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Vision impairment and cognitive decline among older adults: a systematic review
Nagarajan N, Assi L, Varadaraj V, Motaghi M, Sun Y, Couser E, Ehrlich JR, Whitson H et al.. BMJ open, 2022-01-06
Topic: Brain imaging, connectivity and assessment
Objectives There has been increasing epidemiological research examining the association between vision impairment (VI) and cognitive impairment and how poor vision may be a modifiable risk factor for cognitive decline. The objective of this systematic review is to synthesise the published literature on the association of VI with cognitive decline, cognitive impairment or dementia, to aid the development of interventions and guide public policies pertaining to the relationship between vision and cognition. Methods A literature search was performed with Embase, Medline and Cochrane library databases from inception to March 2020, and included abstracts and articles published in peer-reviewed journals in English. Our inclusion criteria included publications that contained subjective/objective measures of vision and cognition, or a diagnosis of VI, cognitive impairment or dementia. Longitudinal or cross-sectional studies with ≥100 participants aged >50 years were included. The search identified 11 805 articles whose abstracts underwent screening by three teams of study authors. Data abstraction and quality assessment using the Effective Public Health Practice Project Quality Assessment Tool were performed by one author (NN). 10% of the articles underwent abstraction and appraisal by a second author (LA/VV), results were compared between both and were in agreement. Results 110 full-text articles were selected for data extraction, of which 53 were cross-sectional, 43 longitudinal and 14 were case-control studies. The mean age of participants was 73.0 years (range 50-93.1). Ninety-one (83%) of these studies reported that VI was associated with cognitive impairment. Conclusion Our systematic review indicates that a majority of studies examining the vision-cognition relationship report that VI is associated with more cognitive decline, cognitive impairment or dementia among older adults. This synthesis supports the need for additional research to understand the mechanisms underlying the association between VI and cognitive impairment and to test interventions that mitigate the cognitive consequences of VI.
Key findings
- Data abstraction and quality assessment using the Effective Public Health Practice Project Quality Assessment Tool were performed by one author (NN). 10% of the articles underwent abstraction and appraisal by a second author (LA/VV), results were compared between both and were in agreement.
- Results 110 full-text articles were selected for data extraction, of which 53 were cross-sectional, 43 longitudinal and 14 were case-control studies.
- Ninety-one (83%) of these studies reported that VI was associated with cognitive impairment.
- Conclusion Our systematic review indicates that a majority of studies examining the vision-cognition relationship report that VI is associated with more cognitive decline, cognitive impairment or dementia among older adults.
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Study details
- Study designsystematic review
- Participants100
- Evidence strengthHigh
How this study scored 79/100
Published in a peer-reviewed journal, and it is a systematic review of all the studies on the question. Scored zero for effect reported because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 46 of the 58 points we could judge it on, which is 79 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (BMJ open) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 12 / 12 | A systematic review of all the studies on the question |
| 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 | 3 / 5 | 2022 — within 6 year(s) of the newest study here |
| Sample size | 2 / 4 | 100 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 | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 34992100) |
| Free to read | 2 / 2 | Free to read |
| Points | 46 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 46 of the 58 points we could judge it on is 79 out of 100. |
| Total | 79 / 100 | — |
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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
Nagarajan, N., Assi, L., Varadaraj, V., Motaghi, M., Sun, Y., Couser, E., et al. (2022). Vision impairment and cognitive decline among older adults: a systematic review. BMJ open. https://doi.org/10.1136/bmjopen-2020-047929
Vancouver
Nagarajan N, Assi L, Varadaraj V, Motaghi M, Sun Y, Couser E, et al. Vision impairment and cognitive decline among older adults: a systematic review. BMJ open. 2022. doi:10.1136/bmjopen-2020-047929. PMID: 34992100.
BibTeX
@article{nagarajan2022-34992100,
author = {Nagarajan, N. and Assi, L. and Varadaraj, V. and Motaghi, M. and Sun, Y. and Couser, E. and Ehrlich, JR. and Whitson, H. and others},
title = {{Vision impairment and cognitive decline among older adults: a systematic review}},
journal = {BMJ open},
year = {2022},
doi = {10.1136/bmjopen-2020-047929},
pmid = {34992100},
url = {https://doi.org/10.1136/bmjopen-2020-047929}
}
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