GSTM1 and anemia (phenotype): Among participants with anemia, 135 (84.91%) had mild anemia (8 g/dL < Hb < 11 g/dL), 22 (13.83%) had moderate anemia (5 g/dL < Hb ≤ 8 g/dL), and only 2 (1.26%) had severe anemia (≤ 5 g/dL).