To investigate the relationship between serum superoxide dismutase (SOD) activity and the presence of chronic complications in patients with type 2 diabetes mellitus (T2DM). We conducted a retrospective cross-sectional study in patients with T2DM. They were assigned to three groups (Q1, Q2, and Q3) by SOD levels in both sexes. Clinical characteristics, cardiovascular disease, diabetic retinopathy, nephropathy, and peripheral neuropathy were compared. The relationship between the SOD and the prevalence of chronic complications was analyzed by binary logistic regression. Statistical analysis was performed in SPSS 26.0 (SPSS Inc., Chicago, IL). A total of 645 T2DM patients (401 men and 244 women) with complete data for SOD and medical records of complications were included. In men, patients in the Q1 group (lowest serum SOD activity) had the highest prevalence of diabetes with atherosclerosis (AS) (p<.001), DN (p=.029), and DPN (p=.001). In comparison, only DN was found to have the highest prevalence in the Q1 group in women (p=.010). In the multivariate analysis, patients in the Q1 group had a 3.0-, 1.6-, 1.9-, and 2.4-fold risk for the prevalence of AS, DR, DN, and DPN, respectively, compared with the Q3 group. In women, a 7.0-fold risk for the prevalence of DN in the Q1 group was found compared with the Q3 group. After adjusting for the age, duration of T2DM, body mass index, pulse pressure, alanine transaminase, clearance of creatinine, triglyceride, glycosylated hemoglobin, and fasting C-peptide in the models, the differences found in both men and women persisted. SOD activity is related to cardiovascular and microvascular diseases in men and the prevalence of diabetic nephropathy in women in T2DM.
Keywords: Cardiovascular disease; diabetic neuropathy; diabetic peripheral neuropathy; diabetic retinopathy; superoxide dismutase.