The influence of livestock ownership and health on the nutritional status of children under 5 years old in Eastern Africa
In many rural low-resource settings, chronic malnutrition-induced linear growth faltering is widely prevalent. In these same areas, household livestock ownership is ubiquitous. Livestock may positively or negatively influence nutritional status through a variety of pathways, including improving food security but also increasing exposure to infectious diseases. We sought to determine whether 1) livestock ownership and 2) livestock disease were associated with growth outcomes among children under five years of age in Eastern Africa.
We used two data sources to address these aims. To test whether livestock ownership influenced child growth outcomes, as measured by stunting prevalence (<-2 standard deviations of Height-for-Age Z-score), we first analyzed the most recent Demographic and Health Surveys (DHS) for Ethiopia (2011), Kenya (2008-2009), and Uganda (2011). We also evaluated the question of livestock ownership and child growth within an ongoing Kenya Medical Research Institute (KEMRI)-Centers for Disease Control (CDC) demographic and health surveillance cohort in rural Western Kenya. The cohort monitors both human and livestock disease, and our team incorporated monthly anthropometry measurements for children. Using data from both the DHS and the surveillance cohort, we tested whether higher numbers of livestock ownership were associated with child nutrition outcomes using linear regression models clustered by household. To assess whether livestock health status was associated with child growth outcomes, we used the Western Kenya surveillance data to evaluate each child’s overall and time-varying exposure to livestock disease and subsequent growth using linear mixed regression models.
The DHS analysis included n=8079 children from Ethiopia, n= 3903 children from Kenya, and n=1645 from Uganda. A ten-fold increase in household livestock ownership was significantly associated with lower stunting prevalence in Ethiopia (Prevalence Ratio [PR] 0.95, 95% CI 0.92-0.98) and in Uganda (PR 0.87, 95% CI 0.79-0.97), but not in Kenya (PR 1.01, 95% CI 0.96-1.07). In the surveillance cohort in Western Kenya, we monitored the growth of 1097 children at least once over the course of 11 months. Higher household livestock ownership at baseline was not related to baseline child height-for-age z-score (β= 0.006 SD, 95% CI -0.02, 0.04) or prospective monthly child growth rate (β=0.002cm, 95% CI -0.003, 0.006). Further, over the entire duration of follow-up, higher numbers of any livestock disease in a household was not related to average 6 monthly growth rate of children in the same household (under 2 β= -0.045, 95% CI -0.186, 0.096; over 2 years β=0.006, 95% CI-0.031, 0.044). However, in the time-varying models of acute livestock disease and 3-month child growth intervals, we observed a trend by which children grew less after exposure to livestock disease, particularly among those children under age two.
The DHS analysis for Ethiopia, Kenya, and Uganda demonstrated a small beneficial impact of livestock ownership on reducing child stunting. The small effect size may be related to limitations of the DHS dataset or the potentially complicated relationship between malnutrition and livestock ownership, including livestock health and productivity. In the cohort of children in Western Kenya, ownership of livestock did not appear to be significantly associated with improvements in linear growth. However, disease in livestock may be associated with short term growth detriment. One Health, a concept by which human, animal, and environmental health improvement are integrated, provides approaches to prevent disease in livestock may promote optimal child growth and nutrition in rural households.