GSTM1 and anemia (phenotype): According to WHO (2011), mild anaemia corresponds to Hb concentration level of 11.0–11.9 g/dL (women) and 11.0–12.9 g/dL (men) with moderate anaemia having Hb concentration of 8.0–10.9 g/dL (for both male and female) and severe anaemia with level less than 8.0 g/dL (for both male and female) [22].