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. 2016 Jul 27;8(7):1485–1504. doi: 10.18632/aging.101005

Table 2. Linear model that regresses DNAm age on HD status and other covariates.

Model 1 Model 2 Model 3
Covariate Contrast Coef (SE) P-value Coef (SE) P-value Coef (SE) P-value
Huntington 2.06 (0.517) 6.7×10−5 1.704 (0.503) 0.00070 0.9 (0.486) 0.065
Age 0.646 (0.012) <2×10−16 0.64 (0.011) <2×10−16 0.632 (0.011) <2×10−16
Sex Female vs Male −0.981 (0.49) 0.046 −0.84 (0.474) 0.077 0.611 (2.637) 0.817
Brain Bank UCLA vs NewZealand −0.093 (1.224) 0.94 1.049 (1.198) 0.382 1.32 (1.139) 0.247
Tissue Caudate Nucleus vs Frontal −1.237 (1.266) 0.33 −3.412 (1.278) 0.008 −3.239 (1.201) 0.007
Cingulate Gyrus vs Frontal −1.631 (1.224) 0.18 −1.961 (1.183) 0.098 −0.729 (1.119) 0.52
CRBM vs Frontal −5.353 (1.121) 1.8×10−6 −3.854 (1.113) 0.001 16.194 (10.299) 0.12
Hippocampus vs Frontal 1.327 (1.191) 0.27 −0.077 (1.175) 0.95 1.08 (1.131) 0.34
Midbrain vs Frontal −1.115 (1.274) 0.38 −4.12 (1.334) 0.002 −1.327 (1.331) 0.32
Motor Cortex vs Frontal 1.539 (1.224) 0.21 1.699 (1.182) 0.151 1.64 (1.112) 0.14
Occipital vs Frontal −2.886 (1.115) 0.01 −1.704 (1.096) 0.121 −2.218 (1.037) 0.033
Parietal vs Frontal 0.835 (1.065) 0.43 1.781 (1.042) 0.088 1.382 (0.982) 0.16
Sensory Cortex vs Frontal −0.173 (1.224) 0.89 0.079 (1.183) 0.95 0.179 (1.116) 0.87
Temporal vs Frontal 0.191 (1.156) 0.87 0.228 (1.116) 0.84 0.621 (1.053) 0.56
Visual Cortex vs Frontal 0.4 (1.233) 0.75 2.178 (1.23) 0.077 0.408 (1.192) 0.73
Prop. Neurons −13.966 (2.395) 5.5×10−9
PC1 862.505 (313.408) 0.006
PC2 147.452 (64.232) 0.022
PC3 −36.821 (13.872) 0.008
PC4 59.519 (11.864) 5.3×10−7
PC5 8.251 (26.496) 0.76

Coefficients, standard error, and corresponding p-values for three multivariate models.

According to model 1, the age acceleration due to HD status amounts to 3.3 years (=2.159/0.646).

Model 2 is similar to model 1 but includes the (estimated) proportion of neurons as covariate. Model 3 is similar to model 1 but includes principal components. Since the analysis ignores the dependency of observations (due to multiple brain regions coming from the same individual), the p-values should only be interested as descriptive measures (as opposed to inferential measures). The multivariate models allow us to estimate the increase in biological age due to HD status. HD status is associated with an increase of 3.2 years (=2.06/0.646) according to model 1, an increase of 2.7 years (=1.704/0.64) according to model 2, and am increase of 1.4 years according to model 3.