Topic: Amyloid, tau and blood-test diagnosis
Results The prevalence of amyloid pathology increased from age 50 to 90 years from 10% (95% CI, 8%-13%) to 44% (95% CI, 37%-51%) among participants with normal cognition; from 12% (95% CI, 8%-18%) to 43% (95% CI, 32%-55%) among patients with SCI; and from 27% (95% CI, 23%-32%) to 71% (95% CI, 66%-76%) among patients with MCI. Amyloid positivity was more common in highly educated participants but not associated with sex or biomarker modality. Conclusions and relevance Among persons without dementia, the prevalence of cerebral amyloid pathology as determined by positron emission tomography or cerebrospinal fluid findings was associated with age, APOE genotype, and presence of cognitive impairment. These findings suggest a 20- to 30-year interval between first development of amyloid positivity and onset of dementia.
Key findings
- Results The prevalence of amyloid pathology increased from age 50 to 90 years from 10% (95% CI, 8%-13%) to 44% (95% CI, 37%-51%) among participants with normal cognition; from 12% (95% CI, 8%-18%) to 43% (95% CI, 32%-55%) among patients with SCI; and from 27% (95% CI, 23%-32%) to 71% (95% CI, 66%-76%) among patients with MCI.
- Amyloid positivity was more common in highly educated participants but not associated with sex or biomarker modality.
- Conclusions and relevance Among persons without dementia, the prevalence of cerebral amyloid pathology as determined by positron emission tomography or cerebrospinal fluid findings was associated with age, APOE genotype, and presence of cognitive impairment.
- These findings suggest a 20- to 30-year interval between first development of amyloid positivity and onset of dementia.
Why it matters
This analysis of many studies found that amyloid buildup in the brain becomes more common with age and is more frequent in people with mild cognitive impairment than in those with normal thinking, and that it can appear 20 to 30 years before dementia symptoms. It helps explain when amyloid pathology starts, but it does not provide a way to treat, cure or prevent Alzheimer's disease.
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Study details
- Study designmeta-analysis
- Participants2,914
- Evidence strengthHigh
How this study scored 84/100
Published in a top-tier journal, and it is a meta-analysis pooling many studies. Scored zero for effect reported because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 10 / 10 | Tier 1 — top-tier general journal (JAMA) |
| Journal's citation record | 4 / 4 | JAMA: journal h-index 1,011 (OpenAlex, 2026-10-29) |
| Study design | 12 / 12 | A meta-analysis pooling many studies |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2015 — within 20 year(s) of the newest study here |
| Sample size | 3 / 4 | 2,914 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | A review of other studies — randomisation is not credited here |
| Times cited | 7 / 7 | Cited 1,609 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 123.8 citations a year over 13 year(s) since 2015 |
| Impact for its field and year | 6 / 6 | Cited 93.5× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 5 / 6 | Cited by 123 other studies in this library |
| Still being cited | 4 / 4 | Cited 427 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Eloy Rodríguez‐Rodríguez: h-index 41 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of California, Berkeley: institution h-index 2,012 (OpenAlex) |
| Multi-centre collaboration | 3 / 3 | OpenAlex lists 96 institution(s) in 20 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 25988462) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 84 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Jansen, W. J., Ossenkoppele, R., Knol, D. L., Tijms, B. M., Scheltens, P., Verhey, F. R., et al. (2015). Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis. JAMA. https://doi.org/10.1001/jama.2015.4668
Vancouver
Jansen WJ, Ossenkoppele R, Knol DL, Tijms BM, Scheltens P, Verhey FR, et al. Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis. JAMA. 2015. doi:10.1001/jama.2015.4668. PMID: 25988462.
BibTeX
@article{jansen2015-25988462,
author = {Jansen, W. J. and Ossenkoppele, R. and Knol, D. L. and Tijms, B. M. and Scheltens, P. and Verhey, F. R. and Visser, P. J. and {Amyloid Biomarker Study Group} and others},
title = {{Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis}},
journal = {JAMA},
year = {2015},
doi = {10.1001/jama.2015.4668},
pmid = {25988462},
url = {https://doi.org/10.1001/jama.2015.4668}
}
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