GSTM1 and anemia (phenotype): Two randomized studies, one in 30 iron deficient children with or without anemia aged 24–81 months [11] and the other in 49 children with IDA aged 6–40 months [12], reported no difference between IPC and ferrous sulfate for the improvement in Hb or other efficacy markers over a two-month period, although one trial observed a more rapid improvement in Hb with ferrous sulfate.