Interventions to promote development in the next 1000 days: A mapping review.

The next 1000 days - the period from 2 to 5 years of age - has been highlighted as a key developmental stage in the life-course. A mapping review was conducted to categorize existing literature on interventions in the next 1000 days that promote key developmental outcomes, including publications between 1990 and July 2020. A total of 805 intervention studies were included for data extraction in the review. The number of intervention studies has increased substantially from 2010. Most interventions were from high-income countries, with few (5%) from low- and lower-middle-income countries. Interventions including typically developing children (n = 593, 74%) were mostly (80%) implemented in early childhood care and education (ECCE) settings, with 15% taking place in the home or with families and 5% in community or healthcare settings. Children's literacy and language outcomes were the target of 27% of these interventions, while 25% of interventions targeted early childhood development more holistically or targeted multiple developmental domains. Social-emotional development and social skills were the target of 15% of interventions, motor development 13%, numeracy 8% and cognitive development 8%. For children with any developmental delay, disability, disease or exposure (n = 212), interventions frequently targeted Autism Spectrum Disorder (24%), language or literacy delays (21%), developmental delays or disability more generally (20%); 16% targeted behavioral (or conduct) problems; and 5% targeted attention deficit hyperactivity disorder. Almost half (49%) took place in ECCE settings; 24% occurred in the home or with families, or in community (13%) and/or healthcare (14%) settings. This review highlights the need for more intervention research in low- and middle-income countries and for interventions supporting development in the next 1000 days. While the evidence base for interventions to promote development in this age group continues to expand, the most vulnerable children are not benefiting from this evidence.