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Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis
Peters R, Booth A, Rockwood K, Peters J, D'Este C, Anstey KJ.. BMJ open, 2019-01-25
Topic: Risk, prevention and care in population studies
Objective To systematically review the literature relating to the impact of multiple co-occurring modifiable risk factors for cognitive decline and dementia. Design A systematic review and meta-analysis of the literature relating to the impact of co-occurring key risk factors for incident cognitive decline and dementia. All abstracts and full text were screened independently by two reviewers and each article assessed for bias using a standard checklist. A fixed effects meta-analysis was undertaken. Data sources Databases Medline, Embase and PsycINFO were searched from 1999 to 2017. Eligibility criteria For inclusion articles were required to report longitudinal data from participants free of cognitive decline at baseline, with formal assessment of cognitive function or dementia during follow-up, and an aim to examine the impact of additive or clustered comorbid risk factor burden in with two or more core modifiable risk factors. Results Seventy-nine full-text articles were examined. Twenty-two articles (18 studies) were included reporting data on >40 000 participants. Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours. A meta-analysis of studies with dementia outcomes resulted in a pooled relative risk for dementia of 1.20 (95% CI 1.04 to 1.39) for one risk factor, 1.65 (95% CI 1.40 to 1.94) for two and 2.21 (95% CI 1.78 to 2.73) for three or more, relative to no risk factors. Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure. Conclusions The strength of the reported associations, the consistency across studies and the suggestion of a dose response supports a need to keep modifiable risk factor exposure to a minimum and to avoid exposure to additional modifiable risks. Further research is needed to establish whether particular combinations of risk factors confer greater risk than others. Prospero registration number 42016052914.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Peters, R., Booth, A., Rockwood, K., Peters, J., D'Este, C., & Anstey, K. J. (2019). Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis. BMJ open. https://doi.org/10.1136/bmjopen-2018-022846
Vancouver
Peters R, Booth A, Rockwood K, Peters J, D'Este C, Anstey KJ. Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis. BMJ open. 2019. doi:10.1136/bmjopen-2018-022846. PMID: 30782689.
BibTeX
@article{peters2019-30782689,
author = {Peters, R. and Booth, A. and Rockwood, K. and Peters, J. and D'Este, C. and Anstey, K. J.},
title = {{Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis}},
journal = {BMJ open},
year = {2019},
doi = {10.1136/bmjopen-2018-022846},
pmid = {30782689},
url = {https://doi.org/10.1136/bmjopen-2018-022846}
}
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Key findings
- Results Seventy-nine full-text articles were examined.
- Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours.
- Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure.
Why it matters
This review of 18 studies with over 40,000 participants found that having more modifiable risk factors or unhealthy behaviors was linked to higher dementia risk, and healthy behaviors to lower risk. It supports risk reduction through lifestyle but does not prove that changing these factors prevents dementia.
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Study details
- Study designsystematic review
- Evidence strengthHigh
How this study scored 68/100
Published in a peer-reviewed journal, and it is a systematic review of all the studies on the question. Scored zero for sample size, effect reported and studied in people because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (BMJ open) |
| Journal's citation record | 2 / 4 | BMJ Open: journal h-index 240 (OpenAlex, 2026-10-29) |
| 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 | 2 / 5 | 2019 — within 10 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 | A review of other studies — randomisation is not credited here |
| Times cited | 5 / 7 | Cited 253 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 28.1 citations a year over 9 year(s) since 2019 |
| Impact for its field and year | 3 / 6 | Cited 5.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 24 other studies in this library |
| Still being cited | 3 / 4 | Cited 108 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Kaarin Jane Anstey: h-index 103 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | Imperial College London: institution h-index 1,744 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 7 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 30782689) |
| Free to read | 2 / 2 | Free to read |
| Total | 68 / 100 | — |
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