The Lancet  
Oct 08, 2011  Volume 378  Number 9799  p1275 – 1354
http://www.thelancet.com/journals/lancet/issue/current

Editorial
Early child development—a winning combination
The Lancet

Preview
4 years ago, a Lancet Series on child development reported that worldwide, more than 200 million children younger than 5 years were failing to reach their developmental potential. In today’s issue a follow-up Series documents progress in reduction of risk factors for poor development, such as inadequate cognitive stimulation, intrauterine growth restriction, HIV infection, and societal violence. The poorest and most vulnerable children benefit most from interventions, such as preschool programmes, because risk factors accumulated over a child’s short life produce greater inequality in educational achievements and development.

Series
Inequality in early childhood: risk and protective factors for early child development
Susan P Walker, Theodore D Wachs, Sally Grantham-McGregor, Maureen M Black, Charles A Nelson, Sandra L Huffman, Helen Baker-Henningham, Susan M Chang, Jena D Hamadani, Betsy Lozoff, Julie M Meeks Gardner, Christine A Powell, Atif Rahman, Linda Richter

Summary
Inequality between and within populations has origins in adverse early experiences. Developmental neuroscience shows how early biological and psychosocial experiences affect brain development. We previously identified inadequate cognitive stimulation, stunting, iodine deficiency, and iron-deficiency anaemia as key risks that prevent millions of young children from attaining their developmental potential. Recent research emphasises the importance of these risks, strengthens the evidence for other risk factors including intrauterine growth restriction, malaria, lead exposure, HIV infection, maternal depression, institutionalisation, and exposure to societal violence, and identifies protective factors such as breastfeeding and maternal education. Evidence on risks resulting from prenatal maternal nutrition, maternal stress, and families affected with HIV is emerging. Interventions are urgently needed to reduce children’s risk exposure and to promote development in affected children. Our goal is to provide information to help the setting of priorities for early child development programmes and policies to benefit the world’s poorest children and reduce persistent inequalities.

Strategies for reducing inequalities and improving developmental outcomes for young children in low-income and middle-income countries
Patrice L Engle, Lia CH Fernald, Harold Alderman, Jere Behrman, Chloe O’Gara, Aisha Yousafzai, Meena Cabral de Mello, Melissa Hidrobo, Nurper Ulkuer, Ilgi Ertem, Selim Iltus, the Global Child Development Steering Group

Summary
This report is the second in a Series on early child development in low-income and middle-income countries and assesses the effectiveness of early child development interventions, such as parenting support and preschool enrolment. The evidence reviewed suggests that early child development can be improved through these interventions, with effects greater for programmes of higher quality and for the most vulnerable children. Other promising interventions for the promotion of early child development include children’s educational media, interventions with children at high risk, and combining the promotion of early child development with conditional cash transfer programmes. Effective investments in early child development have the potential to reduce inequalities perpetuated by poverty, poor nutrition, and restricted learning opportunities. A simulation model of the potential long-term economic effects of increasing preschool enrolment to 25% or 50% in every low-income and middle-income country showed a benefit-to-cost ratio ranging