Evaluation of the effect of probiotics on development of asthma and allergic rhinitis during childhood – follow-up study at age 5 or 6 years

Background: Modification of the intestinal microbiota by administration of probiotic bacteria may establish an immunological balance between Th1 and Th2 cells. Therefore administration of probiotic bacteria may be a potential approach to prevent allergic disease. Objective: The purpose of this follow-up trial was to study the preventive effect of pre- and postnatal supplementation of a selected probiotic mixture on the development of asthma and allergic rhinitis in high-risk children at age 5 or 6. Methods: In a single-blind, randomized, placebo-controlled follow-up trial, a mixture of probiotic bacteria (Bifidobacterium bifidum, Bifidobacterium lactis and Lactococcus lactis, Ecologic® Panda) selected by in vitro experiments was prenatally administered to mothers from 34 weeks of pregnancy till delivery and postnatal to their offspring for the first 12 months of life. Sixty-seven high-risk children aged 5 or 6 years completed follow-up with a questionnaire, physical examination, lung function testing and nitric oxide measurements. The primary objective was to determine the preventive effect on the prevalence of asthma and allergic rhinitis. Secondary endpoints were the severity of allergic rhinitis, the prevalence of eczema and the diagnostic value of fractional exhaled nitric oxide (FeNO) and nasal nitric oxide (nNO). Results: Asthma was diagnosed in 5 (15.6%) of 32 in the probiotic group and in 5 (14.3%) of 35 in the placebo group [P = 1.000]. Allergic rhinitis was diagnosed in 10 (31.3%) of 32 in the probiotic group and in 10 (28.6%) of 35 in the placebo group [P = 0.822]. Severity of allergic rhinitis was comparable between both groups. Eczema was diagnosed in 9 (28.1%) of 32 in the probiotic group and in 9 (25.7%) of 35 in the placebo group [P = 0.824]. FeNO for the diagnosis of asthma has a low sensitivity (33.3%), but a high specificity (100.0%), positive predictive value (100.0%) and negative predictive value (88.9%). nNO has a sensitivity of 50.0%, a specificity of 36.4%, a positive predictive value of 26.3% and a negative predictive value of 61.5%. Conclusion: Supplementation with Ecologic® Panda pre- and postnatal had no preventive effect on the development of asthma and allergic rhinitis in high-risk children at age 5 or 6 years, nor altered the severity of allergic rhinitis in affected children. The preventive effect on the prevalence of eczema during the first 2 years was no longer present at age 5 or 6. Therefore, Ecologic® Panda cannot be generally recommended for primary prevention of asthma and allergic rhinitis. Besides that, fractional exhaled nitric oxide was a valuable diagnostic tool for asthma in our population.