Background: Infancy is a critical period for brain development. Few studies have examined the extent to which infant weight gain is associated with later neurodevelopmental outcomes in healthy populations.
Objective: The purpose of this work was to examine associations of infant weight gain from birth to 6 months with child cognitive and visual-motor skills at 3 years of age.
Patients and methods: We studied 872 participants in Project Viva, an ongoing prospective, longitudinal, prebirth cohort. We abstracted birth weight from the medical chart and weighed infants at 6 months of age. We used the 2000 Centers for Disease Control and Prevention growth charts to derive weight-for-age z scores. Our primary predictor was infant weight gain, defined as the weight-for-age z score at 6 months adjusted for the weight-for-age z score at birth. At 3 years of age, we measured child cognition with the Peabody Picture Vocabulary Test III and visual-motor skills with the Wide Range Assessment of Visual Motor Abilities.
Results: Mean Peabody Picture Vocabulary Test III score was 104.2, and mean Wide Range Assessment of Visual Motor Abilities test score was 102.8. Mean birth weight z score was 0.21, and mean 6-month weight z score was 0.39. In multiple linear regression adjusted for child age, gender, gestational age, breastfeeding duration, primary language, and race/ethnicity; maternal age, parity, smoking status, and cognition; and parental education and income level, we found no association of infant weight gain with child Peabody Picture Vocabulary Test III score (-0.4 points per z score weight gain increment, 95% confidence interval -1.3, 0.6) or total Wide Range Assessment of Visual Motor Abilities standard score (-0.4 points, 95% confidence interval -1.2, 0.5).
Conclusions: Slower infant weight gain was not associated with poorer neurodevelopmental outcomes in healthy, term-born 3-year-old children. These results should aid in determining optimal growth patterns in infants to balance risks and benefits of health outcomes through the life course.