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Odds ratios for mediation analysis for a dichotomous outcome
Tyler J Vanderweele1, Stijn Vansteelandt
1Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA. tvanderw@hsph.harvard.edu
American Journal of Epidemiology
|November 2, 2010
Summary
This study presents new mediation analysis methods for dichotomous outcomes, applicable even with interactions. These techniques extend effect definitions to the odds ratio scale, offering valid alternatives when standard approaches fail.
Area of Science:
- Epidemiology
- Social Sciences
- Biostatistics
Background:
- Standard mediation analysis in epidemiology and social sciences often requires an assumption of no interaction between exposure and mediator effects.
- This assumption limits the applicability of traditional methods when interactions are present.
Purpose of the Study:
- To develop and describe alternative mediation analysis techniques for dichotomous outcomes.
- To extend definitions of direct and indirect effects to the odds ratio scale.
- To provide methods valid even in the presence of exposure-mediator interactions.
Main Methods:
- Extension of controlled direct effects and natural direct/indirect effects from risk difference to odds ratio scale.
- Description of a technique combining logistic and linear regressions for estimating odds ratios of direct and indirect effects.
- Adaptation of the technique for case-control study designs.
Main Results:
- The proposed methods provide valid estimates of direct and indirect effects on the odds ratio scale.
- The technique is applicable when the outcome is rare and the mediator is continuous.
- The methods accommodate situations with interactions between exposure and mediator effects.
Conclusions:
- The developed mediation analysis techniques offer broader applicability than standard methods.
- These approaches are valuable for understanding causal pathways in epidemiological and social science research, especially when interactions are present.
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