The impact of short-term predominate breastfeeding on cognitive outcome at 5 years.

Aim: Breastfeeding is associated with IQ, school attendance and income. Despite the known benefits of breastfeeding, the rate of exclusive breastfeeding up to 6 months is low globally. We examined the effect of short-term breastfeeding on long-term IQ.

Methods: In this secondary analysis of the prospective Cork BASELINE Birth Cohort Study, children were categorised as predominantly breastfed (n = 288) versus exclusively formula-fed (n = 254) at 2-months of age. Infants (n = 404) receiving mixed feeding were excluded. Outcome was assessed using the KBIT-II at 5 years. Multivariable linear regression was used to adjust for confounding variables.

Results: Following adjustment for confounding variables, children, predominately breastfed at 2 months of age, demonstrated increased overall IQ (2.00 points (95% CI: 0.35 to 3.65); P = .018) and non-verbal IQ at 5 years of age (1.88 points (95% CI: 0.22 to 3.54); P = .027) compared with those never breastfed. No significant relationship was found with verbal IQ (P = .154).

Conclusion: A significant increase in composite and non-verbal IQ at 5 years of age was associated with short-term breastfeeding. This study adds to a growing body of evidence that short-term breastfeeding promotes healthy cognitive development.