Salivary glucose, salivary interleukin-18, glycemic control, and periodontal status in patients with type 2 diabetes mellitus

This study aimed to investigate the relationships among salivary glucose, IL-18, glycemic control, and periodontal status in patients with type 2 diabetes mellitus (T2DM). Seventy-five individuals were categorized according to glycemic status: systemically healthy (controls, n = 25), T2DM with controlled glycemic status (CDM, HbA1C ≤ 7%, n = 21), and T2DM with uncontrolled glycemic status (UCDM, HbA_1C > 7%, n = 29). Periodontal parameters, including periodontal probing depth (PPD) were recorded. Unstimulated whole saliva samples were analyzed for glucose and IL-18 using enzymatic and ELISA assays, respectively. Pearson correlation and multiple linear regression were used to assess relationships among variables. Salivary glucose and IL-18 levels were significantly elevated in CDM and UCDM groups compared to controls. Salivary glucose levels were associated with glycated hemoglobin (β = 0.429, P < 0.001) and fasting plasma glucose (β = 0.365, P = 0.001) independent of age, sex, PPD, and salivary flow rate. Salivary glucose and IL-18 levels were associated with each other (β = 0.282, P = 0.018) independent of age, sex, PPD, and salivary flow rate. Salivary glucose may serve as a glycemic biomarker, independent of periodontal status. Salivary glucose and IL-18 levels were significantly elevated in patients with T2DM and correlated with each other.