Effect of Vitamin D deficiency on COVID-19 status: A systematic review

Abstract

BackgroundOne major micronutrient known to have a possible protective effect against COVID-19 disease is vitamin D. This systematic review sought to identify and synthesise available evidence to aid the understanding of the possible effect of vitamin D deficiency on COVID-19 status and health outcomes in COVID-19 patients.MethodsThree databases PubMed, ScienceDirect, and Google Scholar were searched systematically to obtain English language journal article published within 1/12/2019 and 3/11/2020. The search consisted of the terms (“Vitamin D,” OR “25□Hydroxyvitamin D,” OR “Low Vitamin D.”) AND (“COVID-19” OR “2019-nCoV” OR “Coronavirus” OR “SARS-CoV-2”) AND (“disease severity” OR “IMV” OR “ICU admission” OR “mortality” OR “hospitalization” OR “infection”). We followed the recommended PRISMA guidelines in executing this study. After going through the screening of the articles, eleven articles were included in the review.FindingsAlmost all the included studies reported a positive association between Vitamin D sufficiency and COVID-19 status and health outcomes. Vitamin D deficient patients (< 25 ng/mL) are 5.84 times [aOR=6.84, p=0.01] more likely to die from COVID-19 compared to the vitamin D sufficient people. Another study also found that Vitamin D deficiency is associated with higher risk of death with Hazard ratio (HR) 14.73, p<0.001. Vitamin D deficient (<12 ng/mL) people were 2.2 times [aOR=3.2, p=0.07] more likely to develop severe COVID-19 after adjusting for age, gender, obesity, cardiac disease, and kidney disease compared to the vitamin D sufficient people. One study found that after controlling for confounders, patients with low 25(OH)D (<30 ng/mL) level are more likely [aOR=1.45, p=<0.001] to be COVID-19 infected compared to the patients with 25(OH)D level >=30 ng/mL.ConclusionFindings from the study included suggest Vitamin D may serve as a mitigating effect for covid-19 infection, severity and mortality. We recommend the need to encourage people to eat foods rich in vitamin D such as fish, red meat, liver and egg yolks whiles at the same time providing vitamin D supplements for individuals with COVID-19 in order to boost their immune systems.