title: Probiotic administration in early life, atopy, and asthma: a meta-analysis of clinical trials.
abstract: 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.
authors: Division of Pediatric Pulmonology, Department of Pediatrics, University of Miami, Miami, FL, USA.
authors: Nancy
authors: N
authors: Elazab
authors: Angelico
authors: A
authors: Mendy
authors: Janvier
authors: J
authors: Gasana
authors: Edgar R
authors: ER
authors: Vieira
authors: Annabelle
authors: A
authors: Quizon
authors: Erick
authors: E
authors: Forno
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000276:immunology / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000276:immunology / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D019936:Probiotics / Q000008:administration & dosage*; D016032:Randomized Controlled Trials as Topic; D012130:Respiratory Hypersensitivity / Q000276:immunology / Q000517:prevention & control*; D012306:Risk; D016896:Treatment Outcome
chemical_list: D007073:Immunoglobulin E
keywords: atopic sensitization; childhood asthma; childhood atopy; intestinal microbiome; meta-analysis; probiotics; total IgE