Improving causality in microbiome research: can human genetic epidemiology help?

Area of Science:

• Human Gut Microbiome Research
• Causal Inference in Epidemiology
• Population Health Sciences

Background:

• Strong associations exist between human gut microbiome variation and various health outcomes.
• Translating findings from in vivo and in vitro models to modifiable causal relationships remains challenging.
• Observational and randomized controlled trial studies have limitations in establishing causality due to confounding, cost, and time.

Purpose of the Study:

• To explore the utility of Mendelian randomization (MR) for interrogating causality in human gut microbiome research.
• To review existing studies employing MR in this field and discuss their strengths, limitations, and challenges.
• To highlight requirements for robust causal inference and the development of targeted microbiome-based therapies.

Main Methods:

• Focus on Mendelian randomization (MR), a method utilizing human genetic variation as instrumental variables.
• Application of MR to assess causal relationships between gut microbiome traits and health outcomes.
• Review and critical examination of studies that have implemented MR in gut microbiome research.

Main Results:

• MR provides a valuable tool to overcome confounding and bias inherent in observational studies of the gut microbiome.
• Existing MR studies offer insights into potential causal roles of the microbiome in human health.
• Careful interpretation of causal estimates and host genetic effects is crucial for valid conclusions.

Conclusions:

• Mendelian randomization is a promising approach for establishing causality in gut microbiome research.
• Triangulation of evidence across multiple study designs and interdisciplinary collaboration are essential.
• Advancing causal understanding can lead to novel therapies for improving population health.