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. The gene discussed is GSTM1; the disease is major depressive disorder.