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Olfaction and risk of dementia in a biracial cohort of older adults
Yaffe K, Freimer D, Chen H, Asao K, Rosso A, Rubin S, Tranah G, Cummings S et al.. Neurology, 2016-12-30
Topic: Risk, prevention and care in population studies
Objective Prior studies indicate that olfactory function may be an early marker for cognitive impairment, but the body of evidence has been largely restricted to white populations. Methods We studied 2,428 community-dwelling black and white older adults (baseline age 70-79 years) without dementia enrolled in the Health, Aging, and Body Composition (Health ABC) study. Olfaction was measured as odor identification (OI) with the 12-item Cross Cultural Smell Identification Test in year 3. We defined incident dementia over 12 years on the basis of hospitalization records, prescription for dementia medication, or 1.5-SD decline in race-stratified global cognition score. We assessed dementia risk associated with OI score (by tertile) using Cox proportional hazards models. All analyses were stratified by race. Results Poorer OI in older adults without dementia was associated with increased risk of dementia. After adjustment for demographics, medical comorbidities, and lifestyle characteristics, white participants in the poor or moderate OI tertile had greater risk of dementia (adjusted hazard ratio [HR] 3.34, 95% confidence interval [CI] 2.45-4.54; and HR 1.84, 95% CI 1.33-2.54, respectively) compared to those in the good tertile of function. Among blacks, worse OI was associated with an increased risk of dementia, but the magnitude of the effect was weaker (p for interaction = 0.04) for the poor OI tertile (adjusted HR 2.03, 95% CI 1.44-2.84) and for the moderate tertile (adjusted HR 1.42, 95% CI 0.97-2.10). There was no interaction between OI and APOE ε4 and risk of dementia. Conclusions While the magnitude of the association was stronger in whites, we found that poor OI was associated with increased risk of dementia among both black and white older adults.
Key findings
- Objective Prior studies indicate that olfactory function may be an early marker for cognitive impairment, but the body of evidence has been largely restricted to white populations.
- We assessed dementia risk associated with OI score (by tertile) using Cox proportional hazards models.
- Results Poorer OI in older adults without dementia was associated with increased risk of dementia.
- After adjustment for demographics, medical comorbidities, and lifestyle characteristics, white participants in the poor or moderate OI tertile had greater risk of dementia (adjusted hazard ratio [HR] 3.34, 95% confidence interval [CI] 2.45-4.54; and HR 1.84, 95% CI 1.33-2.54, respectively) compared to those in the good tertile of function.
- Among blacks, worse OI was associated with an increased risk of dementia, but the magnitude of the effect was weaker (p for interaction = 0.04) for the poor OI tertile (adjusted HR 2.03, 95% CI 1.44-2.84) and for the moderate tertile (adjusted HR 1.42, 95% CI 0.97-2.10).
Why it matters
This study found that poorer sense of smell in older adults without dementia was associated with increased risk of later dementia, in both Black and White participants, though the effect was weaker among Black participants. It suggests that smell testing may help identify people at higher risk, but it does not test any treatment, cure, or prevention.
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Study details
- Participants2,428
- Effect sizeor 1.5; HR 1.84; HR 2.03
- Evidence strengthLow
How this study scored 60/100
Published in a leading specialty journal. Scored zero for study design 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 | 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 | 2 / 5 | 2017 — within 10 year(s) of the newest study here |
| Sample size | 3 / 4 | 2,428 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 5 / 7 | Cited 126 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 11.5 citations a year over 11 year(s) since 2017 |
| Impact for its field and year | 3 / 6 | Cited 6.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 7 other studies in this library |
| Still being cited | 2 / 4 | Cited 32 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Eleanor Marie Simonsick: h-index 120 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of California, San Francisco: institution h-index 1,915 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 9 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 28039314) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 60 / 100 | — |
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Read the original
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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
Yaffe, K., Freimer, D., Chen, H., Asao, K., Rosso, A., Rubin, S., et al. (2017). Olfaction and risk of dementia in a biracial cohort of older adults. Neurology. https://doi.org/10.1212/wnl.0000000000003558
Vancouver
Yaffe K, Freimer D, Chen H, Asao K, Rosso A, Rubin S, et al. Olfaction and risk of dementia in a biracial cohort of older adults. Neurology. 2017. doi:10.1212/wnl.0000000000003558. PMID: 28039314.
BibTeX
@article{yaffe2017-28039314,
author = {Yaffe, K. and Freimer, D. and Chen, H. and Asao, K. and Rosso, A. and Rubin, S. and Tranah, G. and Cummings, S. and others},
title = {{Olfaction and risk of dementia in a biracial cohort of older adults}},
journal = {Neurology},
year = {2017},
doi = {10.1212/wnl.0000000000003558},
pmid = {28039314},
url = {https://doi.org/10.1212/wnl.0000000000003558}
}
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