In patients with the optimal vitamin D levels (30–100 ng/mL), CRP, IL-6 and erythrocyte sedimentation rate (ESR) were 8.21±0.57, 12.08±0.55 pg/mL and 18.29±4.21 mm/hour, respectively; in other words, they were 19.4%, 27.2% and 52% lower than in patients with vitamin D insufficiency (p<0.05). Here, CRP is linked to vitamin D deficiency.