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 14 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, 14 rows. Every row links to its source.
Exposure	Question	Direction	Outcome measured	Design	People	Effect size, as the source reported it	Source
Mixed neuropathology at autopsy (LATE-NC, Lewy, vascular, ADNC) All modifiable factors together	Prevention	Harm why Direction is for degenerative pathology profiles: more than 80% had mixed pathologies, and of five clustered profiles the LATE-NC/hippocampal sclerosis and the ADNC/amyloid angiopathy profiles showed the fastest cognitive decline.	Latent neuropathologic profiles at autopsy and their associated cognitive trajectories over up to 30 years	cohort study	1,633	not established — pubmed abstract results gives profile sizes but no numeric estimate of the differences in cognitive decline.	JAMA Network Open 2026 ✓ Peer-reviewed PMID 41543852
Mixed neuropathology at autopsy (LATE-NC, Lewy, vascular, ADNC) All modifiable factors together	Prevention	Harm why Direction is for LATE-NC: found in 64% of brains, stages 1a, 2 and 3 were associated with dementia and lower MMSE, it was among the strongest independent predictors of dementia, and its attributable risk (24.2%) exceeded that of Alzheimer's neuropathologic change (18.6%); it usually occurred alongside other pathologies.	Frequency of LATE-NC at autopsy in people aged 85+, and its association with dementia and MMSE alongside other pathologies	cohort study	295	LATE-NC was found in 189 of 295 subjects (64.1%) ... When LATE-NC and ADNC were assessed in a multivariate model without other dementia-associated pathologies, the attributable risk was higher for LATE-NC than ADNC (24.2% versus 18.6%)	Brain 2025 ✓ Peer-reviewed PMID 38938199
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors. The Danish estimate (37.8% across 16 factors) is lower than the Lancet Commission's global 45%.	Population attributable fraction of dementia	cohort study	1,753,515	Overall population attributable fraction 37.8% (95% CI 35.6-40.0); infections 9.4%, depression 8.7%, CVD 7.6%	The Lancet Public Health 2026 ✓ Peer-reviewed PMID 42425116
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors: depression, diabetes, low education, smoking, obesity, physical inactivity and alcohol overconsumption each independently raised the hazard of early-onset dementia, and most associations were stronger for early-onset than late-onset dementia.	Incident early-onset dementia (before 65) and late-onset dementia over a median 13.7 years	cohort study	544,442	Black versus White race (1·61 [1·23-2·11]), grade school education or less (1·99 [1·67-2·38]), diabetes (2·45 [1·99-3·03]), depression (2·73 [2·34-3·20]), smoking (1·86 [1·56-2·22]), obesity (1·24 [1·04-1·48]), physical inactivity (1·33 [1·11-1·59]), and alcohol overconsumption (1·22 [1·01-1·47]) were independently associated with higher hazards of early-onset dementia	The lancet. Healthy longevity 2026 ✓ Peer-reviewed PMID 41936382
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors. Which factor mattered most differed by APOE risk group, on 2,065 cases split across 11 factors and three genetic strata, so the subgroup estimates are imprecise.	Incident all-cause dementia over 12.4 years	cohort study	182,473	Low social contact HR 3.86 (95% CI 2.08-7.17) in low APOE risk group; less education PAF 11.35% in high APOE risk group	Annals of Neurology 2025 ✓ Peer-reviewed PMID 41085200
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying hypertension, diabetes or smoking. The attributable share rose with the age at which the factors were measured (22% at 45-54, 44% at 65-74), which is what you would expect if some of it is reverse causation rather than cause.	Population attributable fraction of dementia by age 80	cohort study	12,274	22-44% of dementia by age 80 attributable to hypertension, diabetes or smoking	JAMA Neurology 2025 ✓ Peer-reviewed PMID 40455489
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors: the Commission attributes 45% of cases to 14 modifiable factors, which is the same number read the other way as prevention potential. The Commission's own caveat is that "some associations might be only partly causal".	Population attributable fraction of dementia	systematic review	not stated	"estimated that the PAF for all 14 risk factors was 45.3%" (Table 1: overall PAF 45.3%, rounded 45%); high LDL cholesterol unweighted PAF 18.7%, weighted 6.9%, rounded 7%; untreated vision loss unweighted 6.0%, weighted 2.2%, rounded 2%	The Lancet 2024 ✓ Peer-reviewed PMID 39096926
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors. 39 candidate factors were screened against 485 cases, so individual estimates are imprecise.	Incident young-onset dementia	cohort study	356,052	485 incident young-onset dementia cases (16.8 per 100,000 person-years) among 356,052 participants; 39 candidate risk factors tested, most of the associated factors modifiable	JAMA Neurology 2024 ✓ Peer-reviewed PMID 38147328
