TABLE 4.
Demographic, neuropsychological, and biomarker values of the ADNI sample at baseline according to the initial diagnostic classification (SMC vs. CN groups).
| Characteristics | SMC (n = 387) | CN (n = 347) | P |
|---|---|---|---|
| Age (years) | 70 (66, 75) | 71 (67, 76) | 0.015 |
| Sex | |||
| Male | 152 (39%) | 157 (45%) | 0.116 |
| Female | 235 (61%) | 190 (55%) | |
| Education (years) | 16 (15, 18) | 16 (15, 18) | 0.944 |
| Cluster | |||
| 1 | 200 (52%) | 200 (58%) | 0.119 |
| 2 | 187 (48%) | 147 (42%) | |
| GDS‐15 | 1 (0, 2) | 0 (0, 1) | <0.001 |
| MMSE | 29 (29, 30) | 29 (28, 30) | 0.251 |
| Delayed recall | 7 (6, 8) | 7 (6, 9) | 0.852 |
| Categorical fluency | 20 (17, 24) | 22 (18, 25) | 0.006 |
| TMT‐A (seconds) | 30 (25, 38) | 31 (25, 39) | 0.254 |
| TMT‐B (seconds) | 73 (56, 95) | 70 (55, 91) | 0.296 |
| Whole brain (mL) | 1055 (985, 1129) | 1044 (976, 1121) | 0.584 |
| Hippocampus (µL) | 7540 (7056, 8090) | 7573 (6946, 8058) | 0.526 |
| Entorhinal (µL) | 4023 (3591, 4464) | 3915 (3551, 4374) | 0.162 |
| PET FDG (SUVR) | 1.29 (1.20, 1.37) | 1.28 (1.19, 1.35) | 0.446 |
| PET florbetapir (SUVR) | 1.06 (1.00, 1.20) | 1.07 (1.01, 1.19) | 0.260 |
| Aβ42 (pg/mL) | 1046 (774, 1351) | 957 (714, 1279) | 0.219 |
| Tau (pg/mL) | 216 (168, 300) | 211 (178, 300) | 0.945 |
| P‐tau (pg/mL) | 18.9 (14.6, 26.3) | 19.5 (15.5, 27.1) | 0.646 |
| Tau/Aβ42 | 0.19 (0.14, 0.37) | 0.23 (0.13, 0.38) | 0.384 |
| P‐tau/Aβ42 | 0.02 (0.01, 0.03) | 0.02 (0.01, 0.04) | 0.311 |
| APOE ε4 (no. alleles) | |||
| 0 | 205 (64%) | 226 (71%) | 0.048 |
| 1 | 108 (34%) | 81 (25%) | |
| 2 | 8 (2%) | 13 (4%) |
Note: Descriptive statistics are given as median (interquartile range) or frequency (percentage). Delayed recall corresponds to the ADAS‐Cog items. PET FDG is a measurement of FDG uptake at the angular, temporal, and posterior cingulate regions. PET florbetapir is a composite measurement of cortical florbetapir deposition normalized by the cerebellum. Aβ42, tau, and P‐tau indicate the levels of biomarkers in cerebrospinal fluid. p values correspond to the Wilcoxon's rank sum test or the Pearson's Chi‐squared test.
Abbreviations: Aβ, amyloid beta; ADAS‐Cog, Alzheimer's Disease Assessment Scale‐Cognitive Subscale; ADNI, Alzheimer's Disease Neuroimaging Initiative; APOE, apolipoprotein E; CN, normal controls without memory concerns; CUN, Clínica Universidad de Navarra; FDG, [18F]Fluorodeoxyglucose; GDS, Geriatric Depression Scale; MMSE, Mini‐Mental State Examination; PET, positron emission tomography; p‐tau, phosphorylated P‐181 tau; SMC, subjective memory concerns; SUVR, standardized uptake value ratio; TMT‐A, Trail Making Test part A; TMT‐B, Trail Making Test part B.