- 40.9% had IDA (mean Hb 11.5 g/dL); others had Hb of 14.3 g/dL - MDA significantly higher in IDA group (3.8 μmol/L vs. 2.5 μmol/L) - Antioxidant enzymes SOD and GPx were significantly lower in IDA patients - Strong association found between IDA and increased oxidative stress among T2DM patients taking metformin. Here, GSTM1 is linked to type 2 diabetes mellitus.