Is the "breast is best" mantra an oversimplification?

Dental health

Dental caries. There is consistent evidence that breastfeeding beyond 12 months of age is associated with the development of dental caries of deciduous teeth to 6 years of age (OR=2.90; 95% CI, 2.33-3.60). Many of the studies that showed this association did not control for the introduction of sugary foods and drinks, and there was a trend toward publication bias showing the association.⁴⁵

Dental malocclusion. There is consistent evidence for approximately a two-thirds reduction in malocclusions in deciduous teeth in breastfed infants (OR=0.32; 95% CI, 0.25-0.40). Although the large majority of these data come from low-income and middle-income countries, the incidence of malocclusion is not thought to be associated with socioeconomic status, as so many other breastfeeding outcomes are.⁴⁶

Childhood leukemia

In the largest meta-analysis available, a statistically significant inverse relationship between any breastfeeding for >6 months and childhood leukemia is evident in developed countries (OR=0.84; 95% CI, 0.78-0.91), although significant heterogeneity among studies and lack of control for confounding variables are significant limitations. In particular, an association has been demonstrated with acute lymphoblastic leukemia (ALL) but not with acute myelogenous leukemia.⁴⁷ Given the rarity of childhood ALL, approximately 12,500 infants would need to be breastfed to prevent one case.⁴⁸

Continue to: Long-term outcomes