TABLE 3.
Biomarker values in the ADNI sample according to cognitive cluster assignment.
| Characteristics | Cluster 1 | Cluster 2 | P |
|---|---|---|---|
| Whole brain (mL) | 1070 (994, 1136) | 1023 (962, 1102) | <0.001 |
| n | 362 | 304 | |
| Hippocampus (µL) | 7641 (7150, 8226) | 7343 (6809, 7893) | <0.001 |
| n | 346 | 296 | |
| Entorhinal (µL) | 4044 (361, 4463) | 3884 (3534, 4312) | 0.019 |
| n | 352 | 285 | |
| PET FDG (SUVR) | 1.31 (1.23, 1.37) | 1.26 (1.17, 1.34) | <0.001 |
| n | 185 | 170 | |
| PET Florbetapir (SUVR) | 1.05 (1.00, 1.19) | 1.07 (1.00, 1.20) | 0.802 |
| n | 258 | 223 | |
| Aβ42 (pg/mL) | 1012 (731, 1384) | 952 (701, 1263) | 0.088 |
| n | 116 | 103 | |
| Tau (pg/mL) | 207 (172, 283) | 219 (176, 313) | 0.172 |
| n | 163 | 141 | |
| P‐tau (pg/mL) | 19.2 (15.1, 26.1) | 19.9 (15.5, 28.8) | 0.246 |
| n | 162 | 141 | |
| Tau/Aβ42 | 0.19 (0.13, 0.35) | 0.28 (0.15, 0.37) | 0.034 |
| n | 116 | 103 | |
| P‐tau/Aβ42 | 0.02 (0.01, 0.03) | 0.03 (0.01, 0.04) | 0.048 |
| n | 115 | 103 | |
| APOE ε4 (no. alleles) | |||
| 0 | 244 (67%) | 187 (68%) | 0.645 |
| 1 | 110 (30%) | 79 (28%) | |
| 2 | 10 (3%) | 11 (4%) | |
| n | 364 | 277 |
Note: Descriptive statistics are given as median (interquartile range) or frequency (percentage). 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 uptake normalized by the cerebellum. Aβ42, tau, and p‐tau indicate the levels of biomarkers in cerebrospinal fluid. The symbol “n” indicates the number of cases available for analysis. P values correspond to Wilcoxon rank sum test or Pearson chi‐squared test.
Abbreviations: Aβ, amyloid beta; APOE, apolipoprotein E; FDG, [18F]Fluorodeoxyglucose; PET, positron emission tomography; p‐tau, phosphorylated P‐181 tau; SUVR, standardized uptake value ratio.