Table 2.
Characteristics of the study population and subgroups in total and stratified by amyloid-PET status
| Study population | CN subgroup | aMCI subgroup | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Total | Aβ− | Aβ+ | Total | Aβ− | Aβ+ | Total | Aβ− | Aβ+ | |
| Number (%) | 199 | 161 (81) | 38 (19) | 161 | 137 (85) | 24 (15) | 38 | 24 (63) | 14 (37) |
| Mean age (SD), years | 70 (6) | 69 (6) | 72 (5)b | 69 (6) | 69 (6) | 71 (5) | 71 (7) | 69 (6) | 74 (6) |
| Female, n (%) | 89 (45) | 72 (45) | 17 (45) | 73 (45) | 61 (45) | 12 (50) | 16 (42) | 11 (46) | 5 (36) |
| Mean education (SD), years | 14 (3) | 14 (3) | 14 (4) | 14 (3) | 14 (3) | 14 (4) | 14 (4) | 14 (4) | 14 (3) |
| APOE-ε4 carriers/homozygous, n (%) | 92/7 (46) | 70/5 (43) | 22/2 (58) | 82/6 (51) | 65/5 (47) | 17/1 (71)a | 10/1 (26) | 5/0 (21) | 5/1 (36) |
| Median MMSE (IQR), /30 | 29 (2) | 29 (2) | 29 (2)a | 29 (2) | 29 (2) | 29 (2) | 29 (2) | 29 (1) | 27 (3)a |
| Median ELISA plasma Aβ1–42/Aβ1–40 (IQR) | 0.17 (0.03) | 0.18 (0.03) | 0.15 (0.02)d | 0.18 (0.03) | 0.18 (0.03) | 0.15 (0.02)d | 0.17 (0.02) | 0.18 (0.03) | 0.16 (0.01)b |
| Median ELISA plasma Aβ1–42/t-tau (IQR) | 1.23 (0.50) | 1.32 (0.49) | 1.00 (0.29)d | 1.25 (0.49) | 1.29 (0.49) | 1.02 (0.34)c | 1.21 (0.58) | 1.41 (0.51) | 0.89 (0.27)d |
| Median SIMOA plasma Aβ1–42/Aβ1–40 (IQR) | 0.26 (0.06) | 0.26 (0.06) | 0.21 (0.05)d | 0.26 (0.06) | 0.26 (0.05) | 0.21 (0.05)d | 0.24 (0.07) | 0.28 (0.06) | 0.22 (0.03)c |
| Median SIMOA plasma Aβ1–42/t-tau (IQR) | 0.93 (0.41) | 0.99 (0.39) | 0.73 (0.24)d | 0.94 (0.37) | 0.99 (0.38) | 0.74 (0.27)c | 0.92 (0.45) | 1.14 (0.33) | 0.70 (0.21)d |
aMCI amnestic mild cognitive impairment, Aβ β-amyloid, CDR Clinical Dementia Rating, CN cognitively normal, ELISA enzyme-linked immunosorbent assay, IQR interquartile range, MMSE Mini-Mental State Examination, SIMOA single molecule array, t-tau total tau. p values reflect comparisons between Aβ−ve and Aβ+ve groups: ap < 0.05; bp < 0.01; cp < 0.001; dp < 0.0001