevated blood pressure were also described; however, these relationships were heterogeneous and frequently attenuated after adjustment. Interventional studies showed largely null or clinically modest effects of vitamin D supplementation on pediatric cardiovascular risk. CONCLUSIONS: Considerable heterogeneity was observed across studies regarding participant age, developmental stage, vitamin D thresholds, outcome definitions, and study design. Current evidence does not support a clearly established causal relationship between vitamin D deficiency and pediatric cardiovascular risk. The observed associations with certain cardiovascular risk markers, particularly those related to obesity and adiposity, appear substantially influenced by confounding and shared lifestyle determinants, and further research is needed to fully elucidate the nature of the relationship. Vitamin D status should be interpreted within a broader cardiometabolic and behavioural framework. Well-designed longitudinal studies and randomized controlled trials are warranted to clarify whether vitamin D plays an independent role in the early development of cardiovascular risk. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. [CRD420251137216].