GSTM1 and diabetes mellitus: In this work, as presented in Table 3, there were no statistically significant differences between the mean and SD of DM group and HC group respecting Hb level, RBCs count, PCV, MCH, MCHC, neutrophil count, lymphocyte count, and basophil count whereas the findings revealed that the mean and SD of FBS, systolic and diastolic BP, MCV, WBCs count, monocyte count, eosinophil count, platelets count, and 1 h and 2 h ESR had statistical significance between DM group and HC group.