Association between vitamin D hypovitaminosis and severe forms of COVID-19

OBJECTIVE: Hypovitaminosis D may be associated with an increased susceptibility to infection, more severe COVID-19 forms, and a higher risk of death. The objective of this study was to investigate any possible connections between vitamin D status [as measured by serum 25-hydroxyvitamin D (25(OH)D) levels] and COVID-19 severity. PATIENTS AND METHODS: In 2021, a cross-sectional study of consecutive adult COVID-19 patients was conducted. Anthropometric data, comorbidities, hospital setting, length of stay, respiratory support, outcome data, and vitamin D status were all evaluated. RESULTS: The length of hospitalization among participants (n = 74; mean age 57.64 +/- 17.83 years, 55.4% male) was 18.58 +/- 10 days, the majority of the hospital setting was a medical ward (67.6%), and the respiratory support in the form of mechanical ventilation was represented by 12.2%. Hypertension (54.1%), obesity (64.9%), and overweight (64.9%) were the most common cardiometabolic risk factors. In the study group, 44.6% of participants had severe vitamin D deficiency (< 30 nmol/l), while 8.1% had vitamin D insufficiency (50 -74.9 nmol/l). Furthermore, patients with severe COVID-19 (semi-intensive care unit, intensive care unit) had significantly lower serum 25(OH)D levels (32.9 vs. 20.5 nmol/l; p = 0.007). Participants with severe vitamin D deficiency were older and had more prevalent hypertension, requiring mechanical ventilation; 24.2% experienced a fatal outcome. CONCLUSIONS: Severe vitamin D deficiency may contribute significantly to the influence of other cardiometabolic risk factors in COVID-19.