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Social isolation and cognitive decline in older adults: a longitudinal study across 24 countries
Wang Zhang, Jingjing Zhang, Na Gao. BMC Geriatrics, 2025-10-14
Topic: Risk, prevention and care in population studies
Social isolation was significantly associated with reduced cognitive ability (pooled effect = -0.07, 95% CI = -0.08, -0.05), with consistently negative effects across memory, orientation, and executive ability. System GMM analyses supported these findings and mitigated endogeneity concerns (pooled effect = -0.44, 95% CI = -0.58, -0.30). Cross-nationally, stronger welfare systems and higher levels of economic development buffered the adverse effects, while impacts were more pronounced in vulnerable groups, including the oldest-old, women, and those with lower socioeconomic status. Our findings underscore the need for cross-national interventions that strengthen social support, increase opportunities for social participation, improve welfare provisions, and foster social integration to mitigate the cognitive health risks posed by social isolation, thereby promoting healthy aging globally.
Key findings
- Social isolation was significantly associated with reduced cognitive ability (pooled effect = -0.07, 95% CI = -0.08, -0.05), with consistently negative effects across memory, orientation, and executive ability.
- System GMM analyses supported these findings and mitigated endogeneity concerns (pooled effect = -0.44, 95% CI = -0.58, -0.30).
- Cross-nationally, stronger welfare systems and higher levels of economic development buffered the adverse effects, while impacts were more pronounced in vulnerable groups, including the oldest-old, women, and those with lower socioeconomic status.
- Our findings underscore the need for cross-national interventions that strengthen social support, increase opportunities for social participation, improve welfare provisions, and foster social integration to mitigate the cognitive health risks posed by social isolation, thereby promoting healthy aging globally.
Why it matters
This longitudinal study across 24 countries found that social isolation was associated with reduced cognitive ability in memory, orientation, and executive function, with stronger effects in the oldest-old, women, and those with lower socioeconomic status. It calls for cross-national interventions to strengthen social support and participation, but it does not test whether such interventions prevent or cure Alzheimer's disease.
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Study details
- Study designmeta-analysis
- Participants101,581
- Evidence strengthHigh
How this study scored 65/100
Published in a peer-reviewed journal, and it is a meta-analysis pooling many studies. Scored zero for effect reported because the record does not state it. We have no data on senior author's track record, so that was left out: it earned 62 of the 96 points we could judge it on, which is 65 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (BMC Geriatrics) |
| Journal's citation record | 2 / 4 | BMC Geriatrics: journal h-index 153 (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 | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 4 / 4 | 101,581 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 | 3 / 7 | Cited 20 times (OpenAlex, 2026-10-10) |
| Citations per year | 2 / 5 | 6.7 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 4 / 6 | Cited 12.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 2 / 4 | Cited 20 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | — / 4 | OpenAlex's profile for last-listed author Na Gao holds only 2 work(s), too few to judge a track record — left out of this score |
| Institution's track record | 0 / 3 | Southeast University: institution h-index 622 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 41087920) |
| Free to read | 2 / 2 | Free to read |
| Points | 62 / 96 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 62 of the 96 points we could judge it on is 65 out of 100. |
| Total | 65 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
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
Zhang, W., Zhang, J., & Gao, N. (2025). Social isolation and cognitive decline in older adults: a longitudinal study across 24 countries. BMC Geriatrics. https://doi.org/10.1186/s12877-025-06430-6
Vancouver
Zhang W, Zhang J, Gao N. Social isolation and cognitive decline in older adults: a longitudinal study across 24 countries. BMC Geriatrics. 2025. doi:10.1186/s12877-025-06430-6. PMID: 41087920.
BibTeX
@article{zhang2025-41087920,
author = {Zhang, Wang and Zhang, Jingjing and Gao, Na},
title = {{Social isolation and cognitive decline in older adults: a longitudinal study across 24 countries}},
journal = {BMC Geriatrics},
year = {2025},
doi = {10.1186/s12877-025-06430-6},
pmid = {41087920},
url = {https://doi.org/10.1186/s12877-025-06430-6}
}
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here.
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