Does rapid rebound height growth come at a neurocognitive cost for previously institutionalized youth?

Background: Height growth faltering is associated with less optimal behavioral outcomes and educational achievement. Although catch-up growth after growth delay may result in developmental gains, it may also present as a double-edged sword, with consequences for neurocognitive functioning such as symptoms of inattention and hyperactivity. As previously institutionalized (PI) children experience height delays at adoption and catch-up growth after adoption, they provide a cohort to test associations between catch-up growth and attention deficit hyperactivity disorder (ADHD) symptoms.

Methods: This study used latent growth curve modeling to examine how catch-up in height-for-age growth is related to attention problems in a population of PI youth followed from adoption in infancy through kindergarten. Participants were assessed within three months of arrival into their families (age at entry: 18-36 months). Anthropometrics were measured four times, approximately 7 months apart. Two visits measured behavioral outcomes with parent and teacher reports of ADHD, internalizing, and externalizing symptoms at age 5 and kindergarten.

Results: The slope of growth in height z-scores, but not the intercept, was positively associated with parent- and teacher-reported ADHD symptoms in children. A one standard deviation increase in the slope of height z-scores across four assessments was associated with a 0.252 standard deviation increase in ADHD symptoms after controlling for internalizing and externalizing problems, iron status, duration of institutional care, sex, and age. The slope of growth was also associated with internalizing but not externalizing symptoms.

Conclusions: This study demonstrates that PI children exhibit individual trajectories of height growth postadoption. Higher rates of change in height-for-age growth were associated with increased ADHD symptoms. These results suggest that catch-up growth comes 'at the cost' of poor attention regulation and hyperactive behavior.