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An Evaluation of Serum 25-Hydroxy Vitamin D Levels in Patients with COVID-19 in New York City

Take Home Message

After adjusting for demographic variables and comorbidities, this retrospective analysis of COVID-positive patients in New York City, shows a significant association between low 25(OH)D levels and an increased likelihood of need for oxygen support. 


Four-hundred thirty-seven adult COVID-19 patients within the Mount Sinai Health System (New York City ) who had serum 25-hydroxy vitamin D levels [25(OH)D] drawn within the three months preceding their COVID-19 diagnosis. 

Length of Study

Between March 1, 2020 and May 8, 2020 



  • Included in the study were 437 COVID-19 positive patients with 25(OH)D measurements recorded in the prior 3 months.  
  • The overall population was older [median, 67 years; range, 56-79 years] with 52% (227/437) women and the main comorbidities being hypertension (68%), diabetes (45%), coronary artery disease (30%) and malignancy (24%).  
  • There were 177 patients classified as vitamin D deficient (<50 nmol/L) compared to 260 patients who were vitamin D sufficient (³50 nmol/L). More males were vitamin D deficient compared to vitamin D sufficient (97, 55% vs 113, 43%, p.0.02) as were patients with chronic kidney disease (49, 28% vs 44, 17%, p.0.008).  
  • Deficient plasma 25(OH)D levels (<20 ng/ml) were associated with an increased likelihood of oxygen support [OR:2.23 (95% CI: 1.46–3.44, p.0.0002)] from COVID-19 when demographic variables and comorbidities were considered 
  • Deficient plasma 25(OH)D levels were not independently associated with 90-day mortality or risk of hospitalization.  
  • Hospitalization rates (98%), oxygen support (93%) and mortality rates (49%) were highest in patients who had 25(OH)D levels less than 10 ng/ml when compared to other 25(OH)D levels. 

Things to Keep in Mind

  • Several demographic variables were not assessed and therefore not controlled, including nursing home residency or bed bound status; socioeconomic status; and genotype and/or condition that impairs vitamin D metabolism such as medication, malnutrition or bariatric surgery.  
  • This study was retrospective in nature.
  • There was no comparison to healthy patients who did not have COVID-19 disease, but also had serum 25(OH)D levels. Therefore, it is unknown the protective benefits vitamin D has on obtaining the disease.  
  • Intensive care unit (ICU) admission was not evaluated, as this data point was difficult to gather as many of the medical center’s medicine wards became ICUs during the pandemic. 
  • The authors did not set mortality at 15-day mortality or 30-day mortality due to the small sample size, and the extended hospital stays the patients were experiencing at the medical center. The addition of patient data from the second wave of COVID-19 infections seen during Fall 2020 would increase the sample size and robustness of the data set. 
  • There is no consensus on the cutoff of vitamin D sufficiency. The Institute of Medicine (IOM) defines vitamin D deficiency as serum 25(OH)D <50 nmol/L, yet many studies utilize different cutoffs. 

Author’s Conclusions

Serum 25-hydroxy vitamin D levels may affect the need for oxygen support therapy in patients with COVID-19. This association was preserved after adjusting for demographic variables and comorbidities.

Study Design

  • This was a retrospective, observational, cohort study of patients with COVID-19 disease within the Mount Sinai Health System 
  • Adult patients were included if they were positive for COVID-19 via polymerase chain reaction (PCR) testing during the study period and had a serum 25(OH)D level measured within the three months prior to their positive COVID-19 test, or on admission to the hospital.  
  • Patients were compared based upon their serum 25(OH)D and categorized as: deficient (<50 nmol/L) or sufficient (³50 nmol/L).  
  • Patient characteristics including demographics, comorbidities and clinical outcomes were obtained from the Mount Sinai Data Warehouse and confirmed by manual chart review.
  • The primary endpoints were hospital admission, need for oxygen support, and mortality. The mortality endpoint was defined as 90-day mortality documented from the first positive COVID-19 test. Oxygen support was defined as the need of invasive mechanical ventilation, noninvasive ventilation (i.e. non-rebreather mask, venturi, high flow nasal cannula) or nasal cannula therapy. 


Gavioli, E. M., Miyashita, H., Hassaneen, O. and Siau, E. (2021) ‘An Evaluation of Serum 25-Hydroxy Vitamin D Levels in Patients with COVID-19 in New York City’, J Am Coll Nutr, pp. 1-6.

View Full Abstract

Research Summaries

Changes in 25‐hydroxyvitamin D levels post‐vitamin D supplementation in people of Black and Asian ethnicities and its implications during COVID‐19 pandemic: A systematic review

Changes in 25‐hydroxyvitamin D levels post‐vitamin D supplementation in people of Black and Asian ethnicities and its implications during COVID‐19

Vitamin D insufficiency in COVID-19 and influenza A, and critical illness survivors: a cross-sectional study

Take Home Message Vitamin D deficiency/insufficiency was present in majority of hospitalized patients with COVID-19 or influenza A and correlated with severity and persisted in critical illness survivors at concentrations expected