Association between Plasma Leptin Level and Systemic Inflammatory Markers in Patients with Aggressive Periodontitis

Background: Increasing evidence supports an association between periodontitis and systemic diseases. Leptin is involved both in the energy metabolism and inflammatory processes and is suggested to be a link between periodontal infection and systemic health. The present study aimed to evaluate the peripheral leptin concentration in patients with aggressive periodontitis (AgP) and to explore the relationship between leptin and systemic inflammation. Methods: Ninety patients with AgP visiting the Clinic of the Periodontology Department, Peking University School and Hospital of Stomatology between July 2001 and May 2006, and 44 healthy controls (staff and student volunteers in the same institute) were recruited. Plasma levels of leptin and inflammatory cytokines including interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP) were measured by enzyme-linked immunosorbent assay. Correlation and multiple linear regression analysis were performed to analyze the association between plasma leptin level and other variables. Results: Plasma leptin level of AgP group was significantly higher than that of the control group (19.7 +/- 4.4 ng/ml vs. 7.5 + 1.3 ng/ml, P < 0.01). After controlling for age, gender, and body mass index, positive correlation was observed between plasma leptin concentration and log-transformed levels of pro-inflammatory cytokines (IL-1 beta, IL-6, TNF-alpha and CRP), and the partial correlation coefficients ranged from 0.199 to 0.376 (P < 0.05). Log-transformed IL-1 beta and IL-6 levels entered the final regression model (standardized beta were 0.422 and 0.461 respectively, P < 0.01). Conclusions: Elevated plasma leptin concentration may be associated with increased systemic levels of inflammatory markers in AgP patients.