Abstract
Respiratory diseases represent a significant global health issue. Currently, there is growing interest in using probiotics [e.g., Lacticaseibacillus rhamnosus GG (LGG)] as adjunctive therapies for the management of respiratory diseases. However, the efficacy of LGG in respiratory diseases remains unknown. Therefore, this study aimed to evaluate the effectiveness of LGG in preventing and treating respiratory diseases. A comprehensive literature search was performed using the PubMed, Embase, Cochrane Library, and Scopus databases using keywords related to LGG and respiratory diseases. Studies were selected on the basis of predefined inclusion and exclusion criteria, and data were extracted for qualitative and quantitative analyses. The Cochrane Risk of Bias tool was used to assess the methodological quality of the included studies, and RevMan 5.4 was used to perform the meta-analysis. Out of 155 studies that were initially identified, 13 randomized controlled trials met the inclusion criteria. The meta-analysis showed that LGG intervention, both as a preventive and therapeutic strategy, significantly reduced the incidence of respiratory disease episodes (mean difference: -0.14, 95% confidence interval: -0.27 to -0.01, P=0.03) and mitigated associated symptoms compared with placebo or no intervention. The results of subgroup analyses indicated that LGG was particularly effective in reducing the duration and severity of respiratory infections in children and high-risk populations. However, heterogeneity (I(2)=62%) was observed, which was likely because of variations in the study design, dosage, and patient populations. These findings suggest that LGG may be a promising adjunctive therapy for respiratory diseases, particularly in preventive settings.