Table 2: Associations between 6-week change in mediator values and intervention group#.

Main cohort*Saliva cohort**
Change in mediatorSE95% CI valueChange in mediatorSE95% CI value

Yoga versus self-care
 Fear avoidance 1.39(−3.00, 2.52)0.8652.671.87(−1.07, 6.41)0.158
 Self-efficacy0.780.30(0.19, 1.38)0.0100.630.37(−0.10, 1.36)0.090
 Conscious awareness of body1.291.24(−1.16, 3.74)0.299 1.51(−3.41, 2.63)0.796
 Psychological distress 1.56(−4.26, 1.92)0.456 1.89(−5.20, 2.36)0.455
 Perceived stress 1.02(−2.24, 1.80)0.828 1.32(−2.77, 2.51)0.922
 Positive states of mind0.510.51(−0.50, 1.52)0.3160.480.59(−0.70, 1.66)0.418
 Improved sleep 0.10(−0.39, 0.00)0.050−0.200.13(−0.45, 0.06)0.131
 Hours of back exercise0.930.27(0.41, 1.46)0.00061.320.31(0.70, 1.95)0.00007
 DHEA change in diurnal average (log scale)0.190.13(−0.06, 0.44)0.139
 Average cortisol awakening response (CAR)−0.120.27(−0.66, 0.42)0.658
Stretching versus self-care
 Fear avoidance 1.26(−4.23, 0.77)0.173 1.56(−3.16, 3.09)0.981
 Self-efficacy0.840.26(0.32, 1.36)0.0020.750.36(0.03, 1.48)0.042
 Conscious awareness of body0.761.49(−2.18, 3.71)0.608 1.82(−4.85, 2.41)0.505
 Psychological distress 1.62(−5.27, 1.16)0.207 2.07(−4.30, 3.96)0.934
 Perceived stress 0.86(−3.05, 0.37)0.122 1.12(−2.35, 2.14)0.926
 Positive states of mind0.640.45(−0.25, 1.52)0.1560.640.55(−0.45, 1.73)0.247
 Improved sleep 0.10(−0.27, 0.12)0.448 0.13(−0.30, 0.22)0.765
 Hours of back exercise1.250.23(0.79, 1.71)0.0000011.720.30(1.13, 2.32)0.0000002
 DHEA change in diurnal average (log scale)0.080.15(−0.21, 0.37)0.595
 Average cortisol awakening response (CAR)0.070.28(−0.50, 0.64)0.799

Each mediator is an outcome variable in a model with intervention as the predictor variable and adjustment for selected baseline variables. Therefore, note that effect size comparison across rows should not be done since outcome variable is changing.
Adjusted for baseline variables age, sex, BMI, back pain days, work type, pain travelling down the leg, bothersomeness, and RDQ. Same adjustments as main cohort analysis with the addition of alcohol, tobacco, and medication use on the day of saliva sample collection.