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Home › Research › What the research found › Every row

Every row of the evidence table

One row per finding: what was tested, which way the result went, and how the study was built. The answer by area, and where the studies disagree, are on the main page.

Every row

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Area All 382 Care, carers and services 140 Medicines 85 Genes (not modifiable) 35 All modifiable factors together 27 Diet and supplements 23 Exercise and activity 21 Sleep, mood and social life 19 Hearing and vision 8 Alcohol, tobacco and cannabis 6 Infection and vaccination 5 Heart and metabolic health 4 Injury, delirium and falls 4 Environment 3 Cognitive activity 2
Question Both Prevention 190 Treatment 192
Direction Any Benefit 144 Harm 105 No effect 38 Mixed 37 No direction reported 58
Design Any meta-analysis 57 randomised trial 44 phase 3 trial 15 systematic review 9 phase 2 trial 10 cohort study 136 phase 1 trial 2 cross-sectional study 31 case-control study 14 modelling study 20 regulatory decision 7 company announcement 1 coverage determination 1 None 35
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Showing 6 of 382 rows. One row per study per exposure: a study that tested two different things appears twice, once for each.

Scroll the table sideways to see every column.

Research and outcomes, 6 rows. Every row links to its source.
Exposure Question Direction Outcome measured Design People Effect size, as the source reported it Source
Multidomain lifestyle intervention Exercise and activity Prevention No effect
why

The intervention did not change any brain biomarker trajectory. Participants with lower baseline hippocampal volume did show a greater cognitive benefit.

 Amyloid, tau, hippocampal volume and white matter trajectories randomised trial 983 Cognitive benefit of structured vs self-guided: 0.077 SD (95% CI 0.022-0.132) with lower hippocampal volume vs 0.002 SD (95% CI -0.037 to 0.041) with higher JAMA Neurology 2026
✓ Peer-reviewed PMID 42008251
Multidomain lifestyle intervention Exercise and activity Prevention No effect
why

A small improvement that did not reach significance (adjusted difference 0.06, 95% CI -0.001 to 0.128, p=0.055).

 Neuropsychological Test Battery at 24 months randomised trial 746 Adjusted mean difference in NTB score at 24 months 0.06 (95% CI -0.001 to 0.128, p=0.055) The Lancet Healthy Longevity 2025
✓ Peer-reviewed PMID 41130254
Physical activity (general / dose) Exercise and activity Prevention No effect
why

No difference between aerobic training and stretching/balance. Cognition was stable in both arms, but with no non-exercising control the trial cannot say whether either arm helped.

 ADAS-Cog-Exec 12-month cognitive trajectory phase 3 trial 296 Between-group cognitive difference -0.078 (SE 0.074, p=0.3); 12-month hippocampal volume loss 0.51% in both arms Alzheimer's & Dementia 2025
✓ Peer-reviewed PMID 40271888
Physical activity (general / dose) Exercise and activity Prevention No effect
why

Neither the combined package nor risk-factor modification beat health advice.

 ADAS-Cog z-score at 15 months randomised trial 456 ADAS-Cog z-score difference vs health advice: -0.04 (95% CI -0.34 to 0.26) for combined package The Lancet Healthy Longevity 2025
✓ Peer-reviewed PMID 40294622
Physical activity (general / dose) Exercise and activity Prevention No effect
why

Explicitly finds no neuroprotective effect, and attributes the lower risk seen in other cohorts to reverse causation: activity fell in the nine years before diagnosis. This contradicts the pooled cohort evidence.

 Incident dementia; 15-year cognitive decline cohort study 10,308 HR 1.00 (95% CI 0.80-1.24) for meeting recommended physical activity levels vs not, for dementia risk; no difference in 15-year cognitive decline across activity levels BMJ 2017
✓ Peer-reviewed PMID 28642251
Resistance training Exercise and activity Prevention No effect
why

The primary outcome did not move between groups. Attention and inhibitory control did improve (SMD 0.43), as did muscular strength.

 Executive function at 24 weeks (primary) randomised trial 90 Between-group executive function SMD 0.13 (P=0.37); attention/inhibitory control SMD 0.43 (P<0.001) Alzheimer's & Dementia 2026
✓ Peer-reviewed PMID 41562376

How this table was built, and where it is weak →