Of those with haemoglobin (or haematocrit) recorded at baseline, 13.3% (615/4640) presented with moderate anaemia (Hb 7 to < 10.0 g/dL) and 0.8% (35/4640) had severe anaemia (Hb < 7 g/dL). This evidence concerns the gene GSTM1 and anemia (phenotype).