title: Impact of breastfeeding on the intelligence quotient of eight-year-old children.
abstract: OBJECTIVE
  This study aimed to determine the influence of breastfeeding on the intellectual capacity of children from a cohort in a developing country, with a control for the main confounding factors.
  
  
  METHODS
  A prospective cohort study was performed including all infants born in the hospitals of a medium-size city, and a random sample of these newborns was monitored at 30, 90, and 180 days of life, and at age 8 years. Several aspects of breastfeeding were assessed in the follow-up and, at 8 years, general intellectual capacity was assessed through the Raven's Colored Progressive Matrices test. The statistical analyses used Student's t-test, ANOVA, and linear regression and logistics, considering p-values less than 0.05 as statistically significant associations.
  
  
  RESULTS
  At age 8 years, 560 children were assessed with Raven's Colored Progressive Matrices test. The average score was 22.56 points, with a standard deviation of 5.93. The difference in the averages found between the breastfed and non-breastfed groups at six months of age was 1.33 (p=0.008). Mother's and child's skin color, social and economic class, maternal education and smoking, and breastfeeding at six months of age (p=0.007) were still associated with the outcome.
  
  
  CONCLUSIONS
  Children that were breastfed for six months or more had better performance in the general intellectual assessment, even after adjusting for the main confounding factors.
authors.affiliation: Programa de Pós-graduação em Saúde e Comportamento, Universidade Católica de Pelotas, Pelotas, RS, Brazil. anamellofonseca@yahoo.com.br
authors.forename: Ana L M
authors.initials: AL
authors.lastname: Fonseca
authors.forename: Elaine P
authors.initials: EP
authors.lastname: Albernaz
authors.forename: Cristina C
authors.initials: CC
authors.lastname: Kaufmann
authors.forename: Ivana H
authors.initials: IH
authors.lastname: Neves
authors.forename: Vera L M de
authors.initials: VL
authors.lastname: Figueiredo
mesh_terms: D000367:Age Factors; D001938:Brazil; D001942:Breast Feeding / Q000523:psychology / Q000706:statistics & numerical data*; D002648:Child; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D012044:Regression Analysis; D012959:Socioeconomic Factors; D013997:Time Factors; D014505:Urban Population
keywords: Aleitamento materno; Breastfeeding; Child; Criança; Desenvolvimento; Development; Inteligência; Intelligence