Odor identification and Alzheimer disease biomarkers in clinically normal elderly
Growdon ME, Schultz AP, Dagley AS, Amariglio RE, Hedden T, Rentz DM, Johnson KA, Sperling RA et al.. Neurology, 2015-05-01
Topic: Amyloid, tau and blood-test diagnosis
Objectives Our objective was to investigate cross-sectional associations between odor identification ability and imaging biomarkers of neurodegeneration and amyloid deposition in clinically normal (CN) elderly individuals, specifically testing the hypothesis that there may be an interaction between amyloid deposition and neurodegeneration in predicting odor identification dysfunction. Methods Data were collected on 215 CN participants from the Harvard Aging Brain Study. Measurements included the 40-item University of Pennsylvania Smell Identification Test and neuropsychological testing, hippocampal volume (HV) and entorhinal cortex (EC) thickness from MRI, and amyloid burden using Pittsburgh compound B (PiB) PET. A linear regression model with backward elimination (p Results In unadjusted univariate analyses, worse olfaction was associated with decreased HV (p Conclusions In CN elderly, worse odor identification was associated with markers of neurodegeneration. Furthermore, individuals with elevated cortical amyloid and thinner EC exhibited worse odor identification, elucidating the potential contribution of olfactory testing to detect preclinical AD in CN individuals.
Key findings
- A linear regression model with backward elimination (p Results In unadjusted univariate analyses, worse olfaction was associated with decreased HV (p Conclusions In CN elderly, worse odor identification was associated with markers of neurodegeneration.
Why it matters
In 215 clinically normal elderly people, worse odor identification was associated with markers of neurodegeneration, and those with elevated cortical amyloid and thinner entorhinal cortex had worse odor identification. This cross-sectional study suggests a possible way to detect preclinical Alzheimer's disease and does not test any treatment, cure, or prevention.
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Study details
- Study designcross-sectional
- Evidence strengthLow
How this study scored 55/100
Published in a leading specialty journal, and it is a snapshot of people at one point in time. Scored zero for sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | 4 / 4 | Neurology: journal h-index 525 (OpenAlex, 2026-10-29) |
| Study design | 4 / 12 | A snapshot of people at one point in time |
| 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 | 1 / 5 | 2015 — within 20 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 | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| 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 | 5 / 7 | Cited 160 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 12.3 citations a year over 13 year(s) since 2015 |
| Impact for its field and year | 4 / 6 | Cited 9.2× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 5 other studies in this library |
| Still being cited | 2 / 4 | Cited 38 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Gad A. Marshall: h-index 75 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Harvard University: institution h-index 3,235 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 4 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 25934852) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 55 / 100 | — |
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Read the original
- DOI: 10.1212/wnl.0000000000001614
- PubMed: 25934852
- Original source →
- Free full text: PubMed Central →
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
Growdon, M. E., Schultz, A. P., Dagley, A. S., Amariglio, R. E., Hedden, T., Rentz, D. M., et al. (2015). Odor identification and Alzheimer disease biomarkers in clinically normal elderly. Neurology. https://doi.org/10.1212/wnl.0000000000001614
Vancouver
Growdon ME, Schultz AP, Dagley AS, Amariglio RE, Hedden T, Rentz DM, et al. Odor identification and Alzheimer disease biomarkers in clinically normal elderly. Neurology. 2015. doi:10.1212/wnl.0000000000001614. PMID: 25934852.
BibTeX
@article{growdon2015-25934852,
author = {Growdon, M. E. and Schultz, A. P. and Dagley, A. S. and Amariglio, R. E. and Hedden, T. and Rentz, D. M. and Johnson, K. A. and Sperling, R. A. and others},
title = {{Odor identification and Alzheimer disease biomarkers in clinically normal elderly}},
journal = {Neurology},
year = {2015},
doi = {10.1212/wnl.0000000000001614},
pmid = {25934852},
url = {https://doi.org/10.1212/wnl.0000000000001614}
}
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