Vitamin D deficiency is associated with higher risks for SARS-CoV-2 infection and COVID-19 severity: a retrospective case–control study
Ariel Israel, Assi Cicurel, Ilan Feldhamer, Felicia Stern, Yosef Dror, Shmuel M Giveon, David Gillis, David Strich, Gil Lavie
Internal and Emergency Medicine, doi:10.1007/s11739-021-02902-w
Robust evidence of whether vitamin D deficiency is associated with COVID-19 infection and its severity is still lacking. The aim of the study was to evaluate the association between vitamin D levels and the risks of SARS-CoV-2 infection and severe disease in those infected. A retrospective study was carried out among members of Clalit Health Services (CHS), the largest healthcare organization in Israel, between March 1 and October 31, 2020. We created two matched case-control groups of individuals for which vitamin D levels and body mass index (BMI) were available before the pandemic: group (A), in which 41,757 individuals with positive SARS-CoV-2 PCR tests were matched with 417,570 control individuals without evidence of infection, and group (B), in which 2533 patients hospitalized in severe condition for COVID-19 were matched with 2533 patients who were tested positive for SARS-CoV-2, but were not hospitalized. Conditional logistic models were fitted in each of the groups to assess the association between vitamin D levels and outcome. An inverse correlation was demonstrated between the level of vitamin D and the risks of SARS-CoV-2 infection and of severe disease in those infected. Patients with very low vitamin D levels (< 30 nmol/L) had the highest risks for SARS-CoV-2 infection and also for severe COVID-19 when infected-OR 1.246 [95% CI 1.210-1.304] and 1.513 [95% CI 1.230-1.861], respectively. In this large observational population study, we show a significant association between vitamin D deficiency and the risks of SARS-CoV-2 infection and of severe disease in those infected.
Conclusion In this large observational population study, we show a significant association between vitamin D deficiency and the risks of SARS-CoV-2 infection and of severe disease in those infected. Author contributions All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Ariel Israel and Ilan Feldhamer. The first draft of the manuscript was written by Ariel Israel and Gil Lavie and all the authors commented on previous versions of the manuscript. All the authors read and approved the final manuscript. Funding None.
Declarations Conflict of interest None.
Human and animal rights statement and Informed consent This study was approved by the CHS Institutional Review Board (IRB) with a waiver of informed consent due to the anonymous nature of the data, approval number: COM-0046-20.
Consent to participate Not applicable.
Consent for publication Not applicable. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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