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why Direction is for carrying the risk factors. The weighted combined estimate (32.0% for seven factors) is lower than the Lancet Commission's 45% for 14.	Population attributable fraction of dementia	meta-analysis	not stated	Weighted combined PAF 32.0% (95% CI 26.6-37.5) for seven modifiable factors	Lancet Healthy Longevity 2024 ✓ Peer-reviewed PMID 38824956
Modifiable risk factors combined All modifiable factors together	Prevention	Harm why For the vascular risk factors: up to a quarter of the education-dementia association ran through hypertension, diabetes and related midlife factors, so carrying them accounted for part of the excess risk.	Incident dementia	cohort study	13,368	8-44% lower dementia risk with higher education vs grade school; up to 25% mediated by midlife vascular risk factors	Annals of Neurology 2023 ✓ Peer-reviewed PMID 36966451
Peripheral diseases combined (population attributable fraction) All modifiable factors together	Prevention	Harm why Direction is for carrying the peripheral diseases: together they were related to about one-third of global dementia burden, led by periodontal disease, chronic liver disease, hearing loss, vision loss and type 2 diabetes. Attributable fractions assume the pooled associations are causal.	Population attributable fraction of global dementia burden for 16 peripheral diseases	meta-analysis	not stated	Globally, these peripheral diseases collectively were related to a combined PAF of 33.18% (95% confidence interval (CI) 16.80-48.43) of dementia burden, corresponding to 18.8 million prevalent cases. The leading ten PAF contributors were periodontal diseases (6.10%, 95% CI 0.95-10.28), cirrhosis and other chronic liver diseases (5.51%, 95% CI 1.77-8.86), age-related and other hearing loss (4.70%, 95% CI 3.51-6.06), blindness and vision loss (4.30%, 95% CI 3.43-5.05), type 2 diabetes mellitus (3.80%, 95% CI 3.06-4.53)	Nature human behaviour 2026 ✓ Peer-reviewed PMID 41559195
Race and ethnicity (population comparison) All modifiable factors together	Prevention	Harm why Direction is for being African-American or American Indian/Alaska Native relative to Asian-American members: incidence was highest in those groups (26.6 and 22.2 per 1000 person-years) and lowest in Asian-Americans (15.2). The authors present this as a benchmark for reducing disparities, not as a biological effect of race.	Dementia incidence 2000-2013 and 25-year cumulative risk at age 65	cohort study	274,283	Dementia incidence (n = 59,555) was highest for African-Americans (26.6/1000 person-years) and AIANs (22.2/1000 person-years); intermediate for Latinos (19.6/1000 person-years), Pacific Islanders (19.6/1000 person-years), and whites (19.3/1000 person-years) and lowest among Asian-Americans (15.2/1000 person-years). Risk was 65% greater for African-Americans (hazard ratio = 1.65; 95% confidence interval = 1.58-1.72) versus Asian-Americans	Alzheimer's & Dementia 2016 ✓ Peer-reviewed PMID 26874595
Sex differences (biological sex as exposure) All modifiable factors together	Prevention	Harm why Direction is for female sex: at higher amyloid levels women had higher plasma p-tau217 than men, greater tau deposition and accumulation at a given p-tau217 level, and faster cognitive decline in two of the cohorts.	Plasma p-tau217 by sex and amyloid load; tau PET accumulation and cognitive decline	cohort study	1,292	Compared with men, women had significantly higher baseline p-tau217 levels at higher aggregated Aβ Centiloid levels (β, -0.21 [95% CI, -0.37 to -0.05], P = .009; highest interaction was found in the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease/Longitudinal Evaluation of Amyloid Risk and Neurodegeneration [A4/LEARN] cohort)	JAMA neurology 2026 ✓ Peer-reviewed PMID 41697669
Sex differences (biological sex as exposure) All modifiable factors together	Prevention	Harm why Direction is for female sex: women had higher odds of a high neuritic plaque burden than men after adjustment, and were more likely to reach Braak stage V-VI. Black non-carriers and non-carriers of African ancestry were least likely to have high plaque burden, a protection weakened in ε4 carriers.	Neuritic plaque burden (CERAD score) at autopsy by sex, and its interaction with APOE ε4, race and African ancestry	cross-sectional study	2,268	Female individuals had higher plaque burden than male individuals (unadjusted odds ratio [OR], 1.97; 95% CI, 1.67-2.29; P < .001), and this association remained significant in adjusted models for sociodemographic and vascular factors and APOEε4 status (adjusted OR, 1.65; 95% CI, 1.33-2.20; P < .001). APOEε4 carriers of both sexes had an approximately 4-fold greater odds of plaques	JAMA neurology 2026 ✓ Peer-reviewed PMID 41729539

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