Table 3.
Indirect, direct, and total effects of the mediation models on respiratory and cognitive outcomes at 6 months.
| Outcomes | Mediators | Indirect effects (mediating-effect) | Direct effect of BFY intervention on outcome (DE) | Total effect (TE) | Proportion mediated (%) |
|---|---|---|---|---|---|
| FEV(L) | SOD | 0.02 (−0.03–0.09) | 1.06 (0.67–1.45)** | 1.01 (0.74–1.29)** | 1.98 |
| MDA | −0.08 (0.07–0.24) | 7.92 | |||
| GSH | 0.01 (0.11–0.21) | 1.00 | |||
| FEV z score | SOD | 0.018 (−0.11–0.15) | 1.90 (1.11–2.69) | 1.78 (1.24–2.33)** | 1.01 |
| MDA | −0.15 (−0.50–0.15) | 8.43 | |||
| GSH | 0.01 (−0.45–0.48) | 0.56 | |||
| GLFEVPP | SOD | 0.02 (−0.03–0.09) | 47.68 (33.93–61.43)** | 48.64 (38.84–58.44)** | 0.04 |
| MDA | 1.08 (−3.53–5.83) | 2.22 | |||
| GSH | 1.11 (−6.74–8.03) | 2.28 | |||
| FVC(L) | SOD | 0.024 (−0.044–0.11) | 1.30 (0.81–1.80)* | 1.12 (0.76–1.48)* | 2.14 |
| MDA | −0.16 (−0.36–0.018) | 14.28 | |||
| GSH | −0.045 (−0.32–0.21) | 4.02 | |||
| FVC z score | SOD | 0.01 (−0.06–1.00) | 2.32 (1.34–3.29) | 2.03 (1.34–2.71) | 2.14 |
| MDA | −0.14 (−0.34–0.02) | 14.28 | |||
| GSH | −0.045 (−0.32–0.21) | 4.02 | |||
| GLFVCPP | SOD | −1.29 (−3.99–0.48) | 49.58 (35.60–63.59)* | 46.47 (36.49–56.45)* | 3.00 |
| MDA | −0.92 (−5.83–3.70) | 2.00 | |||
| GSH | 0.89 (−8.07–5.46) | 1.91 | |||
| FEV1/FVC | SOD | 0.27 (−0.42–1.22) | −1.36 (−6.80–4.08) | 2.54 (−1.43–6.50) | 10.63 |
| MDA | 2.31 (0.68–4.51) | 92.03 | |||
| GSH | 1.31 (−1.18–3.82) | 0.52 | |||
| GLIFEV1/FVCPP | SOD | 0.04 (−0.79–0.95) | −3.15 (−8.54–2.24) | 0.49 (−3.35–4.34) | 8.16 |
| MDA | 2.96 (0.85–5.38) | – | |||
| GSH | 0.64 (−2.37–3.48) | – | |||
| FEV1/FVC z-Score | GSH | 0.00 (−0.11–0.13) | −0.55 (−1.24–0.14) | −0.04 (−0.54–0.45) | – |
| MDA | 0.40 (0.15–0.13) | – | |||
| GSH | 0.10 (−0.30–0.46) | – | |||
| FEF25–75% | SOD | 0.28 (−1.07–2.02) | 18.78 (9.40–28.17)* | 28.39 (21.49–35.29)* | 0.99 |
| MDA | 2.51 (−0.23–5.75) | 8.84 | |||
| GSH | 6.80 (1.51–12.36) | 23.95* | |||
| FEF25–75% z-Score | SOD | 0.03 (−0.33–0.45) | 4.72 (2.36–7.07) | 6.94 (5.34–8.5)* | 0.004 |
| MDA | 0.83 (−0.07–1.80) | 11.95 | |||
| GSH | 1.60 (0.48–2.90) | 23.50* | |||
| PEFR | SOD | 1.43(−0.43–4.02) | 43.64 (31.90–55.38)* | 44.47 (36.15–52.79)* | 3.21 |
| MDA | 1.60 (−1.22–4.95) | 3.59 | |||
| GSH | −0.72 (−6.41–4.90) | 1.62 | |||
| DSST | SOD | 0.11 (−0.69–0.93) | 10.83 (6.74–14.92)* | 11.71 (8.70–14.73)* | 0.94 |
| MDA | 0.026 (−1.39–1.51) | 0.26 | |||
| GSH | 0.71 (−1.23–2.70) | 6.06 | |||
| TMT-A | SOD | 0.24 (−0.76–1.54) | −24.25 [−28.91 –(19.60)]* | −24.60 [−28.13– (−21.07)] * | 0.99 |
| MDA | 0.40 (−1.16–1.78) | 8.69 | |||
| GSH | −0.96 (−3.60–1.41) | 3.90 | |||
| TMT-B | SOD | 1.58(−0.39–4.07) | −44.36 (−54.81– −33.91)* | −42.40 (−50.28– −34.51)* | 3.73 |
| MDA | 1.28 (−1.81–4.75) | 3.02 | |||
| GSH | −0.82 (−6.31–4.87) | 1.93 | |||
| PSS | SOD | −0.06 (−0.63–0.45) | −3.60 (−6.19– −1.01) | −1.63 (−3.51–0.25) | 3.92 |
| MDA | 0.52 (−0.40–1.51) | 31.91 | |||
| GSH | 1.46 (0.15–3.02) | 89.57 | |||
| WHOQOL-Bref | SOD | −0.61 (−1.98–0.25) | 26.07 (20.72–31.41) | 27.61 (23.61–.61.63)* | 2.21 |
| MDA | −0.26 (−1.71–1.12) | 0.94 | |||
| GSH | 2.41 (−0.57–5.86) | 8.72 |
Direct effect (DE) refers to the direct influence of the BFY on the study outcomes that is not mediated by other variables in the model. An indirect (mediated) effect expresses the portion of the intervention effect that is mediated through a specific mediator. The total effect (TE) is the sum of the direct and indirect effects of the BFY and of mediators on the study outcomes.
SOD, Superoxide dismutase; MDA, Malondialdehyde; GSH, Glutathione; FEV, Forced expiraory volume; FVC, Forced vital capacity; PEFR. GLGlobal Lung Initiative (GLI) percent predicted (pp), and GLI z-scores, The adjusted means of all variables are presented along with standard errors. Adjusted for age, BMI, and education (yrs), adjusted for respiratory symptoms.