CRP and rheumatoid arthritis: In the linear regression analysis, statistically significant increases of 0.24 and 0.19 in the DAS28 and DAS28-CRP scores, respectively, were found for each millimeter of periodontal attachment loss in RA patients (p = 0.002 and p = 0.011, respectively, adjusted by age, gender and smoking) (see Additional file 2: Table S2).