Impact of vitaminD deficiency on clinical parameters in treatment-naïve rheumatoid arthritis patients.

Abstract

To determine if patients with rheumatoid arthritis (RA) are at risk of vitaminD deficiency and whether the levels of vitaminD are correlated with clinical parameters in RA. Atotal of 280treatment-naïve RA patients, and 140age- and sex-matched healthy volunteers were enrolled. Serum levels of 1,25-dihydroxycholecalciferol (1,25(OH)2D3), the active form of vitaminD, were measured by enzyme-linked immunosorbent assay (ELISA). Concentrations of 1,25(OH)2D3 less than 25 ng/mL were defined as insufficient. Linear regression was performed to evaluate correlations as (modifying and) confounding factors were controlled. The levels of serum 1,25(OH)2D3 in RA individuals (12.24 ± 6.68 ng/ml) were significantly lower than in healthy controls (21.08 ± 7.14 ng/ml; p < 0.05). An inverse association was found between the levels of 1,25(OH)2D3 and ESR in obese and overweight individuals with RA(βobese = -0.385, βoverweight = -0.395, both p < 0.05), but not in normal and underweight subjects. Asignificant negative association between levels of 1,25(OH)2D3andDAS28score (β = -0.164, p = 0.018) was observed. The levels of 1,25(OH)2D3 were associated moderately and inversely with the absolute numbers of Th-17 (β = -0.158, p = 0.019) and positively with those of CD4+ regulatoryT (Treg) cell (β = 0.146, p = 0.025). The levels of 1,25(OH)2D3 in anti-cyclic citrullinated peptide (anti-CCP)-positive patients with RA were lower than in the anti-CCP-negative RA patients (10.86 ng/ml versus 15.98 ng/ml; t = -3.08, p < 0.01). Asignificant association was observed between levels of vitamin Dand parameters of disease, including body mass index (BMI), DAS28, Th17 cell counts, Treg cell counts, and presence of anti-CCP antibody in RA patients.