title: Influence of prenatal and postnatal growth on intellectual functioning in school-aged children.
abstract: OBJECTIVE
  To assess the relative influence of size at birth, infant growth, and late postnatal growth on intellectual functioning at 9 years of age.
  
  
  METHODS
  A follow-up, cross-sectional study.
  
  
  METHODS
  Three districts in Khon Kaen province, northeast Thailand.
  
  
  METHODS
  A total of 560 children, or 92% of former participants of a trial of iron and/or zinc supplementation during infancy.
  
  
  METHODS
  Prenatal (size at birth), early infancy (birth to 4 months), late infancy (4 months to 1 year), and late postnatal (1 to 9 years) growth. Multiple-stage least squares analyses were used to generate uncorrelated residuals of postnatal growth.
  
  
  METHODS
  Intellectual functioning was measured at 9 years using the Wechsler Intelligence Scale for Children and the Raven's Colored Progressive Matrices (Pearson). Analyses included adjustment for maternal, household, and school characteristics.
  
  
  RESULTS
  Significant relationships were found between growth and IQ (Wechsler Intelligence Scale for children, third edition, Thai version), but only up to 1 year of age; overall, growth was not related to the Raven's Colored Progressive Matrices. The strongest and most consistent relationships were with length (birth, early infancy, and late infancy); for weight, only early infancy gain was consistently related to IQ. Head circumference at birth was not collected routinely; head circumference at 4 months (but not head circumference growth thereafter) was related to IQ. Late postnatal growth was not associated with any outcome.
  
  
  CONCLUSIONS
  Physical growth in early infancy (and, to a lesser extent, physical growth in late infancy and at birth) is associated with IQ at 9 years of age. Early infancy may be a critical window for human development.
authors.affiliation: Nutrition and Health Sciences Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA.
authors.forename: Tippawan
authors.initials: T
authors.lastname: Pongcharoen
authors.forename: Usha
authors.initials: U
authors.lastname: Ramakrishnan
authors.forename: Ann M
authors.initials: AM
authors.lastname: DiGirolamo
authors.forename: Pattanee
authors.initials: P
authors.lastname: Winichagoon
authors.forename: Rafael
authors.initials: R
authors.lastname: Flores
authors.forename: Jintana
authors.initials: J
authors.lastname: Singkhornard
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Martorell
mesh_terms: D001724:Birth Weight; D001827:Body Height; D002648:Child; D002657:Child Development; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006128:Growth; D006257:Head / Q000254:growth & development; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests; D016018:Least-Squares Analysis; D008297:Male; D015999:Multivariate Analysis; D013785:Thailand