Breastfeeding and otitis media: a review of recent evidence.

Human milk provides infants with antimicrobial, anti-inflammatory, and immunomodulatory agents that contribute to optimal immune system function. The act of breastfeeding allows important bacterial and hormonal interactions between the mother and baby and impacts the mouth, tongue, swallow, and eustachian tubes. Previous meta-analyses have shown that lack of breastfeeding and less intensive patterns of breastfeeding are associated with increased risk of acute otitis media, one of the most common infections of childhood. A review of epidemiologic studies indicates that the introduction of infant formula in the first 6 months of life is associated with increased incidence of acute otitis media in early-childhood. More recent research raises the issues of how long this increased risk persists, and whether lack of breastfeeding is associated with diagnosis of otitis media with effusion. However, many studies suffer from lack of study of younger populations and imprecise definitions of infant feeding patterns. These findings suggest that measures of the association between breastfeeding history and otitis media risk are sensitive to the definition of breastfeeding used; future research is needed with more precise and consistent definitions of feeding, with attention to distinctions between direct breastfeeding and human milk feeding by bottle.