Fasting Glucose, Haemoglobin A1C (HbA1c), Blood Lipid, and Triglyceride-Glucose Index Parameters in Relation to Subjective Tinnitus.

This study aimed to analyse blood glucose and lipid levels in subjective tinnitus compared to healthy controls. A total of 414 patients with subjective tinnitus and 274 healthy participants were enrolled. All participants underwent comprehensive laboratory testing, which included measurements of fasting blood glucose, HbA1c, and blood lipids. The tinnitus group had significantly higher glucose levels than the control group ( = 0.024). Additionally, the HbA1c levels were higher in the tinnitus group ( = 0.006). Tinnitus patients exhibited elevated levels of total cholesterol ( < 0.001), triglycerides ( < 0.001), and LDL ( < 0.001). However, HDL levels showed no significant difference ( = 0.984). Although the triglyceride-glucose index tends to show higher values in the tinnitus group, this difference is statistically insignificant ( = 0.688). ROC indicated that LDL had the highest sensitivity for predicting tinnitus (AUC = 0.620; < 0.001, 95% CI: 0.573-0.668). Other parameters showed significant results, excluding the triglyceride-glucose index (AUC = 0.514; = 0.688, 95% CI: 0.443-0.585), which was not a significant predictor. Glucose levels significantly correlate with age (rho = 0.338, < 0.001) and tinnitus onset (rho = 0.107, = 0.034). Additionally, age showed a significant correlation with total cholesterol levels (rho = 0.156, = 0.002) and triglycerides (rho = 0.121, = 0.020) and tinnitus onset (rho = 0.344, < 0.001). Logistic regression analysis revealed that the presence of tinnitus was significantly associated with elevated HbA1c levels ( = 0.007) and TG levels ( = 0.001). Furthermore, the occurrence of chronic tinnitus was significantly influenced by elevated glucose levels ( = 0.026). The results showed increased glucose and blood lipid levels in tinnitus. LDL levels exhibited the highest sensitivity in predicting tinnitus. However, the TyG index was not a significant predictor. Given the cross-sectional design of the study, which may limit the results, further longitudinal studies are necessary.