Abstract
Parkinson’s disease (PD) is the fastest-growing neurodegenerative disorder worldwide, with increasing evidence indicating that environmental exposures, such as farm-living, are linked to its onset and development. PD is also characterized by a taxonomically and functionally distinct gut microbiome. Notably, major shifts in the microbiome have similarly been observed in individuals with farm-living exposure, raising the question of whether this environmental factor may shape the gut microbiome in the context of PD. In this study, we investigated whether the gut microbiome of PD patients with a history of farm-living differs from that of patients without such exposure in terms of diversity, composition, and functional potential. We used 16S rRNA data from fecal samples from 197 PD patients collected by Cirstea et al. to conduct our analyses. Alpha and beta diversity showed no difference based on farm-living status among PD patients. No taxonomic differences were detected, with no differentially abundant or indicator taxa identified. Predictive functional analysis revealed a significant reduction in several KEGG Orthology terms in PD patients with farm-living exposure compared to those without. Although no large-scale functional trends were observed, several terms involved in metabolic and genetic processes were less abundant in patients with farm-living history. Finally, gut microbial genera of PD patients with farm-living exposure were found to have marginal predictive capacity for early vs. late age of PD onset. Overall, these results suggest that farm-living is not associated with any taxonomic differences in the gut microbiome of PD patients, but may be linked to minor alterations in functional potential. These findings provide a foundation for further research investigating whether environmental exposures, like farm-living, influence the gut microbiome, and how such alterations may influence the development or pathogenesis of neurodegenerative diseases like PD.