Does Anemia Protect Children From Malaria?

It is well known that sickle cell trait can protect carriers from developing malaria; yet iron deficiency anemia offers a greater protective effect against malaria than sickle cell trait, according to research published in EBioMedicine. Treating anemia with iron supplementation, the researchers found, erased this protective effect.

“This study is one of the most substantial and systematic attempts to unveil the cellular-level relationship between anemia, iron supplementation, and malaria risk,” said Carla Cerami, MD, PhD, the study’s corresponding author and faculty member at the Medical Research Council Unit The Gambia in Banjul, Gambia. “The long-term consequences of anemia are severe, and it is easily treatable. However, concerns remain about the safety of iron supplements, particularly for children in malaria-endemic countries lacking adequate access to health services.”

In this study, Dr. Cerami and researchers analyzed the red blood cells of 135 anemic children (age range = 6-24 months; hemoglobin <11 g/dl) who were participating in an iron supplementation trial. Patients lived in a malaria-endemic region of The Gambia where sickle cell trait also was common.

The children received iron 12 mg/day (through micronutrient powder) for 84 days. Patients’ red blood cells were analyzed at baseline, day 49, and day 84. Presence of malaria was determined through in vitro growth and invasion assays.

In the entire study population, anemia reduced the incidence of malaria by 15.9 percent. Previous research demonstrated that sickle cell trait reduced malaria incidence by 3.5 percent. Anemia also substantially reduced both the growth and invasion of malaria, the researchers reported, with a roughly 10 percent reduction in growth per standard deviation shift in hemoglobin.

When patients received iron supplementation, however, those protective effects were reversed. Parasite growth was 2.4-fold higher at day 49 than it was at baseline (p<0.001). These results suggest that iron supplementation should be accompanied by malaria prophylaxis, the researchers noted.

“Our finding that anemia offers greater natural protection against blood-stage malaria infection than sickle cell trait has led us to formulate the interesting hypothesis that the widespread prevalence of anemia in people of African descent is a genetic signature of malaria,” the authors concluded.

Source: Goheen MM, Wegmuller R, Bah A, et al. Anemia offers stronger protection than sickle cell trait against the erythrocytic stage of falciparum malaria and this protection is reversed by iron supplementation. EBioMed. 2017 January 5. [Epub ahead of print]

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