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Wise et al.

Page 47

VI.G. Protective factors against allergic rhinitis VI.G.1. Breastfeeding

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Breastfeeding is associated with several beneficial effects on mother and child health and therefore has been recommended for all infants. 619 One potential benefit is the prevention of allergic disease. 620 Breast milk is an immunologically complex solution, containing multiple compounds that support infant growth and facilitate development of the infant immune response. 621,622 The association between breastfeeding and the prevention of allergic disease has been frequently studied and often debated. Mimouni Bloch et al. 623 performed a meta-analysis of prospective studies evaluating the effects of exclusive breastfeeding for the first 3 months of life on the development of AR (Table VI.G.1). Six prospective studies met the inclusion criteria. In their pooled analysis, they found a protective effect of exclusive breastfeeding for the first 3 months of life that approached statistical significance in the general population (OR 0.74; 95% CI, 0.54 to 1.01). Interestingly, the protective effect was not seen in children with a family history of atopic disease (OR 0.87; 95% CI, 0.48 to 1.58). More recently, Lodge et al. 624 performed a systematic review and meta-analysis in 2015. Their analysis evaluated the association between breastfeeding and AR and included 5 cohort studies 550,599,607,625,626 and 11 cross-sectional studies. 627-637 The number of participants varied between 361 and 13,889 for the cohorts, and 1402 to 206,453 for the cross-sectional studies. Pooling of estimates from the various studies found a nonsignificant protective effect of breastfeeding on the development of AR (OR 0.92; 95% CI, 0.84 to 1.01). The results were then stratified by incidence of AR in different age groups. After stratification by age, a reduced risk of AR in patients under 5 years of age was associated with breastfeeding (OR 0.79; 95% CI, 0.63 to 0.98). However, there was no association after 5 years of age (OR 1.05; 95% CI, 0.99 to 1.12). While the authors of this meta-analysis argued for the benefit of breastfeeding in the prevention of AR, they do acknowledge that the protective effect of breastfeeding seen in patients less than 5 years of age may have been confounded by known protective effects of breast milk against viral respiratory infections. The authors hypothesized that, given the difficulty of differentiating between AR and viral rhinitis in young children, a reduction in viral respiratory infections have been possibly interpreted as a reduction in rhinitis symptoms. 624 • Aggregate Grade of Evidence: C (Level 3a: 2 studies; Table VI.G.1). • Benefit: Possible benefit from breastfeeding with reduction in AR, especially seen in young children. • Harm: None. No studies have shown harm with breast-feeding for 6 months. • Cost: Low. • Benefits-Harm Assessment: Possible benefit with no harm. • Value Judgments: There is evidence that breastfeeding may reduce the risk of AR with no perceived harm. Given the general benefits to the mother and child, breast-feeding for 4 months and possibly 6 months has been advocated.

Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.