The D-vitamin metabolite 1,25(OH)2 D in serum is associated with disease activity and Anti-Citrullinated Protein Antibodies in active and treatment naïve, early Rheumatoid Arthritis Patients.

The vitamin D metabolite 1,25(OH)2 D was inversely associated with disease activity and positively associated with ACPA in treatment naïve and inflammatory active early RA. The results indicate that in RA, both the degree of inflammatory activity, and the diagnostic sensitivity and specificity might affect-or might be affected by the level of vitamin 1,25(OH)2 D.