Association between gut microbiota and anxiety symptoms: A large population-based study examining sex differences

Background: This study aimed to examine the association between anxiety symptoms and gut microbial composition and to infer their functional pathways. Methods: In total, 605 participants were included in this study. Participants were categorized into anxious and non-anxious groups according to their Beck Anxiety Inventory scores, and their fecal microbiota was profiled using 16S ribosomal RNA gene sequencing. The microbial diversity and taxonomic profiles of the participants with anxiety symptoms were analyzed using generalized linear models. The function of the gut microbiota was inferred by comparing 16S rRNA data between the anxious and non-anxious groups. Results: The gut microbiome of the anxious group showed lower alpha diversity than that of the non-anxious group, and there were prominent differences in the community structure of the gut microbiota between the two groups. Male participants with anxiety had lower relative abundances of the family Oscillospiraceae, fibrolytic bacteria including those of the family Monoglobaceae, and short-chain fatty acid-producing bacteria such as those of the genus Lachnospiraceae_NK4A136 than those without anxiety symptoms. Female participants with anxiety symptoms had a lower relative abundance of the genus Prevotella than those without anxiety symptoms. Limitation: The direction of causality between anxiety symptoms and the gut microbiota was unclear owing to the cross-sectional design of the study. Conclusion: Our results elucidate the association between anxiety symptoms and gut microbiota and provide insights for developing interventions to treat anxiety symptoms.