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Associations of birth size, infancy, and childhood growth with intelligence quotient at 5 years of age: a Danish cohort study

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DOI

  • Helene Kirkegaard, University of Southern Denmark, Odense University Hospital
  • ,
  • Sören Möller, University of Southern Denmark, Odense University Hospital
  • ,
  • Chunsen Wu
  • Jonas Häggström, MTEK Sciences
  • ,
  • Sjurdur Frodi Olsen, Statens Serum Institut
  • ,
  • Jørn Olsen
  • Ellen Aagaard Nohr, University of Southern Denmark

BACKGROUND: The correlates of prenatal and postnatal growth on Intelligence Quotient (IQ) in childhood in term-born children living in high-income countries are not well known. OBJECTIVES: We examined how birth size and growth in infancy and childhood were associated with IQ at age 5 y in term-born children using path analysis. METHODS: The study sample comprised 1719 children from the Danish National Birth Cohort who participated in a substudy in which psychologists assessed IQ using the Wechsler Primary and Preschool Scales of Intelligence-Revised. Measured weight, length/height, and head circumference at birth, 5 mo, 12 mo, and 5 y were included in a path model to estimate their total, indirect, and direct effects on IQ. All growth measures were included in the model as sex- and age-standardized z-scores. RESULTS: After adjusting for potential confounders, a positive association between birth weight and IQ was observed, and 88% of the association was direct. Weight gain in infancy was associated with IQ [per z-score increase from 5 to 12 mo, IQ increased by 1.53 (95% CI: 0.14; 2.92) points] whereas weight gain from 12 mo to 5 y was not associated with IQ. Height and head circumference growth in childhood was associated with IQ [per z-score increase from 12 mo to 5 y, IQ increased by 0.98 (95% CI: 0.17; 1.79) and 2.09 (95% CI: 0.78; 3.41) points, respectively]. CONCLUSIONS: In children born at term in an affluent country with free access to health care, higher IQ was seen with greater size at birth and greater weight gain in infancy. Also, greater growth in height and head circumference throughout the first 5 y of life was associated with higher childhood IQ whereas greater weight gain after the first year of life was not.

Original languageEnglish
JournalThe American Journal of Clinical Nutrition
Volume112
Issue1
Pages (from-to)96-105
Number of pages10
ISSN0002-9165
DOIs
Publication statusPublished - Jul 2020

    Research areas

  • childhood, growth, infancy, intelligence quotient, path analyses, prenatal

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