Climategeographic and seasonal specific features of vitamin D (25(OH)D) status in patients in Russia

Objective: to assess the climatic and seasonal characteristics of vitamin D status in the population of different cities of the Russian Federation.Material and methods. The study was conducted from September 2014 to June 2018. Surveyed 104321 serum of patients (one hundred four thousand three hundred twenty-one) of the 105 cities of the Russian Federation. Of them women: 80738, which was 77.4% of men 23583 - 22,6%. To determine the concentration of 25(OH)D in serum electrochemiluminescent method was used. The analysis was performed on the automatic analyzer Cobas 8000 (Switzerland).Results. The concentration of calcidiol (25 (OH) D) in patients living in cities located in different climategeographic regions of the Russian Federation varied from 3.0 to 536.10 ng/ml. the Average concentration of 25(OH) D was the lowest in Makhachkala (19.26 ± 0.53 ng/ml), the maximum in Surgut (42.5 ± 0.44 ng/ml). Only 18% of the cities average concentration of 25(OH)D reached the lower limit of positive level of 30 ng/ml. More than half of the patients (60,1-81.7 per cent) of all regions, the concentration of 25(OH)D was below normal - less than 30 ng/ml. Vitamin d deficiency (