More specifically, a patient demonstrating any one of the following is diagnosed as having diabetes: symptoms of diabetes plus random blood sugar ≥200 mg/dL (11.1 mmol/L) or fasting blood sugar ≥126 mg/dL (7 mmol/L) or 2-h plasma glucose during glucose tolerance test (GTT) ≥200 mg/dL (11.1 mmol/L) or glycated hemoglobin (Hb A1) ≥6.5 % [4, 5]. Here, GSTM1 is linked to diabetes mellitus.