Cognitive impairment and reduced antioxidant capacity in patients with type 2 diabetes

Background: Type 2 diabetes (T2D) has been linked to mild cognitive impairment (MCI). Increased oxidative stress and a decrease in antioxidant capacity are believed to be one of the pathophysiological mechanisms mediating MCI in T2D. Objective: The aim of this study was to assess MCI and total antioxidant capacity in T2D patients and their nondiabetic controls. Materials and methods: A total of 34 T2D patients attending the diabetic clinic of Murtala Muhammad Specialist Hospital, Kano, between June and December 2017 and age, sex, and level of education matched controls were recruited for the study. MCI was assessed using Montreal cognitive assessment test (MoCA) version 7.3. Serum albumin, total protein, uric acid, bilirubin, and malondialdehyde (MDA) were determined using spectrophotometric method, whereas Vitamins C and E were determined using competitive-ELISA (Elabscience, USA). Data were analyzed on SPSS version 23.0. The value of P ≤ 0.05 was considered statistically significant. Results: Diabetic group had significantly lower MoCA score (U = 216.50, P = 0.001), compared to the controls (19.5 and 26, respectively). MoCA score was influenced by sex (U = 88.0, P = 0.05) and level of education (χ2 =12.826, P = 0.005) among diabetic patients. MoCA score was correlated with serum levels of Vitamin E (ρ = −0.412, P = 0.015), total protein (ρ = −0.359, P = 0.037), and level of education of the diabetic patients (χ2 =14.664, P = 0.002). Diabetic patients had significantly higher serum MDA (U = 238.50, P = 0.001) (0.19 nmol/ml and 0.11 nmol/ml, respectively) and lower serum bilirubin (U = 351.50, P = 0.05) (1.28 mg/dl and 1.68 mg/dl, respectively). Conclusion: There was MCI with median MoCA score of 19.50 among the diabetics. T2D was associated with MCI, increased oxidative stress and reduced antioxidant capacity. Routine screening for MCI should be employed in the management of T2D.