Per-protocol* analysis of circulating oxidative stress biomarker levels for exercisers and controls in the ALPHA Trial
| Baseline | Six months | Twelve months | Per cent change from baseline to 12 months | TER of exercise/control (95% CI)‡ | Between-group p value | ||||
|---|---|---|---|---|---|---|---|---|---|
| Geometric mean (95% CI)† | n | Geometric mean (95% CI)† | n | Geometric mean (95% CI)† | n | ||||
| SOD (μmol/L/min) | |||||||||
| Exercisers | 12.3 (11.8 to 12.7) | 91 | 12.3 (11.7 to 12.9) | 92 | 12.2 (11.8 to 12.6) | 92 | −0.3 | 0.98 (0.94 to 1.02) | 0.30 |
| Controls | 12.2 (11.9 to 12.6) | 159 | 12.4 (12.0 to 12.7) | 154 | 12.6 (12.2 to 13.0) | 155 | 2.8 | ||
| CAT (μmol/L/min) | |||||||||
| Exercisers | 21.5 (19.2 to 24.0) | 92 | 21.3 (18.8 to 24.2) | 92 | 21.6 (19.1 to 24.4) | 92 | 1.4 | 1.00 (0.92 to 1.09) | 0.99 |
| Controls | 19.1 (17.5 to 20.9) | 159 | 19.5 (17.8 to 21.3) | 154 | 19.5 (17.8 to 21.5) | 156 | 2.2 | ||
| 8-iso-PGF2α (ng/L) | |||||||||
| Exercisers | 220 (199 to 244) | 88 | 224 (207 to 242) | 91 | 212 (188 to 240) | 89 | −3.7 | 0.98 (0.90 to 1.08) | 0.89 |
| Controls | 230 (216 to 245) | 154 | 218 (202 to 237) | 146 | 223 (209 to 239) | 147 | −3.0 | ||
| 8-OHdG (ng/L) | |||||||||
| Exercisers | 7.2 (6.9 to 7.5) | 92 | 7.2 (6.9 to 7.5) | 92 | 7.3 (7.1 to 7.6) | 92 | 1.6 | 0.99 (0.95 to 1.02) | 0.44 |
| Controls | 7.1 (6.8 to 7.4) | 156 | 7.2 (6.9 to 7.5) | 152 | 7.2 (7.0 to 7.5) | 155 | 1.9 | ||
*Per-protocol analysis included all participants in the control group and only those participants who fulfilled ≥90% of the exercise prescription over weeks 13–52 of the study.
†Blood samples from n=159 participants in the control group and n=156 participants in the exercise group were obtained. A further n=1, 12 and 3 participants were removed from the SOD, 8-iso-PGF2α and 8-OHdG analyses, respectively, as they were outliers or below the limit of detection.
‡The TER was calculated based on a linear mixed model for each biomarker, adjusted for time and baseline values of the biomarker. The TER represents the adjusted ratio of geometric means for the exercise group over the control group. A TER of <1.0 indicates lower oxidative stress biomarker or antioxidant activity levels in the exercise group relative to the control group at 6 and 12 months; a TER >1.0 indicates higher oxidative stress biomarker or antioxidant activity levels in the exercise group; and a ratio of 1.0 indicates no difference between groups.
8-iso-PGF2α, 8-isoprostaglandin F2α; 8-OHdg, 8-hydroxy-2′-deoxyguanosine; CAT, catalase; SOD, superoxide dismutase; TER, treatment effect ratio.