Salivary Metal Ions as Potential Biomarkers for Diabetes: An Observational Study

Objective: Saliva is an important body fluid that reflects systemic health. This study is a cross-sectional study aimed at exploring the relationship between salivary metal ion concentrations and diabetes risk. Methods: From the China Multiethnic Cohort (CMEC), 912 eligible participants were enrolled, and their saliva samples were collected. Salivary metal ion concentrations were measured using an inductively coupled plasma mass spectrometer and inductively coupled plasma optical emission spectrometry (ICP-OES). Logistic regression and propensity score matching (PSM) were used to examine the association between salivary metal ions and diabetes. Additionally, restricted cubic spline (RCS) analysis was used to explore the dose-response relationship between specific metal ions and diabetes risk. Results: This research initially revealed a notable nonlinear dose-response association between the levels of iron in saliva and diabetes risk, and it also identified a significant relationship between salivary manganese and diabetes. Conclusions: Significant associations were identified between salivary concentrations of iron and manganese and diabetes risk. Monitoring salivary metal ion levels may aid in the prevention and management of diabetes. Clinical Significance: The findings suggest that analyzing salivary metal ions could serve as a noninvasive tool for assessing diabetes risk, offering a valuable approach for early intervention and management.