Serum C-reactive Protein and Periodontitis in Thai Adults

Epidemiologic studies have implicated periodontitis as a risk factor for cardiovascular disease. C-reactive protein (CRP) is a serological marker of systemic inflammation that has been linked to both periodontal disease and cardiovascular disease. Objectives: To evaluate the association of serum CRP levels with periodontitis and the presence of Porphyromonas gingivalis in Thai adults. Methods: This cross-sectional study was conducted among 121 apparently healthy adults (20-67 years old) in Khon Kaen, Thailand. Sera were obtained from 21 subjects with generalized periodontitis (>30% sites with probing depth ≥5 mm), 62 subjects with localized periodontitis (1-30% sites with probing depth ≥5 mm), and 38 periodontally healthy controls. High-sensitivity CRP levels were assessed using particle-enhanced Nephelometry. The presence of P.gingivalis in subgingival plaque samples was analyzed by polymerase chain reaction. Multivariate linear regression models were performed with log-transformed CRP levels as the outcome controlling for age, body mass index and smoking status. Results: The overall median CRP level was 0.50 (interquartile range [IQR] 0.23-1.53) mg/l, which was lower than those reported in Western populations. Subjects with generalized periodontitis and localized periodontitis had higher median CRP levels than controls (1.78, IQR 0.45-3.51 mg/l and 0.65, IQR 0.28-1.65 mg/l versus 0.25, IQR 0.08-0.51 mg/l, Wilcoxon rank-sum tests, p<0.001). In multivariate analysis, CRP was significantly increased in subjects with generalized periodontitis (p<0.01) and localized periodontitis (p=0.03) as compared with the controls. CRP levels were significantly correlated (p<0.01) with clinical parameters including probing depth (Spearman r=0.36), clinical attachment level (r=0.39) and bleeding on probing (r=0.25). The presence of P.gingivalis in more than 50 percent of sites was associated with elevated CRP levels (multivariate adjusted p<0.001). Conclusion: These findings suggest that increased CRP levels are associated with periodontitis and P.gingivalis in Thai adults.