GSTM1 and anemia (phenotype): A retrospective analysis of 410 patients (Hb <10 g/dL) in South Korea found that those with 25-hydroxyvitamin D < 10 ng/dL before kidney transplantation had a higher risk of developing anemia than those with 25-hydroxyvitamin D ≥ 10 ng/dL, while vitamin D deficiency may also be a risk factor for anemia in patients with ESKD (21).