Also, hypovitaminosis D is associated with an increased risk of anemia, hypoferritinemia, iron deficiency, reduced serum erythropoietin and low Hb levels [44–46], since vitamin D may directly stimulate the erythropoietin precursor, downregulating circulating hepcidin levels that are increased during inflammation to block iron absorption [44, 47, 48]. This evidence concerns the gene GSTM1 and Iron deficiency anemia.