[Vitamin D and childhood disability: diseases of the musculoskeletal system and connective tissue in the Khanty-Mansi Autonomous Okrug - Ugra].

Vitamin D deficiency is more prevalent among children with musculoskeletal and connective tissue disorders (MSCTD), which plays a significant role in childhood disability, which ranks sixth in the structure of childhood disability in the Russian Federation. The aim of the research was to study of the relationship between the incidence of childhood disability associated with MSCTD and the state of vitamin D status of the population living in the territory of the Khanty-Mansiysk Autonomous Okrug - Ugra. Material and methods. A correlation analysis was carried out between the level of childhood disability (that arose in connection with MSCTD in children aged 0-17 years in the Khanty-Mansi Autonomous Okrug - Ugra in 2021) and the prevalence of severe vitamin D deficit [serum 25(OH)D <10 ng/ml] among the population (12 city and 5 district municipalities), using the INVITRO-Ural LLC database (31 595 anonymized measurements of vitamin D level in Ugra residents). In addition, a correlation analysis was conducted between the total incidence of certain types of MSCTD in the constituent entities of the Russian Federation and the geographical latitude of the administrative center of the subjects of the Federation. Results. In the Khanty-Mansi Autonomous Okrug - Ugra, the frequency of childhood disability resulting from MSCTD is associated with a statistically stable (p=0.01) directly proportional relationship with the prevalence of severe vitamin D deficit in the residents of the municipality territory. In the Russian Federation, the dependence of the general morbidity of MSCTD in children (arthropathy, juvenile arthritis, and damage to the tendon synovial membranes) is very stable (p<0.0001) directly proportional associated with the geographical latitude of the territory. This indicates the impact of reduced levels of ultraviolet radiation and, accordingly, the average blood level of vitamin D in the population high in latitudes, along with other reasons, on human health. Conclusion. Low levels of vitamin D have a negative impact on the activity of MSCTD in children and the associated disability. To justify the recommended daily dose and duration of vitamin D intake, which in some cases can reduce the activity of MSCTD, it is necessary to measure its initial level in the blood serum of patients at risk.