Significant increases in haemoglobin and ferritin concentrations were observed within this period (mean Hb increased from 10.2 ± 1.6 to 12.5 ± 1.5 g/dL; ferritin, from  9 ± 11  to 31 ± 23 μg/L), indicating that specific prolonged-release iron preparations may provide relatively high iron bioavailability and are effective in the treatment of iron deficiency anaemia, even in the case of chronic haemorrhage. This evidence concerns the gene GSTM1 and Iron deficiency anemia.