Probiotic administration in early life, atopy, and asthma: a meta-analysis of clinical trials.
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.


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


RESULTS
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]).


CONCLUSIONS
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.
['Elazab|Nancy|N|', 'Mendy|Angelico|A|', 'Gasana|Janvier|J|', 'Vieira|Edgar R|ER|', 'Quizon|Annabelle|A|', 'Forno|Erick|E|']
D000293:Adolescent D001249:Asthma D002648:Child D002675:Child, Preschool D003876:Dermatitis, Atopic D004311:Double-Blind Method D005260:Female D005500:Follow-Up Studies D006801:Humans D007073:Immunoglobulin E D007223:Infant D007231:Infant, Newborn D008297:Male D011247:Pregnancy D019936:Probiotics D016032:Randomized Controlled Trials as Topic D012130:Respiratory Hypersensitivity D012306:Risk D016896:Treatment Outcome
probiotics meta-analysis atopic sensitization total IgE childhood asthma childhood atopy intestinal microbiome