Table 4. Association of specific principal components with CIMT by pregnancy history.
| Analysis Performed on PCs | GlobalTest ‡ | PC#1 | PC#2 | PC#3 | PC#4 | PC#5 | PC#6 | PC#7 |
|---|---|---|---|---|---|---|---|---|
| Correlation with CIMT | Spearman ρ+ | |||||||
| Group with history of normotensive pregnancy | P = 0.009 | -0.130 | -0.055 | -0.037 | 0.327* | -0.169 | -0.359* | 0.181 |
| Group with history of preeclampsia | P = 0.481 | 0.275 | -0.139 | 0.120 | 0.117 | 0.030 | 0.219 | -0.142 |
| Both groups pooled together | P = 0.364 | 0.050 | -0.077 | 0.012 | 0.258* | -0.068 | -0.014 | 0.035 |
| Test of interaction | P = 0.014 | *** | ||||||
+ Group-specific results are reported as Spearman’s ρ rank correlation coefficients, which measure the strength of association of each PC with carotid intima-media thickness (CIMT); group-combined results represent partial Spearman ρ values which measure each correlation controlling for the effects of PE group. Tests for significant correlations are denoted with symbols as described below.
‡For each of the two groups and the combined group, a global test for any association among the 7 PCs with CIMT was performed in a multivariable ordinal logistic model with CIMT as the dependent variable and the PCs simultaneously entered as predictor variables (i.e., 6 degree-of-freedom likelihood ratio test comparing this model to a reduced model without PC predictor terms). As a global test for interaction, a model was constructed that additionally included a PE group indicator and the cross-product (interaction) terms between PE indicator and each PC, with the group of interactions tested for significance by formally comparing these two models with and without interaction terms (6 degree-of-freedom likelihood ratio test)
* P < 0.05
*** P < 0.001.