By Seema Gupta, MD, MSPH

Clinical Assistant Professor, Department of Family and Community Health, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV

Dr. Gupta reports no financial relationships relevant to this field of study.

SYNOPSIS: Investigators found the relative risk of testing positive for COVID-19 was higher for patients who likely are vitamin D deficient.

SOURCE: Meltzer DO, Best TJ, Zhang H, et al. Association of vitamin D status and other clinical characteristics with COVID-19 test results. JAMA Netw Open 2020;3:e2019722.

Currently, there is a lack of evidence supporting any effective pharmacologic interventions that may help prevent COVID-19 infection. However, several agents are under investigation as potential therapeutic targets.1 Of these, vitamin D supplementation has been identified for its potential.2 Recent evidence suggests extra vitamin D can lower the incidence of acute respiratory infection and the severity of respiratory tract diseases in children and adults.

Along with maintaining normal levels of phosphorus and calcium in the blood, vitamin D is an immune system booster. Nevertheless, vitamin D deficiency is common, affecting 40% of the U.S. population, with higher rates among smokers, obese patients, and those with diabetes (three factors that put one at higher risk for contracting COVID-19).3 Deficiency also is more common among non-Hispanic African Americans and Mexican Americans. With winter approaching, more Americans will be confined to homes, significantly reducing sun exposure and potentially increasing the risk for vitamin D deficiency.

Meltzer et al evaluated 489 patients for vitamin D deficiency whose 25-hydroxycholecalciferol or 1,25-dihydroxycholecalciferol level was measured within a year before undergoing a test for COVID-19 from March 3 to April 10, 2020. The average patient age was 49 years, 75% were women, and almost 70% were nonwhite (primarily Black). Controlling for comorbidity and demographic indicators, the authors conducted a multivariable analysis to evaluate whether vitamin D status before a COVID-19 test was associated with testing positive.

Researchers found vitamin D-deficient patients (< 20 ng/mL) who were not treated were almost twice as likely (relative risk, 1.77; 95% CI, 1.12-2.81; P = 0.02) to test positive for COVID-19 vs. those with sufficient vitamin D status. The authors also found testing positive for COVID-19 was associated with increasing age up to 50 years (relative risk, 1.06; 95% CI, 1.01-1.09; P = 0.02) and non-white race (relative risk, 2.54; 95% CI, 1.26-5.12; P = 0.009). By considering possible connections between vitamin D levels and the risk of contracting COVID-19, the results of the Meltzer et al study suggest measuring vitamin D levels and treating deficiency can play a role in safeguarding patients.

COMMENTARY

The FDA granted an Emergency Use Authorization for remdesivir to be used to treat severe COVID-19 cases.4 Otherwise, no other FDA-approved drugs have shown efficacy and safety in trials. Researchers are searching for every available method to move new treatments to patients as quickly as possible. Concurrently, vitamin D deficiency remains a serious public health issue, with an estimated 1 billion people recording low vitamin D levels across all ages and ethnicities.5 The Meltzer et al study provides an initial assessment of the association of vitamin D deficiency with substantially higher risk of testing positive for COVID-19. Certainly, this should not be considered a panacea, since vitamin D deficiency could be associated with several chronic diseases. We need additional randomized clinical trials to further validate these findings.

Nevertheless, many Americans are vitamin D deficient, and diagnosing, treating, and correcting the condition is important. Further, this approach may add another arrow in the quiver of safe and cost-effective interventions to fight the pandemic globally.

REFERENCES

  1. Sanders JM, Monogue ML, Jodlowski TZ, Cutrell JB. Pharmacologic treatments for coronavirus disease 2019 (COVID-19): A review. JAMA 2020;323:1824-1836.
  2. Grant WB, Lahore H, McDonnell SL, et al. Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths. Nutrients 2020;12:988.
  3. Parva NR, Tadepalli S, Singh P, et al. Prevalence of vitamin D deficiency and associated risk factors in the US population (2011-2012). Cureus 2018;10:e2741.
  4. U.S. Food & Drug Administration. Coronavirus (COVID-19) update: FDA issues emergency use authorization for potential COVID-19 treatment. May 1, 2020.
  5. Holick MF, Chen TC. Vitamin D deficiency: A worldwide problem with health consequences. Am J Clin Nutr 2008;87:1080S-1086S.