Exposure to Bottled Breast Milk and Childhood Obesity

Rachel Tumin, Ohio State University
Alicia Croft, Ohio State University

Breastfeeding is protective against child overweight. Yet it is unknown if bottle-feeding breast milk confers equal protection against overweight. Recent findings suggest the advantage of breastfeeding is more behavioral than nutritional: breastfeeding rather than bottle-feeding may teach the infant to self-regulate energy intake. We use Early Childhood Longitudinal Study-Birth Cohort data to compare breastfeeding, formula, and bottle-fed breast milk as predictors of child overweight and obesity at age 2. We proxy exposure to bottle-fed breast milk using data on maternal employment and formula feeding. Relative to breastfeeding, exposure to bottle-fed breast milk in the first three months is associated with increased risk of child overweight (OR=1.55, 95% CI=1.16-2.06) and obesity (OR=1.88, 95% CI=1.15-3.07). The risk is comparable to that associated with formula feeding, whether or not the mother returned to work in the first three months. Our results support the behavioral explanation for breastfeeding’s protective effect against child overweight.