The Longitudinal Early Growth and Development Study: Opportunities for Integration Across Cohorts with Parent-Offspring or Sibling Data

The Early Growth and Development Study (EGDS) began in 2002 as a longitudinal prospective adoption study of birth parents, adoptive parents, and adopted children (n = 361 adoptees). It expanded in 2007 to include a second cohort of adoptees (n = 200), and a third cohort of siblings (siblings reared by the birth mother at age 7 [n = 217 siblings in 2013] and additional siblings in both birth and adoptive family homes [n = 881 siblings in 2016]). Data are available in a national repository within the Environmental influences on Child Health Outcomes (ECHO) study and have been integrated into analyses with national and international cohorts. Birth and adoptive families were originally enrolled through a systematic recruitment approach that began with efforts to partner with all domestic adoption agencies in specific regions of the United States following the birth of a child. Longitudinal assessments are ongoing and occurred in 9-month intervals until the adoptees turned 3 years of age, and in 1- to 2-year intervals thereafter to age 21. Data collection includes child temperament, cognition, behavior, and physical health; birth and adoptive parent personality, mental and physical health, context, parenting, and marital relations; the prenatal environment; genetic, hormonal, and cardiovascular data; and geocoding. A unique aspect of the adoption-sibling design is its ability to detect environmental influences on development and test complex interactions and correlations between genetic, prenatal, and postnatal environmental influences on a range of outcomes. The sample and procedures are described, followed by an overview of multicohort findings and opportunities for integration with other registries.