A0195
Title: Generalized interventional approach for causal mediation analysis with causally ordered multiple mediators
Authors: Sheng-Hsuan Lin - Institute of Statistics (Taiwan) [presenting]
Abstract: Causal mediation analysis has shown the advantage of mechanism investigation. Under conditions with causally ordered mediators, path-specific effect (PSE) is introduced for specifying the effect mediated by a certain combination of mediators. However, most of PSEs are unidentifiable. An alternative approach, called interventional analogue of PSE (iPSE), is widely applied to effect decomposition to address this issue. Previous literature for multiple mediators mainly focused on discussing the case of two mediators due to the complexity of the mediation formula. A generalized method under the settings with an arbitrary number of mediators is attractive to study causal parameter identification and statistical estimation. A generalized interventional approach is proposed to discuss the effect mediated by ordered multiple mediators. It provides a general definition of iPSE by a recursive formula, assumptions for non-parametric identification, a regression-based method and a G-computation algorithm to estimate all iPSEs. This approach is applied to a Taiwanese cohort study for exploring the mechanism among hepatitis C virus on mortality through hepatitis B Virus, liver function, and hepatocellular carcinoma.
