In RA, disease activity, C reactive protein and disability scores are inversely related to serum levels of 25(OH)D, and anticyclic citrullinated peptide antibody positivity in RA patients is correlated with D3 insufficiency [25(OH)D, 21-29 ng/ml] and deficiency [25(OH)D <20 ng/ml] (18, 22–25). Here, CRP is linked to rheumatoid arthritis.