Vitamin D deficiency is associated with higher disease activity and the risk for uveitis in juvenile idiopathic arthritis - data from a German inception cohort

Claudia Sengler,Gerd Ganser,Ina Liedmann,Arnd Heiligenhaus,Martina Niewerth,Dirk Foell,Julian Zink,Kirsten Minden,Anton Hospach,Gerd Horneff,Christoph Kessel,Angela Zink,Johannes-Peter Haas,Angelika Thon,Jens Klotsche,Frank Weller-Heinemann

doi:10.1186/s13075-018-1765-y

Abstract

ObjectiveThe objective was to evaluate the 25(OH) vitamin D (25(OH)D) status of patients with juvenile idiopathic arthritis (JIA) and determine whether the 25(OH)D level is associated with disease activity and the course of JIA.MethodsPatients ≤ 16 years of age with recently diagnosed JIA (< 12 months) were enrolled in the inception cohort of patients with newly diagnosed JIA (ICON), an ongoing prospective observational, controlled multicenter study started in 2010. Clinical and laboratory parameters were ascertained quarterly during the first year and half-yearly thereafter.Of the 954 enrolled patients, 360 patients with two blood samples taken during the first 2 years after inclusion and with follow up of 3 years were selected. The serum 25(OH)D levels were determined and compared with those of subjects from the general population after matching for age, sex, migration status and the month of blood-drawing.ResultsNearly half of the patients had a deficient 25(OH)D level (< 20 ng/ml) in the first serum sample and a quarter had a deficient level in both samples. Disease activity and the risk of developing JIA-associated uveitis were inversely correlated with the 25(OH)D level (β = − 0.20, 95% CI − 0.37; 0.03, hazard ratio 0.95, 95% CI 0.91; 0.99, respectively).ConclusionIn this study, 25(OH)D deficiency was common and associated with higher disease activity and risk of developing JIA-associated uveitis. Further studies are needed to substantiate these results and determine whether correcting 25(OH)D deficiency is beneficial in JIA.

Highlights

Over the last decade, it has become clear that vitamin D is more than the “bone vitamin” that regulates calcium homeostasis and bone mineralization
Vitamin D deficiency was common, as it was found in 44% of patients with juvenile idiopathic arthritis (JIA) and even in 62% of healthy peers
Low levels of 25(OH)D in patients with JIA were associated with higher disease activity and higher risk of developing JIA-associated uveitis

Summary

Introduction

It has become clear that vitamin D is more than the “bone vitamin” that regulates calcium homeostasis and bone mineralization. In addition to its pleiotropic functions in different cells and tissues, the differentiation, polarization and activity of immune cells are affected by 1,25 (OH) vitamin D3 [1]. This is the biologically active form that results from the double hydroxylation of cholecalciferol that is ingested or produced in the skin by ultraviolet sunlight. Nisar et al conducted a meta-analysis of several studies evaluating patients with JIA with reported serum vitamin D levels [2]; the parameters that were measured (25(OH)D, 1,25(OH)2D3), clinical outcomes and the cutoff values that were used differed substantially. We wanted to (1) evaluate the 25(OH)D level in patients with newly diagnosed JIA and compare it with that in individuals from the general population; (2) analyze whether disease activity is correlated with the 25(OH)D level and (3) determine whether the 25(OH)D level might predict the disease course

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