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Systematic evaluation of the associations between environmental risk factors and dementia: An umbrella review of systematic reviews and meta-analyses
Bellou V, Belbasis L, Tzoulaki I, Middleton LT, Ioannidis JPA, Evangelou E.. Alzheimer's & dementia : the journal of the Alzheimer's Association, 2016-09-04
Topic: Risk, prevention and care in population studies
Introduction Dementia is a heterogeneous neurodegenerative disease, whose etiology results from a complex interplay between environmental and genetic factors. Methods We searched PubMed to identify meta-analyses of observational studies that examined associations between nongenetic factors and dementia. We estimated the summary effect size using random-effects and fixed-effects model, the 95% CI, and the 95% prediction interval.
Key findings
- Methods We searched PubMed to identify meta-analyses of observational studies that examined associations between nongenetic factors and dementia.
- We estimated the summary effect size using random-effects and fixed-effects model, the 95% CI, and the 95% prediction interval.
- We assessed the between-study heterogeneity (I-square), evidence of small-study effects, and excess significance.
- Results A total of 76 unique associations were examined.
Why it matters
This umbrella review of meta-analyses examined associations between nongenetic environmental factors and dementia, assessing 76 unique associations. It looks at possible risk factors and provides no treatment, cure or prevention.
Study details
- Study designmeta-analysis
- Participants76
- Evidence strengthHigh
How this study scored 71/100
Published in a leading specialty 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 | 9 / 10 | Tier 2 — leading specialty journal (Alzheimer's & dementia : the journal of the Alzheimer's Association) |
| Journal's citation record | 2 / 4 | Alzheimer s & Dementia: journal h-index 228 (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 | 2 / 5 | 2017 — within 10 year(s) of the newest study here |
| Sample size | 1 / 4 | 76 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 | 5 / 7 | Cited 287 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 26.1 citations a year over 11 year(s) since 2017 |
| Impact for its field and year | 3 / 6 | Cited 3.8× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 9 other studies in this library |
| Still being cited | 3 / 4 | Cited 59 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Εvangelos Εvangelou: h-index 94 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Stanford University: institution h-index 2,684 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 5 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 27599208) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 71 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1016/j.jalz.2016.07.152
- PubMed: 27599208
- Original source →
- Free full text: Spiral (Imperial College London) →
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
Bellou, V., Belbasis, L., Tzoulaki, I., Middleton, L. T., Ioannidis, J. P. A., & Evangelou, E. (2017). Systematic evaluation of the associations between environmental risk factors and dementia: An umbrella review of systematic reviews and meta-analyses. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1016/j.jalz.2016.07.152
Vancouver
Bellou V, Belbasis L, Tzoulaki I, Middleton LT, Ioannidis JPA, Evangelou E. Systematic evaluation of the associations between environmental risk factors and dementia: An umbrella review of systematic reviews and meta-analyses. Alzheimer's & dementia : the journal of the Alzheimer's Association. 2017. doi:10.1016/j.jalz.2016.07.152. PMID: 27599208.
BibTeX
@article{bellou2017-27599208,
author = {Bellou, V. and Belbasis, L. and Tzoulaki, I. and Middleton, L. T. and Ioannidis, J. P. A. and Evangelou, E.},
title = {{Systematic evaluation of the associations between environmental risk factors and dementia: An umbrella review of systematic reviews and meta-analyses}},
journal = {Alzheimer's \& dementia : the journal of the Alzheimer's Association},
year = {2017},
doi = {10.1016/j.jalz.2016.07.152},
pmid = {27599208},
url = {https://doi.org/10.1016/j.jalz.2016.07.152}
}
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