Serum ferritin, erythrocyte protoporphyrin and hemoglobin are valid indicators of iron status of school children in a malaria-holoendemic population

In many African populations, the prevalences of both iron deficiency and malarial infection exceed 50%. The control of iron deficiency anemia is of urgent public health importance, but assessment of iron status in these contexts has been controversial because of the effects of malarial disease on common iron status indicators. We assessed iron status in 3605 school children in Zanzibar by measuring hemoglobin, erythrocyte protoporphyrin (EP) and serum ferritin concentrations. Malaria parasitemia was quantified by counting against leukocytes. Iron deficiency was highly prevalent: 62.4% of hemoglobin concentrations were <110 g/L, 59.7% of EP values were >80 mu mol/mol heme, and 41.5% of ferritin concentrations were <12 mu g/L. Prevalence of Plasmodium falciparum parasitemia was 60.6%, but <1% of children had densities above 5000 parasites/mu l blood. Neither hemoglobin nor EP concentration was associated with malaria parasite density, but prevalence of abnormal values increased by less than or equal to 25% with parasite density. Erythrocyte protoporphyrin and hemoglobin were strongly inversely related regardless of parasite density. The relationship of EP to hemoglobin was slightly attenuated when parasite density exceeded 1000 parasites/mu l blood. Ferritin rose by 1.5 mu g/L per 1000 parasites/mu l for parasite densities >1000 parasites/mu l, but the relationship of ferritin to hemoglobin or EP was strong even when parasite densities exceeded this cutoff. The population prevalences of iron deficiency were not significantly biased by malarial infection. In this population of school children, iron status assessment using these indicators was not seriously influenced by malarial infection. We hypothesize that these indicators perform reliably in populations in which malarial infection is infrequently associated with disease; namely older children and adults in holoendemic environments.