Evaluating the effectiveness of probiotics in relieving constipation in Parkinson?s disease: A systematic review and meta-analysis

Objectives: The aim of this study was to evaluate the effects of probiotics on the treatment of constipation in patients with Parkinson's disease (PD) by analyzing data from published ran-domized clinical trials (RCTs). PD is a neurodegenerative disease characterized by clinical symptoms such as rigidity, bradykinesia, and resting tremor. Constipation is a common complaint reported by PD patients. Probiotics are often used to treat functional constipation. The potential mechanisms behind PD-related constipation include dysfunction of the enteric nervous system due to alpha-synuclein aggregation, dyssynergic contractions of the puborectalis muscle, and alterations of the gut microbiome.Method: To conduct this study, we searched Scopus, PubMed, and Google Scholar for published articles on PD, probiotics, and constipation. We selected RCTs from 944 studies, and ultimately included 3 RCTs in our meta-analysis. The frequency of bowel movements per week was the only index that could be summarized among the records. We extracted and analyzed the results as means and standard deviations.Result: We calculated a standardized mean difference (SMD) of 0.92 (95% CI, 0.65 to 1.19; I -squared = 57.0%; p < 0.001) to determine the treatment effect in terms of frequency of bowel movements per week in the RCTs.Conclusion: Our results show that probiotic intake has beneficial effects on constipation in PD patients. Further research, including multicenter studies, is needed to assess the long-term effi-cacy and safety of probiotic supplements in neurodegenerative diseases.