The observation that 7- and 8-year-old children infected with P. falciparum alone had lower Hb and higher sTfR concentrations compared with children coinfected with hookworm, whilst serum ferritin concentrations were normal in both groups, suggests that mono-infected children might be more prone to anemia due to tissue iron deficiency, potentially associated with inflammation [47]. This evidence concerns the gene GSTM1 and anemia (phenotype).