Rainfall and drought linked to childhood growth outcomes in Uganda

HERSHEY, Pa. — Rainfall and long-term water availability in a region before a woman becomes pregnant and during pregnancy predicted future growth outcomes of children in Uganda, according to new research led by a team from the Penn State Health Milton S. Hershey Medical Center and the Penn State College of Medicine. Women living in an area that did not receive adequate rainfall or experienced drought were more likely to give birth to children who don’t grow at the expected rate for their age between birth and age five. Children who are under-nourished and behind in their growth are more susceptible to infections and may experience cognitive, physical and metabolic developmental impairments.

These environmental factors, like rainfall, influence the availability of food, the researchers said, which, in turn, can affect a woman’s nutritional status before and during pregnancy. If a mother doesn’t eat enough or is under-nourished, the effect can be passed on to her child — the child may be born at a low birth weight or experience growth faltering.

The findings, published today (March 19) in the journal JAMA Network Open, could help inform the design of precision public health programs to improve women’s nutrition and improve children’s nutritional outcomes at birth and later in life.

“This is the first paper to tease out longer-term weather dynamics and how they may affect child nutrition status,” said Paddy Ssentongo, infectious disease fellow, Penn State Health Milton S. Hershey Medical Center and lead author of the study. “If a child is born within a specific time period, in a specific environment and under specific conditions, we are able to predict whether or not they would be malnourished.”

Children who falter in their growth — those who experience stunting, where their height is significantly below the average for their age, or wasting, where they were too thin for their height — often begins at or shortly after birth. Stunting, the researchers explained, is a long-term response to poor dietary intake or repeated illness while wasting can be an acute response to undernutrition.

Previous research on risk factors for malnutrition have focused on economic status and food availability, the researchers explained. However, few studies have looked at why people in countries like Uganda, which have environments conducive to agriculture, experience under-nutrition. Did environmental factors such as rainfall, drought, temperature and the land’s topography — factors that sustain agriculture production — influence the risk of malnutrition in children?

The team set out to understand the prevalence of malnutrition among children in Uganda and how environmental factors affected the risk of malnutrition. Ssentongo explained that Uganda served as a good representative for Sub-Saharan Africa as well as for low- and middle-income countries. It also served as an example of areas within high-income countries where food isn’t easily accessible.

Using the 2016 Ugandan Demographic and Health Survey, they analyzed data on weight and length or height, depending on the child’s age, for over 5,200 children between birth and just under five years old. The researchers assessed each child according to growth curves from the World Health Organization to determine how each child compared to the average for their age.

They found that more than 30% of children had stunting, which translates to an estimated 2.2 million of the 7.2 million children under the age of five. Over 12% of children were underweight, and nearly 4% had wasting, indicating a failure to gain weight or severe weight loss. The incidence of stunting was particularly high in the northeastern and western regions of the country, where 40% of children under five years old were short for their age.

The team then examined the relationship between meteorological and environmental factors and childhood malnutrition outcomes. Using data from the National Oceanic and Atmospheric Administration and NASA, they looked at factors such as rainfall, temperature and drought at a village level, from 12 months before the child’s birth to when they were born.

“With this data, we were able to look at the long-term effect of weather and capture periods of drought, not just whether it rained today,” Ssentongo said.

The team mapped the children to their geographical location, down to a one kilometer by one kilometer scale. They found that if a mother lived in a location with higher rainfall 11 months before birth — or up to two months before conception — her child had a lower risk of being malnourished. Conversely, if a mother lived in a location that experienced drought three months before birth, her child had a higher risk of malnutrition.

The researchers also noted that they expected to find that areas of higher poverty were associated with poor growth outcomes, but they didn’t find such a link.

“It’s often assumed that socioeconomic status is a primary driver of malnutrition due to limited access to nutritious food, but our analysis suggests that there are other actionable factors at play,” Ssentongo said.

Understanding how these environmental factors influence nutrition and growth outcomes in children and the spatial distribution of these outcomes can help inform the design of more cost-effective and precise public health programs, the researchers explained. In addition to sending food aid to regions of a country that have the highest burden of malnutrition, public health official could also identify areas that are struggling with water availability.

“We can prevent kids from being malnourished from day one or even before they are born,” Ssentongo said. “We can make water available through irrigation or provide ‘smart seeds,’ which can still grow in harsh and water-poor environments. By doing this even before the babies are born, we are setting up mothers for success, pregnancies for success and these babies will be born healthy.”

Other Penn State authors on the paper include Jessica Erison, associate professor of pediatrics; Helen Greatrex, assistant professor of geography and statistics; and Steven Greybush, associate professor of meteorology. Laila Al-Shaar was an assistant professor at the Penn State College of Medicine during the time of the research.

Other authors on the paper include Claudio Fronterre at Lancaster University in the United Kingdom; Ming Wang at Case Western Reserve University; Philip Omadi, Joseph Muvawala, Pamela Mbabazi and Abraham Muwanguzi at the National Planning Authority in Uganda; Laura Murray-Kolb at Purdue University; and Steven Schiff at Yale University.

Funding from the National Institutes of Health supported this work.