[Long-term and seasonal dynamics of vitamin D supply indicators for the population of the Western Siberia region].

Despite the active study of vitamin D, today the problem of its insufficient supply remains relevant both in Russia and throughout the world. In our country, the situation is affected by the geographical, climatic, as well as ethnic and cultural characteristics of each region. It is of interest to assess the temporal and territorial characteristics of the population's sufficiency. The purpose of the study was to analyze long-term and intra-annual dynamics of vitamin D status among residents of the Western Siberia region for the correction of prevention programs. Material and methods. An analysis of the vitamin D status in the residents of Western Siberia, located at 53-58° northern latitude, was carried out. The study was carried out among adults aged 18 to 93 years, the median age was 49 [36; 62] years (n=2586). Vitamin D status was determined by the level of 25(OH)D in venous blood serum. The determination was carried out using chemiluminescence immunoassay. Study period - 2017-2023. Results. The results of the study demonstrate an improvement in vitamin D status in residents of Omsk region in dynamics. This is manifested in a decrease in the proportion of people with deficiency from 41.6±1.6% in 2017-2019 to 33.5±1.7% in the period 2022-2023 (p<0.001) and an increase in the proportion of the examined with optimal sufficiency from 26.7±1.4 to 38.2±1.8% (p<0.001). An obvious dependence of vitamin D serum level on the month of the year has been established: low values were noted in the winter and spring months with a minimum in March (18.4 [12.1; 27.9] ng/ml). Conclusion. Seasonal variations are an important factor influencing 25(OH)D blood level. The decrease in the proportion of individuals with deficiency states most likely indicates an increase in vitamin D intake from food or supplements, which requires further study.