260074 Breastfeeding and cognition: The role of confounders

Tuesday, October 30, 2012

Kelly K. Gurka, MPH, PhD , Department of Epidemiology/Injury Control Research Center, West Virginia University, Morgantown, WV
Ann L. Kellams, MD, IBCLC , Department of Pediatrics, University of Virginia, Charlottesville, VA
Jennifer Locasale-Crouch, PhD , The Center for Advanced Study of Teaching and Learning, University of Virginia, Charlottesville, VA
Matthew Gurka, PhD , Department of Biostatistics, West Virginia University, Morgantown, WV
Background: The association between breastfeeding and intelligence has been researched extensively; studies suggest a link between breastfeeding and cognition. However, these associations may not be causal, but due to residual confounding. Objectives: To determine whether breastfeeding initiation and duration enhances cognition at 4 years of age, and to identify what factors confound this association. Methods: Cognitive data from 1,050 children, followed prospectively from birth during the National Institute of Child Health and Development Study of Early Child Care and Youth Development, were analyzed. Of primary interest was breastfeeding (never, 0-6 months, or longer than 6 months) and its association with standardized (mean = 100; SD = 15) cognitive outcomes. Extensive modeling was performed to measure the impact of suspected confounders on this relationship. Results: Significant (p < 0.05) positive associations were observed between breastfeeding and cognitive outcomes before adjusting for other factors. After adjusting for typically measured factors, particularly during retrospective studies (e.g., maternal age, education), significant - albeit smaller - positive associations persisted. However, after adjusting for variables typically not collected and often unavailable in retrospective studies namely observed quality of the home environment, mother's attitude regarding modernity of parenting, and maternal verbal IQ - no association between breastfeeding and cognition was observed. Conclusions: This study suggests that the association between breastfeeding and childhood cognition may be due to residual confounding. It is important in examining this relationship to collect data on certain confounding factors that may explain most, if not all, of the observed association.

Learning Areas:
Epidemiology
Public health or related research

Learning Objectives:
Learning Objective One: Discuss the role that residual confounding may play in observed associations between breastfeeding and cognitive function in observational studies.

Keywords: Breastfeeding, Epidemiology

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have been well-trained in epidemiologic methods and have experience conducting analyses of observational studies in particular.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.