Home › Research › Prevention and risk
No association between metformin initiation and incident dementia in older adults newly diagnosed with diabetes
Wu CY, Wang C, Saskin R, Shah BR, Kapral MK, Lanctôt KL, et al.. Journal of Internal Medicine, 2023-09-25
Topic: Risk, prevention and care in population studies
Background Metformin has been suggested to reduce dementia risk; however, most epidemiologic studies have been limited by immortal time bias or confounding due to disease severity. Objectives To investigate the association of metformin initiation with incident dementia using strategies that mitigate these important sources of bias. Methods Residents of Ontario, Canada ≥66 years newly diagnosed with diabetes from January 1, 2008 to December 31, 2017 entered this retrospective population-based cohort. To consider the indication for metformin monotherapy initiation, people with hemoglobin A1c of 6.5%-8.0% and estimated glomerular filtration rate ≥45 mL/min/1.73 m 2 were selected. Using the landmark method to address immortal time bias, exposure was grouped into "metformin monotherapy initiation within 180 days after new diabetes diagnosis" or "no glucose-lowering medications within 180 days." To address disease latency, 1-year lag time was applied to the end of the 180-day landmark period. Incident dementia was defined using a validated algorithm for Alzheimer's disease and related dementias. Adjusted hazard ratios (aHR) and confidence intervals (CIs) were estimated from propensity-score weighted Cox proportional hazard models. Results Over mean follow-up of 6.77 years from cohort entry, metformin initiation within 180 days after new diabetes diagnosis (N = 12,331; 978 events; 65,762 person-years) showed no association with dementia risk (aHR [95% CI] = 1.05 [0.96-1.15]), compared to delayed or no glucose-lowering medication initiation (N = 22,369; 1768 events; 117,415 person-years). Conclusion Early metformin initiation was not associated with incident dementia in older adults newly diagnosed with diabetes. The utility of metformin to prevent dementia was not supported.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Wu, C. Y., Wang, C., Saskin, R., Shah, B. R., Kapral, M. K., Lanctôt, K. L., et al. (2023). No association between metformin initiation and incident dementia in older adults newly diagnosed with diabetes. Journal of Internal Medicine. https://doi.org/10.1111/joim.13723
Vancouver
Wu CY, Wang C, Saskin R, Shah BR, Kapral MK, Lanctôt KL, et al. No association between metformin initiation and incident dementia in older adults newly diagnosed with diabetes. Journal of Internal Medicine. 2023. doi:10.1111/joim.13723. PMID: 37747779.
BibTeX
@article{wu2023-37747779,
author = {Wu, C. Y. and Wang, C. and Saskin, R. and Shah, B. R. and Kapral, M. K. and Lanctôt, K. L. and others},
title = {{No association between metformin initiation and incident dementia in older adults newly diagnosed with diabetes}},
journal = {Journal of Internal Medicine},
year = {2023},
doi = {10.1111/joim.13723},
pmid = {37747779},
url = {https://doi.org/10.1111/joim.13723}
}
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.
Key findings
- Results Over mean follow-up of 6.77 years from cohort entry, metformin initiation within 180 days after new diabetes diagnosis (N = 12,331; 978 events; 65,762 person-years) showed no association with dementia risk (aHR [95% CI] = 1.05 [0.96-1.15]), compared to delayed or no glucose-lowering medication initiation (N = 22,369; 1768 events; 117,415 person-years).
- Conclusion Early metformin initiation was not associated with incident dementia in older adults newly diagnosed with diabetes.
Why it matters
This population-based cohort study of older adults newly diagnosed with diabetes found that early metformin initiation was not associated with incident dementia. It does not support metformin as a way to prevent dementia in this group.
New to this subject? Start with our plain-English guide: Prevention →
Study details
- Study designcohort
- Participants34,700
- Effect sizeAdjusted HR 1.05 (95% CI 0.96-1.15), no association
- Evidence strengthNull-result
Limitations
Observational; older adults only; dementia from administrative algorithm; cannot assess long-term use effects beyond initiation.
How this study scored 60/100
Published in a peer-reviewed journal, and it is a cohort study following people over time. Scored zero for randomised / blinded because the record does not state it. We have no data on free to read, so that was left out: it earned 59 of the 98 points we could judge it on, which is 60 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of Internal Medicine) |
| Journal's citation record | 2 / 4 | Journal of Internal Medicine: journal h-index 237 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A cohort study following people over time |
| Strength of evidence | 3 / 5 | Rated “null-result” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2023 — within 6 year(s) of the newest study here |
| Sample size | 4 / 4 | 34,700 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 2 / 7 | Cited 12 times (OpenAlex, 2026-10-10) |
| Citations per year | 1 / 5 | 2.4 citations a year over 5 year(s) since 2023 |
| Impact for its field and year | 2 / 6 | Cited 2.2× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 4 other studies in this library |
| Still being cited | 1 / 4 | Cited 11 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Walter Swardfager: h-index 47 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Toronto: institution h-index 1,923 (OpenAlex) |
| Multi-centre collaboration | 3 / 3 | OpenAlex lists 10 institution(s) in 2 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 37747779) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 59 / 98 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 59 of the 98 points we could judge it on is 60 out of 100. |
| Total | 60 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — Unpaywall lists this copy as free to read: the link above (checked 10 Oct 2026).
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here.
Later studies that cite this one
4 studies in the alzhub library list this one in their references.
Related studies in Prevention and risk
Also tagged “biobank”
1,084 studies in the library carry the topic tag “biobank”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 1,084 tagged studies.