Background 25hydroxy-vitamin D not only plays a key role in calcium homeostasis, but also has antiinflammatory and immunomodulatory properties. Hypovitaminosis D prevalence in children suffering from Juvenile Idiopathic Arthritis (JIA) ranges from 6% to 30% according to different publications.
Objectives Evaluate hypovitaminosis D prevalence in JIA pediatric patients in Spain and assess involved factors.
Methods Observational cross-sectional study in JIA Spanish patients from 4 to 15 years, monitored by a Pediatric Rheumatology Unit. Monoarticular forms and patients with other chronic diseases or receiving different treatments from those indicated for JIA were excluded.
Anthropometric, clinical and treatment data were recorded. Bone metabolism parameters and validated diet (KIDMED) and exercise (PAQ-C/PAQ-A) questionnaires were obtained.
Hypovitaminosis D was defined as 25hydroxy-vitamin D plasma levels lower than 30 ng/ml
Results 76 children participated. Their characteristics are included in table 1.
The population's prevalence estimation of hypovytaminosis D in children with JIA was 16 - 35% (CI 95%).
We found no relationship between 25 hydroxy-vitamin D levels and sex, JIA subtype neither duration or dose of systemic glucocorticoids.
In bivariate analysis we found direct association between hypovitaminosis D and Body Mass Index percentile (BMIp) (p=0,05), received dose of prednisone (p=0,03) and clinical activity duration (p=0,04); and an inverse relationship with physical activity level (p=0,04).
In multivariate analysis, relationship between hypovitaminosis D and BMIp (B 0,024; p 0,016) and with disease activity (B 0,015; p 0,01) were maintained. Moreover, we found an inverse association with biological disease-modifiying antirheumatic drugs (B-4,69; p 0,048), specifically with anti-tumoral necrosis factor α (antiTNFα) (B -4,7; p 0,042)
Conclusions Hypovitaminosis D prevalence in our population is similar to previously described.
JIA patients with higher BMIp have more hypovitaminosis D, as it has been reported in other inflammatory diseases.
A direct relationship exists between inflammatory activity and vitamin D, but we need more studies to asses if one is cause or consecuence of the other.
Patients treated with antiTNF have better plasma levels of 25 hydroxy-vitamin D, this can be explained because these drugs may increase 25 hydroxy-vitamin D levels or due to a better response to antiTNF of those patient with higher plasma levels of 25 hydroxy-vitamin D.
Nisar MK, Masood F, Cookson P, Sansome A, Östör AJ. What do we know about juvenile idiopathic arthritis and vitamin D? A systematic literature review and meta-analysis of current evidence. Clin Rheumatol 2013; 32:729–734.
Santos-Antunes J, Corte-Real Nunes A, Lopes S, Macedo G. The Relevance of Vitamin D and Antinuclear Antibodies in Patients with Inflammatory Bowel Disease Under Anti-TNF Treatment: A Prospective Study. Inflamm Bowel Dis 2016;22:1101–1106.
Ham M, Longhi MS, Lahiff C, Cheifetz A, Robson S, Moss AC. Vitamin D levels in adults with Crohn's disease are responsive to disease activity and treatment. Inflamm Bowel Dis. 2014; 20(5):856–60.
Disclosure of Interest None declared