Contrary to Earlier Research, Vitamin D May Not Protect Against COVID-19

Observational studies have suggested that elevated vitamin D levels may protect against COVID-19. However, these studies were inconclusive and may be confusing. A study published in PLOS Medicine by Guillaume Butler-Laporte and Tomoko Nakanishi at McGill University in Quebec, Canada, and colleagues suggests that genetic evidence does not support vitamin D as a protective measure against COVID-19.

Vitamin D’s ability to protect against severe COVID-19 disease is of great interest to public health experts, but has limited supporting evidence. To assess the relationship between vitamin D levels and COVID-19 sensitivity and severity, researchers conducted a Mendelian randomization study with genetic variants strongly associated with increased vitamin D levels. The authors analyzed genetic variants of 4,134 subjects with COVID-19 and 1,284,876 without COVID-19 from 11 countries to determine whether genetic predisposition to higher vitamin D levels was associated with less severe disease outcomes in people with COVID-19.

The results showed no evidence for an association between genetically predicted vitamin D levels and COVID-19 sensitivity, hospitalization, or severe illness, suggesting that increasing circulating vitamin D levels through supplementation could increase the COVID-19 results in the overall population may not improve. However, the study had several important limitations, including that the study did not include individuals with vitamin D deficiency, and it remains possible that truly deficient patients may benefit from supplementation for COVID-19-related protection and outcomes. In addition, the genetic variants were only obtained from individuals of European descent, so future studies will be needed to determine the relationship to COVID-19 results in other populations.

According to the authors, “Vitamin D supplementation as a public health measure to improve outcomes is not supported by this study. Most importantly, our results suggest that investment in other therapeutic or preventive avenues should be prioritized for randomized clinical trials of COVID-19. “

Dr. Butler-Laporte notes, “Most vitamin D studies are very difficult to interpret because they cannot be corrected for the known risk factors for severe Covid-19 (eg, older age, hospitalization, chronic disease) which are also predictors. are of a low vitamin D value. Therefore, the best way to answer the question of the effect of vitamin D is through randomized trials, but these are complex, labor-intensive and take a long time during a pandemic. Mendelian randomization can provide more clear insights into the role of risk factors such as vitamin D, as they can reduce the potential bias of associated risk factors such as institutionalization and chronic disease. In the past, Mendelian randomization has consistently predicted results from large, expensive, and timely vitamin D studies. Here, this method does not show clear evidence that vitamin D supplementation would have a major effect on Covid-19 outcomes. “

Reference: “Vitamin D and COVID-19 Sensitivity and Severity in the COVID-19 Host Genetics Initiative: A Mendelian Randomization Study” by Butler-Laporte G, Nakanishi T, Mooser V, Morrison DR, Abdullah T, Adeleye O, et al. June 1, 2021, PLOS Medicine.
DOI: 10.1371 / journal.pmed.1003605

Funding: The Richards research group is supported by the Canadian Institutes of Health Research (CIHR: 365825; 409511), the Lady Davis Institute of the Jewish General Hospital, the Canadian Foundation for Innovation, the NIH Foundation, Cancer Research UK, Genome Québec, the Public Health Agency of Canada and Fonds de Recherche Québec Santé (FRQS). GBL is supported by the CIHR and a joint grant from the FRQS and the Québec Ministry of Health and Social Affairs. TN is supported by Research Fellowships of Japan Society for the Promotion of Science (JSPS) for Young Scientists and JSPS Overseas Challenge Program for Young Researchers. JBR is supported by a FRQS Clinical Research Scholarship. Support from Calcul Québec and Compute Canada is recognized. TwinsUK is funded by the Welcome Trust, Medical Research Council, European Union, the National Institute for Health Research (NIHR) funded BioResource, Clinical Research Facility and Biomedical Research Center located at Guy’s and St Thomas’ NHS Foundation Trust in partnership with King’s College London. VM is supported by the Canada Excellence Research Chair Program. The funders had no role in the design of the research, the collection and analysis of data, the decision to publish or the preparation of the manuscript.