[SARS-CoV-2 morbidity depending on vitamin D status]

The association between vitamin D deficiency and the severity of COVID-19 is currently being actively discussed around the world.

The aim of this study was to assess the prevalence of vitamin D insufficiency and deficiency and compare it with the incidence rates of SARS-CoV-2 in eight Federal Districts of the Russian Federation.

We included 304,564 patients (234,716 women; 77,1%) with serum 25(OH)D levels results performed September 2019 through October 2020.

Only 112,877 people (37.1%) had a normal serum 25(OH)D level, others had a deficiency. Vitamin D insufficiency and deficiency was presented with the same frequency in women and men, and no differences were found depending on the geographical location and age in subjects from 18 to 74 years old. However, subjects over 75 years more often had vitamin D deficiency, while subjects under 18 years had normal levels in over 50% cases. In addition, 21,506 patients were tested for SARS-CoV-2 by PCR with further comparison of results with serum 25(OH)D level. The SARS-CoV-2 positivity rate was detected in 3,193 subjects, negative in 18,313. There were no differences in the morbidity in a vitamin D deficiency and a normal level. Thus, 14.8% subjects had positive PCR rates among vitamin D deficiency patients (4,978 tests), 14.9% when 25(OD)D level was from 20 to 30 ng/ml (7,542 tests), 15.0% among those who had 25(OH)D 30- 50 ng/ml (6,622 tests), and 13.9% when vitamin D was more than 50 ng/ml (4,612 tests).

There was no association between the COVID-19 incidence and vitamin D status in different regions of Russia. Although the nutrient deficiency persists in all regions and is most often diagnosed in people over 75 years old.