Review the Research
Get summaries of key research on vitamin D and COVID-19
The relationship between 25(OH) vitamin D levels and COVID-19 onset and disease course in Spanish patients.
Take Home Message
In a retrospective observational study of 1549 COVID-19 patients hospitalized in Madrid, Spain from March 12, 2020 to May 20, 2020, vitamin D deficiency was correlated with an increased risk of hospital admission and the need for critical care. However, no clear relationship was found between vitamin D levels and mortality.
- Of the hospitalized COVID-19 patients, 112 were admitted to the ICU and 324 experienced a fatal outcome.
- More patients hospitalized for COVID-19 (66%, n=1017) had low baseline levels of serum 25(OH)D (<20 ng/ml) than individuals in the general Spanish population (45%, n=815).
- An analysis by age group revealed that COVID-19 patients between the ages of 20 and 80 years old had significantly lower vitamin D levels than those of the general population.
- COVID-19 patients admitted to the ICU tended to have statistically lower levels of serum 25(OH)D (14.2±4 ng/ml or 35.5±18.5 nmol/l) than COVID-19 patients receiving normal inpatient care (18.4±12.1 or 46±30.3 nmol/l); if patients were stratified by serum 25(OH)D levels, the rate of ICU admission was statistically higher among patients with vitamin D deficiency.
- COVID-19 ICU admission was significantly related to sex (higher rates in men) and advanced age.
- Vitamin D levels continued to show a statistically significant relationship with COVID-19 ICU admission rates, even when adjusted for sex and age.
- Patients that died of COVID-19 tended to have lower levels of serum 25(OH)D than members of the general population of the same age. However, no significant differences were found between the levels of serum 25(OH)D of COVID-19 patients who survived the disease and those who did not, even when the data were adjusted for age and sex.
Enrolled in this study were 1549 patients in Madrid, Spain (835 men, 53.9%; 714 women, 46.1%) who were diagnosed with SARS-CoV-2 infection detected by polymerase chain reaction (PCR) or RT-PCR. The mean age was 70 years, ranging from 21-104 years.
Things to Keep in Mind
- The observational design of the study cannot substantiate causality between serum vitamin D levels and severity of COVID-19 disease.
- Comorbidities were not adjusted for but have been shown in other studies to alter COVID-19 patient outcomes.
- Historical serum 25(OH)D values for the Spanish population were used as the control group. A more accurate comparison would have been COVID-19 negative outpatients or hospitalized patients at the same institutions and during the same study period to account for seasonal variations.
- This study had a small sample size of COVID-19 patients admitted to the ICU. A larger sample size would increase the power and robustness of the study.
Vitamin D deficiency in patients with COVID-19 is correlated with an increased risk of hospital admission and the need for critical care. We found no clear relationship between vitamin D levels and mortality.
- This was a retrospective observational study of 1549 COVID-19 patients who were admitted to one of several Quironsalud Hospitals in Madrid, Spain from March 12, 2020 to May 20, 2020.
- Serum 25(OH)D levels were measured at the time of admission, but prior treatments and comorbidities were not evaluated in the enrolled patients.
- Low serum 25(OH)D levels were defined as <20 ng/ml (<50 nmol/l).
- The serum 25(OH)D levels of COVID-19 positive patients were compared to serum 25(OH)D values published for the general Spanish population.
- Mean serum 25(OH)D levels were compared between COVID-19 patients admitted to the ICU and those not requiring ICU care. A similar analysis was performed to determine whether the COVID-19 mortality rate was related to low serum 25(OH)D levels.
Diaz-Curiel M, Cabello A, Arboiro-Pinel R, Mansur L, Heili-Frades S, Mahillo-Fernandez I, Herrero-González A, Andrade-Poveda M. The relationship between 25(OH) vitamin D levels and COVID-19 onset and disease course in Spanish patients. J Steroid Biochem Mol Biol. 2021 Jun 3:105928. doi: 10.1016/j.jsbmb.2021.105928. Epub ahead of print. PMID: 34091026; PMCID: PMC8180342.