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Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins
Andel R, Crowe M, Pedersen NL, Fratiglioni L, Johansson B, Gatz M.. The journals of gerontology. Series A, Biological sciences and medical sciences, 2008-01-01
Topic: Risk, prevention and care in population studies
Background With the number of people with dementia increasing, identifying potential protective factors has become more important. We explored the association between physical exercise at midlife and subsequent risk of dementia among members of the HARMONY study. Methods Measures of exercise were obtained by the Swedish Twin Registry an average of 31 years prior to dementia assessment. Dementia was diagnosed using a two-stage procedure--screening for cognitive impairment followed by full clinical evaluation. We used two study designs: case-control analyses included 264 cases with dementia (176 had Alzheimer's disease) and 2870 controls; co-twin control analyses included 90 twin pairs discordant for dementia. Results In case-control analyses, controlling for age, sex, education, diet (eating fruits and vegetables), smoking, drinking alcohol, body mass index, and angina, light exercise such as gardening or walking and regular exercise involving sports were associated with reduced odds of dementia compared to hardly any exercise (odds ratio [OR] = 0.63, 95% confidence interval [CI], 0.43-0.91 for light exercise; OR = 0.34, 95% CI, 0.16-0.72 for regular exercise). Findings were similar for Alzheimer's disease alone. In co-twin control analyses, controlling for education, the association between higher levels of exercise and lower odds of dementia approached significance (OR = 0.50, 95% CI, 0.23-1.06; p =.072). Conclusions Exercise at midlife may reduce the odds of dementia in older adulthood, suggesting that exercise interventions should be explored as a potential strategy for delaying disease onset.
Key findings
- Results In case-control analyses, controlling for age, sex, education, diet (eating fruits and vegetables), smoking, drinking alcohol, body mass index, and angina, light exercise such as gardening or walking and regular exercise involving sports were associated with reduced odds of dementia compared to hardly any exercise (odds ratio [OR] = 0.63, 95% confidence interval [CI], 0.43-0.91 for light exercise; OR = 0.34, 95% CI, 0.16-0.72 for regular exercise).
- In co-twin control analyses, controlling for education, the association between higher levels of exercise and lower odds of dementia approached significance (OR = 0.50, 95% CI, 0.23-1.06; p =.072).
- Conclusions Exercise at midlife may reduce the odds of dementia in older adulthood, suggesting that exercise interventions should be explored as a potential strategy for delaying disease onset.
Why it matters
In case-control analyses, light exercise such as gardening or walking and regular sports exercise at midlife were associated with lower odds of dementia decades later. In the co-twin analyses, which control for genetic factors, the link between more exercise and lower odds of dementia only approached significance, so the evidence is not conclusive.
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Study details
- Study designcase-control study
- Participants264
- Effect sizeOR = 0.34; OR = 0.50
- Evidence strengthModerate
How this study scored 61/100
Published in a peer-reviewed journal, and it is a case-control study. Scored zero for randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (The journals of gerontology. Series A, Biological sciences and medical sciences) |
| Journal's citation record | 3 / 4 | The Journals of Gerontology Series A: journal h-index 274 (OpenAlex, 2026-10-29) |
| Study design | 6 / 12 | A case-control study |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2008 — within 20 year(s) of the newest study here |
| Sample size | 2 / 4 | 264 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 | 5 / 7 | Cited 285 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 14.2 citations a year over 20 year(s) since 2008 |
| Impact for its field and year | 4 / 6 | Cited 13.8× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 18 other studies in this library |
| Still being cited | 2 / 4 | Cited 29 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Margaret Gatz: h-index 95 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of South Florida: institution h-index 806 (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 18245762) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 61 / 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. Check the citation against the original before you use it.
APA 7th
Andel, R., Crowe, M., Pedersen, N. L., Fratiglioni, L., Johansson, B., & Gatz, M. (2008). Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins. The journals of gerontology. Series A, Biological sciences and medical sciences. https://doi.org/10.1093/gerona/63.1.62
Vancouver
Andel R, Crowe M, Pedersen NL, Fratiglioni L, Johansson B, Gatz M. Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins. The journals of gerontology. Series A, Biological sciences and medical sciences. 2008. doi:10.1093/gerona/63.1.62. PMID: 18245762.
BibTeX
@article{andel2008-18245762,
author = {Andel, R. and Crowe, M. and Pedersen, N. L. and Fratiglioni, L. and Johansson, B. and Gatz, M.},
title = {{Physical exercise at midlife and risk of dementia three decades later: a population-based study of Swedish twins}},
journal = {The journals of gerontology. Series A, Biological sciences and medical sciences},
year = {2008},
doi = {10.1093/gerona/63.1.62},
pmid = {18245762},
url = {https://doi.org/10.1093/gerona/63.1.62}
}
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