Abstract
BACKGROUND: Microbial dysbiosis has been reported to contribute to development of neurodegenerative diseases, however, there is a need to identify causative/prognostic indicators. OBJECTIVES: To comparatively analyze gut microbiome composition in symptomatic LBD (dementia/mild cognitive impairment), iRBD, and cohabiting controls without LBD or iRBD. METHODS: 16S rRNA amplicon sequencing was performed in 38 cases (27 LBD, 11 iRBD) and 39 cohabitant controls. 19 non-cohabitant healthy controls (HCs) were also included to contrast differences between cohabitant cases and controls. RESULTS: Microbiome composition of cohabitant controls and LBD and iRBD cases were strikingly similar. No differences were observed between LBD, and iRBD only showed reduced Bacteroides, compared with cohabitant controls. There were several taxonomic differences in gut microbiome composition between non-cohabitant HCs and cases. CONCLUSIONS: Minimal microbiome differences were observed between iRBD or LBD cases and cohabitant controls. These findings underscore the importance of using cohabiting controls in future gut microbiome studies.