Since disease severity in this cohort was generally characterized by anaemia, the children with malaria were stratified into three categories based on haemoglobin levels: UM (Hb ≥ 11 g/dL, n = 194), MMA (8.0 ≤ Hb < 11 g/dL, n = 279) and MSMA (Hb < 8.0 g/dL n = 65). This evidence concerns the gene GSTM1 and anemia.