Global progress in combating child malnutrition masks problem spots

The percentage of children with serious malnutrition decreased around the world from 2000 to 2017, a new study finds. But the problem stayed flat or even worsened in some countries, including swaths of Nigeria, Congo, Pakistan, Afghanistan and Guatemala. And trouble spots remained in even relatively well-off countries such as China and Peru, researchers report January 8 in Nature.

“There are areas that have been left behind,” says Damaris Kinyoki, a public health expert at the University of Washington in Seattle. The results were especially disappointing for middle-income countries, she says. “We expected them to have better progress.”  

Prolonged childhood malnutrition is associated with lifelong cognitive and physical impairments, or even death. It’s difficult to directly measure so researchers use a proxy measurement called childhood growth failure, defined as insufficient height and weight for children under age 5. Typically, growth failure rates are assessed at the state or national level, but that broad geographic scale can obscure more localized health disparities. So municipal leaders can struggle to develop targeted programs for their communities.    

Now, building on their earlier research in Africa, Kinyoki and her colleagues zoomed in individually on almost 3.7 million five-kilometer-square “pixels” across 105 low- and middle-income countries — an area encompassing 99 percent of all children suffering from malnutrition. The team then estimated annual childhood growth failure rates in each pixel from 2000 to 2017 using information from household surveys representing 4.6 million children.

All surveys documented children’s age, weight, height and gender, which the researchers used to calculate the three components of growth failure: stunting (short stature for age), wasting (low weight for height) and underweight (low weight for age). While stunting arises from chronic malnutrition, wasting arises from acute events, such as drought, famine or conflict, and is often lethal.

Serious malnutrition among children under 5 has been going down worldwide, the researchers found. For instance, across the 105 countries studied, childhood stunting — the most prevalent and widespread indicator of growth failure — dropped from 36.9 percent in 2000 to 26.6 percent in 2017, the team estimates, although 176.1 million children under 5 were still stunted in 2017. Areas that saw the most progress include Central America, the Caribbean, the Andean region of South America, North Africa, East Asia and some parts of sub-Saharan Africa.

But progress remains slow. Only 28 of those 105 countries are set to meet the World Health Organization’s national-level malnutrition reduction targets for 2025, the researchers found. Those global targets, aimed at children under age 5, include getting the number of stunted children down to about 100 million and reducing wasting levels from about 7.8 percent to less than 5 percent of children. (Some 58.3 million children suffered from wasting in 2017.)

Zooming in further paints a more troubling picture. When the researchers looked at countries set to meet both of those targets in every district, that number dropped to just five countries: Palestine, Paraguay, Peru, Turkmenistan and São Tomé and Príncipe. A district, typically made up of several pixels, is the equivalent of a town or suburb.

That discrepancy between national- and district-level data revealed widespread disparities within countries. For instance, although Peru on average has achieved the WHO’s national-level target for stunting, almost of a third of children in the central provinces of Angaraes and Huancavelica are still affected. Similarly, though South Africa has dropped its countrywide wasting level to less than 5 percent of children under 5, that success masks higher wasting rates in 10 of the country’s districts. For instance, in the district of Central Karoo in Western Cape Province, wasting rates still hover around almost 9 percent.

These sorts of mapping projects should be approached with caution, says geographer Andrew Tatem of the University of Southampton in England. The surveys used can vary widely in quality, and overall population counts for many countries may be out of date. But, Tatem adds, such maps still provide an invaluable tool for policy makers, particularly those working to understand the global picture. “It’s the best estimate [of childhood malnutrition] given existing data.”