Vitamin D in individuals before onset of rheumatoid arthritis - relation to vitamin D binding protein and its associated genetic variants

• Main Authors: Brink, Mikael, Johansson, Linda, Nygren, Evelina, Ärlestig, Lisbeth, Hultdin, Johan, Rantapää-Dahlqvist, Solbritt
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Figshare 2018
• Subjects: Biochemistry; Genetics; FOS Biological sciences; Immunology; FOS Clinical medicine; 69999 Biological Sciences not elsewhere classified; Northern Sweden
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.4229246; https://figshare.com/collections/Vitamin_D_in_individuals_before_onset_of_rheumatoid_arthritis_-_relation_to_vitamin_D_binding_protein_and_its_associated_genetic_variants/4229246

Abstract Background Vitamin D has been implicated as being involved in the aetio-pathogenesis of several autoimmune diseases including rheumatoid arthritis (RA). Previous studies present contradictory results. Vitamin D binding protein (DBP), the major transport protein, is also involved in various inflammatory processes. The aim of this study was to investigate the relationship between circulating levels of 25-hydroxyvitamin D [25(OH) D], DBP and polymorphisms in group-specific component (GC) in pre-symptomatic individuals and matched controls within prospective cohorts of the Northern Sweden. Methods Blood samples donated to the Medical Biobank prior to the onset of symptoms of RA (n = 515, mean [SD] time before the onset of symptoms 6.2 [9.3] years) and from matched (2:1) population-based controls (n = 267) were used. Plasma 25(OH) vitamin D levels were analyzed using liquid chromatography tandem-mass spectrometry and DBP levels were analyzed using enzyme-linked immunosorbent assay. GC polymorphisms (rs4588 and rs7041) were analyzed with TaqMan assays (Applied Biosystems). Results Levels of 25(OH) D or DBP were not statistically different between pre-symptomatic individuals and controls in a crude, or a multiple-adjusted logistic regression model. However, an increased risk for future RA was found in females of DBP (OR 1.014 [95%CI 1.001–1.028]) per 10 mg/L adjusted for carriage of the minor allele of rs4588, in a multiple-adjusted model (p