Table 2.
Sample characteristics
| Variable | AD8 < 2 | AD8 ≥ 2 | P-value |
|---|---|---|---|
| Demographics | |||
| Age (years) | 75.3 (7.2) | 75.5 (7.5) | ns |
| Education (years) | 15.3 (3.2) | 14.8 (3.2) | ns |
| Gender, % male | 40.9 | 50.8 | ns |
| Race, % Caucasian | 84.7 | 93.3 | 0.03 |
| ApoE, % at least 1 ε4 allele | 30.1 | 48.7 | 0.003 |
| Dementia ratings | |||
| CDR-SB, range 0–18 | 0.06 (0.19) | 2.8 (2.5) | <0.001 |
| AD8, range 0–8 | 0.3 (0.5) | 5.0 (2.1) | <0.001 |
| MMSE, range 30–0 | 28.5 (1.5) | 25.8 (4.6) | <0.001 |
| SBT, range 0–28 | 2.5 (3.1) | 6.4 (6.3) | <0.001 |
| Biomarker studies | |||
| MCBP (units) | 0.12 (0.23) | 0.45 (0.42) | <0.001 |
| CSF Aβ42 (pg/ml) | 590.7 (266.2) | 435.6 (209.6) | <0.001 |
| CSF tau (pg/ml) | 303.6 (171.2) | 500.5 (261.3) | <0.001 |
| CSF p-tau181 (pg/ml) | 52.2 (23.9) | 76.7 (39.9) | <0.001 |
| CSF tau/Aβ42 ratio | 0.72 (0.75) | 1.4 (1.1) | <0.001 |
| CSF p-tau181/Aβ42 ratio | 0.12 (0.11) | 0.22 (0.16) | <0.001 |
ApoE = apolipoprotein E; CDR-SB = CDR sum of boxes; MCBP = mean cortical binding potential; p-tau181 = tau phosphorylated at threonine 181; SBT = Short Blessed Test. Higher MCBP, CSF tau(s) and tau(s)/Aβ42 are abnormal; lower CSF Aβ42 is abnormal. Numbers of participants in each row are not equal: 151 participants had PiB scans, 149 had CSF studies and 31 had both studies completed.