Evidence of malnutrition having a threshold effect on the risk of childhood diarrhoea in Zimbabwe

Abstract

Objective: Diarrhoeal disease is a major cause of childhood morbidity and mortality in Zimbabwe. This paper examines the relationship between diarrhoea and malnutrition to determine whether there is a threshold effect in operation.

Design: Multivariate analysis of a retrospective survey.

Setting/subjects: Using a nationally representative sample, the Zimbabwe Demographic and Health Survey, 1994, collected diarrhoeal, anthropometric and socio-economic data for 2,073 children aged 0 to 35 months.

Results: Age of the child, residence, and severe stunting and wasting were found to be significant predictors of childhood diarrhoea. However, moderate stunting and wasting failed to show any relationship.

Conclusions: Moderate malnutrition is the main nutritional complaint in Zimbabwe. Thus malnutrition may have a relatively small role in determining the prevalence of childhood diarrhoea. Instead, factors related to exposure--namely sanitation, water supply, population density and hygiene--may be more important. Consequently supplementary feeding programmes should work in tandem with initiatives to reduce exposure if the morbidity burden of children is to be reduced.

PIP: Multivariate analysis of data collected in the 1994 Zimbabwe Demographic and Health Survey on 2073 children 0-35 months of age failed to document the expected linear relationship between malnutrition and diarrheal disease. The diarrheal prevalence in the 2-week period preceding the survey was 23.6%. Infants 6-11 months of age were 2.91 times more likely than younger infants to have had diarrhea. The diarrhea risk remained high in the 12-17 and 18-23 month age groups--periods of increased exposure to intestinal pathogens through supplementary feeding and exploration of hazardous living environments--then declined sharply. Rural children had a 55% greater diarrhea risk than their urban counterparts, presumably because of their greater exposure to intestinal pathogens. Children living in a household without a radio were 21% more likely to have had diarrhea than those who did. Moderate stunting and wasting were not associated with diarrhea risk; however, severely stunted children were 1.47 times more likely than children of normal height and severely wasted children were 4.14 times more likely than those of normal weight to have diarrhea. These findings suggest that malnutrition has a threshold rather than linear effect on the prevalence of diarrhea. Unless exposure to intestinal pathogens is also addressed, interventions that seek to lower levels of moderate malnutrition may have only a limited impact on diarrhea prevalence. Recommended are supplementary feeding programs that operate in tandem with initiatives to improve environmental health.