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March 5, 2007

Research identifies causes contributing to poor development of over 200 million children worldwide

Theodore Wachs
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Inadequate intellectual stimulation and poor nutrition, especially iodine and iron deficiencies, are likely to blame for hindering more than 200 million children in developing countries from meeting their full potential, says a Purdue University researcher."These problems are robbing children under age 5 of full development, contributing to a cycle of low educational attainment and poverty later in life," said Theodore Wachs, a professor of psychological sciences at Purdue and a lead researcher on the project. "We're not talking about genetics here. These are all preventable risks, which makes the situation that much more urgent."

"Child Development: Risk Factors for Adverse Outcomes in Developing Countries," is the second in a three-part series from Wachs and colleagues across the globe aimed at identifying the scope, causes and current prevention efforts regarding the loss of developmental potential among children in countries from Brazil to Vietnam. The series appeared in successive January editions of The Lancet.

The researchers drew from data in studies performed from 1985 to February 2006 by searching eight databases using keywords such as "developing countries," "cognitive development" and "educational attainment." They also worked with documents published by the World Bank, UNICEF and UNESCO's International Bureau of Education.

UNICEF provided funding for a working group meeting for all of the authors with assistance from the Bernard van Leer Foundation.

Of the major concerns identified, growth stunting could be the most rampant, affecting as many as 40 percent to 50 percent of children under 5 in some developing countries. Stunting, a measure of chronic undernutrition, is often compounded by infectious diseases.

Studies consistently show associations between stunting and later cognitive deficits, with one study in Jamaica indicating that stunted children score lower on IQ tests through age 18.

"Stunted or undernourished children often show more apathy, lower levels of play and more insecure attachment issues than their healthy peers," said Wachs, a member of the International Child Development Steering Group that headed up the work. "In the long-term, we found conduct problems coupled with poor attention and social relationships."

The paper also details the relatively low levels of intellectual stimulation many children in developing countries receive. Researchers found only between 10 percent and 41 percent of parents provide cognitively stimulating materials, such as toys or puzzles, to their children. Even fewer - between 11 percent and 33 percent of parents - actively involved their children in intellectually stimulating activities.

"Proper intellectual stimulation increases both cognitive and social-emotional competencies not only in the short term, but also throughout a child's life," Wachs said.

Iodine deficiency, which was shown to affect about 35 percent of children in developing countries, is the most common preventable cause of mental retardation. An analysis of 12,291 children younger than 16 who grew up in iodine-deficient areas of China were found to have IQs about 12.5 points lower on average than children in other areas.

Nineteen of 21 studies comparing iron-deficient infants with healthy infants found poorer mental, motor, social-emotional and neurophysiologic functioning among those infants with low iron levels.

"We also found that anemic children remained behind their peers even after iron supplementation," Wachs said. "Generally speaking, the sooner children receive supplements, the more good it will do in the long term. It's a strong case for prevention. Our best hope may be to try to reach these children before their iron deficiency becomes severe."

In addition to the problems outlined, the research also identified other less well-studied factors that adversely affect child development enough to warrant intervention, including malaria, maternal depression, exposure to violence, low infant birth weight, and exposure to toxic substances such as arsenic and lead.

"While we looked at these factors individually, it is important to note that many children are simultaneously exposed to more than one of the risk factors identified," Wachs said. "To truly be effective, intervention programs must take account of this."

Wachs said members of the International Child Development Steering Group plan to meet with international relief agencies in October to discuss how the findings from the Lancet series can be used to tailor existing intervention programs or create new ones that better address the causes of developmental deficiencies in children.

"We don't want this to be just another report that sits on a shelf," Wachs said. "To be more than that, we have to make specific recommendations about what is needed and what works best."

Writer: Tanya Brown, (765) 494-2079,

Source: Theodore Wachs, (765) 494-6992,

Purdue News Service: (765) 494-2096;


Child Development: Risk Factors for Adverse Outcomes in Developing Countries

Prof Susan P Walker PhD, Prof Theodore D Wachs PhD, Julie Meeks Gardner PhD, Prof Betsy Lozoff MD, Prof Gail A Wasserman PhD, Prof Ernesto Pollitt PhD, Julie A Carter PhD and the International Child Development Steering Group

Poverty and associated health, nutrition, and social factors prevent at least 200 million children in developing countries from attaining their developmental potential. We review the evidence linking compromised development with modifiable biological and psychosocial risks encountered by children from birth to 5 years of age. We identify four key risk factors where the need for intervention is urgent: stunting, inadequate cognitive stimulation, iodine deficiency and iron deficiency anemia. The evidence is also sufficient to warrant interventions for malaria, intrauterine growth restriction, maternal depression, exposure to violence and exposure to heavy metals. We discuss the research needed to clarify the effect of other potential risk factors on child development. The prevalence of the risk factors and their effect on development and human potential are substantial. Furthermore, risks often occur together or cumulatively, with concomitant increased adverse effects on the development of the world's poorest children.


Developmental Potential in the First 5 Years for Children in Developing Countries

Prof Sally Grantham-McGregor FRCP, Yin Bun Cheung PhD, Santiago Cueto PhD, Prof Paul Glewwe PhD, Prof Linda Richter PhD, Barbara Strupp PhD and the International Child Development Steering Group

Many children younger than 5 years in developing countries are exposed to multiple risks, including poverty, malnutrition, poor health and unstimulating home environments, which detrimentally affect their cognitive, motor and social-emotional development. There are few national statistics on the development of young children in developing countries. We therefore identified two factors with available worldwide data ? the prevalence of early childhood stunting and the number of people living in absolute poverty ? to use as indicators of poor development. We show that both indicators are closely associated with poor cognitive and educational performance in children and use them to estimate that over 200 million children under 5 years are not fulfilling their developmental potential. Most of these children live in south Asia and sub-Saharan Africa. These disadvantaged children are likely to do poorly in school and subsequently have low incomes, high fertility and provide poor care for their children, thus contributing to the intergenerational transmission of poverty.


Strategies to Avoid the Loss of Developmental Potential in more than 200 Million Children in the Developing World

Prof Patrice L Engle PhDa, Prof Maureen M Black PhDb, Prof Jere R Behrman PhD, Meena Cabral de Mello DES psy clind, Prof Paul J Gertler PhDf, Lydia Kapiriri PhDg, Prof Reynaldo Martorell PhDh, Mary Eming Young DrPHe and the International Child Development Steering Group

This paper is the third in the Child Development Series. The first paper showed that more than 200 million children under 5 years of age in developing countries do not reach their developmental potential. The second paper identified four well-documented risks: stunting, iodine deficiency, iron deficiency anemia and inadequate cognitive stimulation, plus four potential risks based on epidemiological evidence: maternal depression, violence exposure, environmental contamination and malaria. This paper assesses strategies to promote child development and to prevent or ameliorate the loss of developmental potential. The most effective early child development programmes provide direct learning experiences to children and families, are targeted toward younger and disadvantaged children, are of longer duration, high quality, and high intensity, and are integrated with family support, health, nutrition, or educational systems and services. Despite convincing evidence, programme coverage is low. To achieve the Millennium Development Goals of reducing poverty and ensuring primary school completion for both girls and boys, governments and civil society should consider expanding high quality, cost-effective early child development programmes.

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