---
address:
- ', , '
- ', , '
- ', , '
- ', , '
- ', , '
author:
- 'Tat-Thang Vo\*'
- 'Hilary Davies-Kershaw'
- Ruth Hackett
- Stijn Vansteelandt
bibliography:
- 'longitudinal.bib'
nocite: '[@*]'
title: ' Longitudinal mediation analysis of time–to–event endpoints in the presence of competing risks'
---

Introduction {#sec1}
============

This article is motivated by an analysis of the English Longitudinal Study of Ageing, a longitudinal cohort study of individuals aged 50 and older living in the community in England [@steptoe2013cohort; @davies2017], which follows participants biennially since 2002/03. In previous studies, it was shown that both self-reported hearing loss and loneliness are significantly associated with a higher risk of dementia [@davies2017; @davies18; @rafnsson2020loneliness]. The question of interest, which we shall address here, is whether loneliness mediates the impact of hearing loss on incident physician-diagnosed dementia.

The focus on time-to-event endpoints (dementia) complicates the planned mediation analysis. It renders the popular difference- and product-of-coefficient methods inappropriate [@vdw16; @robin92; @pearl01], necessitating the use of more complex causal mediation analysis methods. While such methods have been developed for the analysis of time-to-event endpoints, most ignore that the mediator is not assessed at baseline and that 