Association Between the Level of Vitamin D and COVID-19 Infection in Children and Adolescents: A Systematic Review.

The COVID-19 pandemic has exerted a notable impact on worldwide health across diverse age groups. Although children and adolescents were initially considered less vulnerable, they have also shown susceptibility to the virus, emphasizing the importance of understanding associated risk factors. Epidemiological data reveal an increasing number of COVID-19 cases in this age group. The aim is to conduct a systematic assessment of the association between the level of vitamin D and COVID-19 infection in children and adolescents following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed across various databases up to October 7, 2023. Studies assessing laboratory-confirmed COVID-19 patients, the level of 25-hydroxyvitamin D in serum, and clinical outcomes were encompassed. Quality assessment was performed using the Newcastle-Ottawa Scale. Thirteen studies, conducted across six countries and involving 1,071 pediatric patients, were included. Vitamin D deficiency was prevalent among children and adolescents with COVID-19. Some studies suggested that vitamin D deficiency significantly increased the risk of COVID-19 infection and was linked to disease progression. Furthermore, deficiency in vitamin D demonstrated an association with increased levels of inflammatory markers, reduced lymphocyte counts, and heightened clinical symptoms, including fever and cough. Maintaining adequate vitamin D levels may be a crucial strategy for reducing COVID-19 severity and associated complications in children and adolescents. Nevertheless, there is a requirement for additional high-quality research to establish specific guidelines regarding vitamin D supplementation in this population amid the ongoing COVID-19 pandemic.