Diarrhoea and growth faltering in rural Zimbabwe

Abstract

Objective: To assess the evidence that diarrhoea is an important cause of growth faltering in young children in developing countries.

Design: Prospective, longitudinal cohort study.

Setting: Worker's compounds on commercial farms in Shamva, rural Zimbabwe.

Subjects: 204 children < 12 months old were enrolled, 73 from birth. The median age at enrolment was 4 months. Eleven children died and 39 were lost to follow-up.

Interventions: Prospective weekly diarrhoea surveillance by farm health workers and monthly anthropometry.

Results: Growth faltering was severe, but there was little difference in average rates of growth between children with frequent diarrhoea and infrequent diarrhoea. The results of an interval-based data analysis were consistent with there being only a transient effect of diarrhoea on weight gain. Estimation of weight faltering following episodes of diarrhoea and the rate of return to the trend in the 9-14 month age range, indicated that weight loss associated with each episode was small (approximately 2%) and return to the child's trend was 90% complete within a month. At older ages than this, weight loss appeared to be less, and estimates were not statistically significant.

Conclusions: These observations lend weight to the hypothesis that recurrent episodes of diarrhoea are not a potent cause of growth faltering in early childhood except in a small minority of largely catastrophic cases. Inadequate food intake is a more plausible explanation.

PIP: In Zimbabwe, health workers collected data on diarrhea incidence every week and anthropometric data once a month from 204 children aged less than 12 months to examine the association between diarrhea and growth faltering. 73 children were enrolled at birth. 148 children were followed throughout the entire study. 11 children died (8 because of diarrhea or protein-energy malnutrition). 39 children were lost to follow-up. The children's parents were farm laborers who lived on large-scale commercial farms in Shamva district. Diarrhea incidence peaked between 13 and 18 months. In 91% of attacks, the diarrhea was watery rather than bloody. 31 children had more than 9 diarrhea episodes (high diarrhea frequency). 25 had no more than 4 diarrhea episodes (low diarrhea frequency). There was little difference in the children's mean weight and mean length from 1 to 30 months of age between high and low diarrhea frequency subjects. The average loss of overall growth per diarrhea episode in the age range 9-23 months was 51 g and 0.18 cm. In the age range of 9-14 months, weight loss after the diarrhea episode was 2.3% of body weight, and 90% of the sudden weight decline below the child's trend was recovered in 30 days. Weight loss was less than 2.3% among older children. A 2.3% weight loss in an 8 kg child is 180 g. Assuming that diarrhea is responsible for the entire weight loss (about 66 g/episode), the reduction in overall growth is about 120 g (1.5%). The total energy needed to accumulate 120 g is 480 kcal; thus, a child would require an additional 2-3 kcal/kg/day (a small amount) to gain 120 g. These findings support the hypothesis that recurrent diarrhea episodes do not induce growth faltering except in a few cases. Inadequate food intake is a more plausible explanation.