title: Long-term effects of iron and zinc supplementation during infancy on cognitive function at 9 y of age in northeast Thai children: a follow-up study.
abstract: BACKGROUND
  Iron and zinc are important micronutrients for child growth and development. One would expect that iron and zinc supplementation in infancy would affect long-term cognitive development and school achievement, but this has not been evaluated.
  
  
  OBJECTIVE
  We investigated the effect of iron or zinc supplementation or both during infancy on cognitive performance 8 y later.
  
  
  METHODS
  A follow-up study was performed in 560 children aged 9 y or 92% of those who had participated in a randomized controlled trial involving 4 groups who received daily iron, zinc, iron plus zinc, or a placebo at 4-6 mo of age for 6 mo. Cognitive performance was assessed by using the Wechsler Intelligence Scale for Children-Third Edition (Thai version), the Raven's Colored Progressive Matrices (CPM), and school performance tests. General linear mixed models were used to assess long-term effects.
  
  
  RESULTS
  No significant differences in any of the outcomes at 9 y of age were observed at follow-up between the 4 groups. Mean intelligence quotients ranged across groups from 92.9 to 93.7 for full scale, 93.9-95.4 for verbal, and 93.1-94.0 for performance. The Raven's CPM score ranged from 21.4 to 22.4.
  
  
  CONCLUSIONS
  Supplementation with iron or zinc or both during infancy does not lead to long-term cognitive improvement in 9-y-old children. This trial was registered at clinicaltrials.gov as NCT00824304.
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: Ann M
authors.initials: AM
authors.lastname: DiGirolamo
authors.forename: Usha
authors.initials: U
authors.lastname: Ramakrishnan
authors.forename: Pattanee
authors.initials: P
authors.lastname: Winichagoon
authors.forename: Rafael
authors.initials: R
authors.lastname: Flores
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Martorell
mesh_terms: D002648:Child; D002657:Child Development; D003072:Cognition Disorders / Q000453:epidemiology / Q000517:prevention & control*; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007360:Intelligence; D007361:Intelligence Tests; D019266:Iron, Dietary / Q000008:administration & dosage*; D008297:Male; D013647:Task Performance and Analysis; D013785:Thailand / Q000453:epidemiology; D015032:Zinc / Q000008:administration & dosage*
chemical_list: D019266:Iron, Dietary; D015032:Zinc