An estimated 32.9% % of all 3- and 4-yr old children living in low- and middle-income countries scored poorly on either their cognitive or socioemotional development, according to a study published by Dana McCoy and colleagues from Harvard University, Boston, USA, in PLOS Medicine.

The researchers used data collected between 2005 and 2015 based on caregiver report using the Early Childhood Development Index (ECDI) for 99,222 3- and 4-y-old children living in 35 LMICs as part of the Multiple Indicator Cluster Survey (MICS) and Demographic and Health Surveys (DHS) programs. They estimated that 14.6% of children in these 35 countries had low ECDI scores in the cognitive domain, 26.2% had low socioemotional scores, and 36.8% performed poorly in either or both domains. Of the 35 LMICs studied, those with the highest percentage of low-scoring children included Chad (67.0%), Sierra Leone (54.3%), and Central African Republic (54.1%), while those with the lowest percentage included Bosnia (4.4%) and Montenegro (4.3%). When extrapolating models to all LMICs, the authors estimate that 80.8 million 3- and 4-y-old children - or 32.9% of those living in these countries - are failing to meet basic cognitive or socioemotional milestones. An additional 16.7% of children are estimated to do well with respect to their cognitive and socioemotional development, but experience stunted physical growth.

The measure used to define cognitive and socioemotional development in this study focused on a narrow range of early skills, including children's ability to follow simple directions, work independently, control aggression, avoid distraction, and get along well with other children. Future research is needed to examine a broader range of developmental skills and age groups, as well as to identify possible interventions for mitigating these developmental setbacks.

Developmental deficits are most common in the poorest countries of the world. As the authors write: "Low development scores were largely concentrated in areas of the world facing continued high exposure to risk factors such as infectious disease, malnutrition, poverty, and low availability of high-quality healthcare and educational resources."

This study was supported by Grand Challenges Canada, which is funded by the Government of Canada.

Funding for the present study was provided by the Saving Brains Program from Grand Challenges Canada (grant number 0073-03;http://www.grandchallenges.ca/saving-brains/). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

The authors have declared that no competing interests exist.

Article: Early Childhood Developmental Status in Low- and Middle-Income Countries: National, Regional, and Global Prevalence Estimates Using Predictive Modeling, McCoy DC, Peet ED, Ezzati M, Danaei G, Black MM, Sudfeld CR, et al., PLOS Medicine, doi:10.1371/journal.pmed.1002034, published 7 June 2016.