Association between probiotic supplementation and asthma incidence in infants: a meta-analysis of randomized controlled trials

Objective: The increased social and economic burdens for asthma in infants make the prevention of asthma a major public health goal. Probiotics may reduce the risk of asthma in infants. However, randomized controlled trials (RCTs) have shown mixed efficacy outcomes. We performed a meta-analysis of RCTs to investigate whether probiotics are associated with a lower asthma incidence in infants. Methods: The PubMed, Cochrane library, and EMBASE databases were systematically searched from the inception dates to August 2018. RCTs comparing the effects of probiotic supplements with a placebo for asthma or wheeze incidence in infants were included. A meta-analysis was performed to calculate risk ratio (RR) and 95% confidence interval (CI) using the Mantel-Haenszel statistical method. Results: A total of 19 randomized trials involving 5157 children fulfilled the inclusion criteria. There was no significant association of probiotics with risk of asthma (RR, 0.94 [95% CI, 0.82-1.09]) or wheeze (RR, 0.97 [95% CI, 0.88-1.06]) compared with placebo. Subgroup analysis by asthma risk showed that probiotics significantly reduced wheeze incidence among infants with atopy disease (RR, 0.61 [95% CI, 0.42-0.90]), but no significant associations were found in the other subgroup analyses by participants receiving the intervention, timing of intervention, prevention regimen, probiotic organism, duration of intervention, and duration of follow-up. Conclusions: The use of probiotic supplementation compared with placebo was not associated with a lower risk of asthma in infants. These findings do not support recommendation to use probiotics in the prevention of asthma in infants.