GSTM1 and anemia (phenotype): Clinical studies in Kenya [12, 13] have shown that profound anaemia (Hb < 4 g/dl) is independently associated with death (odds ratio; OR = 2 · 5), as is SA (defined in this study as a Hb < 5 g/dl) complicated by reduced consciousness (OR = 7 · 4) or respiratory distress (OR = 4 · 1).