Iron status and associated malaria risk among African children

Background It remains unclear whether improving iron status increases malaria risk, and few studies have looked at the effect of host iron status on subsequent malaria infection. We therefore aimed to determine whether a child’s iron status influences their subsequent risk of malaria infection in sub-Saharan Africa. Methods We assayed iron and inflammatory biomarkers from community-based cohorts of 1309 Kenyan and 1374 Ugandan children aged 0 - 7 years and conducted prospective surveillance for episodes of malaria. Poisson regression models were fitted to determine the effect of iron status on the incidence rate ratio of malaria using longitudinal data covering a period of 6 months. Models were adjusted for age, sex, parasitemia, inflammation and study site. Results At baseline, the prevalence of iron deficiency (ID) was 36.9% and 34.6% in Kenyan and Ugandan children, respectively. Iron deficiency anemia (IDA) affected 23.6% of Kenyan and 17.6% of Ugandan children. Malaria risk was lower in children with ID (IRR = 0.7; 95% CI: 0.6, 0.8; p≺0.001) and IDA (IRR = 0.7; 95% CI: 0.6, 0.9; p=0.006). Low transferrin saturation (≺10%) was similarly associated with lower malaria risk (IRR = 0.8; 95% CI: 0.6, 0.9; p=0.016). However, variation in hepcidin, soluble transferrin receptors (sTfR) and hemoglobin / anemia was not associated with altered malaria risk. Conclusions ID appears to protect against malaria infection in African children when defined using ferritin and transferrin saturation, but not when defined by hepcidin, sTfR or hemoglobin. Further research is required to determine causality.