Figure 1.

A-C: Pathway diagrams for three versions of the model. The variables typed in bold font are the observed variables; those in italic font are unobserved. Figure 1a represents the model where the diet effect on disease is not mediated by the biomarker (no mediation). Figure 1b represents the model where the diet effect is entirely mediated by the biomarker (full mediation). Figure 1c represents the general form of the model in which diet affects disease both through a pathway mediated by the biomarker and another pathway not mediated by the biomarker (partial mediation).