Background Juvenile idiopathic arthritis (JIA) and familial Mediterranean fever (FMF) are the most common chronic inflammatory rheumatic disorder in children and is a significant cause of both short- and long-term disabilities. The fact that vitamin D inactivates Th1 and Th17, both of which are thought to have a role in JIA pathophysiology, supports the claim that there may be a relationship between vitamin D deficiency and JIA. However, data are limited regarding the association between disease activity and serum 25(OH)D levels in children with JIA. In the few studies serum 25(OH)D levels were found to correlate inversely with disease activity in patients with FMF.
Objectives The aims of this study were to determine the frequency of vitamin D deficiency and/or insufficiency of children with JIA and FMF and to assess the relationship between vitamin D and disease activity for JIA and FMF.
Methods 64 patients with JIA, 36 patient with FMF and 100 healthy children were included in this prospective cross-sectional study. The children with JIA were diagnosed according to classification criteria of the International League of Associations for Rheumatology (ILAR), and children with FMF according to the criteria set by Livneh. Serum 25-hydroxyvitamin D levels [25(OH)D] of children with JIA and FMF during activation and remission periods were measured using chemiluminescence immunoassay (CLIA). The serum levels of <20 ng/ml was defined as vitamin D deficiency.
Results Mean serum 25(OH)D levels of patients with JIA during activation and remission periods of disease were 18,9±11 ng/ml and 18,6±9,2 ng/ml respectively. Mean serum 25(OH) D levels of patients with FMF during attack and attack-free periods were 16±8,5 ng/ml and 13,1±6,4 ng/ml respectively. Mean serum 25(OH)D levels of healthy children were 26,7±10,5 ng/ml. Serum Vitamin D levels of patients with JIA and FMF both during active and remission periods of diseases were lower than control group (p<0,001). There was no significant difference between 25(OH)D levels of patients with JIA during activation and remission periods, whereas serum vitamin D levels during remission period of patients with FMF lower than activation period (p<0.05). No significant relationship was found between disease activity and serum vitamin D levels. During activation period, vitamin D deficiency and insufficiency were found in 57,9% and 29,7% of patients with JIA and during remission period, 58,4% and 33,9% of them, respectively. During activation period, vitamin D deficiency and insufficiency were found in 69,5% and 19,4% of patients with FMF and during remission period, 83,3% and 16,6% of them, respectively. Vitamin D deficiency and insufficiency were found in 26% and 33% of control group, respectively.
Conclusions Serum 25(OH)D levels of children with JIA and FMF were significantly lower than healthy children. Frequency of vitamin D deficiency and insufficiency were quitely high among patients with JIA and FMF. There was no relationship between disease activity and serum vitamin D levels.
Gowdie PJ, Tse SM. Juvenile idiopathic arthritis. Pediatr Clin North Am 2012;59(2): 301-2.
Hewison M. Vitamin D and the immune system: new perspective on an old theme. Endocrinol Metab Clin North Am 2010;39(2):365-79.
Disclosure of Interest None declared