Probiotic Administration in Early Life, Atopy, and Asthma: A Meta-analysis of Clinical Trials

Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
PEDIATRICS (Impact Factor: 5.47). 08/2013; 132(3). DOI: 10.1542/peds.2013-0246
Source: PubMed


Background and objective:
Probiotics may reduce the risk of atopy and asthma in children. However, results from clinical trials have been conflicting, and several of them may have been underpowered. We performed a meta-analysis of randomized, placebo-controlled trials to assess the effects of probiotic supplementation on atopic sensitization and asthma/wheeze prevention in children.

Random-effects models were used to calculate pooled risk estimates. Meta-regression was conducted to examine the effect of potential factors on probiotics efficacy.

Probiotics were effective in reducing total immunoglobulin E (IgE) (mean reduction: -7.59 U/mL [95% confidence interval (CI): -14.96 to -0.22]; P = .044). Meta-regression showed that the reduction in IgE was more pronounced with longer follow-up. Probiotics significantly reduced the risk of atopic sensitization when administered prenatally (relative risk: 0.88 [95% CI: 0.78 to 0.99]; P = .035 for positive result on the skin prick test and/or elevated specific IgE to common allergens) and postnatally (relative risk: 0.86 [95% CI: 0.75 to 0.98]; P = .027 for positive result on skin prick test). Administration of Lactobacillus acidophilus, compared with other strains, was associated with an increased risk of atopic sensitization (P = .002). Probiotics did not significantly reduce asthma/wheeze (relative risk: 0.96 [95% CI: 0.85 to 1.07]).

Prenatal and/or early-life probiotic administration reduces the risk of atopic sensitization and decreases the total IgE level in children but may not reduce the risk of asthma/wheeze. Follow-up duration and strain significantly modified these effects. Future trials for asthma prevention should carefully select probiotic strain and consider longer follow-up.

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    • "Various studies have investigated the potential of probiotics, both for primary prevention and for treatment of eczema and other atopic diseases. Results are inconsistent; while some studies have shown a preventive effect of probiotics on the development of eczema, others showed no effects (Elazab et al., 2013; Panduru et al., 2015). This inconsistency could be explained by differences in study design, amount and duration of probiotic supply, and the strain-specific effects of probiotic bacteria. "
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    • "However, if the new environment induces epigenetic changes, a transgenerational amplification of the atopic phenotype would be expected even with stable exposure (Figure 5). Furthermore, according to this hypothesis, it would be expected that the benefit of some interventions to prevent allergies (such as pro- and prebiotics) could take a full generation before reaching their full effect, hence possibly the somewhat disappointing results so far [66]. "
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