November 4, 2008 (San Diego, California) — Breastfeeding is associated with better intellectual and emotional development than bottle feeding, according to findings presented here at the American Public Health Association 136th Annual Meeting.

Parents or guardians of breastfed children were less likely to express concern about learning capacities, and the children were less likely to have required treatment for behavioral, conduct, or mental-health problems, authors Katherine Hobbs Knutson, MD, and Alexy Arauz Boudreau, MD, MPH, from the Massachusetts General Hospital (MGH) in Boston, reported in an oral presentation.

Good research supports the association between breastfeeding and cognitive and intellectual development, but its effect on behavioral and psychological development are not as well understood, Dr. Knutson, a psychiatrist at MGH, told Medscape Public Health & Prevention. "What's new here is that breastfeeding during infancy is associated with decreased parental concern about behavior, fewer diagnoses of behavioral or conduct disorder by healthcare professionals, and [less need for] mental healthcare during childhood."

The authors drew on data from the National Survey of Children's Health, which included interviews with more than 100,000 parents and guardians on the health of their children, who ranged in age from 10 months to 18 years. This study included data on children from 1 to 5 years of age. The parents or guardians were asked if they were concerned a lot, a little, or not at all about how well the child was learning to do things for him- or herself; how well the child was learning preschool or school skills, and how he or she was behaving in general. Answers indicating any degree of concern were combined for the analysis. The parents and guardians were also asked whether the child had ever been diagnosed with conduct or behavioral problems, and whether the child had ever received any mental-health care or counseling.

The authors controlled for the child's age, race, sex, and socioeconomic status, as well as parental education and maternal mental health.

Breastfeeding was associated with an odds ratio (OR) of 0.77 that parents or guardians would report concern about the child's ability to learn for him- or herself, and an OR of 0.76 for the child's ability to learn preschool skills. It was also associated with less concern about the child's behavior (OR, 0.85), and a lower likelihood of medically diagnosed behavior or conduct problems, or receipt of mental-health care (OR, 0.63 for both).

The reasons for these findings are still unclear, Dr. Knutson said. "Our study is unable to explain why breastfeeding may affect behavior, but it is possible that nutrients in human milk may influence the neurologic mechanisms or psychological development in children."

Although the authors did control for parental education and maternal mental health, "mothers who breastfeed are different than those who do or did not," warned Sheela R. Geraghty, MD, MS, assistant professor of pediatrics, and medical director of the Center for breastfeeding Medicine at Cincinnati Children's Hospital Medical Center in Ohio. "Mothers who breastfeed answer behavioral expectations about their children differently than those who do not."

Still, she said, "while the data presented are preliminary, this abstract highlights [the fact] that parents who reported that their children were breastfed also reported that their children had less behavioral and conduct problems," said Dr. Geraghty, who was not involved in the study. "These findings cannot be causally linked, but they highlight the point that choices made for the infant — including the feeding choices — in the early infancy period can have a lasting impact throughout childhood."

American Public Health Association 136th Annual Meeting: Abstract 173228