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73/100

✓ Peer-reviewed alzhub usefulness score 73 out of 100. Prevention and risk

Topic: Amyloid, tau and blood-test diagnosis

Plain-language summary

Pooling 29 studies and over 2 million people, this meta-analysis found that people who were more physically active, especially at moderate-to-vigorous intensity, had a notably lower risk of developing Alzheimer's disease, though the protective association was stronger in studies with shorter follow-up periods.

Cite this study APA, Vancouver, BibTeX · download .bib or .ris

APA 7th

Zhang, X., Li, Q., Cong, W., Mu, S., Zhan, R., Zhong, S., et al. (2023). Effect of physical activity on risk of Alzheimer's disease: A systematic review and meta-analysis of twenty-nine prospective cohort studies. Ageing Research Reviews.

Vancouver

Zhang X, Li Q, Cong W, Mu S, Zhan R, Zhong S, et al. Effect of physical activity on risk of Alzheimer's disease: A systematic review and meta-analysis of twenty-nine prospective cohort studies. Ageing Research Reviews. 2023.

BibTeX

@article{zhang2023-d24630eb,
  author  = {Zhang, X. and Li, Q. and Cong, W. and Mu, S. and Zhan, R. and Zhong, S. and Zhao, M. and Zhao, C. and Kang, K. and Zhou, Z.},
  title   = {{Effect of physical activity on risk of Alzheimer's disease: A systematic review and meta-analysis of twenty-nine prospective cohort studies}},
  journal = {Ageing Research Reviews},
  year    = {2023}
}

Built from the record alzhub holds for this paper, not looked up. This record has no DOI, so the citation leaves it out. Volume, issue and page numbers are not held in the record. The record names 10 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.

How to read this study

Design: this is a pooled review. It combines earlier studies, so it is only as good as the studies it pools. Check how many were included, whether they were similar enough to combine, and whether the authors report inconsistency between them.
Size: the record lists 2,068,519 participants. Ask whether that is enough for the question, and who they were.
Effect: the record reports “Pooled HR 0.72 (95% CI 0.65-0.80) overall; HR 0.85 (95% CI 0.79-0.91) after maximal confounder adjustment; high-intensity activity HR 0.56 (95% CI 0.45-0.68); moderate-intensity HR 0.85 (95% CI 0.80-0.93); low-intensity HR 0.94 (95% CI 0.77-1.15, not significant)”. A statistically significant result can still be small in daily life.

What the evidence grade means here

This page is graded moderate. alzhub.org assigns the grade automatically from keywords in the abstract, not from reading the paper. Moderate means the abstract mentions a cohort, case-control or longitudinal design. It can add at most 5 of the 100 points in the study score, and it is a label about design, not a verdict on whether the findings are true.

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Key findings

Physical activity was linked to a 28% lower risk of Alzheimer's disease overall (HR 0.72)
High-intensity physical activity showed the strongest protective association (HR 0.56, a 44% risk reduction)
Low-intensity activity alone was not significantly protective (HR 0.94)
The protective association weakened in studies with more than 15 years of follow-up, consistent with possible reverse causation in shorter studies

Why it matters

Pooling 29 studies, more physically active people had a lower risk of Alzheimer's disease, with the strongest link for high-intensity activity. However, the protective association weakened in studies with more than 15 years of follow-up, which the authors note is consistent with possible reverse causation.

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Study details

Study designmeta-analysis
Participants2,068,519
Effect sizePooled HR 0.72 (95% CI 0.65-0.80) overall; HR 0.85 (95% CI 0.79-0.91) after maximal confounder adjustment; high-intensity activity HR 0.56 (95% CI 0.45-0.68); moderate-intensity HR 0.85 (95% CI 0.80-0.93); low-intensity HR 0.94 (95% CI 0.77-1.15, not significant)
Evidence strengthModerate

Limitations

All included studies are observational, so reverse causation is a major concern (people in early undiagnosed disease may become less active first, as directly shown in the Whitehall II study); high heterogeneity in how physical activity was measured across the 29 pooled cohorts.

How this study scored 73/100

Published in a peer-reviewed journal, and it is a meta-analysis pooling many studies. Scored zero for indexed in PubMed 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, still being cited, senior author's track record, institution's track record, multicenter collaboration and free to read, so those were left out: it earned 45 of the 62 points we could judge it on, which is 73 out of 100.

Component	Points	Why
Journal tier	7 / 10	Tier 3 — peer-reviewed journal (Ageing Research Reviews)
Journal's citation record	— / 4	No journal record from OpenAlex — left out of this score
Study design	12 / 12	A meta-analysis pooling many studies
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	3 / 5	2023 — within 6 year(s) of the newest study here
Sample size	4 / 4	2,068,519 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)
Randomized / blinded	0 / 2	A review of other studies — randomization 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	0 / 6	No other study in this library cites it
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
Multicenter collaboration	— / 3	Institutions not listed — left out of this score
Indexed in PubMed	0 / 2	No PubMed ID and no DOI — scores zero (not stated in the record — scored 0)
Free to read	— / 2	Access not recorded — left out of this score
Points	45 / 62	Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 45 of the 62 points we could judge it on is 73 out of 100.
Total	73 / 100	—

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