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Selenium level and cognitive function in rural elderly Chinese
Gao S, Jin Y, Hall KS, Liang C, Unverzagt FW, Ji R, Murrell JR, Cao J et al.. American journal of epidemiology, 2007-01-31
Topic: Risk, prevention and care in population studies
Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity. Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results. A cross-sectional survey of 2,000 rural Chinese aged 65 years or older from two provinces in the People's Republic of China was conducted from December 2003 to May 2005 by use of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test, the Indiana University Story Recall Test, the Animal Fluency Test, and the Indiana University Token Test. Over 70% of the study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Analysis-of-covariance models were used to estimate the association between quintile selenium levels measured in nail samples and cognitive test scores, with adjustment for other covariates. Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378). A dose-response effect of selenium quintiles was also seen for those significant associations. Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.
Key findings
- Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity.
- Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results.
- Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378).
- A dose-response effect of selenium quintiles was also seen for those significant associations.
- Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.
Why it matters
This cross-sectional study found that lower selenium levels were associated with lower cognitive scores in rural elderly Chinese. It is observational and does not show that selenium supplementation prevents or treats Alzheimer's disease.
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Study details
- Study designcross-sectional
- Evidence strengthModerate
How this study scored 50/100
Published in a peer-reviewed 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 | 7 / 10 | Tier 3 — peer-reviewed journal (American journal of epidemiology) |
| Journal's citation record | 3 / 4 | American Journal of Epidemiology: journal h-index 416 (OpenAlex, 2026-10-29) |
| Study design | 4 / 12 | A snapshot of people at one point in time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2007 — 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 193 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 9.2 citations a year over 21 year(s) since 2007 |
| Impact for its field and year | 3 / 6 | Cited 7.3× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 1 / 6 | Cited by 2 other studies in this library |
| Still being cited | 2 / 4 | Cited 26 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Hugh C. Hendrie: h-index 76 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Indiana University School of Medicine: institution h-index 784 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 6 institution(s) in 2 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 17272290) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 50 / 100 | — |
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Read the original
- DOI: 10.1093/aje/kwk073
- PubMed: 17272290
- Original source →
- Free full text: IUScholarWorks (Indiana University) →
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. 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
Gao, S., Jin, Y., Hall, K. S., Liang, C., Unverzagt, F. W., Ji, R., et al. (2007). Selenium level and cognitive function in rural elderly Chinese. American journal of epidemiology. https://doi.org/10.1093/aje/kwk073
Vancouver
Gao S, Jin Y, Hall KS, Liang C, Unverzagt FW, Ji R, et al. Selenium level and cognitive function in rural elderly Chinese. American journal of epidemiology. 2007. doi:10.1093/aje/kwk073. PMID: 17272290.
BibTeX
@article{gao2007-17272290,
author = {Gao, S. and Jin, Y. and Hall, K. S. and Liang, C. and Unverzagt, F. W. and Ji, R. and Murrell, JR. and Cao, J. and others},
title = {{Selenium level and cognitive function in rural elderly Chinese}},
journal = {American journal of epidemiology},
year = {2007},
doi = {10.1093/aje/kwk073},
pmid = {17272290},
url = {https://doi.org/10.1093/aje/kwk073}
}
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