Association of Vitamin D Deficiency with COVID-۱۹ Susceptibility and Severity in Hospitalized Children: A Case–Control Study

Background: Vitamin D exerts immunomodulatory and anti-inflammatory effects that may influence outcomes of viral respiratory infections, including COVID-۱۹. However, pediatric data remain limited. This study examined the relationship between serum ۲۵-hydroxy-vitamin D [۲۵(OH)D] levels and susceptibility to and severity of COVID-۱۹ among hospitalized children in Iran. Methods: In this retrospective case–control study, ۶۳ children (۰–۱۶ years) with RT-PCR-confirmed COVID-۱۹ admitted to Firouzabadi Hospital, Tehran (۲۰۱۹–۲۰۲۱) were compared with ۶۸ age- and sex-matched historical controls hospitalized two years before the pandemic for non-respiratory conditions. Moreover, historical controls were used to avoid pandemic-era confounding due to widespread supplementation and asymptomatic infection. Demographic, clinical, and laboratory data including ۲۵(OH)D, C-reactive protein (CRP), lymphocyte count, and need for pediatric intensive-care-unit (PICU) admission-were also extracted. Statistical analysis employed non-parametric tests with P-value < ۰.۰۵ as significant. Results: Vitamin D deficiency (<۲۰ ng/ml) occurred in ۶۱% of cases versus ۱۴% of controls (P<۰.۰۰۱). Mean ۲۵(OH)D levels were lower in cases (۱۸.۶±۹.۶ ng/ml) than controls (۴۳.۴±۲۵.۳ ng/ml, P<۰.۰۰۱). PICU-admitted patients showed lower vitamin D than non-PICU patients (۱۳.۸±۶.۴ vs ۱۹.۷±۹.۹ ng/ml, P=۰.۰۳۵). Conclusions: Vitamin D deficiency was strongly associated with COVID-۱۹ susceptibility but not with in-hospital severity. Therefore, routine screening and correction of vitamin D deficiency may be a cost-effective preventive strategy for pediatric populations.

کلیدواژه ها:

COVID-۱۹ ، Vitamin D deficiency ، Pediatric ، Hospitalization ، Iran.