As expected from previous studies [21], the patients with periodontitis exhibited higher levels of CRP (median difference 0.6 mg/ml, 95%CI 0.1–1.2, P<0.05), IL-6 (median difference 0.6 pg/ml, 95%CI 0.3–1.0, P<0.01) and total leukocyte counts (mean difference 0.8 109cells/L, 95%CI 0.2–1.4, P<0.01) when compared to controls. This evidence concerns the gene CRP and periodontitis.