T2DM patients with DR had higher levels of FPG, HbA1c, Ox-LDL, GGT, 8-OHdG, 8-isoprostane, SOD, TBARS, and uric acid but lower levels of selenium, zinc, magnesium, TAOS, vitamin C, vitamin E, and vitamin D than those from controls. Here, SOD1 is linked to type 2 diabetes mellitus.