Assessment of Serum Tumor Necrosis Factor-alpha (TNF-α) Levels in Type 2 Diabetes Mellitus Patients

Abstract Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent hyperglycemia, resulting from insulin resistance and pancreatic beta-cell dysfunction. Tumor necrosis factor-alpha (TNF-α), a pro-inflammatory cytokine, has been linked to insulin resistance and to the mechanisms underlying diabetic complications. This study aimed to compare serum TNF-α levels between patients with T2DM and healthy controls, and to examine their relationship with random blood glucose (RBG), age, body mass index (BMI), reported diabetic complications, infections, and clinical symptoms. Methods: In this case–control study (January–March 2026, Diyala, Iraq), 40 male patients with T2DM (ADA criteria; aged 19–73 years) were compared with 40 apparently healthy male controls (aged 20–55 years). Smokers, users of tobacco products, participants with chronic inflammatory diseases, and those receiving immunosuppressive therapy were excluded. Serum TNF-α was measured by ELISA. Group differences were tested with non-parametric tests (data were non-normal) and by ANCOVA on log-transformed TNF-α adjusted for age and body mass index (BMI). Written informed consent was obtained from all participants. tests (Mann–Whitney U, Kruskal–Wallis, and Spearman’s correlation) were used. Results: Median (IQR) serum TNF-α was significantly higher in patients than in controls (59.66 [45.10] vs. 29.53 [16.28] pg/mL; P < 0.001). The difference remained significant after adjustment for age (adjusted geometric means 63.4 vs. 29.4 pg/mL; P < 0.001) and for age and BMI (P < 0.001). Among patients, TNF-α was not significantly correlated with RBG (rs = 0.264, P = 0.100), age, or BMI, and did not differ significantly according to reported complications, infections, or symptoms (all P > 0.05). Conclusion: Serum TNF-α was higher in male patients with T2DM than in male controls, independent of age and BMI, supporting a link between T2DM and systemic inflammation. However, the groups were not age-matched, the sample was small, and complications were self-reported, so the findings should be interpreted cautiously and confirmed in larger, age-matched studies.