Earlier assessments of the IHDP found that, at age 3, children who received early intervention services had significantly higher IQs and fewer behavior problems than those who had not received the services. By age 8, the advantages persisted, although at a more modest level and only among the heavier low-birthweight children.
Between 2001 and 2005, researchers from the Harvard School of Public Health and their colleagues at Teachers College Columbia University conducted a follow-up study of adolescents who, as babies, had participated in the Infant Health and Development Program (IHDP), an early intervention program for low-birthweight, premature infants funded by the Robert Wood Johnson Foundation (RWJF).
The program, which began in 1982, is the first and—as of 2006—only multisite, randomized study of the effectiveness of a comprehensive early intervention program for low-birthweight, premature infants. It offered home visits, center-based education and family support.
This grant enabled researchers to contact 636 (64.6%) of the original 985 children in the study to determine whether the children (now age 18) still experienced any benefits from their participation in the early intervention services.
At age 18, youth who had been in the subgroup of heavier low-birthweight infants (whose birthweights were close to normal) and who received early intervention services scored significantly higher on tests of math and cognitive ability than similar youth who had not received the services. They were also somewhat less likely to engage in risk-taking behavior.
Among 18-year olds who had been in the lighter low-birthweight subgroup as infants, there were no differences on any cognitive or behavioral measures between those who had received intervention services and those who had not.