Single-nucleotide polymorphisms related to vitamin D metabolism and severity or mortality of COVID-19: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to verify the association between single-nucleotide polymorphisms (SNPs) in vitamin D-related genes and the severity or mortality of coronavirus disease 19 (COVID-19). We systematically searched PubMed, BVS/Bireme, Scopus, Embase, and Web of Science for relevant studies published until November 24, 2023. Twelve studies were included. Thirty-one SNPs related to four genes were studied (VDR, 13 SNPs; GC, 6 SNPs; DHCR7/NADSYN1, 6 SNPs; CYP2R1, 6 SNPs). Eight SNPs were examined in two or more studies (VDR rs731236, rs2228570, rs1544410, rs7975232, rs739837, rs757343, rs11568820, and rs4516035). Meta-analysis showed a significant association between the VDR rs1544410 Bb + bb genotype and b allele and an increased odds of developing severe/critical COVID-19 (Bb + bb vs. BB = 2 studies, OR = 1.73, 95% confidence interval (CI): 1.16-2.57, P = 0.007, I2 = 0%; b allele vs. B allele = 2 studies, OR = 1.31, 95% CI: 1.03-1.67; P = 0.03; I2 = 0%). Regarding the mortality rate, VDR rs731236 TT-genotype, TT + Tt genotype, and T allele; VDR rs1544410 bb-genotype, Bb + bb genotype, and b allele; VDR rs7975232 AA-genotype, AA + Aa genotype, and A allele; and VDR rs2228570 ff-genotype, Ff + ff genotype, and f allele were associated with increased odds of death due to COVID-19. In conclusion, the present study suggests that SNPs rs1544410 may serve as a predictive biomarker for COVID-19 severity and rs731236, rs1544410, rs7975232, and rs2228570 as predictive biomarkers for COVID-19 mortality. More well-designed studies involving a larger number of COVID-19 patients are required to validate and replicate these findings.