Background Vitamin D plays an important role in immune regulation. There are a lot of studies which prove that vitamin D deficiency may be a risk for development of autoimmune diseases [1,3,6]. Preliminary studies suggest that low levels of vitamin D may be common in rheumatoid arthritis (RA) [2,5,7].
Objectives The aim of this study is to estimate the prevalence of vitamin D deficiency in patients with RA, and to analyze the association of vitamin D with disease activity and disability.
Methods The study includes 52 RA premenopausal women aged between 35- 48 years, 32,7 % (17 pacients) with vitamin D supplements. Clinical evaluation included: disease onset and duration, presence of extraarticular manifestations, 28 tender joint count (TJC28) and 28 swollen joint count (SJC28), Disease Activity Score (DAS 28) was calculated using C-reactive protein (CRP), Health Assessment Questionnaire Disability Index (HAQ). RA specific treatment included the glucocorticoids, disease modifying antirheumatic drugs (DMARDs: methotrexate, cyclosporine, sulfasalazine, antimalarials, and azathioprine) and biologic therapy (anti-TNF or no). Exposure to sunlight from March to September (sun exposure time) was quantified as <10, 10 to 20, 20 to 30 or >30 minutes daily. Laboratory assessment included: rheumatoid factor (RF), anti Cyclic Citrullinated Peptide (anti-CCP), routine biochemistry, CRP, ESR and 25(OH)D level (25(OH)D level <30 ng/ml was considered as vit D deficiency).
Results A total of 67,3 % of RA patients were not taking vitamin D supplements; the proportion of these with vitamin D deficiency (25(OH)D level <30 ng/ml) was 68%. In non-supplemented RA patients, 25(OH)D levels were negatively correlated with the Health Assessment Questionnaire Disability Index, Disease Activity Score (DAS28). In patients not taking vitamin D supplements, a significant negative correlation between 25(OH)D serum levels and age was observed (P < 0.05), and mean values from June to December were significantly higher than from January to May (24.5 versus 18.0 ng/ml, respectively). Significantly lower 25(OH)D values were found in patients not experiencing disease remission or with DAS28 >5.1 or poorlyresponding to treatment. Vitamin D deficiency was found in 56% of the entire cohort.
Conclusions Vitamin D deficiency is common in RA patients. Patients with very active disease are at higher risk of vitamin D deficiency rather than the other. Patients with uncontrolled RA and/or with severe functional impairment are less prone to spend time outdoors in sunshine and are, therefore, at higher risk of vitamin D deficiency.
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Disclosure of Interest None Declared
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