Temporal stability of child growth associations in Demographic and Health Surveys in 25 countries.

BACKGROUND: Socio-economic and demographic determinants of child growth at ages 0-5 years in developing countries are well documented. However, Precision Public Health interventions and population targeting require more finely grained knowledge about the existence and character of temporal changes in child growth associations. METHODS: We evaluated the temporal stability of associations between height-for-age z-score (HAZ) of children aged 0-59 months and child, parental, household, and community and infrastructure factors by following 25 countries over time (1991-2014) in repeated cross-sections of 91 Demographic and Health Surveys using random effect models and Wald tests. RESULTS: We found that child growth displayed relatively more time stable associations with child, parental, and household factors than with community and infrastructure factors. Among the unstable associations, there was no uniform geographical pattern in terms of where they consistently increased or decreased over time. There were differences between countries in the extent of temporal instability but there was no apparent regional grouping or geographic pattern. The instability was positively and significantly correlated with annual changes in HAZ. CONCLUSIONS: These findings inform about the generalizability of results stemming from cross-sectional studies that do not consider time variation - results regarding effects of child, parental, and household factors on HAZ do not necessarily need to be re-evaluated over time whereas results regarding the effects of infrastructure and community variables need to be monitored more frequently as they are expected to change. In addition, the study may improve the Precision Public Health population targeting of interventions in different regions and times - whereas the temporal dimension seems to be important for precision targeting of community and infrastructure factors, it is not the case for child, parental, and household factors. In general, the existence of temporal instability and the direction of change varies across countries with no apparent regional pattern.

Age-Specific Correlates of Child Growth.

Growth faltering describes a widespread phenomenon that height- and weight-for-age of children in developing countries collapse rapidly in the first two years of life. We study age-specific correlates of child nutrition using Demographic and Health Surveys from 56 developing countries to shed light on the potential drivers of growth faltering. Applying nonparametric techniques and exploiting within-mother variation, we find that maternal and household factors predict best the observed shifts and bends in child nutrition age curves. The documented interaction between age and maternal characteristics further underlines the need not only to provide nutritional support during the first years of life but also to improve maternal conditions.

What has driven the decline of infant mortality in Kenya in the 2000s?

Substantial declines in early childhood mortality have taken place in many countries in Sub-Saharan Africa. Kenya's infant mortality rate fell by 7.6 percent per year between 2003 and 2008, the fastest rate of decline among the 20 countries in the region for which recent Demographic and Health Survey (DHS) data are available. The average rate of decline across all 20 countries was 3.6 percent per year. Among the possible causes of the observed decline in Kenya is a large-scale campaign to distribute insecticide-treated bednets (ITN) which started in 2004. A Oaxaca-Blinder decomposition using DHS data shows that the increased ownership of bednets in endemic malaria zones explains 79 percent of the decline in infant mortality. Although the Oaxaca-Blinder method cannot identify causal effects, given the wide evidence basis showing that ITN usage can reduce malaria prevalence and the huge surge in ITN ownership in Kenya, it is likely that the decomposition results reflect at least in part a causal effect. The widespread ownership of ITNs in areas of Kenya where malaria is rare suggests that better targeting of ITN provision could improve the cost-effectiveness of such programs.