Breastfeeding moderates the association between family socioeconomic status and child behavior scores

Background Children living in low socioeconomic status (SES) environments are more likely to develop behavior problems. Breastfeeding is one behavior that has been positively linked to mental health throughout childhood. We investigated whether breastfeeding modifies the association between low SES and behavior problems. Methods We studied a subset of the Canadian CHILD cohort ( N = 2,342). Lower SES ( n = 592) was defined as one or more of: (1) low income based on family size, (2) single parenthood, or (3) maternal education below a post-secondary degree. Breastfeeding was reported by caregivers from birth to 2 years. The Child Behavior Checklist (mean 50, SD (10), comprising internalizing, externalizing, and total behavior scores) was administered at 5 years. We tested main effects and interactions between SES and breastfeeding on child behavior, adjusting for several maternal and child characteristics. Results Lower SES was related to higher (worse) behavior scores ( B = 2.06 [95%CI: 1.06, 3.07] for total behavior scores), while longer and more exclusive breastfeeding was related to lower (better) behavior scores ( B = −2.43 [95% CI: −3.74, −1.11] for exclusive breastfeeding at 6 months, compared to no breastfeeding, for total behavior scores). We observed significant interactions between longer and more exclusive breastfeeding and family SES on internalizing and total behavior scores, indicating that the “socioeconomic gap” in behavior scores becomes smaller with more exclusive and longer breastfeeding. Conclusion This study provides new evidence that breastfeeding may be one factor that can help reduce socioeconomic inequities in child behavior scores.