Child growth: a new map of Africa

Geneva, 28 March 2018 - 

Osgood-Zimmerman and colleagues just published an article in Nature that, for the first time, provides high-resolution maps of child growth failure (stunting, wasting, and underweight) across Africa. They mapped data from over 1 million children from 51 countries at a 5×5 km resolution as well as at the largest administrative subdivision from 2000 to 2015.

Much of southern and eastern sub-Saharan Africa as well as coastal areas of western sub-Saharan Africa have made great progress, with many countries on track at the national level to meet the Global Nutrition Targets for stunting and wasting by 2025. However, large differences exist subnationally, and all countries have areas that will not meet the targets if current trends continue. A large burden of stunting, wasting, and underweight remains in the Sahel, where progress has been slow.

The study reveals substantial reductions in stunting over large areas in Algeria, Angola, Mozambique, Zambia, Tanzania, Burkina Faso, Liberia, and Ghana. But prevalence remains particularly high in northwestern and southeastern Nigeria, southern Niger, west central Chad, north central Ethiopia, northeastern Zambia, east central and southeastern Madagascar, most of Burundi, and parts of Democratic Republic of the Congo (DRC) and Tanzania. Wasting had less consistent trends over time and space. A few countries saw overall declines, particularly the DRC, but prevalence in many areas has fluctuated or even increased. High prevalence is confined mostly to the Sahel, the Horn of Africa, northern South Sudan and Kenya, and Madagascar, areas prone to drought and famine. Underweight has declined considerably in many countries, but large differences exist subnationally.

Boy playing with ball in a courtyard in Africa

Boy playing with ball in a courtyard in Africa. © GAIN

The analysis was really well done. To estimate values in areas and years without data, the authors used statistical models that included predictors of nearby locations over time and associated socioeconomic and environmental variables that varied geographically. They also mapped the uncertainty in their estimates, so we can know how confident to be in the results for any given area. The article is available for free online, as well as a supplementary document with additional figures and tables.

There were a few weaknesses. Data used in the analysis was subject to measurement error and did not include children who had died or children from conflict zones, so the prevalence of child growth failure may be even higher. Also, the study did not look at inequalities between subgroups—estimates disaggregated by age, ethnicity, education, wealth, and other sociodemographic variables would help us know who the most vulnerable children are and how to help them. Further, it would have been helpful to see maps of the total number of children who have experienced child growth failure, since population densities vary considerably. Lastly, coordinates of sampling areas where data was collected have been shifted 0-10 km to protect privacy, which reduces the locational accuracy of these estimates.

These new high-resolution maps show us that monitoring progress towards the Global Nutrition Targets at the national level or even the largest administrative subdivision is insufficient and can mask vast disparities in child growth failure within subdivisions. Governments, community leaders, NGO’s, and researchers should use these maps to target vulnerable children subnationally and monitor inequalities. While policies are commonly set at administrative levels, their boundaries often do not correspond with immediate changes in prevalence. GAIN and other actors must challenge national governments to think more critically about program design and advocate for interventions to be targeted and tailored geographically, which can have a greater impact and make more efficient use of resources. The scale of targeting should correspond with the geographical size of high-burden areas, while being programmatically feasible.

The big result is that it is now clear precisely where child growth failure is most common in Africa, which should put pressure on governments and community leaders to act in these areas. Only when we fully embrace a geographical approach to addressing child growth failure will we achieve our shared vision of a world without malnutrition.