Vitamin D levels in children and adolescents are associated with coronavirus disease-2019 outcomes: A systematic review and meta-analysis.

Background: To explore the relationship between vitamin D levels and risk of SARS-CoV-2 infection and its severity in children and adolescents, and provide a theoretical basis for clinical practice.

Methods: The PubMed, Web of Science, Embase, MEDLINE, and Cochrane Library databases were searched for comprehensive cohort and case-control studies on the association between childhood vitamin D deficiency and the risk and prognosis of coronavirus disease-2019 (COVID-19). The search period was set from December 1, 2019, to December 31, 2023.

Results: The vitamin D insufficiency rate in children with COVID-19 was 80.78% (95% CI, 62.6% to 93.89%), with a deficiency rate of 32% (95% CI: 19.01% to 46.61%). Vitamin D insufficiency was more common in children with COVID-19 than in healthy children (OR, 4.86; 95% CI: 2.56-9.26). The incidence of severe illness was higher (OR, 4.73; 95% CI: 1.39-16.11) whereas that of asymptomatic illness was lower (OR, 0.38; 95% CI: 0.38-0.81) in children with COVID-19 who had vitamin D insufficiency than in those who did not.

Conclusions: Vitamin D insufficiency in children may increase the risk of COVID-19 infection and is associated with poor prognostic outcomes. Further research is required to confirm the optimal Vitamin D dose to prevent insufficiency in various sections of the population.