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. 2024 Mar 6;76(1):124–133. doi: 10.3138/ptc-2021-0118

Table 2.

Mixed Model Analyses on Changes in VO2 Max over Five Years after Controlling for Baseline Age, Baseline VO2 Max, and Enrolment Delay in Males and Females

Males (n = 151, 524 observations)
Fixed effects variables β (SE) 95% CI P
 Enrolment duration  6.45 (1.51)  3.49, 9.41 < 0.001
 Enrolment duration2  −0.32 (0.06)  −0.44, -0.19 < 0.001
 Enrolment delay  −0.09 (0.07)  −0.23, 0.04  0.16
 Covariate: baseline age  −0.03 (0.02)  −0.08, 0.01  0.15
 Covariate: baseline VO2peak  0.93 (0.03)  0.87, 0.99  < 0.001
 Enrolment delay × enrolment Duration  0.07 (0.05)  −0.02, 0.16  0.12
 Baseline age × enrolment duration  −0.05 (0.02)  −0.09, −0.02  0.004
 Baseline VO2peak x enrolment duration  −0.08 (0.02)  −0.12, −0.03  0.002
 Constant  3.99 (1.79)  0.49, 7.49  0.026
Random effects Variance (SE) 95% CI
 Slope  1.85 (0.34)  1.30, 2.65
 Intercept  0.70 (0.60)  0.13,3.69
 Residual  6.70 (0.53)  5.74, 7.82
Model fit statistics Statistic
 Log likelihood  −1371.7
 Bayesian information criteria  2818.5
Females (n = 32,107 observations)
Fixed effects variables β (SE) 95% CI P
 Enrolment duration  0.21 (0.20)  −0.19,0.61  0.30
 Enrolment delay  −0.01 (0.30)  −0.59, 0.58  0.98
 Covariate: baseline age  −0.05 (0.05)  −0.14, 0.05  0.32
 Covariate: baseline VO2peak  0.81 (0.10)  0.60, 1.01  < 0.001
 Enrolment delay x enrolment duration  0.07 (0.13)  −0.18,0.33  0.57
 Constant  6.60(4.10)  −1.44, 14.63  0.11
Random effects Variance (SE) 95% CI
 Intercept  3.05 (1.11)  1.49, 6.23
 Residual  5.08(0.81)  3.72, 6.93
Model fit statistics Statistic
 Log likelihood  −255.8
 Bayesian information criteria  549.0

VO2peak = peak oxygen consumption; p = Beta coefficient; CI = confidence interval; SE = standard error.