GSTM1 and anemia (phenotype): The categories were: severely anemic (RBC <3.0 M/μL, Hb <5.0 g/dL or HCT <15%); mildly anemic (RBC 3.0–5.0 M/μL, Hb 5.0–8.0 g/dL or HCT 15–24%), and without anemia (RBC >5.0 M/μL, Hb >8.0 g/dL or HCT >24%).