Objective Plasma cell-free extra-cellular mitochondrial DNA (cf-exmtDNA) shows pro-inflammatory potential. This study aims to investigate the correlation between cf-exmtDNA and baseline periodontitis clinical parameters in patients in general health. Methods A total of 78 participants aged 18-45 years were enrolled: 11 periodontal healthy volunteers, 11 patients with gingivitis, and 56 patients with periodontitis. Baseline periodontal index, age, gender, body mass index (BMI), and baseline fasting blood glucose (FBG) were examined and recorded. Anticoagulated venous blood (4 mL) was collected, and cf-mtDNA was extracted by secondary centrifugation. cf-exmtDNA concentration was measured through real-time quantitative polymerase chain reaction. Different states of periodontal inflammation were compared in terms of plasma cf-exmtDNA copy number, and the relationship among plasma cf-exmtDNA, mean probing depth (mPD), mean clinical attachment level (mCAL), mean bleeding index (mBI), mean plaque index, age, FBG, and BMI were examined through correlation and multiple linear regression analyses. Results Patients with periodontitis had significantly higher plasma cf-exmtDNA levels than the healthy volunteers (P=0.042). The overall plasma cf-exmtDNA was significantly positively correlated with age (P=0.023), mPD (P<0.001), mCAL (P=0.006), and mBI (P=0.026). Multiple regression analysis showed that plasma cf-exmtDNA level was significantly dependent on mPD. Conclusion In the general population aged 18–45, patients with periodontitis had significantly higher plasma cf-exmt-DNA level than the healthy volunteers, and plasma cf-exmtDNA concentration was significantly positively correlated with age, mPD, mCAL, and mBI.
