Influence of malaria on markers of iron status in children: implications for interpreting iron status in malaria-endemic communities

To investigate Fe nutritional indices in malaria infection in children, haematology (blood haemoglobin, plasma ferritin, transferrin, Fe, and transferrin saturation), acute phase markers (albumin and caeruloplasmin) and liver function tests were studied in fifty consecutive cases of severe and mild falciparum malaria, fifty matched controls and twenty-three cases of asymptomatic malaria. Blood haemoglobin and transferrin were lower, while ferritin and transferrin saturation were higher, in groups with symptomatic malaria in comparison with the control group. The differences were greatest with the severest form of the disease. There were no differences between any of the groups in plasma Fe. Plasma transferrin correlated directly with albumin in asymptomatic, mild and severe malaria groups (r 0.48, 0.65 and 0.83; P < 0.05, P < 0.01 and P < 0.001 respectively), and inversely with caeruloplasmin (r -0.65, -0.34 and -0.43; P < 0.01, P < 0.05 and P < 0.01 respectively). For ferritin, the correlation was inverse with albumin (r -0.65, -0.57 and -0.64; P < 0.01, P < 0.001 and P < 0.001 respectively and direct with caeruloplasmin (r 0.83, 0.21 and 0.49, P < 0.001, NS and P < 0.001 respectively). Multiple regression analysis on data from all patients combined indicated that albumin, and to a lesser extent alanine aminotransferase (EC 2.6.1.2) activity, explained 62 % of the variance in transferrin. Caeruloplasmin, parasite count and albumin explained 59 % of the variance in ferritin, and transferrin and unconjugated bilirubin explained 62 % of the variance in Fe values. In conclusion, these data suggest that low transferrin and high ferritin values are primarily due to the acute phase response. High transferrin saturation and lack of differences in plasma Pe between the groups are probably due to Fe released from lysed erythrocytes. Finally, in both symptomatic and asymptomatic malaria, indices of Fe status can be misleading and may be especially problematic in community studies in malaria-endemic areas where asymptomatic malaria may be common.