Mediation analysis in a case ‐control study when the mediator is a censored variable

In this study, we propose an approach (denoted as MAC‐CC) to analyze the mediation model with a censored mediator given data from a case‐control study , based on the semiparametric accelerated failure time model along with a pseudo‐likelihood function. We adapted the measures for assessing the indirect and direct effects using counterfactual definitions. We conducted simulation studies to investigate the performance of MAC‐CC and compared it t o those of the naïve approach and the complete‐case approach. MAC‐CC accurately estimates the coefficients of different paths, the indirect effects, and the proportions of the total effects mediated. We applied the proposed and existing approaches to the mediation study of genetic variants, a w oman's age at menopause, and type 2 diabetes based on a case‐control study of type 2 diabetes. Our results indicate that there is no mediating effect from the age at menopause on the association between the genetic variants and type 2 diabetes.
Source: Statistics in Medicine - Category: Statistics Authors: Tags: RESEARCH ARTICLE Source Type: research