Breastfeeding decisions.

Abstract

To the Editor.—Forste and colleagues1 analyzed two cycles of the National Survey of Family Growth to examine breastfeeding and infant mortality by race. Although the sample includes 24 566 live births, the authors do not report the number of infant deaths, necessary in considering variability of the sample and the ability to draw conclusions.The single survey question used to determine reasons for formula feeding included only problems with employment, physical or medical problems, bottle-feeding preference, lack of knowledge, or “other” as options. “Preferred to bottle-feed” may have become a catch-all for mothers lacking role models, family or professional support, or those who had previous difficulties, lived in crowded conditions, or had other concerns.The authors modeled infant mortality using only 3 predictors: race, low birth weight, and “ever breastfed.” They concluded that “breastfeeding accounts for the race difference in infant mortality in the United States at least as well as low birth weight does.” However, other predictors of both infant mortality and breastfeeding, such as maternal income, education, age, smoking, and access to and quality of health care, are excluded from the model. As a result, the effect of breastfeeding is likely to be overstated.The authors include low birth weight as a covariate to adjust for the effects of low weight on infant mortality, but most mortality from low birth weight and prematurity occurs in the neonatal period, and their model excludes these infants. Neonatal deaths were excluded from the model because the authors believe that infants who died shortly after birth were unlikely to have been breastfed. However, older infants who died neonatally (eg, at 1–3 weeks of age) would have had the opportunity to breastfeed.There is little evidence to support the conclusion “Efforts to increase breastfeeding of infants in the black community should help narrow the racial gap in infant mortality.” While breastfeeding of black infants has increased over the past decade, the black/white gap in infant mortality has remained essentially stable.This article may be interpreted to imply that personal preference is the primary factor in predicting bottle-feeding among black women and that the causes of infant mortality may be explained by only 2 factors. This interpretation could undermine efforts to provide professional culturally appropriate guidance to childbearing women and trivialize the need to examine issues of disparity in access to lactation support and, more generally, to health care among diverse populations.Reply.—The letter by Dr Heinig points to the importance of developing more complex models to further understanding of public health issues. As noted by Dr Heinig, breastfeeding in our model could co-vary with other factors such as maternal education or smoking, but this could also be true of the measure of low birth weight. As with all survey-based analyses, more complex models that examine intervening mechanisms are needed, and, in this case, the analysis of panel data would also be useful in sorting out the effects of breastfeeding and low birth weight on infant mortality. We were constrained by the limitations of our data. For example, the data do not allow us to further define the preference for bottle-feeding, or the timing of breastfeeding and death during the neonatal period. Our purpose was not to identify a comprehensive model of infant mortality, but to consider other potential avenues of influence beyond the consideration of low birth weight. To this end, our results do indicate that breastfeeding accounts for the race difference in mortality as well as does low birth weight. Our analyses were not meant to suggest that only 2 factors explain infant mortality, but to draw attention to additional factors, beyond the prevalent emphasis on low birth weight, as possible explanations for the racial difference in infant mortality.