13 Mar Longer Breastfeeding Not Linked To Higher Childhood IQ
MedicalResearch.com Interview with:
Sabine Roza MD Ph.D. and
Ayesha Sajjad MD, Phd student
Department of Child and Adolescent Psychiatry & Psychology
Department of Psychiatry, Erasmus MC,
Rotterdam, The Netherlands.
Medical Research: What is the background for this study? What are the main findings?
Dr. Roza: WHO guidelines recommend six months of exclusive breastfeeding followed by partial breastfeeding until two years for overall optimum growth and development of children. However, the role of breastfeeding duration on child cognitive development remains a topic of continual debate. Previous research has shown mixed results on the role of breastfeeding duration and exclusivity on child IQ. Several methodological differences in study design inhibit comparisons of these studies and thus limit their generalizability. Furthermore, the association of breastfeeding with child cognitive development is subject to confounding by various factors especially maternal IQ. Therefore, we aimed to study the association between breastfeeding duration and breastfeeding exclusivity with non-verbal IQ in children. We used data the Generation R Study, which is a prospective cohort study from fetal life until young adulthood. Due to the large variability in ethnic backgrounds in our study participants, we focused on non-verbal IQ. In a large sample of 3761 children aged on average 6 years, we found an initial advantage of 0.32 points in non-verbal IQ for every increasing month of breastfeeding, which strongly attenuated after adjustments were made for child factors, maternal factors, sociodemographic factors, parental lifestyle and maternal IQ. Similar attenuation of effect sizes was observed for breastfeeding duration as a categorical variable and duration of exclusive breastfeeding.
Medical Research: What should clinicians and patients take away from your report?
Dr. Roza: Breastfeeding is important for over-all optimum growth of children conferring various health advantages. However, improved IQ with longer duration of breastfeeding is not among those advantages. Sociodemographic factors, parental lifestyle and most importantly maternal IQ mostly explain the association between breastfeeding and child IQ.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Roza: Future research should be aimed to investigate other factors that can further explain the complex association between breastfeeding and child IQ such as paternal IQ. Furthermore, other domains of child cognitive development should be investigated in relation to the effects of confounding.
Breastfeeding duration and non-verbal IQ in children
Sajjad A1, Tharner A2, Kiefte-de Jong JC3, Jaddoe VV4, Hofman A5, Verhulst FC6, Franco OH3, Tiemeier H7, Roza SJ8.
J Epidemiol Community Health. 2015 Feb 19. pii: jech-2014-204486. doi: 10.1136/jech-2014-204486. [Epub ahead of print]
MedicalResearch.com Interview with:, & Sabine Roza MD Ph.D. (2015). Longer Breastfeeding Not Linked To Higher Childhood IQ