Evaluating Salivary Interleukin-6 as a Biomarker for Periodontitis in Type II Diabetes: A Cross-sectional Study

Introduction: A similar inflammatory mechanism drives the well-established bidirectional link between type 2 diabetes mellitus (T2DM) and periodontitis. Both diseases have the same pathophysiology with the pleiotropic pro-inflammatory cytokine interleukin-6 (IL-6). The diagnostic value of salivary IL-6 in detecting periodontitis in type 2 diabetes patients is not yet completely understood, while saliva provides a non-invasive platform for biomarker research. Materials and Methods: This cross-sectional study assessed 120 participants in three groups: healthy controls, type 2 diabetes (T2DM) patients with mild periodontitis and T2DM patients with severe periodontitis. Researchers performed periodontal evaluations and measured salivary IL-6 levels via ELISA. The data were then statistically analysed using ANOVA, Tukey’s post hoc test and Spearman’s correlation to compare the groups. Results: Salivary IL-6 levels differed significantly among the groups. The highest concentration was found in patients with type 2 diabetes and moderate-to-severe periodontitis (Group C), which was substantially higher than in healthy controls (Group A) and T2DM patients with mild periodontitis (Group B). Among all T2DM patients, elevated IL-6 levels strongly correlated with worse periodontal health indicators. Conclusion: There is a robust correlation between the clinical severity of periodontal damage and salivary IL-6 concentrations, which are considerably higher in type 2 diabetic individuals with periodontitis. These results provide credence to the idea that IL-6 in saliva might be a useful non-invasive biomarker for the screening and monitoring of periodontitis in type II diabetic patients.