Every finding in the evidence table: 382 rows, filterable

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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

Showing 13 of 382 rows. One row per study per exposure: a study that tested two different things appears twice, once for each.

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Research and outcomes, 13 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	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	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	Benefit why Concentrating activity into one or two days worked about as well as spreading it across the week.	Incident dementia	cohort study	91,512	HR 0.73 (95% CI 0.60-0.89) for >300 min/week concentrated in 1-2 days vs <150 min/week	Journal of Prevention of Alzheimer's Disease 2025 ✓ Peer-reviewed PMID 40514301
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why Direction is for 12 weeks of cycle-ergometer exercise: putative glymphatic influx in the putamen and meningeal lymphatic vessel size and flow increased, and inflammation-related plasma proteins fell in step with the imaging changes. A mechanistic imaging result, not a cognitive outcome.	MRI measures of glymphatic influx and meningeal lymphatic vessel size and flow, and plasma inflammatory proteins, after 12 weeks of cycling in healthy volunteers	cohort study	not stated	not established — pubmed abstract reports no numeric effect size.	Nature Communications 2025 ✓ Peer-reviewed PMID 40204790
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why The authors call the association weak (RR 0.97), and it was absent beyond 10 years of follow-up.	Cognitive impairment or decline	meta-analysis	341,471	Pooled RR 0.97 (95% CI 0.97-0.99) for cognitive impairment/decline; no association beyond 10 years of follow-up	JAMA Network Open 2024 ✓ Peer-reviewed PMID 38300618
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why Pooled across 29 cohorts. The association weakened to HR 0.85 after maximal confounder adjustment and was not significant for low-intensity activity.	Incident Alzheimer's disease	meta-analysis	2,068,519	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)	Ageing Research Reviews 2023 ✓ Peer-reviewed PMID 37979700
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why The authors state the association held in longer follow-ups, which is their answer to the reverse-causation objection raised by the Whitehall II cohort.	Incident all-cause dementia and Alzheimer's disease	meta-analysis	257,983	Pooled RR 0.80 (95% CI 0.77-0.84) for all-cause dementia	British Journal of Sports Medicine 2022 ✓ Peer-reviewed PMID 35301183
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why 866 cases over a short follow-up for a disease with a long prodrome, so some of the association may be people already declining moving less.	Incident all-cause dementia over a median 6.9 years	cohort study	78,430	HR 0.49 (95% CI 0.39-0.62) at 9,826 steps/day vs lowest activity	JAMA Neurology 2022 ✓ Peer-reviewed PMID 36066874
Physical activity (general / dose) Exercise and activity	Prevention	Benefit why The largest effect for physical activity anywhere in this table by a wide margin. On 678 cases over 6.3 years, in a disease with a long prodrome, reverse causation is the more likely explanation for an effect that size.	Incident dementia over a median 6.3 years	cohort study	84,854	Trend across MVPA categories HR 0.66 (95% CI 0.62 to 0.70). "The lowest risk was identified in individuals who performed more than 1200 MET/min/week, those who had 84% (95% CI 0.12 to 0.21) lower risk of incident dementia compared to those who performed < 300 MET/min/week."	BMC Medicine 2021 ✓ Peer-reviewed PMID 34852818
Physical activity (general / dose) Exercise and activity	Treatment	Benefit why Pools 27 small trials in people who already have dementia, and reports a much larger effect (SMD 0.69) than the single largest such trial, DAPA, which found none.	Cognitive function	meta-analysis	2,242	SMD 0.691 (95% CrI 0.373-1.039) at 650 MET-min/week; aerobic SMD 0.909 (0.495-1.362) at 660 MET-min/week	BMC Geriatrics 2024 ✓ Peer-reviewed PMID 38824515
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
Resistance training Exercise and activity	Prevention	Benefit why Seven small trials; working memory did not improve (P=0.14).	General cognitive function and executive function	meta-analysis	not stated	General cognition SMD 0.53 (P=0.04); executive function SMD 0.50 (P=0.0003)	International Journal of Sports Medicine 2020 ✓ Peer-reviewed PMID 32599643

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