Table 1.
Participant characteristics
| Analytic sample | CN subgroup n = 499 | MCI subgroup n = 825 | Total sample N = 1324 |
|---|---|---|---|
| Mean age at baseline, y (SD) | 74.43 (5.85) | 73.20 (7.60) | 73.66 (7.01) |
| Women, n (%) | 255 (51.10) | 334 (40.48) | 589 (44.49) |
| Education years (SD) | 16.38 (2.69) | 15.92 (2.86) | 16.09 (2.80) |
| APOE ε4 positive, n (%) | 140 (28.06) | 424 (51.39) | 564 (42.59) |
| Race | |||
| African American, n (%) | 32 (6.41) | 24 (2.91) | 56 (4.23) |
| American Indian/Alaskan Native, n (%) | 1 (0.20) | 2 (0.24) | 3 (0.23) |
| Asian American, n (%) | 9 (1.80) | 14 (1.69) | 23 (1.74) |
| Native Hawaiian/Pacific Islander, n (%) | 0 (0.00) | 1 (0.12) | 1 (0.08) |
| White, n (%) | 452 (90.58) | 774 (93.81) | 1226 (92.59) |
| More than one, n (%) | 5 (0.1.00) | 7 (0.85) | 12 (0.91) |
| Unknown, n (%) | 0 (0.00) | 3 (0.36) | 3 (0.23) |
| Ethnicity | |||
| Non-Hispanic, n (%) | 477 (95.59) | 644 (78.1) | 1121 (84.67) |
| Hispanic, n (%) | 16 (3.20) | 18 (2.18) | 34 (2.57) |
| Unknown, n (%) | 4 (0.80) | 3 (0.36) | 7 (0.53) |
| Final diagnosis | |||
| Cognitively healthy, n (%) | 424 (84.97) | 39 (4.73) | 463 (34.96) |
| MCI, n (%) | 63 (12.63) | 507 (61.5) | 570 (43.05) |
| AD, n (%) | 12 (2.40) | 279 (33.8) | 291 (21.97) |
| Diagnostic converters, n (%) | 69 (13.83) | 276 (33.45) | 345 (26.05) |
| Diagnostic reverters, n (%) | 1 (0.20) | 51 (6.18) | 52 (3.93) |
Abbreviations: AD, Alzheimer's disease; MCI, mild cognitive impairment; APOE, apolipoprotein E.
NOTE. Percentiles were calculated using the sample size for that group (i.e., CN, MCI, or Total Sample).