Table 2.
Overview of all mediation models
| Model | Treatment (X) | Alternative mediator (M2) at 6 weeks | Primary mediator (M1) at 6 months | Outcome (Y) at 6 months |
| If the total effect of the intervention on the selected outcome is significant: | ||||
| 1.0 | Rx | Weight | Pain/Disability/QoL | |
| If the indirect effect through weight is significant (from model 1.0): | ||||
| 1.1* | Rx | Diet | Weight | Pain/Disability/QoL |
| 1.2* | Rx | Physical activity | Weight | Pain/Disability/QoL |
| 1.3* | Rx | Pain beliefs | Weight | Pain/Disability/QoL |
| If the indirect effect through weight is not significant (from model 1.0): | ||||
| 1.4 | Rx | Diet | Pain/Disability/QoL | |
| 1.5 | Rx | Physical activity | Pain/Disability/QoL | |
| 1.6 | Rx | Pain beliefs | Pain/Disability/QoL | |
| If the total effect of the intervention on the selected outcome is not significant: | ||||
| 2.0 | Rx | Weight | Pain/Disability/QoL | |
| 2.1 | Rx | Diet | Pain/Disability/QoL | |
| 2.2 | Rx | Physical activity | Pain/Disability/QoL | |
| 2.3 | Rx | Pain beliefs | Pain/Disability/QoL | |
*Multiple mediator models will only be tested if there is a significant relationship between M1 and M2. If the relationship is non-significant, then the alternative mediators will be tested in separate single mediator models with the mediator measured at week 6. Significance levels are set a priori at p<0.05.
QoL, quality of life.