Effect of malnutrition on child mortality

cooperating nations. Intellectual property agreements are negotiated among participating institutions to ensure that economic benefits

accrue

to

local

communities

and

indigenous peoples involved in the discovery of the natural product. Toward this end, contributions from pharmaceutical companies include screening for therapeutic potential, training opportunities, equipment donations, financial support, and a percentage of royalties from the sales of products developed from this programme. Five cooperative grants have been awarded in the pilot phase of this programme, representing twenty research institutes in Africa, in Central, North, and South America, and in the USA, as well as pharmaceutical companies in the USA and elsewhere. Projects led by Dr David Kingston of Virginia Polytechnic Institute and State University, Dr Walter Lewis of Washington University, Dr Jerrold Meinwald of Cornell University, Dr Brian Schuster of Walter Reed Army Institute of Research, and Dr Barbara Timmermann of the University of Arizona are under way in the rainforests of Suriname, Cameroon, and Nigeria, the cloud forests of Peru, the dry forests of Costa Rica, and the deserts of Argentina, Chile, and Mexico. Those of us involved in the International Cooperative Biodiversity Groups Program share a high degree of enthusiasm and expectation. The programme not only addresses an urgent global challenge for both the environment and public health, but also tests for sustainable development by demonstrating the medical and economic value of biodiversity. Many such efforts are needed and we hope ours will go beyond the pilot phase. Francesca T Grifo ICBG Program, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA

L-

Effect of malnutrition

on

child

mortality

SiR—To explain mortality in children from tropical areas, Pelletier and co-workers proposed a model of multiplicative, and not additive, interaction of malnutrition and disease exposure.’ The model implies that mortality rates are linearly related to the product of disease exposure and malnutrition. Hence loge (mortality) should be linearly related to malnutrition, which was indeed observed in a reanalysis of 6 studies’ in which weight for age was taken as an indicator of malnutrition. Booth (March 5, p 554) emphasised that, if the model is correct, mild malnutrition has a much greater effect upon child mortality than previously thought. In our sample of 4238 children from Zaire,23-month mortality and weight for age Z scores were exponentially related (figure, upper panel). The log linearity predicted by the Pelletier model was not observed, and neither was it seen with weight for height or mid-upper-arm circumference for age (MUAC-FA) Z scores (figure, middle panel). First, loge (mortality) decreases between weight for age Z score -1 and - 2, as was also seen in the data of Chen et aP and Vella et al.4 Second, there is an acceleration of loge (mortality) increase at Z score -3. No initial decrease in weight for height and MUAC-FA is found, but the acceleration, at -3 Z score for MUAC-FA and at -2 Z score for weight for height remains. Our results do not exclude an underlying multiplicative interaction between malnutrition and disease exposure but suggest that other mechanisms may be

involved too. The figure (lower panel) depicts

a hypothetical model how several factors that influence severity of protein-energy malnutrition could be related to weight for age and mortality. It takes into account that children with normal anthropometric scores can be malnourished, even

JIiVIG z-

Figure: Relations between malnutrition and mortality PEM=protein-energy malnutrition.

severely. The model supposes that the acute more dangerous forms of protein-energy malnutrition have a higher weight for age than the chronic ones. Furthermore, the degrees of metabolic depletion and of immunodeficiency are expected to be negatively related to weight for age. All these factors might explain the initial decrease in mortality and the acceleration below -3 Z score, as we observed. We agree that the "risk factor" approach to nutritional intervention, limiting nutritional support to children below some anthropometric points, is inappropriate because only the top of the iceberg of malnutrition is reached. However, the "risk factor" and "community" approaches should not be considered mutually exclusive. Those children who, in spite of community action, become severely malnourished, deserve detection and special therapeutic attention. Jan Van den

Broeck, Roger Eeckels

Department of Paediatrics, University of Leuven, 3000 Leuven, Belgium

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Pelletier DL, Frongillo EA, Habicht JP. Epidemiologic evidence for a potentiating effect of malnutrition on child mortality. Am J Public Health 1993; 83: 1130-33. Van de Broeck J, Eeckels R, Vuylsteke J. Influence of nutritional status on child mortality in rural Zaire. Lancet 1993; 341: 1491-95. Chen LC, Chowdhury A, Huffman SL. Anthropometric assessment of energy-protein malnutrition and subsequent risk of mortality among preschool aged children. Am J Clin Nutr 1980; 33: 1836-45. Vella V, Tomkins A, Ndiku J, Marshal T, Cortinovis I. Anthropometry as a predictor for mortality among Ugandan children, allowing for socio-economic variables. Eur J Clin Nutr 1994; 48: 189-97. Van den Broeck J, Meulemans W, Eeckels R. Nutritional assessment: the problem of clinical-anthropometrical mismatch. Eur J Clin Nutr

1994;

48: 60-65.

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