GSTM1 and malaria: The proportions of children with a Hb concentration of <7 g/dL at the end of the malaria transmission season, the primary trial endpoint, were similar in the two groups of children, 14/464 (3.0%, 95%CI 1.5%, 4.6%) in children who received SP and 16/471 (3.4%, 95%CI 1.8%, 5.0%) in those who received placebo (prevalence ratio 0.89 (0.44,1.8) P = 0.742).