Table 1.
Demographical and neurobiological characteristics of study cohorts
| Characteristics | ADC (n = 496) | ADNI (n = 376) | DCN (n = 521) | UCSF (n = 589) | Pooled sample (n = 1.982) |
|---|---|---|---|---|---|
| Demographics | |||||
| Age (years) | 67 ± 8 | 75 ± 8 | 72 ± 8 | 71 ± 10 | 71 ± 9 |
| Female | 258 (52%) | 165 (44%) | 313 (60%) | 328 (56%) | 1064 (54%) |
| Education* | 5 (4–6) | 16 (13–18) | 11 (10–13) | 16 (14–18) | 0.00 ± 1.00 |
| Duration complaints (years) | 2 (2–4) | — | 2 (1–3) | — | 2 (1–4) |
| Global cognition | |||||
| MMSE | 22 ± 3 | 23 ± 2 | 23 ± 3 | 24 ± 4 | 23 ± 3 |
| APOE ε4 genotype | |||||
| APOE ε4 positive | 299 (67%) | 128 (65%) | 255 (64%) | 100 (57%) | 782 (64%) |
| AD biomarkers† | |||||
| AD biomarker available | 389 (79%) | 102 (27%) | 193 (37%) | 53 (9%) | 737 (37%) |
| AD biomarker positive | 358 (92%) | 89 (87%) | 164 (85%) | 52 (98%) | 654 (89%) |
| MRI | |||||
| Hippocampus‡ | 1.5 (1–2) | 2882 ± 511 | 2933 ± 473 | — | 0.00 ± 1.00 |
| Posterior cortex§ | 1 (1–2) | — | 1 (0–2) | — | 0.00 ± 1.00 |
| WMH | 1 (0–2) | 0.41 (0.16–1.25) | 0.5 (0–1) | — | 0.02 ± 1.01 |
Abbreviations: AD, Alzheimer’s disease; ADC, Amsterdam Dementia Cohort; ADNI, Alzheimer’s Disease Neuroimaging Initiative; APOE, apolipoprotein E; CSF, cerebrospinal fluid; DCN, German Dementia Competence Network; MMSE, Mini–Mental State Examination; MRI, magnetic resonance imaging; UCSF, University of California, San Francisco; WMH, white matter hyperintensity.
NOTE. Data are presented in the mean ± standard deviation, number (%), or median (2nd–4th quantile).
Education is given according to the Verhage scale (1–7, respectively, low-high education [21]) for ADC, years of education for ADNI, DCN, and UCSF, and normalized scores for the pooled sample.
AD biomarkers are available as CSF total tau/amyloid β1–42 (abnormal when >0.52 according to Duits et al. [38] in the ADC and DCN cohorts, and abnormal when >0.39 according to Shaw et al. [39] in the ADNI cohort), or as Pittsburgh compound B positron emission tomography positivity in the UCSF cohort.
Hippocampal atrophy is measured according to the medial temporal lobe atrophy (MTA) visual rating scale for the ADC (0–4, higher scores reflect more severe atrophy [28]), and hippocampal volumes in cubic millimeters for the ADNI and DCN, and z-scores (in which normalized MTA scores are inverted) for the pooled sample.
Posterior atrophy is scored using a visual rating scale for the ADC [29] and the DCN, inverted z-scores are given for the pooled sample. WMH are scored according to a visual rating scale for the ADC [30] and the DCN (0–3, higher scores reflect more sever pathology), WMH volumes for the ADNI [33] and z-scores are given for the pooled sample.