LAUSR

The article presents the analysis of vitamin D levels in children of various age groups residing in Moscow and assesses the seasonality of vitamin D variations in this population group. In this work, the results of 25 (ОН) D level measurement in 1041 children in the age from 1 month to 18 years collected in the period since 2012 to 2015 have been analyzed. In accordance with the analysis, in spite of the age, the high percentage of vitamin D insufficiency was detected among children in Moscow. The generally accepted optimum level of vitamin D metabolite – calcidiol in blood (>30 ng/ml) was observed only in the small part of the study participants (26%), while the larger part (74%) had the insufficient level of vitamin D of various intensity: 28% - insufficiency (20-29 ng/ml), 33% - deficiency (<20 ng/ml), 13% - severe deficiency (<10 ng/ml). With the age, the insufficiency level was more pronounced. The seasonality analysis showed the significant difference of vitamin D level between summer and winter seasons (p=0.01). The greatest decrease of vitamin D levels was observed in winter (median level of 25(ОН)D 17.0 (11.0; 25.0) ng/ml). In summer months, the relative calcidiol gain was fixed (median – 22.9 (18.0; 33.0) ng/ml) which, however, did not achieve the normal level. Children and, in particular, adolescents residing in Moscow need year-round hypovitaminosis D prophylaxis with cholecalciferol products.