Severe acute respiratory syndrome coronavirus 2 (SARS-Co-V-2) has caused a global pandemic of coronavirus disease 2019 (COVID-19). Infected persons display varied symptoms ranging from mild to severe illness, even death. Yet, to date, the mechanisms underlying this variability are still poorly understood.  Studies have indicated a correlation between vitamin D deficiency and COVID-19 infection, suggesting that vitamin D supplementation could reduce COVID-19 infection risk and/or severity. However, the association between vitamin D status and COVID-19 incidence remains controversial.

A study conducted by Liming Cheng (Huazhong University of Science and Technology) and colleagues investigated whether vitamin D deficiency is associated with COVID-19 incidence and disease severity in Chinese people.  A cross-sectional study design was used involving 335 COVID-19 patients admitted to the hospital between February and March 2020. The study also included a healthy age- and sex-matched population of 560 individuals, who had blood vitamin D concentrations measured during the same period from 2018-2019. Vitamin D concentrations between the COVID-19 and 2018-2019 control group were compared.

Vitamin D concentrations were significantly lower among COVID-19 patients than the 2018-2019 controls.  Factors significantly associated with COVID-19 severity include being male, being 65 years of age and older, and having vitamin D deficiency.   In the COVID-19 group, 78% of patients were categorized as non-severe and 22% were categorized as severe.  Blood vitamin D concentrations in severe COVID-19 patients were lower than in non-severe patients. Study results showed that vitamin D deficiency was more common among patients with COVID-19 infection and particularly in those with severe illness.  While additional research is necessary, this study indicates that vitamin D deficiency could be a risk factor for SARS-Co-V-2 infection risk and severity.


Luo X, Lial Q, Li H, Cheng L. Vitamin D Deficiency is Associated with COVID-19 Incidence and Disease Severity in Chinese People. The Journal of Nutrition, Volume 151, Issue 1, January 2021, Pages 98–103,

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