GSTM1 and malaria: The proportions of children with a Hb concentration of < 8 g/dL at the end of the malaria transmission season were similar in the two groups of children, 44/513(8.6%) in children who received SP/AQ and 45/533 (8.4%) in those who received placebo (OR adjusted for baseline Hb 0.81, 95% CI 0.48, 1.36; P = 0.41).