Executive Functions and Academic Outcomes of Low Birthweight Infants: A Prospective Longitudinal U.S. Cohort

OBJECTIVE: Executive functions such as working memory and cognitive flexibility are key to lifelong learning. Our hypothesis was that children born low birthweight (LBW), defined as weight < 2,500 g, would have lower cognitive outcomes than those born normal weight, and children with poor executive functioning would be at risk for poor academic outcomes. STUDY DESIGN: We evaluated data from 12,656 children followed prospectively in the Early Childhood Longitudinal Study, Kindergarten Class 2010-2011, assessing outcomes from kindergarten, first grade, and second grade. Multivariable linear and logistic regressions were run evaluating the relationship between birthweight and cognitive outcomes, and the odds of infants with poor executive functioning having poor academic outcomes. RESULTS: Compared with children with normal birthweight, those born LBW had lower mean z-scores for academic and directly assessed executive functions from kindergarten through second grade. LBW children were at an increased risk of scoring in the bottom 20% of children at all time points: second-grade reading odds ratio (OR) = 1.60 (95% confidence interval [CI:] 1.23-2.09), math OR = 1.49 (95% CI: 1.21-1.84), science OR = 1.41 (95% CI: 1.11-1.81), cognitive flexibility OR = 1.61 (95% CI: 1.27-2.02), and working memory OR = 1.40 (95% CI: 1.10-1.77). CONCLUSION: LBW infants remain at risk of poor cognitive outcomes in second grade. Early difficulties with executive functioning can increase the risk of a child's academic performance years later.