Studies in HA populations of Asia and the Andes have shown an association between elevated Hb concentration (>18 g/dL) and glucose intolerance (Okumiya et al., 2010, 2011, 2016), indicating a poor glycemic control in individuals presenting abnormally high Hb values for the altitude of residence (Okumiya et al., 2010, 2011, 2016). This evidence concerns the gene GSTM1 and Glucose intolerance.