Evaluation of Serum Telomerase Activity and Oxidative Stress Markers in Type 2 Diabetes Mellitus: Relationship with Early Renal Dysfunction

Background: Telomerase activity and oxidative stress are emerging biomarkers of aging and chronic metabolic disorders. Type 2 diabetes mellitus (T2DM) accelerates telomere attrition through persistent hyperglycemia, systemic inflammation, and oxidative stress, which may contribute to early renal dysfunction even before the onset of overt nephropathy. Despite this link, limited studies have examined the combined role of telomerase and oxidative stress markers in early renal impairment among T2DM patients. Objective: To evaluate serum telomerase activity and oxidative stress markers in T2DM patients at different stages of early renal dysfunction and to determine their inter-relationship. Methods: This prospective observational study included 150 T2DM patients aged 30–65 years, divided equally into three groups based on estimated glomerular filtration rate (eGFR): Group A (≥90 mL/min/1.73 m²), Group B (60–89), and Group C (45–59). Fasting blood sugar, glycated hemoglobin (HbA1c), lipid profile, serum creatinine, eGFR, serum telomerase activity (ELISA), malondialdehyde (MDA; TBARS assay), total antioxidant capacity (TAC; ABTS assay), and superoxide dismutase (SOD; spectrophotometry) were measured. Data were analyzed using ANOVA with Bonferroni post hoc test, Pearson correlation, and multiple linear regression. Results: Serum telomerase activity declined progressively from Group A (1020 ± 95 AU) to Group C (690 ± 80 AU; p