SIGNIFICANCE OF VITAMIN D DEFICIENCY IN THE FORMATION OF BRONCHIAL OBSTRUCTIVE SYNDROME IN CHILDREN

The literature published over the last decades indicates increasing awareness of vitamin D's multidirectional action in the human body. Evidence from large scale studies contributed to the understanding of vitamin D deficiency being a significant risk factor for many diseases. Receptors to vitamin D (VDR) are identified in more than 40 target tissues. Vitamin D may modify immune function, cell proliferation, differentiation and apoptosis. Vitamin D deficiency has been associated with numerous consequences for health, including rickets in children or osteomalacia in adults, increased risk of cancer, autoimmune diseases, infectious diseases, type 1 and type 2 diabetes mellitus, arterial hypertension, cardiovascular pathology and other diseases. Vitamin D regulated genes code for antimicrobial peptides providing protection against bacteria, viruses and fungi. The role of vitamin D deficiency in the predisposition of children to frequent respiratory diseases including those with broncho-obstructive syndrome has been actively studied in recent decades. To date, it has been proven that children with vitamin D deficiency have a greater risk of respiratory infections. It was demonstrated that administration of vitamin D to children with recurrent wheezes as adjuvant therapy in parallel with inhalation glucocorticoids, reduces the risk of exacerbation of wheezing caused by respiratory infections. However, antenatal hypovitaminosis D prophylaxis does not affect the frequency of this pathology. Vitamin D status is estimated by blood concentration of 25(OH)D. Currently, the prevalence of vitamin D deficiency in the population reaches an epidemic level, incl. in Russia. The results of a multicentre study «Rodnichok» showed insufficient vitamin D levels in 48% and the deficit in 90.8% toddlers in different cities. According to numerous studies, the use of the recommended preventive doses of vitamin D is insufficient to implement the «non-classic» functions of vitamin D. Thus, to date, the understanding of the role of vitamin D in the body has significantly expanded, but the possibility of using vitamin D in a complex of preventive measures and adjuvant therapy infections with wheezing, requires further scientific research.