Malnutrition, Morbidity, and Mortality

This paper reviews clinical epidemiological and experimental studies of mild and moderate malnutrition and child survival. 2 general issues are discussed as a preface: 1) the measurement of mild and moderate malnutrition and 2) the factors responsible for their existence. It is argued that anthropometry offers many advantages over other indicators of nutritional status. The foremost is that body measurements are sensitive over the full range of malnutrition. The main disadvantage of anthropometry is its lack of specificity; anthropometric data indicate the presence of a problem but reveal very little about its causes which in developing countries are socioeconomic. The discussion of mild and moderate malnutrition and survival is divided into 4 parts. The 1st deals with immunocompetence and considers whether children with mild and moderate malnutrition are more susceptible to infection. Findings form Nepal India and Colombia suggest that mild and moderately malnourished children have cellular immunity measures consistently lower than those of better nourished children. However the functional significance of these findings remains unmeasured. The 2nd part considers whether the frequency and severity of infections are in fact increased in children with these forms of malnutrition. Clinical studies of the case fatality for common infections are informative yet they have not generally differentiated between grades of malnutrition. Few studies of nutritional status and risk of infection support the notion that nutritional status is associated with a greater incidence of infection. On the other hand a greater number of studies indicate an association with the % of time ill with diarrhea and with the duration of episodes of diarrhea. Although not all studies agree weight-for-height a measure of wasting tends to be a stronger predictor of future illness than height a measure of stunting. Epidemiological evidence on the relationship between nutritional status and mortality is presented in a 3rd part. It suggests that children with mild to moderate malnutrition show some impairment in immunocompetence and that they also tend to have more severe infections than healthy children. 2 of the 3 studies reviewed also show increased mortality risks with mild to moderate malnutrition. To date no investigation has assessed the relationship between longitudinal data in children (i.e. growth velocities) and mortality risks. Finally the effects of nutrition interventions (supplementary feeding programs) on morbidity and mortality are summarized in a 4th part. Although these interventions have been shown to improve nutritional status they have not been shown to reduce the incidence of infections or their severity. On the other hand nutrition intervention studies indicate that dietary improvements are associated with lower mortality rates during infancy and early childhood.