GSTM1 and anemia (phenotype): We identified 5 distinct Hb trajectories: persistent anemia (5.6 %; n = 109), improved anemia (4.8 %, n = 93), mild anemia (21.0%; n = 406), low normal Hb (46.6 %; n = 899), and normal Hb (21.9%; n = 424).