Aim: To systematically review the association between breastfeeding and childhood allergic disease.Methods: Predetermined inclusion/exclusion criteria identified 89 articles from PubMed, CINAHL and EMBASE databases. Meta‐analyses performed for categories of breastfeeding and allergic outcomes. Meta‐regression explored heterogeneity.Results: More vs. less breastfeeding (duration) was associated with reduced risk of asthma for children (5–18 years), particularly in medium‐/low‐income countries and with reduced risk of allergic rhinitis ≤5 years, but this estimate had high heterogeneity and low quality. Exclusive breastfeeding for 3–4 months was associated with reduced risk of eczema ≤2 years (estimate principally from cross‐sectional studies of low methodological quality). No association found between breastfeeding and food allergy (estimate had high heterogeneity and low quality). Meta‐regression found differences between study outcomes may be attributable to length of breastfeeding recall, study design, country income and date of study inception. Some of the protective effect of breastfeeding for asthma may be related to recall bias in studies of lesser methodological quality.Conclusion: There is some evidence that breastfeeding is protective for asthma (5–18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low‐income countries.

Aim: To synthesise the evidence on the association between duration and exclusivity of breastfeeding and the risk of acute otitis media (AOM).Methods: Systematic review and meta‐analysis following searching of PubMed, CINAHL and EMBASE electronic databases.Results: Twenty‐four studies, all from the USA or Europe, met the inclusion criteria. In the pooled analyses, any form of breastfeeding was found to be protective for AOM in the first 2 years of life. Exclusive breastfeeding for the first 6 months was associated with the greatest protection (OR 0.57 95% CI 0.44, 0.75), followed by ‘more vs less’ breastfeeding (OR 0.67; 0.59, 0.76) and ‘ever vs never’ breastfeeding (OR 0.67; 0.56, 0.80).Conclusion: This systematic review and meta‐analysis provides evidence that breastfeeding protects against AOM until 2 years of age, but protection is greater for exclusive breastfeeding and breastfeeding of longer duration. Exclusive breastfeeding during the first 6 months was associated with around a 43% reduction in ever having AOM in the first 2 years of life. After 2 years of age, there is no evidence that breastfeeding protects against AOM; however, there were few studies and the evidence quality was low.

Aim: To synthesise the current evidence for the associations between breastfeeding and dental caries, with respect to specific windows of early childhood caries risk.Methods: Systematic review, meta‐analyses and narrative synthesis following searches of PubMed, CINAHL and EMBASE databases.Results: Sixty‐three papers included. Children exposed to longer versus shorter duration of breastfeeding up to age 12 months (more versus less breastfeeding), had a reduced risk of caries (OR 0.50; 95%CI 0.25, 0.99, I² 86.8%). Children breastfed >12 months had an increased risk of caries when compared with children breastfed <12 months (seven studies (OR 1.99; 1.35, 2.95, I² 69.3%). Amongst children breastfed >12 months, those fed nocturnally or more frequently had a further increased caries risk (five studies, OR 7.14; 3.14, 16.23, I² 77.1%). There was a lack of studies on children aged >12 months simultaneously assessing caries risk in breastfed, bottle‐fed and children not bottle or breastfed, alongside specific breastfeeding practices, consuming sweet drinks and foods, and oral hygiene practices limiting our ability to tease out the risks attributable to each.Conclusion: Breastfeeding in infancy may protect against dental caries. Further research needed to understand the increased risk of caries in children breastfed after 12 months.