The Association Between Infant Temperament and Breastfeeding Duration: A Cross-Sectional Study

Background: Little is known about the relationship between infant temperament and breastfeeding. The few studies investigating this report mixed results. Some suggest that difficult infants are breastfed for shorter duration, others report opposing results or no association between the two. Aim: This study investigated associations between infant difficult temperament and breastfeeding duration in a nationally representative cohort of Irish 9-month-old infants. Methods: Breastfed, normal birth-weight singletons from The Infant Cohort of the Growing Up in Ireland Study (n = 5,955) were considered in this research. The Infant Characteristics Questionnaire (ICQ), completed by the mother, was used to assess four different dimensions of difficult temperament: fussy, unpredictable, unadaptable, and dull. Our main interest was the fussy dimension as this is captured best by the ICQ. Initially, a logistic regression (LR) model having the binary version, short (<90 days) or long breastfeeding (>= 90 days) as outcome variable, was constructed. Next, a proportional odds logistic regression (POLR) model examining the five-level categorical version (<= 1 week, 2 weeks-<1 month, 1-<3 months, 3-<6 months, and >= 6 months) of breastfeeding duration was developed. All regression models were adjusted for relevant sociodemographic data. Results: A total of 3,119 infants were breastfed for less than 90 days, while 2,836 were breastfed for 90 days or longer. The LR and POLR models showed a mild inverse association between infant fussiness/difficultness and breastfeeding duration (LR: OR = 0.98, 95% CI: 0.97-0.99, POLR: OR = 0.98, 95% CI: 0.97-0.99). Higher infant unpredictability is associated with longer breastfeeding duration (LR: OR = 1.04, 95% CI: 1.02-1.07, POLR: OR = 1.04, 95% CI: 1.02-1.06). Conclusions: In this cross-sectional study, we found that breastfeeding duration was inversely associated with infant fussiness and positively associated with infant unpredictability.