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Alzheimer's Disease: Epidemiology and Clinical Progression
Tahami Monfared AA, Byrnes MJ, White LA, Zhang Q.. Neurology and therapy, 2022-03-14
Topic: Amyloid, tau and blood-test diagnosis
Alzheimer's disease (AD) is prevalent throughout the world and is the leading cause of dementia in older individuals (aged ≥ 65 years). To gain a deeper understanding of the recent literature on the epidemiology of AD and its progression, we conducted a review of the PubMed-indexed literature (2014-2021) in North America, Europe, and Asia. The worldwide toll of AD is evidenced by rising prevalence, incidence, and mortality due to AD-estimates which are low because of underdiagnosis of AD. Mild cognitive impairment (MCI) due to AD can ultimately progress to AD dementia; estimates of AD dementia etiology among patients with MCI range from 40% to 75% depending on the populations studied and whether the MCI diagnosis was made clinically or in combination with biomarkers. The risk of AD dementia increases with progression from normal cognition with no amyloid-beta (Aβ) accumulation to early neurodegeneration and subsequently to MCI. For patients with Aβ accumulation and neurodegeneration, lifetime risk of AD dementia has been estimated to be 41.9% among women and 33.6% among men. Data on progression from preclinical AD to MCI are sparse, but an analysis of progression across the three preclinical National Institute on Aging and Alzheimer's Association (NIA-AA) stages suggests that NIA-AA stage 3 (subtle cognitive decline with AD biomarker positivity) could be useful in combination with other tools for treatment decision-making. Factors shown to increase risk include lower Mini-Mental State Examination (MMSE) score, higher Alzheimer's Disease Assessment Scale (ADAS-cog) score, positive APOE4 status, white matter hyperintensities volume, entorhinal cortex atrophy, cerebrospinal fluid (CSF) total tau, CSF neurogranin levels, dependency in instrumental activities of daily living (IADL), and being female. Results suggest that use of biomarkers alongside neurocognitive tests will become an important part of clinical practice as new disease-modifying therapies are introduced.
Key findings
- Data on progression from preclinical AD to MCI are sparse, but an analysis of progression across the three preclinical National Institute on Aging and Alzheimer's Association (NIA-AA) stages suggests that NIA-AA stage 3 (subtle cognitive decline with AD biomarker positivity) could be useful in combination with other tools for treatment decision-making.
- Results suggest that use of biomarkers alongside neurocognitive tests will become an important part of clinical practice as new disease-modifying therapies are introduced.
Why it matters
A review of 2014–2021 PubMed literature from North America, Europe and Asia reports that, among people with mild cognitive impairment, Alzheimer's is estimated to be the cause in 40% to 75% of cases, "depending on the populations studied and whether the MCI diagnosis was made clinically or in combination with biomarkers." For people with both amyloid buildup and neurodegeneration, it cites lifetime risk of Alzheimer's dementia estimated at 41.9% for women and 33.6% for men, while noting that data on the earliest, preclinical stage are sparse. The authors expect biomarkers used alongside cognitive tests to become an important part of clinical practice as new disease-modifying therapies arrive.
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Study details
- Effect size41.9%; 33.6%
- Evidence strengthLow
How this study scored 55/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Neurology and therapy) |
| Journal's citation record | 0 / 4 | Neurology and Therapy: journal h-index 57 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2022 — within 6 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 6 / 7 | Cited 621 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 103.5 citations a year over 6 year(s) since 2022 |
| Impact for its field and year | 6 / 6 | Cited 68.4× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 21 other studies in this library |
| Still being cited | 4 / 4 | Cited 522 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Quanwu Zhang: h-index 23 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | McGill University: institution h-index 1,373 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 2 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 35286590) |
| Free to read | 2 / 2 | Free to read |
| Total | 55 / 100 | — |
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Read the original
- DOI: 10.1007/s40120-022-00338-8
- PubMed: 35286590
- Original source →
- Free full text: Neurology and Therapy →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
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. Check the citation against the original before you use it.
APA 7th
Tahami Monfared, A. A., Byrnes, M. J., White, L. A., & Zhang, Q. (2022). Alzheimer's Disease: Epidemiology and Clinical Progression. Neurology and therapy. https://doi.org/10.1007/s40120-022-00338-8
Vancouver
Tahami Monfared AA, Byrnes MJ, White LA, Zhang Q. Alzheimer's Disease: Epidemiology and Clinical Progression. Neurology and therapy. 2022. doi:10.1007/s40120-022-00338-8. PMID: 35286590.
BibTeX
@article{tahamimonfared2022-35286590,
author = {Tahami Monfared, A. A. and Byrnes, M. J. and White, L. A. and Zhang, Q.},
title = {{Alzheimer's Disease: Epidemiology and Clinical Progression}},
journal = {Neurology and therapy},
year = {2022},
doi = {10.1007/s40120-022-00338-8},
pmid = {35286590},
url = {https://doi.org/10.1007/s40120-022-00338-8}
}
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