Iron deficiency and malaria as determinants of anaemia in African children

Approximately three quarters of east African children <5 y of age suffer from anaemia, which is due, at least in part, to malaria and iron deficiency. In children in areas of seasonal malaria, the benefits of iron supplementation may not outweigh possible inherent risks of adverse effects caused by malaria. Intermittent administration of sulfadoxine-pyrimethamine (SP) might improve haemoglobin concentrations while allowing children to develop protective immunity against severe disease and subsequent death caused by malaria. With a view to contribute to the development of programmes for anaemia control in preschool children in Africa, the immediate objectives of this thesis were as follows: 1) to measure the efficacy in improving haemoglobin concentrations in children aged 2-36 mo of intermittent iron supplementation and intermittent administration of SP, either alone or when given in combination; 2) to develop and evaluate survey methods for rapid assessment at community level of the burden of anaemia and its risk factors; 3) to contribute to improved methods for diagnosis of anaemia, iron deficiency, and malaria; 4) to evaluate the role of impaired erythropoiesis in the pathogenesis of malarial anaemia.In randomised controlled trial (n=328) in anaemic, asymptomatic children aged 2-36 mo, the effect on change in haemoglobin concentration in the group receiving iron plus sulfadoxine-pyrimethamine relative to the placebo group, adjusted for prognostic factors at baseline, was 12.5 g/L (95% CI: 8.5 to 16.4 g/L). In the former group, the estimated prevalence of anaemia reduced from 100% at baseline to 36% at 12 w, and prevalence of iron deficiency reduced correspondingly from 66% to 8%. Administration of SP in addition to iron supplementation gave no haemoglobin response. Survival analysis indicated no evidence of increased risk of malaria following iron supplementation. Iron supplementation over a 12-week period resulted in a marked improvement of haemoglobin concentrations.Analysis of haematological indicators from both the trial and a cross-sectional study (n=318) suggested that malaria-induced haemolysis is accompanied by increased erythropoiesis, which seemed adequate for the resulting degree of anaemia. Serum transferrin receptor concentration is not useful to detect iron deficiency in individuals with malaria. Inflammation probably plays no or a minor role in the pathogenesis of anaemia associated with asymptomatic malaria.A new and inexpensive colour scale to facilitate anaemia diagnosis in developing countries performed satisfactory and was for many purposes superior to all other methods for detection of anaemia at primary care level. The methodology presented may facilitate development of strategies for its use in various target groups. A large proportion of unnecessary treatments for febrile diseases can be avoided by teaching mothers to palpate their child's forehead, and by confirming the presence of fever by thermometer.