GSTM1 and anemia (phenotype): The article published in PLoS Medicine this week by Magalhães and Clements [4] explores the use of model-based geostatistics to investigate the risks of anaemia and mean Hb concentrations among preschool-age children (aged 1–4 years) attributable to malnutrition, malaria, and helminth infections in three West African countries (Burkina Faso, Ghana, and Mali).