mediation analysis
Definition
Mediation analysis is a statistical framework used to investigate the mechanism by which an independent variable (exposure) influences a dependent variable (outcome) through one or more intermediate variables called mediators. In biological research, it helps decompose causal effects into direct effects (exposure to outcome) and indirect effects (exposure through mediator to outcome). This approach is crucial for understanding biological pathways, identifying therapeutic targets, and elucidating disease mechanisms. Mediation analysis quantifies the proportion of total effect explained by specific mediating pathways, enabling researchers to distinguish between correlation and causation in complex biological systems.
Visualize mediation analysis in Nodes Bio
Researchers can visualize mediation pathways as directed network graphs where nodes represent variables (exposures, mediators, outcomes) and edges indicate causal relationships with weighted connections showing effect sizes. Nodes Bio enables interactive exploration of multi-mediator models, highlighting direct versus indirect pathways, and allowing users to test alternative causal structures by rearranging network topology to identify key biological intermediates.
Visualization Ideas:
- Multi-level mediation networks showing exposure-mediator-outcome chains with effect size annotations
- Comparative pathway diagrams displaying direct versus indirect effects across different biological conditions
- Time-resolved mediation networks illustrating temporal sequences of molecular events in disease progression
Example Use Case
A research team investigating how obesity leads to type 2 diabetes uses mediation analysis to identify inflammatory cytokines as key mediators. They measure BMI (exposure), multiple inflammatory markers including IL-6 and TNF-α (mediators), and insulin resistance (outcome) in 500 patients. The analysis reveals that 60% of obesity's effect on diabetes operates through IL-6-mediated inflammation, suggesting IL-6 as a potential therapeutic target for preventing diabetes in obese individuals.