GSTM1 and anemia (phenotype): At enrolment, mean Hb was 10.3 g/dL (standard deviation [SD] = 1.7 g/dL) and 69.9% had anaemia (<11.0 g/dL), highest in Burkina Faso (79.3%) followed by Kenya (70.3%) and South Africa (57.8%; P-value < 0.001).