Tippawan PongcharoenUsha RamakrishnanAnn M. Di GirolamoPattanee WinichagoonRafael FloresJintana SingkhornardReynaldo MartorellNutrition and Health Sciences ProgramRollins School of Public HealthEmory UniversityMahidol UniversityKhon Kaen University2018-06-112018-06-112012-05-01Archives of Pediatrics and Adolescent Medicine. Vol.166, No.5 (2012), 411-41615383628107247102-s2.0-84860747533https://repository.li.mahidol.ac.th/handle/20.500.14594/14826Objective: To assess the relative influence of size at birth, infant growth, and late postnatal growth on intellectual functioning at 9 years of age. Design: A follow-up, cross-sectional study. Setting: Three districts in Khon Kaen province, northeast Thailand. Participants: A total of 560 children, or 92% of former participants of a trial of iron and/or zinc supplementation during infancy. Main Exposures: 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. Multiplestage least squares analyses were used to generate uncorrelated residuals of postnatal growth. Main Outcome Measures: 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. Conclusion: 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. © 2012 American Medical Association.Mahidol UniversityMedicineArticleSCOPUS10.1001/archpediatrics.2011.1413