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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 9 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, 9 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 Benefit
why

Compared with flexible health advice, not with nothing; both groups improved.

 Global cognitive composite (SD per year) over 2 years randomised trial 1,065 Between-group difference in global cognitive composite 0.11 SD per year (95% CI 0.06-0.15) The Lancet 2026
✓ Peer-reviewed PMID 42442374
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 Benefit
why

Both groups improved; the structured programme improved more. The trial compares two active interventions, so there is no untreated comparison.

 Global cognition (SD per year) over 2 years randomised trial 2,111 Structured 0.243 SD/year vs. self-guided 0.213 SD/year; difference 0.029 SD/year JAMA 2025
✓ Peer-reviewed PMID 40720610
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
Multidomain lifestyle intervention Exercise and activity Prevention Benefit Neuropsychological test battery Z-score at 2 years randomised trial 1,260 NTB Z-score change 0.20 (intervention) vs. 0.16 (control); annual between-group difference 0.022 The Lancet 2015
✓ Peer-reviewed PMID 25771249
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 Treatment Harm
why

The primary cognitive outcome was significantly WORSE in the exercise arm (adjusted difference -1.4, 95% CI -2.6 to -0.2, favouring usual care). The authors conclude the programme does not slow cognitive impairment and treat the difference as of uncertain clinical importance. Fitness did improve. This is the sharpest counterweight to the observational exercise evidence.

 ADAS-cog at 12 months (primary) randomised trial 494 ADAS-cog adjusted difference -1.4 (95% CI -2.6 to -0.2) favouring usual care BMJ 2018
✓ Peer-reviewed PMID 29769247
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
Resistance training Exercise and activity Prevention Benefit
why

The authors call the effect small (-0.18 points). Significant in women, not in men, on 91 randomised and 76 completing.

 ADAS-Cog-Plus at 12 months randomised trial 91 ADAS-Cog-Plus mean difference -0.18 (95% CI -0.35 to -0.01; P=0.04) Alzheimer's & Dementia 2026
✓ Peer-reviewed PMID 41795685

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