Breastfeeding and Cognition

Abstract

In the developed world,where the benefits of breastfeeding arenotmeasured in termsof life or deathor even seriousmorbidity, the question has been what benefits might motivate mothers toboth initiateandsustain it consistentwith theWorld Health Organization and American Academy of Pediatrics recommendations.1,2 The reduction of gastroenteritis, otitismedia, andatopic eczema in the first year of life is supported by a strong evidence base.3 While these are important and desirable outcomes, none in and of themselves have dramatic public health consequences, particularly beyond early childhood. On the other hand, the connection between breastfeeding and cognition has lifelong and widespread implications. Whether a causal linkage between the two exists has long been debated, in part, because most existing studies are observational andhave failed to adjust for maternal IQ. Given the known association between educational attainment or intelligence and breastfeeding, failure to adjust formaternal IQmay confound any observed effects on infants.ThestudybyBelfortetal4 in thismonth’s issueofJAMA Pediatrics, althoughobservational,hasmanynotable strengths including controlling formaternal intelligence, aswell as features of the home environment that promote cognitive function. Assuming these findings are in fact robust, what are the public health implications? The authors reported an IQ benefit at age 7 years from breastfeedingof 0.35points permonthon theverbal scale and 0.29points permonthon thenonverbal one. Put anotherway, breastfeeding an infant for the first year of life would be expected to increase his or her IQ by about 4 points or one-third of a standarddeviation.While othersmight quibble about the size of this effect (I do not), it must be put into an intergenerational context tobe fully appreciated.Havingamotherwho breastfed increases the chances that a woman will herself breastfeed her infant.5 Without getting into the details of whether the cumulative effects are additive (or evenmultiplicative), it is clear that a vicious cycle can be created wherein lack of breastfeeding begets lower IQ, which begets lower socioeconomic status and thereby decreases the probability of breastfeeding thenext generation and soon.6,7 Given the connection between IQ and educational attainment and delinquency, these effects begin to have real implications both for the individuals involvedand for societyas awhole.8Of course, the inverse would also be true: over successive generations, breastfeedingwould be expected to increase IQ, which could increase socioeconomic status and in turn increase the probability of breastfeeding, creating a virtuous cycle and facilitating a rise from poverty. Butmostpeopleandmostorganizationshavealreadybeen convinced that breastfeeding is an important cause, so what does this study add? It is possible that cognitive ability (and what itmight lead to,namely, educational achievement,higher lifetime income, etc) might be more powerful motivators for breastfeeding than reduced risk for otitis media and diarrhea and eczema; however, the problem currently is not so much that most women do not initiate breastfeeding, it is that they do not sustain it. In the United States, about 70% of women overall initiate breastfeeding, although only 50% of African American women do.9 However, by 6 months, only 35% and 20%, respectively, are still breastfeeding.9 The lackof sustainabilitysuggests thatotherstructural changesareneededtosupport newmothers in thisworthy endeavor.Merely reiterating the importance of breastfeeding is clearly not enough; another call for action is not enough either, instead, real action is in order. We might use the case of lead and children as an example. The magnitude of the effect of not breastfeeding on IQ is comparable with the differences attributable to a 10-μg/dL increase in blood lead concentrations.10 The movement to reduce childhood lead exposure had a lot of heft behind it. Gasoline was made unleaded by legislation. National public service announcements were launched. Lead screening became routine—even required—during pediatric health supervision visits. These actions resulted in dramatic reductions in population blood lead levels in the 1970s and 1980s. An analogous large, robust, and sustained effort is needed to provide the infrastructure to support breastfeeding at all levels. First, postpartum public health nurse visits for all newborns should be covered. Several states have these, but many have cut back or eliminated them under the current fiscal crisis. Second, inmuch the sameway that babyfriendly hospitals were shown to improve breastfeeding initiation rates (and are now certified as such) baby-friendly practices should be certified to help sustain them.3,11 Third, breast pumps should be covered by insurance companies. Furthermore, workplaces need to provide opportunities and spaces for mothers to use them. Fourth, breastfeeding in public should be destigmatized. Clever social media campaigns and high-quality public service announcements might help with that. As with lead, some of these actions may require legislative action either at the federal or state level. Let’s allow our children’s cognitive function be the force that tilts the scale, and let’s get on with it. Related article page 836 Opinion