key: cord-0983719-4bubt6lt authors: Speeckaert, Marijn M.; Delanghe, Joris R. title: Association of Vitamin D Status and COVID-19-Related Hospitalization and Mortality date: 2022-05-17 journal: J Gen Intern Med DOI: 10.1007/s11606-022-07658-3 sha: f26cfe69b9cc551507052928c4474040fda916c8 doc_id: 983719 cord_uid: 4bubt6lt nan investigated the association of vitamin D status and COVID-19-related hospitalization and mortality. 25-Hydroxyvitamin D [25(OH)D] concentrations were connected in an inverse dose-response relationship to COVID-19-related hospitalization and mortality in a heterogeneous population of veteran patients. Although various confounders were considered, we want to emphasize the significance of vitamin Dbinding protein (DBP) and its polymorphism on the obtained results. Normally, 25(OH)D circulates mainly bound to DBP (approximately 85%) and albumin (15%), while only 0.03% exists in free form. DBP is the main transporter of vitamin D metabolites, and an extensive DBP polymorphism with a distinct allele distribution in various geographic areas has been identified. 2 The genetic polymorphisms rs7041 and rs4588 in exon 11 of the DBP gene identify the three major DBP alleles: DBP1F [rs7041-T (ASP), rs4588-C (Thr)], DBP1S [rs7041-G (ASP), rs4588-C (Thr)], and DBP2 [rs7041-T (ASP), rs4588-A (Lys)]. 2,3 rs2282679 is an rs4588 proxy, and rs2282679-A is generally coinherited with rs4588-C, whereas rs2282679-C is usually coinherited with rs4588-A. 4 The concentrations of free and total 25(OH)D, as well as DBP, increase with the following phenotypes: DBP2-2