Anemia is defined as “a condition in which the number of red blood cells is insufficient to meet the body’s physiologic needs” [1], and it is defined conventionally using the World Health Organization (WHO) laboratory reference range for hemoglobin concentration [Hb], namely, < 120 g/L for women or < 130 g/L for men. This evidence concerns the gene GSTM1 and anemia (phenotype).