Compared with the Non-Anemia group, the level of hemoglobin (Hb) (98.68 ± 18.76 g/L vs. 145.32 ± 15.33 g/L in males; 88.45 ± 15.67 g/L vs. 131.69 ± 14.42 g/L in females) remarkably decreased in the IDA group. Here, GSTM1 is linked to anemia (phenotype).