ESPE Abstracts

Background: 25-Hydroxyvitamin D (25(OH)D) deficiency is reported to be common in patients with rheumatoid arthritis and associated with disease activity, physical disability, and cardiometabolic intermediates; data in patients with juvenile idiopathic arthritis (JIA) are inconsistent.

Objective and hypotheses: To assess serum 25(OH)D in children, adolescents, and young adults with JIA, and to identify the risk factors for vitamin D deficiency in JIA patients.

Method: We evaluated 152 patients with JIA (115 female, 37 males, mean age 16.2±7.4 years; 96 oligoarticular, 35 polyarticular, seven systemic and 14 enthesitis-arthritis onset). These patients were compared with a sex- and age-matched control group. All patients and controls performed laboratory evaluation of plasma 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, bone alkaline phosphatase levels, and dual energy X-ray absorptiometry of the lumbar spine examination to evaluate bone mineral density (BMD) expressed as estimation, bone mineral apparent density.

Results: JIA patients showed significantly reduced 25(OH)D levels in comparison to controls (P<0.001), even if divided into subtypes (oligoarticular P<0.05; polyarticular P<0.005; systemic P<0.001; ERA P<0.005). Patients with active disease and/or frequent relapses had significantly reduced 25(OH)D levels than patients with no active disease and no frequent flares (P<0.005, respectively). Nevertheless, JIA patients had significantly higher PTH levels compared to controls (P<0.0001). Finally, JIA patients with 25(OH)D deficiency showed a significant lower BMAD Z-score than those with normal 25(OH)D levels (P<0.001).

Conclusion: JIA patients have reduced 25(OH)D and higher PTH values. These data may explain, at least partially, why JIA patients do not reach bone normal condition over the time, despite more effective current drugs. JIA patients with more severe subtype, such as polyarticular and systemic onsets, may require higher supplementation of Vitamin D to maintain normal 25(OH)D serum levels. Future long-term studies are needed to explore the relationship between serum 25(OH)D levels and disease activity.