Associations between Serum Zinc Levels and the Presence of Distal Symmetric Polyneuropathy in Patients with Type 2 Diabetes Mellitus

INTRODUCTION: Distal Symmetric Polyneuropathy Is the Most Common Form of Diabetic Neuropathy and a Major Source of Morbidity in Type 2 Diabetes. Oxidative Stress Plays a Key Role in Its Pathogenesis, and Zinc-An Essential Trace Element Involved in Antioxidant Defence-Has Been Proposed as a Protective Factor. However, Clinical Evidence on the Association Between Serum Zinc Levels and Diabetic Neuropathy Remains Limited and Inconsistent. This Study Examined the Relationship Between Serum Zinc Levels and the Presence of Distal Symmetric Diabetic Polyneuropathy in Type 2 Diabetes. METHODS: This Nested Case-Control Study Was Conducted Between December 2023 and March 2025 at the Internal Medicine Clinic of Shahid Beheshti Hospital in Hamadan, Iran. Ninety Patients With Type 2 Diabetes Were Enrolled, Including 45 With Distal Symmetric Polyneuropathy and 45 Without Neuropathy, Diagnosed According to American Diabetes Association Criteria. Serum Zinc Levels Were Measured Photometrically. Group Comparisons Used Independent t-Tests and Chi-Square Tests. Multivariable Logistic Regression Analysis Was Used to Examine the Association Between Serum Zinc Levels and DSPN While Adjusting for Potential Confounders. RESULTS: Patients With Distal Symmetric Polyneuropathy Had Significantly Lower Serum Zinc Levels Than Those Without (70.6 ± 12 μg/dL vs. 82.2 ± 16.9 μg/dL, p < 0.001). In Multivariable Logistic Regression, Zinc Levels Remained Independently Associated With the Presence of Neuropathy; Each One μg/dL Increase Was Associated With a 5.4% Reduction in Odds of Neuropathy. CONCLUSIONS: Lower serum zinc levels were independently associated with the presence of distal symmetric polyneuropathy in type 2 diabetes. This finding suggests that zinc deficiency may contribute to the development of diabetic neuropathy.