SIGNIFICANCE OF VITAMIN D DEFICIENCY IN RHEUMATOID ARTHRITIS; RELATION TO DISEASE SEVERITY AND ACTIVITY

Abstract

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology (McInnes and Schett, 2011). Both T and B lymphocytes are involved in the pathogenesis of the disease (Choy, 2012). There is mounting evidence suggesting that vitamin D has a role in RA pathogenesis. Vitamin D deficiency is common in RA (Kerr et al., 2011) and correlates with increased risk of bone loss and disease severity, as well as increased risk for disability (Rossini et al ., 2010). The aim of the present study is to estimate the level of active vitamin D in patients with Rheumatoid arthritis and to assess the impact of vitamin D deficiency on disease severity and activity. Our study was performed on 35 patients with RA who fulfilled the American College of Rheumatology (ACR) criteria for RA (Arnett et al., 1988), and 30 healthy age and sex matched controls. All patients were subjected to full history taking and clinical examination, Routine Laboratory Investigations. Serum level of 25 (25) OH vitamin D was measured by ELISA at baseline for patients and controls. Follow up every 3 months was done for the RA patients for one year, each time reassessment of the disease activity and functional ability was done. Assessment of disease severity was done at baseline and after one year by X ray using the 1995 modification of the Larsen score (Rau and Herborn, 1995). All data were collected, tabulated and statistically analyzed revealing the following: In our studied group of patients (35), thirty (85.7%) were females while five (14.3%) were males, their ages ranged from19 to 51years. Our study revealed statistically significant higher frequency of vitamin D deficiency in RA patients compared to controls even more non of our RA patients had normal vitamin D level versus 13 (43.33%) in controls with statistical significant difference. The mean serum vitamin D level was significantly lower in RA patients compared to the control group. Statistically significant difference in the mean serum vitamin D level was detected between group I&II and group I & controls. At baseline, vitamin D deficiency was associated with higher number of tender and swollen joints, higher DAS28 score, even more, higher frequency of severe disease activity and higher ESR and CRP titer, also vitamin D level was negatively correlated with these parameters.