Table 1. Parameter estimates from step 1 and step 2 “factor of curves” models in VCAP.
ρFi,Fsa = −0.075 (P = 0.053), ρFi,Fqa = −0.963 (P < 0.001), and ρFs,Fqa = 0.086 (P = 0.305). The variances of Fi, Fs, and Fq were fixed to 1.0 to define the metrics of the latent growth factors. We specified age-based growth curve modeling, such that the basis coefficients for each of the five slopes were set to the age in decades of individual n at each assessment on variable w, centered at 50 years. Each of the five cognitive outcomes was standardized by subtracting the mean of all datapoints at the baseline occasion and dividing by the SD of the age and age-squared residuals of all the datapoints at baseline. Gf, abstract reasoning; Gv, visuospatial reasoning; Gm, memory; Gs, perceptual speed; Gc, crystallized ability. See Materials and Methods for explanation of model parameters.
|
Cognitive
domain |
Latent variable
means (SE) |
Unstandardized
loadings (SE) |
Standardized
loadings |
Residual variances and covariances (SE) | |||||||||||||
| μr | μi | μs | μq | Fi | Fs | Fq | Fi | F s | Fq | σ2e[t] | σ2ui | σ2us | σ2uq | σui,us | σui,uq | σus,uq | |
| Gf* | 0.118 (0.009) |
0.164 (0.015) |
−0.186 (0.007) |
−0.037 (0.003) |
0.867 (0.016) |
0.252 (0.016) |
0.064 (0.006) |
1.011 (0.007) |
1.022 (0.068) |
0.988 (0.002) |
0.115 (0.003) |
−0.016 (0.011) |
−0.003 (0.008) |
0.000 (0.000) |
0.007 (0.003) |
0.001 (0.004) |
0.001 (0.000) |
| Gv* | 0.175 (0.008) |
0.090 (0.015) |
−0.190 (0.007) |
−0.014 (0.003) |
0.696 (0.014) |
0.173 (0.014) |
0.050 (0.007) |
0.817 (0.009) |
0.875 (0.087) |
0.949 (0.015) |
0.107 (0.004) |
0.242 (0.011) |
0.009 (0.007) |
0.000 (0.000) |
−0.014 (0.003) |
−0.006 (0.004) |
0.000 (0.000) |
| Gm* | 0.116 (0.010) |
0.184 (0.015) |
−0.172 (0.007) |
−0.039 (0.003) |
0.576 (0.018) |
0.191 (0.011) |
0.060 (0.004) |
0.724 (0.014) |
0.776 (0.064) |
0.835 (0.028) |
0.137 (0.005) |
0.301 (0.013) |
0.024 (0.009) |
0.002 (0.000) |
0.004 (0.004) |
−0.020 (0.005) |
−0.001 (0.001) |
| Gs* | 0.100 (0.010) |
0.198 (0.014) |
−0.315 (0.006) |
−0.039 (0.003) |
0.453 (0.017) |
0.166 (0.010) |
0.047 (0.004) |
0.582 (0.017) |
0.764 (0.083) |
0.848 (0.045) |
0.133 (0.005) |
0.399 (0.015) |
0.020 (0.010) |
0.001 (0.000) |
−0.025 (0.005) |
−0.016 (0.005) |
0.001 (0.001) |
| G c † | −0.030 (0.006) |
0.117 (0.010) |
0.134 (0.004) |
−0.038 (0.002) |
0.713 (0.012) |
0.145 (0.006) |
0.046 (0.003) |
0.774 (0.009) |
0.933 (0.082) |
0.907 (0.033) |
0.050 (0.002) |
0.341 (0.012) |
0.003 (0.004) |
0.000 (0.000) |
−0.007 (0.003) |
−0.008 (0.002) |
0.000 (0.000) |
*First step: unconstrained factor of curves model excluding Gc.
†Second step: constrained factor of curves model including Gc.