Breastfeeding helps explain racial and socioeconomic status disparities in adolescent adiposity

OBJECTIVES Studies suggest that breastfeeding is protective for later obesity; however, this association has not held among all racial and socioeconomic status groups. Racial and socioeconomic status differences in breastfeeding behavior have also been noted. In this study, we formally test whether breastfeeding mediates the relationship between race and socioeconomic status with adolescent adiposity.
METHODS Data were analyzed from 739 black and white 10- to 19-year-old adolescents who participated in a large, school-based study. Parents provided information on parental education, used to measure socioeconomic status, and whether the child was breastfed as an infant. {BMI} was used to measure adolescent adiposity and was analyzed as a continuous measure {(BMI} z score) using linear regression and categorically {(BMI} > or = 85th and > or = 95th percentile) using logistic regression.
RESULTS Black adolescents and those without a college-educated parent were less likely to have been breastfed for > 4 months. Race and parental education were each independent predictors of {BMI} z score and of having {BMI} > or = 85th percentile or {BMI} > or = 95th percentile. When added to the model, being breastfed for > 4 months was also independently associated with lower {BMI} z score and lower odds of having {BMI} > or = 85th percentile or {BMI} > or = 95th percentile. Inclusion of being breastfed for > 4 months resulted in a 25% decrease in racial and parental education differences in adolescent {BMI} z score, supporting partial mediation.
CONCLUSIONS Having been breastfed for > 4 months was associated with lower adolescent {BMI} z score and lower odds of having a {BMI} > or = 85th percentile or {BMI} > or = 95th percentile, independent of race or parental education. Furthermore, these analyses suggest that being breastfed for > 4 months partially explains the relationship between social disadvantage and increased adiposity. Increasing breastfeeding duration could result in lower adolescent adiposity for all racial and socioeconomic status groups and potentially minimize socioeconomic disparities in adiposity.