Breastfeeding and atopy – does breastmilk reduce the risk of developing allergy and atopic disease?
Background:Atopic eczema is a chronic relapsing inflammatory skin disorder that often presents as the first clinical manifestation of atopy in infants. As many as 80 % of infants with eczema will at some point develop other atopic diseases such as allergies, rhinoconjuncivitis or asthma. There seems to have been an increase in the prevalence of atopic eczema the last three decades, and in industrialized countries the prevalence is over 20 %. This rise in prevalence cannot be explained by genetics alone, but seems to be attributed to changes in lifestyle, nutrition and other environmental factors.
Purpose:To investigate if breastfeeding reduces the risk of developing atopic disease.
Method:Literature study based on searches in Pubmed using breastfeeding, breast-feeding, breast-milk, breastmilk, human milk, humanmilk, infant feeding, lactation, and allergy, atopy, atopic disease, atopic dermatitis, atopic eczema, asthma, dermatitis, eczema as search words.
Results:Five prospective cohort studies, two retrospective studies and two large systematic reviews where breastfeeding reduced the risk of developing atopic disease, were identified. Although these studies could document an effect among infants in high risk for atopic disease when breastfed for more than four months, three other studies where beastfeeding increased the risk of atopic disease, were identified. In one study breastfeeding reduced the incidence of atopic disease before age 7, but increased the risk from 7 to 44 years of age.
Interpretation:Studies on the effect of breastfeeding are conflicting. Most studies indicate that breastfeeding reduces the risk of atopic disease, although some indicates that breastfeeding in fact increases the risk of atopy. Long-term studies are lacking.