Relation between Vitamin D and COVID-19 in Aged People: A Systematic Review.

Background: Vitamin D has diverse and extensive effects on the immune system, including activating innate immunity and reducing the overactive adaptive immune response. A systematic review was performed to identify and synthesize the best available evidence on the association between vitamin D level and risk of COVID-19, adverse outcomes and possible benefits of supplementation in aged 60 years or over.

Methods: A literature search was performed in PubMed© and Scopus© for all publications from inception published before 15 March 2021.