TABLE 5.
Sample characteristics in larger sample used to examine the progression hypothesis.
| Baseline cognitive status (n = 1229) | |||
| CU-S | CU-D | p-value** | |
| Demographics | n = 1110 | n = 119 | |
| Age, mean (SD) | 54.0 (6.6) | 55.8 (5.9) | 0.006 |
| Years of education (max 20), median (Q1–Q3) | 16 (14–18) | 16 (14–18) | 0.25 |
| Literacy/VIQ, mean (SD) WRAT3 Reading standard score | 106.1 (9.1) | 105.1 (9.5) | 0.29 |
| Female, n (%) | 792 (71.4) | 60 (50.4) | <0.0001 |
| APOE ε4 carrier, n (%) | 425 (38.3) | 46 (38.7) | 0.94 |
| Race/ethnicity = non-Hispanic Caucasian, n (%)* | 1052 (94.8) | 103 (86.6) | 0.002 |
| Self-report of memory problems | 0.34 | ||
| Yes, n (%) | 264 (23.9) | 32 (26.9) | |
| Don’t know, n (%) | 208 (18.8) | 27 (22.7) | |
| No, n (%) | 634 (57.3) | 60 (50.4) | |
| Baseline IICV*, adjusted mean (SE) | 0.69 (0.012) | 1.18 (0.033) | <0.0001 |
| AVLT Total, adjusted mean (SE) | 0.02 (0.027) | −1.22 (0.076) | <0.0001 |
| AVLT Delay, adjusted mean (SE) | 0.04 (0.027) | −1.30 (0.077) | <0.0001 |
| Trails B, adjusted mean (SE) | 0.07 (0.029) | −0.95 (0.082) | <0.0001 |
*Among the n = 58 in CU-S group who are not non-Hispanic Caucasian, 30 (51.7%) were African American compared with 11 of 16 (68.8%) in the CU-D group.
**p-values are from t-tests for rows reporting mean (SD), Mann–Whitney U or Kruskal–Wallis for rows reporting medians, and chi-square or Fisher’s exact for rows reporting n (%).
CU-S, cognitively unimpaired-stable; CU-D, cognitively unimpaired-declining; MCI, mild cognitive impairment; IICV, intraindividual cognitive variability calculated as the standard deviation of the baseline z-scores of WRAT reading, AVLT Total, AVLT delayed recall, and Trails B.