Observational studies suggest that the risk and clinical prognosis of coronavirus disease 2019 (COVID-19) are related to low vitamin D status; however, the data are inconsistent..
..A total of 10 articles with 361, 934 participants were selected for meta-analysis. Overall, the pooled OR in the fixed-effect model showed that vitamin D deficiency or insufficiency was associated with an increased risk of COVID-19 (OR = 1.43, 95% CI 1.00 to 2.05). In addition, COVID-19-positive individuals had lower vitamin D levels than those with COVID-19-negative individuals (SMD = −0.37, 95% CI = −0.52 to −0.21). Significant heterogeneity existed in both endpoints. Funnel plots and Egger regression tests revealed significant publication bias.
This systematic review and meta-analysis indicated that low vitamin D status may be associated with an increased risk of COVID-19 infection. Further studies are needed to evaluate the impact of vitamin D supplementation on the clinical severity and prognosis in patients with COVID-19.