As shown in Table 3, age (p < 0.001), sex (p < 0.001), education (p < 0.001), hypertension (p = 0.017), smoking (p < 0.001), drinking (p = 0.026), RBC (p = 0.004), Hb (p < 0.001), PLR (p = 0.001) were significantly correlated with cognitive impairment in diabetic patients. This evidence concerns the gene GSTM1 and Cognitive impairment.