Background: Vitamin D (Vit D) insufficiency has been implicated in a number of autoimmune diseases. Its role in the pathogenesis of juvenile idiopathic arthritis (JIA) however is unclear including its relation to disease subtype and severity.

Objectives: To establish a link between Vit D insufficiency and JIA

Methods: We undertook a retrospective cohort study of Vit D levels in patients with a diagnosis of JIA. Demographic data, JIA subtype, medication use, comorbidities, disease severity, bone profile, inflammatory markers and autoantibody status were documented. Vit D levels were then correlated in each subgroup and with the other blood parameters. We predefined Vit D insufficiency as being <50 nmol/L.

Results: In the 37 patients where Vit D levels were available, 34 (91.9%) were females, 22 white (59.9%) and the age groups were evenly split: 0-10 (n=13), 11-20 (n=12) and >21 years (n=12). The mean Vit D concentration was 49.6 nmol/L (range 13.2- 112.0 nmol/L). Seventeen patients (45.9%) had Vit D levels above 50nmol/l, 9 (24.3%) between 30 and 50 nmol/l, 10 (27.0%) between 15 and 30 nmol/l, and 1 patient (2.7%) had a serum concentration below 15 nmol/l. A trend for lower Vit D levels was seen in older patients. There were no significant differences in mean Vit D levels among various ethnicities or JIA subtypes however ESR and CRP were inversely related to Vit D concentrations. Vit D levels were significantly lower in patients who were not receiving methotrexate (MTX) (p=0.04 ) and in those receiving opioids (p=0.03).

Conclusions: In our cohort half of patients with JIA have low Vit D levels which are inversely related to disease activity and disease duration. JIA subsets do not appear to have a direct association with Vit D however patients not receiving MTX had lower levels of Vit D. This study suggests that Vit D plays a role in JIA however further research is required to clarify its precise influence.

Disclosure of Interest: None Declared