VanderWeele TJ, Vansteelandt S. Odds ratios for mediation analysis with a dichotomous outcome

Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
American journal of epidemiology (Impact Factor: 5.23). 10/2010; 172(12):1339-48. DOI: 10.1093/aje/kwq332
Source: PubMed


For dichotomous outcomes, the authors discuss when the standard approaches to mediation analysis used in epidemiology and
the social sciences are valid, and they provide alternative mediation analysis techniques when the standard approaches will
not work. They extend definitions of controlled direct effects and natural direct and indirect effects from the risk difference
scale to the odds ratio scale. A simple technique to estimate direct and indirect effect odds ratios by combining logistic
and linear regressions is described that applies when the outcome is rare and the mediator continuous. Further discussion
is given as to how this mediation analysis technique can be extended to settings in which data come from a case-control study
design. For the standard mediation analysis techniques used in the epidemiologic and social science literatures to be valid,
an assumption of no interaction between the effects of the exposure and the mediator on the outcome is needed. The approach
presented here, however, will apply even when there are interactions between the effect of the exposure and the mediator on
the outcome.

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