title: Breastfeeding and child development outcomes: an investigation of the nurturing hypothesis.
abstract: This study investigated whether the nurturing hypothesis - that breastfeeding serves as a proxy for family socio-economic characteristics and parenting behaviours - accounts for the association of breastfeeding with children's academic abilities. Data used were from the Child Development Supplement of the Panel Study of Income Dynamics, which followed up a cohort of 3563 children aged 0-12 in 1997. Structural equation modelling simultaneously regressed outcome variables, including three test scores of academic ability and two subscales of behaviour problems, on the presence and duration of breastfeeding, family socio-economic characteristics, parenting behaviours and covariates. Breastfeeding was strongly related to all three tests scores but had no relationships with behaviour problems. The adjusted mean differences in the Letter-Word Identification, Passage Comprehension) and Applied Problems test scores between breastfed and non-breastfed children were 5.14 [95% confidence interval (CI): 3.14, 7.14], 3.46 (95% CI: 1.67, 5.26) and 4.24 (95% CI: 2.43, 6.04), respectively. Both socio-economic characteristics and parenting behaviours were related to higher academic test scores and were associated with a lower prevalence of externalising and internalising behaviour problems. The associations of breastfeeding with behaviour problems are divergent from those of socio-economic characteristics and parenting behaviours. The divergence suggests that breastfeeding may not be a proxy of socio-economic characteristics and parenting behaviours, as proposed by the nurturing hypothesis. The mechanism of breastfeeding benefits is likely to be different from those by which family socio-economic background and parenting practices exert their effects. Greater clarity in understanding the mechanisms behind breastfeeding benefits will facilitate the development of policies and programs that maximise breastfeeding's impact.
authors.affiliation: School of Social Work, College for Public Health and Social Justice, Saint Louis University, St. Louis, Missouri, USA. jhuang5@slu.edu.
authors.forename: Jin
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Social Work, College for Public Health and Social Justice, Saint Louis University, St. Louis, Missouri, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Vaughn
authors.affiliation: School of Social Work, College for Public Health and Social Justice, Saint Louis University, St. Louis, Missouri, USA.
authors.forename: Kristen P
authors.initials: KP
authors.lastname: Kremer
mesh_terms: D000293:Adolescent; D001942:Breast Feeding; D002648:Child; D002652:Child Behavior; D002657:Child Development; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D016487:Parenting; D012959:Socioeconomic Factors
keywords: academic ability; behaviour problems; breastfeeding; child development