Exploring Causal Links Between Gut Microbiota and Geriatric Syndromes: A Two-Sample Mendelian Randomization Analysis

Area of Science:

• Gerontology
• Microbiology
• Genetics

Background:

• Observational and clinical studies suggest a link between gut microbiota and geriatric syndromes.
• The precise causal nature of this gut microbiota-geriatric syndrome relationship remains unclear.
• Mendelian randomization (MR) offers a genetic approach to infer causality between exposures and outcomes.

Purpose of the Study:

• To investigate potential genetic causal effects of gut microbiota on geriatric syndromes using a two-sample Mendelian randomization (TSMR) study.
• To examine the causal relationships between specific gut microbiota and frailty, Parkinson's disease (PD), delirium, insomnia, and depression.
• To provide insights into the role of gut microbiota in the development of age-related conditions.

Main Methods:

• Utilized genome-wide association studies (GWAS) data for gut microbiota and geriatric syndromes.
• Employed inverse-variance weighted (IVW) method as the primary analysis, supplemented by MR Egger, simple mode, weighted mode, and weighted median.
• Assessed robustness via MR-Egger intercept, MR-presso for pleiotropy, Cochran's Q test for heterogeneity, and leave-one-out for sensitivity.

Main Results:

• Identified 41 probable causal relationships between gut microbiota and five geriatric syndromes.
• Frailty: 5 positive, 2 negative causal links. Parkinson's disease: 3 positive, 4 negative causal links.
• Delirium: 3 positive, 2 negative; Insomnia: 9 positive, 2 negative; Depression: 9 positive, 2 negative causal links.

Conclusions:

• The TSMR study revealed associations between specific gut microbiota and geriatric syndromes.
• Findings indicate a potential causal role for gut microbiota in the pathogenesis of geriatric syndromes.
• Results highlight the importance of gut microbiota in aging research and suggest avenues for future causal investigations.