Perinatal probiotic intervention prevented allergic disease in a Caesarean-delivered subgroup at 13-year follow-up

Background: The long-term effects of probiotic intervention for primary prevention of allergic diseases are not well known. We previously reported less eczema until 10 years in our probiotic intervention trial. Objective: To investigate the effect of early probiotic intervention on the prevalence of allergic diseases up to 13 years of age. Methods: Pregnant women (n = 1223) carrying a child at a high risk of allergy (at least one parent with allergic disease) were randomized to receive a mixture of probiotics (Lactobacillus rhamnosusGG and LC705, Bifidobacterium breve Bb99 and Propionibacterium freudenreichii) or placebo in a double-blind manner from 36 weeks of gestation until birth. Their infants received the same product for the first six months (registration number NCT00298337). At 13-year follow-up, the participants were requested to return a questionnaire and to provide a blood sample. Results: A questionnaire was returned by 642 participants (63.1% of intention-to-treat infants), and 459 provided a blood sample. In the whole cohort, there were no statistically significant differences in doctor-diagnosed allergic disease (55.2% and 59.0%, probiotic and placebo group, respectively) or allergic disease (47.9% and 51.6%) based on the ISAAC questionnaire data. Inhalant-specific IgE sensitization (>0.7 kU/L) was 59.3% in the probiotic group and 49.8% in the placebo group (P = 0.040). In a post hoc analysis made in Caesarean-delivered subgroup, allergy was reported in 41.5% of the probiotic group and 67.9% of the placebo group (P = 0.006), and eczema in 18.9% and 37.5%, respectively (P = 0.031). In the whole cohort, 8.5% of the probiotic group had suffered from wheezing attacks during the previous 12 months vs 14.7% in the placebo group (P = 0.013). There were no statistically significant differences discovered between the characteristics of the participating group and the dropout group. Conclusions: Probiotic intervention protected Caesarean-delivered subgroup from allergic disease and eczema, but not the total cohort.