Table 3.
Adjusted Changes in New Learning, Verbal Memory, and Executive Function over Time among All Participants: REGARDS Study, 2003 to 2013
| Word-List Learning Score (n=10,321) | Word-List Delayed Recall Score (n=10,053) | Animal Fluency Test Score (n=11,214) | ||||
|---|---|---|---|---|---|---|
| No. of incident strokes | 107 | 102 | 120 | |||
| Model | Model A | Model B | Model A | Model B | Model A | Model B |
| Variable | Coefficient (95% CI) P |
Coefficient (95% CI) P |
Coefficient (95% CI) P |
Coefficient (95% CI) P |
Coefficient (95% CI) P |
Coefficient (95% CI) P |
| Baseline cognitive score per 1 unit increase | 0.41 (0.39 – 0.43) <0.001 |
0.41 (0.39 – 0.43) <0.001 |
0.34 (0.33 – 0.36) <0.001 |
0.34 (0.33 – 0.36) <0.001 |
0.54 (0.52 – 0.55) <0.001 |
0.54 (0.52 – 0.55) <0.001 |
| Baseline slope without incident stroke, per year | 0.22 (0.17 – 0.28) <0.001 |
0.22 (0.17 – 0.28) <0.001 |
0.08 (0.06 – 0.10) <0.001 |
0.08 (0.06 – 0.10) <0.001 |
−0.31 (−0.35 – −0.27) <0.001 |
−0.31 (−0.35 – −0.27) <0.001 |
| Acute change after incident stroke compared to before stroke | −1.75 (−2.45 – −1.05) <0.001 |
−1.80 (−2.86 – −0.73) 0.001 |
−0.67 (−0.97 – −0.37) <0.001 |
−0.60 (−1.07 – −0.13) 0.012 |
−0.90 (−1.57 – −0.23) 0.009 |
0.15 (−0.94 – 1.24) 0.78 |
| Change in slope after incident stroke, per year | Not included | 0.03 (−0.45 – 0.51) 0.91 |
Not included | −0.04 (−0.25 – 0.17) 0.70 |
Not included | −0.63 (−1.15 – −0.12) 0.017 |
| Age, per year | −0.14 (−0.15 – −0.13) <0.001 |
−0.14 (−0.15 – −0.13) <0.001 |
−0.06 (−0.06 – −0.06) <0.001 |
−0.06 (−0.06 – −0.06) <0.001 |
−0.12 (−0.13 – −0.11) <0.001 |
−0.12 (−0.13 – −0.11) <0.001 |
| Intercept | 18.17 (17.06 – 19.28) <0.001 |
18.17 (17.06 – 19.29) <0.001 |
7.91 (7.45 – 8.38) <0.001 |
7.91 (7.45 – 8.38) <0.001 |
16.58 (15.52 – 17.65) <0.001 |
16.57 (15.50 to 17.63) <0.001 |
| Log likelihood | −41683.4 | −41683.3 | −27920.2 | −27920.1 | −44213.4 | −44210.5 |
Interpretative Key: The Consortium to Establish a Registry for Alzheimer’s Disease Word-List Learning assesses new learning (scores range 0–30), the Word-List Delayed Recall assesses verbal memory (scores range 0–10), and the Animal Fluency Test assesses executive function with scores representing number of animals generated in 1 minute. For all cognitive tests, higher scores indicate better performance.
Linear mixed-effects models (Model B) included a random intercept, calendar time, and adjust for time-varying incident stroke, time since incident stroke, and baseline values of cognitive scores, age, sex, race, race*time (for Word-List Learning and Word-List Delayed Recall only), education, region, systolic blood pressure, cigarette smoking, waist circumference, diabetes, self-reported stroke, depressive symptoms, income, alcohol use, and self-reported health status.
Interpretative Example: An average participant gained 0.22 points per year on the Word-List Learning (WLL) test of new learning (95% confidence interval, 0.17–0.28; P<0.001) before having a stroke. An average stroke survivor’s WLL score decreased 1.80 points at the time of the stroke (95% confidence interval, 0.73–2.86; P=0.001). Over the years following stroke, survivors experienced no significant annual change in WLL scores (point estimate, 0.03 points; 95% confidence interval, −0.45–0.51; P=0.91) compared to the baseline (prestroke) slope.