Table 5.
Adjusted longitudinal changes in global cognition score and physical function relative to baseline ccf-mtDNA levels (N = 672)
| Outcome | Intercept on ccf-mtDNA (95% CI) | Slope on ccf-mtDNA (95% CI) |
|---|---|---|
| Short ccf-mtDNA | ||
| Global cognition | -1.77 (-4.56, 1.02) | -0.01 (-0.57, 0.56) |
| Frailty a | 0.04 (-0.12, 0.19) | 0.02 (-0.001, 0.05) |
| Gait speed | -0.04 (-0.10, 0.01) | -0.01 (-0.02, 0.004) |
| Grip strength | -0.29 (-4.40, 3.82) | -0.04 (-0.68, 0.61) |
| Motor gait b | -0.06 (-0.13, 0.01) | -0.01 (-0.02, 0.002) |
| Motor composite score c | -0.06 (-0.12, 0.01) | -0.002 (-0.01, 0.01) |
| Long ccf-mtDNA | ||
| Global cognition | 3.55 (-0.82, 7.91) | -0.52 (-1.39, 0.34) |
| Frailty | -0.13 (-0.37, 0.11) | 0.03 (-0.01, 0.07) |
| Gait speed | -0.02 (-0.11, 0.07) | -0.01 (-0.02, 0.01) |
| Grip strength | 2.89 (-3.39, 9.17) | -0.45 (-1.42, 0.52) |
| Motor gait | -0.01 (-0.11, 0.10) | -0.02 (-0.03, -0.001) |
| Motor composite score | 0.002 (-0.09, 0.10) | -0.01 (-0.02, 0.004) |
Abbreviations: CI = Confidence interval; ccf-mtDNA = circulating cell-free mitochondrial DNA.
aFrailty is composite variable consisting of grip strength, timed walk, body mass index and fatigue. Larger values correspond to higher frailty
bMotor gait is a z-standardized composite variable comprised of walking time, walking steps, turning time, and turning steps. Larger values correspond to less time and fewer steps to complete task
cMotor composite score is calculated using the following items: Purdue Pegboard Test, Finger-tapping test, Time to cover 8 feet, Number of steps required to cover 8 feet, 360 degree turn time, Number of steps to complete a 360 degree turn, Leg stand, Toe stand, Grip strength, Pinch strength. Larger values correspond to better functionality
Model-estimated intercept and slope parameters from latent growth models of each outcome domain regressed on baseline ccf-mtDNA levels over a mean 8-year period
Intercept on ccf-mtDNA represents the difference in the mean baseline levels of outcome per 1000 copies per uL change in the ccf-mtDNA predictor on the log scale
Slope on ccf-mtDNA represents the difference in the mean rate of change in levels of outcome per 1000 copies per uL change in the ccf-mtDNA predictor on the log scale
Ccf-mtDNA variables are log-transformed. Each row of coefficients was estimated from a separate latent growth model. All models were adjusted for baseline age, sex, race, education, baseline levels of CRP and TNFR1. Bold indicates p < 0.05