CRP and rheumatoid arthritis: Moreover, for patients with RA, each 10 ng/mL increase of the serum 1,25(OH)2D3 level is associated with a 0.3-point decrease of the Disease Activity Score 28-joint assessment (DAS28) and a 25% decrease of C-reactive protein (CRP) levels [18], suggesting that vitamin D supplement is benefit for RA treatment and should be advocated in clinical practice.