GSTM1 and anemia (phenotype): Hemoglobin (Hb), the primary outcome indicator of anemia, was measured in grams per deciliter (g/dL), and categorized as mild, moderate, and severe based on the hemoglobin threshold as mentioned in the updated guideline on hemoglobin cutoffs to define anemia, released in 2024 (Table 2) (27, 28).