Assessment of Salivary Amylase, IL-6, and Glucose as Non-Invasive Bi-omarkers for the Early Diagnosis of Type 2 Diabetes Mellitus

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a chronic, progressive metabolic disorder marked by insulin resistance and progressive β-cell dysfunction. Early diagnosis is critical to preventing long-term complications, including cardiovascular disease and diabetic neuropathy. Conventional diagnostic techniques, such as blood sampling, are invasive and require significant resources. Saliva, a non-invasive and easily accessible biofluid, may contain biomarkers indicative of systemic metabolic changes.

Methods: This case-control study evaluated salivary levels of glucose, interleukin-6 (IL-6), and alpha-amylase in 30 newly diagnosed T2DM patients and 30 age- and gender-matched healthy controls. Unstimulated saliva samples were collected, processed, and analyzed using enzymatic and ELISA-based methods. Data were assessed using independent t-tests and Receiver Operating Characteristic (ROC) curve analysis.

Results: T2DM patients showed significantly higher salivary IL-6 (12.8 ± 3.1 pg/mL and 6.3 ± 2.2 pg/mL, respectively) and glucose (10.2 ± 2.7 mg/dL and 5.1 ± 1.8, respectively) compared to controls. Salivary amylase levels showed no significant difference (p = 0.28). ROC curve analysis demonstrated that IL-6 had the highest diagnostic accuracy (AUC = 0.86), followed by glucose (AUC = 0.84). Alpha-amylase exhibited limited diagnostic utility (AUC = 0.63).

Conclusions:  Silvery IL-6 and glucose appear to be promising non-invasive biomarkers for the early detection of T2DM. While alpha-amylase alone lacks sufficient diagnostic value, it may have adjunctive utility when combined with other markers in broader panels. These findings support the potential of saliva-based diagnostics in diabetes screening.