Substantiation of methods for the correction of vitamin D deficiency in children with juvenile idiopathic arthritis

Abstract

Background. Plenty of studies demonstrated the role of vitamin D in the pathogenesis of autoimmune diseases, inclu­ding chronic childhood arthritis. Calciferol is able to suppress the immune response. Also, its deficiency is associated with increased activity of autoimmune diseases. The purpose of this study was: 1) to determinate vitamin D status in children with juvenile idiopathic arthritis (JIA) depending on the age of patients, variant of disease and therapy; 2) to analyze changes in the vitamin D status after its 3-month supplementation. Materials and methods. The study included 40 children with JIA (30 females, 10 males). Patients were divided into groups depending on the age, disease variant (oligo, -polyarticular variant, undifferentiated arthritis) and therapy (pre­sence or absence of methotrexate, duration of therapy and doses). The research was conducted twice (the first — without additional intake of vitamin D, the second — after its 3-month supplementation of 2,000 IU). The serum level of vitamin D was measured through blood test by chemiluminescence method. Results. The average level of vitamin D was 22.26 ± 2.53 ng/ml. Dependence on gender and variant of the disease at the first stage of research was not found. Children under 6 years of age had a higher vitamin D status than older individuals (p < 0.05). At the second stage of research, the level of vitamin D in the general group of patients was 27.61 ± 3.56 ng/ml that proves a significant rise (p < 0.05). Male patients had a significant positive dynamics in comparison with female patients (p < 0.05). Vitamin D levels in little children increased to the optimal level. Positive changes in vitamin D status were found in patients with oligoarticular JIA (p < 0.05) in contrast to those with other variants of the disease. Patients who received methotrexate showed the better response to vitamin D intake than children who were not treated (p < 0.05). Positive dynamics was also observed in patients who were treated with methotrexate for no more than 2 years (p < 0.05). But the optimal status of vitamin D was achieved only in those who received basic therapy for no more than 6 months. The patients whose do­ses of methotrexate were less than 10 mg/m2/week have not showed the dynamics, in contrast to the subjects who received methotrexate at a dose of 10–15 mg/m2/week (p < 0.05). Conclusions. Children with JIA, who are older than 6 years; suffer from polyarthritis and undifferentiated JIA; whose duration of disease is more than 2 years; who receives methotrexate therapy over 6 months or at a dose below 10 mg/m2/week, have an insufficient response to vitamin D supplementation. Such patients require increasing the doses of vitamin D supplementation for both prophylactic and therapeutic purposes.

Keywords

• vitamin d
• juvenile idiopathic arthritis
• cholecalci­ferol
• vitamin d status
• vitamin d supplementation