Breastfeeding and cognitive development: is there an association?

The holy grail of pediatric medicine has been to design the definitive study that will ultimately resolve the question of the relationship between breastfeeding and cognitive development in otherwise healthy term infants. Unfortunately, by definition such a quest is doomed to fail, as a grail is something very much wanted, but very hard or impossible to achieve. A corollary is that, despite the inevitability of failure, continuing with the quest per se is encouraged, as there is secondary value in the process itself. As such, one should welcome, despite all its limitations, the publication of the study by Fonseca et al.1 in this issue of the journal. The authors attempted to measure the impact of breastfeeding on the ultimate intelligence of children. In assessing the quality of such a study, one is best guided by the monumental publication by the Agency for Health Care Research and Quality (AHRQ) of the United States Department of Health and Human Services entitled ‘‘Breastfeeding andmaternal and infant health outcomes in developed countries’’.2 This report provided both detailed discussion of the methodological issues involved in assessing the published studies on this subject and a series of conclusions based on meta-analyses using appropriate statistical techniques, and