A methodology for estimating the contribution of malnutrition to child mortality in developing countries

According to conventional methods of classifying cause of death, approximately 70% of child deaths (0-4 y) worldwide are due to a small number of priority infectious diseases which, in turn, receive the vast majority of donor and national resources in the health sector. Despite the long-recognized synergism between malnutrition and infection in the causation of child mortality, malnutrition does not appear as a major cause of death in health statistics from developing countries. Part of the reason for this has been the difficulty of estimating the percent of deaths due to malnutrition, because the conventional methods of classifying cause of death do not recognize the potentiating effect of malnutrition on the disease. The purpose of this paper is to develop and test a simple methodology to estimate the percent of child deaths in a given country or community that is due to malnutrition's potentiating effects on prevailing infectious diseases. The cornerstone of the methodology is knowledge of the strength of the association between malnutrition and mortality in developing countries, as measured in eight prospective studies. These studies reveal remarkable consistency in relative risk across different grades of malnutrition. The mean and SE of relative risk for severe malnutrition is 8.4 +/- 2.1, for moderate malnutrition it is 4.6 +/- 0.9, and for mild malnutrition it is 2.5 +/- 0.3. When applied to survey data from Ethiopia, Malawi, Guatemala and India for illustrative purposes, this methodology indicates that 42-57% of all child deaths in these samples (6-59 mo) are due to malnutrition's potentiating effects on infectious disease, of which 76-89% is attributable to mild-to-moderate malnutrition. This methodology is recommended for use in a variety of policy and planning applications.