| Abstract: | Coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic1]. Primary prevention, which is aimed at delaying disease onset by modulating modifiable risk factors, has been proposed to address the global challenge posed by COVID-19.
Vitamin D plays a critical role in the immune system, and vitamin D deficiency is a risk factor for several adverse health outcomes, such as cancer, cardiovascular diseases, metabolic disorders, infectious diseases, and autoimmune diseases. Some studies have shown that low 25 hydroxyvitamin D (25OHD) concentrations are associated with a high risk of COVID-192], but other studies have found no association3]. Therefore, the association between 25OHD concentrations and the risk of COVID-19 has not been established. The above studies were observational, and traditional epidemiological studies are vulnerable to reverse causality and residual confounding. |
