Breast-feeding influences cognitive development in Filipino children.

The importance of breast-feeding (BF) for cognitive development has been researched widely over the past several decades. Although scholars agree that children who breast-feed are generally more intelligent, it is uncertain whether this advantage is due to BF effects or to other accompanying healthy characteristics of women who breast-feed. This is a problem in nearly every study, and even in studies controlling for known confounding variables, residual confounding remains a concern. This study tried a new approach, evaluating the relation between BF and cognitive development or ability in a population in which BF was inversely correlated with socioeconomic advantages and other healthy maternal behaviors. Normal birthweight (NBW, n = 1790) and low birthweight (LBW, n = 189) (<2500 g) infants born in 1983-84 in Metropolitan Cebu, Philippines were followed from birth through middle childhood. Cognitive ability was assessed at ages 8.5 and 11.5 y with the Philippines Nonverbal Intelligence Test. Multivariable linear regressions were created to estimate crude and adjusted relations of various BF measures and later cognitive ability. After controlling for confounding variables, scores at 8.5 y were higher for infants breast-fed longer (1.6 points and 9.8 points higher among NBW and LBW infants, respectively, breast-fed for 12 to <18 mo vs. <6 mo). BF coefficients in both NBW and LBW 11.5-y models were attenuated but remained positive. This analysis highlights the importance of long-term BF after initial introduction of complementary foods, particularly in LBW infants born close to term.