COVID-19: What is the evidence to support a role for vitamin D?


COVID-19: What is the evidence to support a role for vitamin D?

Vitamin D is one of the most beloved of vitamins, being the target of several studies and one of the most accessed topics on our PEBMED Portal. This vitamin and its metabolites play an important clinical role due to its interrelation with calcium homeostasis and bone metabolism, and it is also cited as an agent capable of bringing positive results in conditions related to immunity and respiratory infections.

During the pandemic, researchers questioned whether there was any relationship between the severity of Covid-19 and serum vitamin D levels (25OHD) in hospitalized patients. The study was published in The Journal of Clinical Endocrinology & Metabolism (JCEM) and we will bring the main points in this publication.

Vitamin D and Covid-19

This is a retrospective case-control study with 413 patients (216 patients with Covid-19 and 197 population controls). Serum levels of 25OHD were measured and the severity of Covid-19 was assessed in each participant.

In the group of patients with Covid-19, the mean 25OHD levels were 13.8 ± 7.2 ng / mL, compared to 20.9 ± 7.4 ng / mL in controls (p <0.0001). Vitamin D deficiency was found in 82.2% of cases of SARS-CoV-2 infection and 47.2% of population-based controls (p <0.0001).

Patients with vitamin D and Covid-19 deficiency had a higher prevalence of hypertension and cardiovascular disease, elevated serum levels of ferritin and troponin, as well as a longer hospital stay than those with serum levels of 25OHD ≥ 20 ng / mL. No causal relationship was found between vitamin D deficiency and Covid-19 severity.

It should be noted that these data should be evaluated with caution, since the behavior of vitamin D in inflammatory states usually raises some controversies: some defend the hypothesis that inflammation reduces the concentration of 25 (OH) D, while others believe that the increase Vitamin D level reduces inflammation.

In this study, we saw that patients with Covid-19 had a high prevalence of vitamin D deficiency, negatively correlated with ferritin and D-dimer (which increase in inflammatory states). However, the real relationship between vitamin D deficiency and the inflammatory issue is not clear, not least because the collection of serum vitamin D levels was made at admission, when the patient was already in the full inflammatory state, and vitamin D was not made available. basal.

Interestingly, the 25OHD concentrations in patients with Covid-19 who were supplementing vitamin D when they entered the study were lower than expected, supporting their behaviour as a negative acute-phase reagent. However, the number of patients with Covid-19 taking oral vitamin D supplements, nineteen in total, is too small to draw solid conclusions about their role in the clinical outcomes of the disease.

The study has other limitations, starting with those inherent in an observational study that does not allow establishing whether vitamin D is simply an exposure biomarker or an effect biomarker on the disease. In addition, the survey was conducted at a single Spanish health center and the data cannot be generalized.

It was concluded that patients with vitamin D levels below 25 nmol / L should receive supplementation in the dose necessary to reach values ​​above 25 nmol / L. To learn more about the study, check out the text here on the Portal.

Practical message:

  1. 25OHD levels are lower in hospitalized Covid-19 patients compared to population controls and these patients had a higher prevalence of disability.
  2. The study found no relationship between vitamin D concentration and disease severity.
  3. In practice, it is not possible to conclude the need for changes in the Covid-19 approach or supplementation of vitamins based on this study, since no causal relationship is established between hypovitaminosis D and risk / severity of infection.
  • José L Hernández, Daniel Nan, Marta Fernandez-Ayala, Mayte García-Unzueta, Miguel A Hernández-Hernández, Marcos López-Hoyos, Pedro Muñoz Cacho, José M Olmos, Manuel Gutiérrez-Cuadra, Juan J Ruiz-Cubillán, Javier Crespo, Víctor M Martínez-Taboada, Vitamin D Status in Hospitalized Patients With SARS-CoV-2 Infection, The Journal of Clinical Endocrinology & Metabolism,, dgaa733,
  • Waldron JL, Ashby HL, Cornes MP, et al. Vitamin D: a negative acute phase reactant. J Clin Pathol. 2013;66(7):620‐622.
  • Cannell JJ, Grant WB, Holick MF. Vitamin D and inflammation. Dermatoendocrinol. 2015;6(1):e983401. Published 2015 Jan 29. doi:10.4161/19381980.2014.983401
  • Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017;356:i6583. Published 2017 Feb 15. doi:10.1136/bmj.i6583