Prolonged breastfeeding for 24 months or more and mental health at 6 years of age: evidence from the 2004 Pelotas Birth Cohort Study, Brazil

Carlos Alberto Delgado, Tiago N. Munhoz, Iná S. Santos, Fernando C. Barros, Alicia Matijasevich

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: There is scarce and conflicting evidence on medium- to long-term effects of prolonged breastfeeding on child behavior. Method: A population-based birth cohort study started in 2004 in the city of Pelotas, Southern Brazil. Children were followed up at 3, 12, 24, and 48 months and 6 years of age. Breastfeeding duration was determined based on information collected around the time of weaning. Psychiatric disorders were assessed using the Development and Well-Being Assessment (DAWBA). Children who were never breastfed were excluded from the analysis. Crude and adjusted analyses were performed using Poisson regression with robust variance. Results: Data on breastfeeding and mental health at the age of 6 years were available for 3377 children. Prevalence of breastfeeding for 24–35 months and ≥36 months was 16.1% (95% CI: 14.8–17.3) and 8.1% (95% CI: 7.2–9.1), respectively. Prevalence of psychiatric disorders among those who were breastfed for <24 months, 24–35 months and ≥36 months was 12.4% (95% CI: 11.1–13.7), 13.1% (95% CI: 10.4–16.2) and 12.3% (95% CI: 8.7–16.8), respectively. No association was found between breastfeeding for 24 months or more and psychiatric disorders among children aged 6 years both in the crude and adjusted analyses. Conclusions: In this cohort there was no association between breastfeeding for 24 months or more and an increased prevalence of psychiatric disorders at the age of 6 years. Studies analyzing the medium- and long-term effects of prolonged breastfeeding for 2 years or more are scarce and further research is needed regarding this practice.

Original languageEnglish
Pages (from-to)209-215
Number of pages7
JournalChild and Adolescent Mental Health
Issue number4
StatePublished - Nov 2017
Externally publishedYes

Bibliographical note

Funding Information:
This article is based on data from the study ‘Pelotas Birth Cohort, 2004’ conducted by Postgraduate Program in Epidemiology at Universidade Federal de Pelotas, with the collaboration of the Brazilian Public Health Association (ABRASCO). From 2009 to 2013, the Wellcome Trust supported the 2004 birth cohort study. The World Health Organization, National Support Program for Centers of Excellence (PRONEX), Brazilian National Research Council (CNPq), Brazilian Ministry of Health, and Children’s Pastorate supported previous phases of the study. The present analyses were supported by the Program in science and technology from the Peruvian Presidency of the Council of Ministers (FINCyT-Peru) and the Brazilian Federal Agency for Post-graduate Education (CAPES-Brazil). ISS, FCB, and AM are supported by the CNPq. The authors have declared that they have no competing or potential conflicts of interest.

Publisher Copyright:
© 2017 Association for Child and Adolescent Mental Health

Copyright 2017 Elsevier B.V., All rights reserved.


  • Mental disorders
  • prolonged breastfeeding
  • psychological phenomena


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