Table 3. Characteristics of Study Participants in the Alzheimer Disease Neuroimaging Initiative.
Characteristic | Median (IQR) | P valueb | |
---|---|---|---|
Aβ negative (n = 63)a | Aβ positive (n = 59)a | ||
Diagnosis, CN/MCI/AD, No. | 35/26//2 | 16/25/18 | <.001 |
Age, y | 70.7 (65.7-76.0) | 74.2 (69.9-77.5) | .02 |
Female, No. (%) | 28 (44.4) | 25 (42.4) | .86 |
Duration of education, y | 18.0 (15.0-19.0) | 16.0 (13.0-18.0) | .24 |
MMSE | 29.0 (28.0-30.0) | 27.0 (23.0-29.0) | <.001 |
APOE ε4 positivity, No. (%) | 18 (28.6) | 32 (54.2) | .006 |
Aβ-PET, [18F]florbetapir SUVR | 1.006 (0.960-1.037) | 1.321 (1.235-1.470) | <.001 |
CSF Aβ42/40 | NA | NA | NA |
Plasma Aβ42/40 | |||
IP-MS-WashU | 0.132 (0.128-0.141) | 0.122 (0.117-0.127) | <.001 |
IP-MS-Shim | 0.040 (0.037-0.045) | 0.037 (0.034-0.039) | <.001 |
IP-MS-UGOT | 0.071 (0.061-0.089) | 0.064 (0.052-0.073) | .002 |
IA-Elc | 0.171 (0.154-0.182) | 0.152 (0.141-0.164) | <.001 |
IA-N4PE | 0.049 (0.042-0.054) | 0.043 (0.039-0.047) | <.001 |
IA-Quan | 0.040 (0.037-0.044) | 0.037 (0.034-0.041) | .01 |
Abbreviations: Aβ, amyloid-β; AD, Alzheimer disease dementia; CSF, cerebrospinal fluid; CU, cognitively unimpaired; IA-Elc, Elecsys immunoassay from Roche Diagnostics; IA-N4PE, N4PE Simoa immunoassay from Quanterix; IA-Quan, Simoa immunoassay from Quanterix; IP-MS-Shim, immunoprecipitation coupled mass spectrometry method developed by Shimadzu; IP-MS-UGOT, immunoprecipitation-coupled mass spectrometry method developed at the University of Gothenburg; IP-MS-WashU, immunoprecipitation-coupled mass spectrometry method developed at Washington University; IQR, interquartile range; MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; PET, positron emission tomography; SUVR, standardized uptake value ratio.
Differences between the groups were tested using Mann-Whitney U test, χ2 (diagnosis), or Fisher exact test (sex and APOE).