One third of young children living in developing nations are failing to meet basic mental development milestones, which could adversely affect their health, success in adulthood, and education levels, researchers said on Tuesday.

Nearly 81 million children between three and four were not meeting basic developmental benchmarks with the highest numbers of affected children coming from sub-Saharan Africa, including Chad, Sierra Leone and Central African Republic, they said in a report.

While poverty and malnutrition are contributing factors, more research needs to be done to understand the root causes of the problem, according to Dana McCoy, lead author of the study which uses data from the U.N. children's agency UNICEF and the U.S. Agency for International Development.

"By virtue of the fact that these children are not meeting these milestones doesn't mean they can't go on to have a very healthy, happy and productive life," said McCoy, who conducted the study with the Harvard T.H. Chan School of Public Health and funding body Grand Challenges Canada.

"There are a number of programs and interventions that can be implemented at any age group to really support children's development, help them to thrive in their settings."

Children were assessed on their ability to follow simple directions, work independently, maintain attention, get along with others, and inhibit aggressive behaviors such as hitting and kicking.

McCoy said mental development was essential in predicting a child's transition into adulthood, setting the foundation for school readiness, mental and physical wellbeing, as well as economic earnings later in life.

Since fewer children are dying from malnutrition and preventable diseases, the international community should now start to focus on the potential of children, and not just their survival, McCoy added.

"With a lot of the efforts that have been made internationally in the public health and medical realm, we've come to a lot of success in helping children to survive," McCoy, an assistant professor at the Harvard Graduate School of Education, told the Thomson Reuters Foundation.

"But now we're moving into an era where we can not only help children to survive, but really focus on helping them to thrive."

Nearly half of all under-five deaths are associated with malnutrition, according to the World Health Organisation, but the rate of improvement is accelerating, with child mortality falling quicker since the millennium than it did in the 1990s.

McCoy noted that despite the challenges, the majority of young children living in poor nations are meeting developmental benchmarks.

"There are a number of children who are quite resilient and they are able to thrive and so we can and should look to those children as examples of how to really think about development"

Source: Reuters