Vitamin D Deficiency and Comorbidities as Risk Factors of COVID-19 Infection: A Systematic Review and Meta-Analysis

Low serum vitamin –D levels were significantly associated with the risk of COVID-19 infection. This relationship was stronger in female than in male COVID-19 patients.

• Significantly lower vitamin D levels were found in COVID-19-positive patients but with variation by study design with the case control being the only design that showed significance 
• This relationship was more prominent in female patients  than in male patients. 
• Male patients showed higher odds of having low vitamin D than female patients   
• Comorbidities showed inconsistent, but generally non-significant, associations with COVID-19 infection. 

Sixteen  studies were included including 5377 COVID-19 positive subjects.

• There were discrepancies in the number and sample size of the included studies, leading to some instances of large variance in effect size estimates. 
• The authors found significant heterogeneity. They used random-effects models to address heterogeneity, but it may have affected the strength and extrapolation of conclusions. 

Low serum vitamin D levels were significantly associated with a high risk of acquiring COVID-19 infection; however, the results varied by study design. This relationship was more prominent in female patients than in male patients. Limited evidence was found regarding relationships between reported comorbidities and COVID-19 infection; therefore, large population-based studies are recommended to establish any association. Vitamin D-deficient individuals should be provided special attention. Vitamin D levels can be monitored and supplementation of vitamin D could be considered in patients to improve their recovery if they contract COVID-19. Vitamin D levels can be monitored and supplementation of vitamin D could be considered in patients to improve their recovery if they contract COVID-19.

• This meta-analysis investigated the association of lower levels of vitamin D and comorbidities with the risk of COVID-19 infection. 
• The search was conducted using MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for articles published until August 20, 2021. 
• Observational, cohort and case-control studies that evaluated serum levels of vitamin D in COVID-19-positive and COVID-19-negative patients were included. 

Mishra P, Parveen R, Bajpai R, Agarwal N. Vitamin D Deficiency and Comorbidities as Risk Factors of COVID-19 Infection: A Systematic Review and Meta-analysis. J Prev Med Public Health. 2022 Jul;55(4):321-333. doi: 10.3961/jpmph.21.640. Epub 2022 Jun 13. PMID: 35940187; PMCID: PMC9371781.