This result is consistent with the findings of a cross-sectional analysis in which depression was independently associated with lower Hb levels (β = -0.074; P = 0.05).43 To some extent, anemia might affect the brain and mood; thus, correcting anemia may be beneficial in improving the oxygen supply to brain tissue and reducing the risk of cognitive dysfunction and depression symptoms.8,9,44. This evidence concerns the gene GSTM1 and anemia (phenotype).