Table 2.
Intention‐to‐treat analysis of circulating anti‐inflammatory cytokine levels for exercisers and controls in the Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA) and high‐volume and moderate‐volume exercisers in the Breast Cancer and Exercise Trial in Alberta (BETA) at baseline, 6, and 12 months
| Baseline | 6 months | 12 months | n | Percent change from baseline to 12 months | TER of exercise/control or high/moderate (95% CI)b | Between‐group P | |
|---|---|---|---|---|---|---|---|
| Geometric mean (95% CI)a | Geometric mean (95% CI)a | Geometric mean (95% CI)a | |||||
| ALPHA | |||||||
| IL‐4 (pg/mL) | |||||||
| Exercisers | 1.37 (1.23, 1.54) | 1.34 (1.20, 1.49) | 1.32 (1.18, 1.47) | 150 | −4.28 | 0.98 (0.92, 1.05) | 0.54 |
| Control | 1.57 (1.40, 1.76) | 1.52 (1.35, 1.71) | 1.52 (1.35, 1.71) | 147 | −3.44 | ||
| IL‐10 (pg/mL) | |||||||
| Exercisers | 1.27 (1.13, 1.42) | 1.25 (1.12, 1.41) | 1.25 (1.11, 1.40) | 150 | −1.51 | 0.99 (0.91, 1.08) | 0.84 |
| Control | 1.36 (1.22, 1.52) | 1.35 (1.19, 1.52) | 1.34 (1.19, 1.51) | 147 | −1.63 | ||
| BETA | |||||||
| IL‐4 (pg/mL) | |||||||
| High | 0.82 (0.70, 0.97) | 0.81 (0.69, 0.95) | 0.76 (0.64, 0.89) | 192 | −8.24 | 0.94 (0.84, 1.06) | 0.32 |
| Moderate | 0.89 (0.75, 1.05) | 0.94 (0.79, 1.11) | 0.83 (0.70, 0.99) | 191 | −6.32 | ||
| IL‐10 (pg/mL) | |||||||
| High | 0.82 (0.73, 0.92) | 0.78 (0.70, 0.88) | 0.76 (0.68, 0.85) | 192 | −7.53 | 0.98 (0.92, 1.06) | 0.68 |
| Moderate | 0.88 (0.78, 0.99) | 0.84 (0.75, 0.94) | 0.82 (0.73, 0.93) | 191 | −6.35 | ||
CI, confidence interval; IL‐4, interleukin‐4; IL‐10, interleukin‐10; TER, treatment effect ratio.
Of the 310 ALPHA and 386 BETA participants who provided blood samples at any time point, we excluded those with IL‐4 or IL‐10 levels above a threshold for extremely high levels, specifically: 10 pg/mL for both IL‐4 (n = 5 excluded) and IL‐10 (n = 5 excluded) in ALPHA; and 50 pg/mL for IL‐4 (n = 1 excluded) and 35 pg/mL for IL‐10 (n = 1 excluded) in BETA. Participants (n = 2 for BETA and n = 8 for ALPHA) missing a blood sample at any time point were also removed.
The TER was calculated based on a linear mixed model for each cytokine, adjusted for time and baseline value. The TER represents the adjusted ratio of geometric means for the exercise group over the control group (ALPHA) or the high‐volume exercise group over the moderate‐volume exercise group (BETA). A TER of <1.0 indicates lower anti‐inflammatory cytokine levels in the exercise group relative to the control group (ALPHA) or the high‐volume exercise group relative to the moderate‐volume exercise group (BETA) at 6 and 12 months; a TER greater than 1 indicates higher anti‐inflammatory markers in the exercise group (ALPHA) or the high‐volume exercise group (BETA); and a TER of 1.0 indicates no differences between groups.