Table 3.
Direct and bootstrap indirect effects in the mediation/moderation models of biomarkers in FM functional status
| Biomarkers | R 2 | F (df) | p a | Direct Effects | Indirect Effects | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| path | Coeff. | SE | t | p b | path | Boot. | SE | 95% CI | ||||
| BDNF | 0.24 | 4.81(2, 30) | 0.015 | a | 2.81 | 1.24 | 2.26 | 0.031 | a x b | 5.24 | 3.48 | 0.24 to 13.68 |
| b | 1.87 | 0.61 | 3.08 | 0.004 | ||||||||
| c′ | 1.90 | 4.56 | 0.42 | 0.680 | ||||||||
| d | −0.02 | 0.84 | −0.02 | 0.983 | ||||||||
| GI-comp | 0.15 | 2.57 (2, 30) | 0.094 | a | 0.27 | 0.18 | 1.48 | 0.148 | a x b | 2.70 | 2.36 | −0.98 to 8.27 |
| b | 10.07 | 4.45 | 2.27 | 0.031 | ||||||||
| c′ | 4.44 | 4.65 | 0.96 | 0.347 | ||||||||
| d | −1.48 | 3.85 | −0.39 | 0.703 | ||||||||
| CRP | 0.28 | 5.85 (2, 30) | 0.007 | a | 0.06 | 0.15 | 0.41 | 0.685 | a x b | 1.05 | 2.56 | −5.53 to 4.97 |
| b | 17.56 | 5.18 | 3.39 | 0.002 | ||||||||
| c′ | 6.09 | 4.13 | 1.47 | 0.151 | ||||||||
| d | −6.10 | 4.48 | −1.36 | 0.183 | ||||||||
| IL-6 | 0.02 | 0.27 (2, 30) | 0.768 | a | 0.12 | 0.09 | 1.45 | 0.158 | a x b | −0.26 | 1.80 | −3.15 to 4.21 |
| b | −2.12 | 10.09 | −0.21 | 0.835 | ||||||||
| c′ | 7.40 | 4.97 | 1.49 | 0.147 | ||||||||
| d | 13.15 | 18.32 | 0.72 | 0.479 | ||||||||
| TNF-α | 0.01 | 0.09 (2, 30) | 0.912 | a | 0.09 | 0.05 | 1.77 | 0.085 | a x b | 0.14 | 2.30 | −3.39 to 6.22 |
| b | 1.62 | 19.60 | 0.08 | 0.935 | ||||||||
| c′ | 7.00 | 5.13 | 1.37 | 0.182 | ||||||||
| d | 5.96 | 14.30 | 0.42 | 0.680 | ||||||||
| IL-10 | 0.03 | 0.49 (2, 30) | 0.617 | a | −0.04 | 0.02 | −2.00 | 0.054 | a x b | 1.27 | 2.97 | −4.70 to 6.05 |
| b | −36.19 | 60.62 | −0.60 | 0.555 | ||||||||
| c′ | 5.87 | 5.23 | 1.12 | 0.271 | ||||||||
| d | 17.16 | 65.43 | 0.26 | 0.795 | ||||||||
BDNF, GI-comp, CRP, IL-6, TNF-α and IL-10 difference scores were calculated as pre-post change scores (FIQ difference scores are pre-follow up change scores). Path coefficients are unstandardized ordinary least squares (OLS)-based regression coefficients. R2: determination coefficient (variance explained by regression models). F: Snedecor’s F associated with the adjustment of the regression model by using ANOVA. Coeff: unstandardized slope. t: Student’s t associated with the unstandardized slope by using the Wald test. SE: standard error. pa: p-value related to F-test. pb: p-value related to t-test. Boot: bootstrapped indirect effects using 10,000 samples. 95% CI: 95% confidence interval. “a x b” = indirect effects. c′ = direct effects adjusted by the mediating effect. d = moderating effect (see Fig. 2).