However, although Avastin confers a survival benefit to patients with colon, lung and kidney cancer when used in combination with chemotherapy (Hurwitz et al, 2004), this agent is rarely curative, as tumours often secrete multiple mediators of angiogenesis that compensate for the loss of VEGF-A activity.
For path models, we used Mplus software [ 46] and for explicit statistical tests for multiple mediators, SPSS [ 47].
We ran two mediation analyses: (1) single mediation models (unadjusted, a model that has single mediator), (2) multiple mediation model (adjusted, to obtain the significance of individual mediators within the context of a model that has multiple mediators simultaneously and account for the biological direction between mediators).
Model 3: Adjusted for age, education, physical activity, menopausal status and hysterectomy Table 6 shows the multiple mediator models for age at first birth and parity on the three physical performance tests.
Cross-lagged multiple regressions and bootstrapping procedures for testing multiple mediators supported all of the relationships proposed by the TPB.
Figure 1C shows the proposed mediation model with multiple mediators.
For example, incorporating multiple mediators using insufficient sample sizes can actually reduce the quality of a mediational study instead of enhancing it.
This is a nonparametric sampling procedure recommended for simultaneous testing for indirect effects of multiple mediators [ 58].
The model was explored using Conditional Process analysis, http://www.afhayes.com/, [60, 61], which allows for assessment of multiple mediators working in parallel using recommended bootstrap methodology [62].
These multiple mediators provide a host of targets for therapeutic intervention.
