Trending Clinical Topic: Vitamin D and COVID-19

Ryan Syrek


November 06, 2020

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As researchers continue to explore its possible association with COVID-19, vitamin D once again emerged as a top trending clinical topic. A study published in The Journal of Clinical Endocrinology & Metabolism found that serum 25-hydroxyvitamin D [25(OH)D] levels were lower in hospitalized COVID-19 patients compared with population-based controls (see Infographic below).

These findings come after separate research found that patients hospitalized with COVID-19 who had sufficient vitamin D levels had significant reductions in severe outcomes and a lower risk for death compared with those who had insufficient levels. Yet another study found that individuals in the United States with sufficient vitamin D levels had as much as a 54% reduced risk of becoming infected with COVID-19.

Still, the exact nature of the relationship between vitamin D levels and COVID-19 remains unclear. Experts point to similar complicated findings seen with other diseases. Low levels of vitamin D have been reported in a wide variety of conditions, from multiple sclerosis to cancer, with little evidence that supplementation does much to prevent disease or control severity. However, a small randomized trial recently found that vitamin D may have helped reduce ICU admission among hospitalized patients with COVID-19 from 50% to 2%.

Whether vitamin D is beneficial in ICU outcomes in general remains uncertain. Last year, a trial found no statistical benefit when a 540,000 IU boost of vitamin D was administered to 2624 critically ill patients. Regardless, the potential benefit during the pandemic has prompted investigations of supplementation in key populations, such as residents of elder care homes. A study published in BMJ Nutrition, Prevention & Health found glaring gaps between recommendations for vitamin D supplementation and actual practice in this population. Because that group is at particular risk for severe outcomes associated with COVID-19, experts are calling for increased efforts to achieve adequate vitamin D levels. 

Researchers caution that vitamin D has not been established as clearly protective against contracting COVID-19 or preventing severe disease course. However, the possibility that a readily available supplement with few known significant adverse effects may be beneficial has captured wide attention, resulting in this week's top trending clinical topic.

Read more clinical information about COVID-19.


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