Background
Allergic diseases are common and represent a considerable health and economic burden worldwide. We aimed to examine the effect of a combination of two probiotic strains administered in late infancy and early childhood on the development of allergic diseases and sensitization.
Methods
In this double‐blind, placebo‐controlled intervention trial, participants were randomized to receive a daily mixture of Lactobacillus rhamnosus and Bifidobacterium animalis subsp lactis or placebo—starting prior to attending day care. The intervention period was 6 months, and the parents answered web‐based questionnaires on allergic symptoms and doctor's diagnosed allergic disease monthly. IgE was measured at baseline and follow‐up.
Results
A total of 290 participants were randomized: 144 in the probiotic group and 146 in the placebo group. Mean age at intervention start was 10.1 months. At follow‐up (mean age 16.1 months), the incidence of eczema was 4.2% in the probiotic group and 11.5% in the placebo group (P = 0.036). The incidence of asthma and conjunctivitis did not differ between groups, and no children presented with rhinitis. Sensitization was equal in the two groups at intervention start (7.5% and 9.5%, respectively), and two children in each group were sensitized during the intervention.
Conclusions
We observed a significantly lower incidence of eczema in the probiotic group compared to the placebo group. The probiotics were administered in late infancy—prior to attending day care—suggesting a broader window of opportunity using probiotics in the prevention of eczema. The incidence of asthma, rhinitis, conjunctivitis, and sensitization did not differ.