Assessment and comparison of the antioxidant defense system in patients with type 2 diabetes, diabetic nephropathy and healthy people: A case–control study

Findings of previous studies in the field of antioxidant defense system in patients with type 2 diabetes (T2DM), diabetic nephropathy (DM) are limited and conflicting. Therefore, we evaluated the antioxidant defense system status in type 2 diabetes patients, diabetic nephropathy and healthy subjects in Iranian population.This population-based case–control study was conducted in 2019 and included 30 individuals with T2DM and 30 patients with DN, as the case groups and 30 healthy subjects for the control group. Individuals entered to the study for case group were diagnosed as T2DM patients based on fast glucose blood tests (FGB) (≥126 mg/dL) and HbA₁ (≥6.5%). DN was defined based on these tests and macroalbuminuria (>300 mg/day). Serum was carefully separated and antioxidant defense system status was estimated. Dietary intakes were evaluated by using a food frequency questionnaire (FFQ).Energy intake in control group was higher than case groups; BMI was higher in the DN group compared to the other groups. Significantly higher levels of MDA were observed in T2DM patients compared to control group in crude model (1.255 vs. 1.079 nmol/L; P = 0.006). The same results were shown after adjustment for potential confounders (1.256 vs. 1.085 nmol/L; P = 0.022). Total antioxidant capacity (TAC) was less in case groups compared with control group; level of catalase (CTL) and superoxide dismutase enzymes comparisons showed that DN patients had higher level than control group, but these associations were not significant.We found that MDA levels were significantly higher in T2DM patients compared to control group. Level of TAC was less in case groups in comparison to controls. SOD and CTL levels were higher in DN compared to controls; these associations were not significant.