GSTM1 and anemia (phenotype): Mean haemoglobin levels were significantly higher in G1–G4 in the trial by ter Kuile et al., who also reported a significant delay in the time to the first episode of any anaemia (Hb < 110 g/l) in G1–G4 (hazard ratio [HR] 0.79, 95% CI 0.65–0.96, p = 0.02), but not in G5+ (HR 1.00, 0.86–1.18, p = 0.97) [27].