Discrepancies between WHO- and data-analysis-based diagnosis of anemia in children have also been reported from Peru17,18,48 and Bolivia.49 The Bolivian study shows that iron deficiency contributed only marginally49 to [Hb] considered below-normal based on the WHO-guidelines indicating that those [Hb] may have been diagnosed false-low. Here, GSTM1 is linked to Iron deficiency anemia.