GSTM1 and anemia (phenotype): In the severe anemia group, Hb content was 51.40 ± 6.22 g/L, 60.10 ± 10.18 g/L, 61.30 ± 10.97 g/L, and 60.20 ± 13.04 g/L before treatment and after one, two and three months of treatment, respectively.