Table 1.
Baseline characteristics of subjects with normal cognition according to disease-stage classification at baseline
| Baseline characteristics | Total sample cognitively normal (N = 522) | Cognitively normal with normal amyloid and injury markers (N = 221) | Preclinical AD (N = 146) | Preclinical AD stage-1 (N = 110) | Preclinical AD stage-2 (N = 34) | P value differences stage-1 and stage-2 |
|---|---|---|---|---|---|---|
| Age (years) | 74.24 (5.79) | 73.01 (5.76) | 74.8 (5.5) | 74.2 (5.5) | 76.84 (4.94) | .036 |
| Females (%) | 51% (0.5) | 49% (0.5) | 60% (0.5) | 66% (0.5) | 44% (0.5) | .064 |
| Years of education | 16.38 (2.7) | 16.50 (2.6) | 16.06 (2.7) | 15.95 (2.8) | 16.47 (2.33) | .62 |
| 1/2 APOE ε4 alleles (%) (n = 410) | 103/11 (19/2) | 29/1 (13/0.5) | 46/7 (32/5) | 30/6 (28/5) | 15/0 (44/0) | .96 |
| CSF Aβ1–42 (pg/mL) (n = 174) | 209.6 (53.5) | 243.6 (31.55) | 155.27 (31.9) | 160.1 (33.8) | 144.29 (27.2) | .079 |
| 18F-AV-45 (SUVr) (n = 286) | 1.1 (0.17) | 1.01 (0.05) | 1.29 (0.17) | 1.30 (0.18) | 1.29 (0.14) | .65 |
| CSF tau (pg/mL) (n = 172) | 68.2 (32.9) | 57.4 (19.2) | 80 (41) | 65.3 (32.9) | 126.39 (28.4) | .0001 |
| FDG-PET (SUVr) (n = 402) | 1.31 (0.12) | 1.34 (0.09) | 1.31 (0.12) | 1.35 (0.1) | 1.17 (0.06) | .0001 |
| Whole-brain volume (cm3) (n = 364) | 1045 (50) | 1054 (50) | 1043 (49) | 1043 (49) | 1039 (51) | .83 |
| Hippocampal volume (mm3) (n = 474) | 3709 (385) | 3771 (369) | 3676 (368) | 3710 (384) | 3525 (288) | .014 |
| Ventricular volume (cm3) (n = 363) | 46.5 (40.6) | 38.3 (29) | 49.7 (40.9) | 48 (39) | 59.5 (47) | .68 |
| CDR sum of boxes (n = 520) | 0.05 (0.18) | 0.03 (0.12) | 0.05 (0.16) | 0.059 (0.18) | 0.015 (0.09) | .17 |
| MMSE score (n = 521) | 29.1 (1.15) | 29.1 (1.18) | 29.1 (0.95) | 29.04 (0.99) | 29.12 (1.09) | .64 |
| ADAS-Cog (n = 522) | 5.95 (3.03) | 5.67 (2.99) | 6.08 (2.9) | 6.12 (2.73) | 6.55 (3.6) | .84 |
| ADCS-PACC (n = 197) | 2.63 (1.78) | 2.64 (1.74) | 2.62 (1.71) | 2.63 (1.81) | 2.62 (1.56) | .79 |
| ADCS-PACC without digit symbol test (n = 521) | 2.15 (1.41) | 2.25 (1.40) | 2.19 (1.30) | 2.15 (1.23) | 2.12 (1.74) | .44 |
| Follow-up time (n = 522) | 2.14 (1.03) | 2.10 (0.96) | 2.18 (0.97) | 2.12 (1.00) | 2.35 (0.81) | .18 |
| Number of visits per subject (n = 522) | 5.14 (1.78) | 5.30 (1.70) | 5.34 (1.76) | 5.29 (1.78) | 5.44 (1.58) | .64 |
Abbreviations: Aβ1–42, amyloid β 1–42; AD, Alzheimer's disease; ADAS-Cog, Alzheimer's Disease Assessment Scale-Cognitive; ADCS-PACC, Alzheimer's Disease Cooperative Study Preclinical Alzheimer Cognitive Composite; CDR, Clinical Dementia Rating scale; CSF, cerebrospinal fluid; FDG, fludeoxyglucose; AV-45, florbetapir; MMSE, Mini–Mental State Examination; PET, positron emission tomography.
NOTE. Data are mean (standard deviation) unless specified otherwise.