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A meta-analysis of vitamin D levels and COVID-19 infection


Vitamin D has been the subject of heavy investigation in the context of COVID-19 infection, severity, and mortality. Is there a relationship between vitamin D and COVID-19 status?

The study

This meta-analysis included 10 case-control studies that investigated the relationship between blood vitamin D levels and COVID-19 infection in a total of 361,934 participants. The studies were conducted in North America, Europe, and Asia, and the average of participants in most studies was over 50.

The results

Having vitamin D insufficiency (29–21 ng/mL) or deficiency (20 ng/mL) was associated with about a 43% increase in odds of COVID-19 infection, although there was a high degree of heterogeneity among studies. Additionally, participants with COVID-19 tended to have somewhat lower vitamin D levels than participants without COVID-19. Overall, these findings do suggest that vitamin D levels can be used to gain information about COVID-19 status, but given the observational nature of the included studies, it still isn’t clear whether this relationship is causal.

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