Association of Growth During Infancy with Neurodevelopment and Obesity in Children Born Very Preterm: The Environmental Influences on Child Health Outcomes Cohort

To evaluate associations between change in weight z score after neonatal intensive care unit (NICU) discharge and neurodevelopmental outcomes and obesity at 12-48 months of age among individuals born very preterm. This secondary analysis used data from infants born very preterm participating in the Environmental influences on Child Health Outcomes cohort (n = 1400). Growth during infancy was calculated as change in weight z score between NICU discharge and follow-up at a mean of 27 months of age. Very low weight gain was defined as a change in weight z score 1.67. Neurodevelopmental outcomes included the Bayley Scales of Infant and Toddler Development, Child Behavior Checklist 1.5-5 years, and Modified Checklist for Autism in Toddlers. Multivariable linear regression was used to estimate associations between increase in weight z score and neurodevelopmental outcomes. Very low weight gain between NICU discharge and follow-up (experienced by 6.4% of participants) was associated with lower scores on cognitive (adjusted mean difference: −4.26; 95% CI: −8.55, −0.04) and language (adjusted mean difference: −4.80; 95% CI: −9.70, −0.11) assessments. Very high weight gain (experienced by 13.6% of participants) was associated with an increased obesity risk (adjusted relative risk: 6.20; 95% CI: 3.99, 9.66) but not with neurodevelopmental outcomes. Very high weight gain in the first 12-48 months after NICU discharge was associated with a higher risk of obesity at follow-up; very low weight gain was associated with lower scores on cognitive and language assessments.