SOD1 and Impaired glucose tolerance: While individuals with impaired glucose regulation (impaired fasting glucose and impaired glucose tolerance) show similar levels of oxidative stress, but slightly reduced erythrocyte SOD activity compared to glucose-tolerant people, levels of plasma lipid peroxides, and DNA damage are elevated and total antioxidant capacity, GPx, GSH, and SOD activity are decreased in T2D [51, 52].