Abstract
Background Using a double blind randomized placebo-controlled trial (Australian New Zealand Clinical Trials Registry: ACTRN12607000518460), we have shown that in a high risk birth cohort, maternal supplementation from 35 weeks gestation until 6 months if breastfeeding and infant supplementation until 2 years with Lactobacillus rhamnosus HN001 (HN001) (6 X 109 cfu/day) halved the cumulative prevalence of eczema by age 2 years. Bifidobacterium animalis subsp lactis HN019 (HN019) (9 X 109 cfu/day) had no effect. Objective The aim of this study was to investigate the associations of HN001 and HN019 with allergic disease and atopic sensitization among these children at age 4 years, 2 years after stopping probiotic supplementation. Methods The presence (UK Working Party's Diagnostic Criteria) and severity SCORing Atopic Dermatitis (SCORAD) of eczema and atopy (skin prick tests) and parent-reported symptoms of asthma and rhinoconjunctivitis were assessed using standard protocols and questions. Results Four-hundred and seventy-four infants were eligible at birth of whom 425 (90%) participated in this follow-up. The cumulative prevalence of eczema by 4 years (Hazard ratio (HR) 0.57 (95% CI 0.390.83)) and prevalence of rhinoconjunctivitis at 4 years (Relative risk 0.38 (95% CI 0.180.83)) were significantly reduced in the children taking HN001; there were also nonsignificant reductions in the cumulative prevalence of SCORAD = 10 (HR 0.74 (95% CI 0.521.05), wheeze (HR 0.79 (95% CI 0.591.07)) and atopic sensitization (HR = 0.72 (95% CI 0.481.06)). HN019 did not affect the prevalence of any outcome. Conclusions and Clinical Relevance This study showed that the protective effect of HN001 against eczema, when given for the first 2 years of life only, extended to at least 4 years of age. This, together with our findings for a protective effect against rhinoconjunctivitis, suggests that this probiotic might be an appropriate preventative intervention for high risk infants.