The object of the research is deficiency and insufficiency of vitamin D (VDD and VDI) in residents of Lviv region and patients with rheumatoid arthritis (RA); the aim treatment improvement of rheumatoid arthritis on base of the studying the influence of vitamin D deficiency on the disease activity and to find the ways of its corrections; methods clinical, dual-energy X-ray absorptiometry, quantitative ultrasound densitometry, electroluminescence and immunochemical with chemiluminescent detection, immunoturbidimetric assay, biochemical, flow cytometry, questionnaires, questionnaire-weight method of reproduction of a daily diet, mathematical methods for statistical processing of the obtained results; novelty and results - the first time in Ukraine the frequency of VDD and VDI in patients with RA is determined, it has been proved that age, female sex and body mass index (BMI) are the risk factors of VDD, it has been established that the mean serum 25(OH)D level is significantly lower in patients with third degree of disease activity and in patients with second or third radiological stage compared to those whose disease activity is minimal and who has initial radiological disorders, it has been proved that VDD increases the risk of the highest activity of RA in three times compared to the group with optimal 25(OH)D level, it has been determined the significant negative correlation between serum 25(OH)D level and indexes of RA activity (DAS28-ESR, CRP, ESR) and all this associations remained statistically significant after adjustment for gender, age and BMI which allows to consider VDD as a significant predictor of the highest activity of RA, it has been proved that correction of serum 25(OH)D level by developed individual targeted therapy of VDD in combination with basic treatment of RA reduces the disease activity and significant decreases the pain syndrome measured by visual analog scale, it has been developed and implemented in health care system algorithm of correction and monitoring of VDD and VDI in patients with RA, it has been introduced in the educational process of the Department of Internal Medicine No 2 of SHEI "I. Horbachevsky Ternopil State Medical University", as well as in the clinical practice of the rheumatologic departments of the Lviv Regional Clinical Hospital, 4th Municipal City Clinical Hospital of Lviv, A. Novak Zakarpattya Regional Clinical Hospital (Uzhgorod), Ivano-Frankivsk Regional Clinical Hospital, State Institution "D.F. Chebotarev Institute of Gerontology NAMS of Ukraine" (Kyiv), E.N. Neiko Department of Internal Medicine No 1, Clinical Immunology and Allergology SHEI "Ivano-Frankivsk National Medical University", Therapeutic Department No 2 of Ternopil Communal City Hospital No 2; industry use medical and diagnostic process of rheumatological and therapeutic departments, scientific and pedagogical processes of therapeutic profile departments of the medical educational institutions.
