Vitamin D levels and COVID-19 severe pneumonia: a prospective case-control study

Introduction: The hypothesis that a low vitamin D levels is associated with a higher risk for severe COVID-19 has not been completely proven, especially with severe pneumonia. Objective: The goal of this study was to confirm the link between vitamin D levels and COVID-19 severe pneumonia. Methods: This prospective case-control study involved 307 patients who developed severe SARS-CoV-2 pneumonia and were hospitalized in an intensive care unit. Age- and sex-matched controls (307) were selected from the same population; 307 patients with mild to moderate forms of COVID-19 who were not hospitalized. Vitamin D levels were assessed during the duration of the disease. Results: The mean vitamin D level was lower in the severe COVID-19 pneumonia group as compared to the control group; 26.8 7.6 ng/mL vs 28.6 7.4 ng/mL, p<0.002. There were more patients with a sufficient level of vitamin D in the control group as compared to the control group; 127 (20.6%) vs 89 (14.5%), p<0.001. Multivariable analysis showed that a deficient vitamin D level was associated with a higher risk for severe COVID-19 pneumonia (OR=3.0; 95% CI: 1.79, 5.10CI), p<0.001. Conclusion: A sufficient vitamin D level is linked to a lower risk of COVID-19 severe pneumonia.