Is breastfeeding protective against the development of asthma or wheezing in children? A systematic review and meta-analysis

Abstract

Background Although breastfeeding is strongly recommended for its many benefits, the association between breastfeeding and childhood asthma development remains controversial. Our objective was to systematically review and metaanalyze the association between physician-diagnosed asthma (PDA) or wheezing development and exclusive or any breastfeeding. Methods Prospective cohort studies of preschool (4-6 years) and school-aged (7-9 years) children were identified from Medline (1948-June 2011) and Embase (1980-June 2011). Breastfeeding exposure for at least the first 3-4 months of life was defined as exclusive (breast milk as the only source of nutrition) or any (breast milk included in the diet). Outcomes were parent-reported PDA or wheezing. Risk of bias in included studies was assessed using the Newcastle-Ottawa scale. Data were analyzed using the Revman software package and adjusted odds ratios were meta-analyzed using random-effects models. Results Ten studies enrolling 35,411 participants were included. Decreased odds of PDA or wheezing development at ages 7-9 years were identified for those who received exclusive breastfeeding [adjusted odds ratio (OR) 0.69, 95% confidence interval (CI): 0.58-0.83] and any breastfeeding (OR 0.53, 95% CI: 0.41-0.68) and at ages 4-6 years for those who received exclusive breastfeeding (OR 0.75, 95% CI: 0.61-0.93). Among the clinically-heterogeneous studies with outcome assessment at ages 4-6 years, any breastfeeding did not change the odds of PDA or wheezing (OR 1.08, 95% CI: 0.76-1.54). Conclusions Exclusive or any breastfeeding for at least the first 3-4 months of life was associated with lower odds of PDA or wheezing in children, strengthening support for the current breastfeeding recommendations.