Trending Clinical Topic: Vitamin D

Ryan Syrek


August 07, 2020

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New findings about the role of vitamin D in various conditions, along with recent guidance from medical societies about vitamin D in the era of COVID-19, resulted in this week’s top trending clinical topic.

Results of a study published online in the FEBS Journal showed that low plasma vitamin D levels are an independent risk factor for COVID-19 infection and hospitalization (see Infographic below). The large, population-based study found that a higher proportion of patients who tested positive for COVID-19 had low plasma 25(OH)D concentrations, about 90%, vs 85% of participants who tested negative.

The study also linked low plasma vitamin D levels to an increased likelihood of hospitalization for COVID-19 infection. Researchers say that these findings should prompt physicians to regularly monitor patients' vitamin D levels, in order to keep them in the optimal range for overall health and to potentially aid in an immune response to COVID-19.

In terms of specific guidance, six medical societies from around the world recently released joint recommendations that emphasize the importance of individuals obtaining the daily recommended dose of vitamin D during the pandemic. The American Society for Bone and Mineral Research, the Endocrine Society, and the American Association of Clinical Endocrinologists, among others, issued "Joint Guidance on Vitamin D in the Era of COVID-19."

Central to the guidance is the recommendation to directly expose the skin to sunlight for 15-30 minutes per day, while taking care to avoid sunburn. They also noted that supplementation of 400-1000 IU daily may help keep levels in the optimal range, especially as outside activity declines given the continued spread of COVID-19.

Recent studies have also examined the role of vitamin D in other conditions. Research published in the journal Cancer showed that taking vitamin D before starting immune checkpoint inhibitor (ICI) therapy decreased the risk for treatment-related colitis. ICIs can dramatically improve outcomes for certain patients with cancer but can also cause serious inflammatory reactions and immune-related adverse events. The most frequent and severe of these adverse reactions is colitis. Encouragingly, the study found that vitamin D use was linked to a 65% decreased odds of developing ICI colitis.

A separate study out of the United Kingdom found that higher serum vitamin D concentrations are nonlinearly associated with a lower risk for all-cause, cardiovascular disease, and cancer mortality. Findings from more than 365,000 participants suggest that thresholds of 45-60 nmol/L may represent a potential target to reduce the risk for premature death, which needs to be confirmed in future randomized controlled trials.

From its role in COVID-19 to its relationship to other serious conditions, vitamin D remains a key focus of evolving research, which helped it to become this week's top trending clinical topic.

Take a short quiz about vitamin D supplementation and deficiency.


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