The prevalence of all grades of anaemia (Mild = haemoglobin (Hb) <13.0 [male] <12.0 [female] g/dl—>11.0 g/dl; Moderate Hb ≤11.0–8.0 g/dl; Severe Hb <8.0 g/dl). Here, GSTM1 is linked to anemia (phenotype).