Background. In addition to regulating mineral metabolism and bone metabolism, vitamin D is important for supporting structure and other types of connective tissue. Studies have shown the role of vitamin D deficiency in the pathogenesis of systemic inflammatory diseases of the connective tissue, autoimmune diseases. The results of studying this problem in countries with different geographic locations are also of interest.

Aim. Comparative assessment of vitamin D status of patients with systemic inflammatory diseases of the connective tissue and patients without rheumatic diseases.

Materials and methods. This cross-sectional observational study analyzed the vitamin D supply of the following groups: patients with systemic inflammatory diseases of the connective tissue who do not take vitamin D preparations, patients with systemic inflammatory diseases of the connective tissue who take vitamin D preparations, and «conditionally healthy» individuals, without complaints, examined in the same period comparable in gender and age with the patients of the main group. The vitamin D supply of the studied patients was determined by the level of the content of the vitamin D metabolite calcidiol in the blood serum 25 (OH) D. Study period: January 2019 to December 2020.

Results. The data of 625 patients who applied to the Osteoporosis Prevention and Treatment Center for the specified period were analyzed. Among the patients of the main group who did not take vitamin D preparations, a deficiency was revealed in 54.7% of the examined, the optimal provision in 11.2%. The median serum 25 (OH) D concentration was in the range of 19.0 ng / ml deficiency. The study participants belonging to the comparison group had a deficit in 44.1% of cases and an optimal provision in 21.5%. The study group of the main group receiving vitamin D preparations had the maximum number of individuals with the optimal status – 37.0%, while a significant part of the examined had a deficit of varying severity – 29.1%. In addition, this group was characterized by the highest median serum metabolite 25 (OH) D – 26.0 ng / ml.

Conclusion. A comparative analysis of the D-vitamin status of patients with systemic inflammatory diseases of the connective tissue and «conditionally healthy» individuals without complaints was carried out, which made it possible to establish differences in the provision depending on the existing disease, as well as depending on the therapy with vitamin D preparations. a lower supply of vitamin D than control group «healthy» individuals. In the case of receiving vitamin subsidies, the provision with it in the group of patients was statistically significantly higher, both in comparison with patients who did not take the vitamin, and in comparison, with individuals from the comparison group.

Diabetes mellitus (DM) type 2 is reported to be among the most common diseases both worldwide and in Russian Federation, whereby chronic implications that develop under hyperglycemia pose a serious socioeconomic problem. Besides of classic microvascular complications like diabetic retinopathy, nephropathy and polyneuropathy it’s recently worthy of note the presence of high fracture risk in DM type 2 even in normal bone mass density, known as “diaporosis” or “diabetoporosis” considered as another DM complication. It is well known that osteoporosis is reported to be widespread disease as same as DM type 2 and likewise is a widely abundant in older age that makes their combination is really possible in a single patient. Taking into account high social value and disability due to osteoporotic fractures and chronic DM type 2 complications it becomes necessary to continue physiologic and biochemical basis investigations of bone formation and remodeling and pathogenesis of osteoporosis development in the context of chronic hyperglycemia. One of the fairly new factors which the experts believe it is link between impaired glucose metabolism and bone remodeling is osteocalcin which concentration is dependent on vitamin K2 maintenance considered as a potential agent in osteoporotic fractures prevention. In this review current information on vitamin K2 influence on bone status and possibility of using this nutrient in clinical practice in the focus on patients with DM will be covered.

McCune Albright syndrome (MAS) is a rare disorder caused by a sporadic postzygotic mutation in the GNAS gene, which encodes the alpha subunit of the Gs signaling protein.

Permanent activation of the Gs protein leads to uncontrolled production of intracellular cAMP, and autonomic hyperfunction of target organs. Estimated prevalence of the disease – 1\100000 to 1\1000000. For the first time, MAS syndrome was described in 1936 as a triad of symptoms – fibrous dysplasia of bones (FD), spots on the skin of the color of «coffee with milk» and premature sexual development. However, it is now known, that the phenotype of the disease is much more complex. This is primarily due to the mosaic type of mutation in the GNAS gene, which determines a wide range of clinical manifestations, and presents certain difficulties in the diagnosis of this syndrome. Various endocrinopathies can be manifestations of MAS like an acromegaly, a hyperthyroidism, Cushing’s syndrome, hypophospatemic osteomalacia as well as damage to other organs and systems, namely the pathology of the gastrointestinal tract, hepato-biliary cardiovascular systems. This article presents three late diagnosed clinical cases of MAS in patients with coffee-milk spots and FD, multinodular goiter; in two cases in combination with acromegaly. We have demonstrated the possibilities of drug therapy for acromegaly in MAS, as well as the experience of using bisphosphonate for the treatment of FD.

The knowledge of clinical manifestations of the MAS, early diagnostics and possibilities of drug therapy in the management of these patients have the important prognostic value for improving the quality of patient’s life.