Impact of intestinal helminthiases on the nutritional status of primary-school children in Osun state, south-western Nigeria

In January-March 2000, the impact of intestinal helminthiases on the nutritional status of 749 pupils (353 boys and 396 girls) attending public primary schools in the Ife Central local government area of Osun state, in south-western Nigeria, was investigated. Demographic, socio-economic and other relevant information was collected on the pupils, on the same day that a single stool sample was collected from each subject and examined, using Stoll's dilution egg-count technique. The weights, heights and ages of the subjects were recorded and converted to percentages of the reference medians for weight-for-height, weight-for-age and height-for-age. The overall prevalences of helminth infection detected among the 465 malnourished pupils (i.e. those with any form of under-nutrition) and the 284 well-nourished pupils were 32.9% and 25.4%, respectively (P=0.029). The nutritional indices of the pupils who were found helminth-infected were generally lower than those of the pupils who appeared free of intestinal helminths. The mean values for weight-for-height, for example, were higher in the apparently uninfected pupils than in those found infected with any intestinal helminth (P=0.02) or only with Ascaris lumbricoides (P=0.05). Similarly, the mean height-for-age of the pupils who were apparently uninfected was higher than the corresponding value for the pupils found hookworm-positive (P=0.003). The pupils who were each found infected with two or more species of intestinal infection had significantly lower weights-for-heights, weights-for-ages and heights-for-ages than the pupils who appeared to be helminth-free. The results of a multivariate logistic-regression analysis indicated that hookworm infection was a significant risk factor for underweight (P=0.015), wasting (P=0.033) and stunting (P=0.015) whereas Trichuris was only a significant risk factor for stunting (P=0.025). It appears that intestinal helminthiasis may play a causal or contributory role in the occurrence of childhood malnutrition, at least in the present study area. Steps should be taken to control both of these important health problems, through functional school-health programmes that provide regular deworming, supervised school meals and health education.