Role of vitamin D in severe outcomes of COVID-19: A systematic: review and meta-analysis

There are contradictory information regarding the Vitamin D impact on the COVID-19 pandemic. The current meta-analysis was conducted aiming to clarifying the relation between severe outcomes of Covid-19 and vitamin D. We searched electronic databases, such as Web of Science, Scopus, and PubMed until October 16, 2020, and "Vitamin D” AND “COVID‐19” we’re used as keywords without any time limitation. The relationship between severe outcomes of covid-19 and vitamin d levels was calculated as hazard ratio (HR) and odds ratio (OR).  Results were combined using a random-effect meta-analysis. Ten observational surveys were implemented including 359,819 participants. As shown by Meta-analysis, subjects with vitamin D deficiency (serum 25-(OH)-D levels <20ng/mL) encountered a considerably higher risk of death (HR) = 1.93, (95% CI; 1.29 to 2.88). Moreover, the risk of severe outcomes of disease significantly increased with vitamin D insufficiency (VID) (OR) = 2.33, (95% CI; 1.52 to 3.59) in COVID-19 patients. This meta-analysis showed a negative relationship between vitamin D and the higher risk severity of disease and death from COVID-19 patients. However, despite interventional studies being required to confirm this effect, taking vitamin D may be recommended to prevent COVID-19.