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
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
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
Sleep EEG brain age index (digital marker) Care, carers and services	Prevention	Harm why Direction is for an older-than-chronological sleep EEG brain age: each 10-year increase in the index was associated with a 39% higher risk of incident dementia, consistent across sex and age groups.	Incident dementia per 10-year increase in sleep-EEG brain age index	meta-analysis	7,105	each 10-year increase in BAI was associated with a 39% higher risk of incident dementia (hazard ratio [HR], 1.39 [95% CI, 1.21-1.59]; P < .001) after adjustment for covariates. These associations remained after additional adjustment for comorbidities and apnea-hypopnea index scores (HR, 1.31 [95% CI, 1.14-1.50]; P < .001) and apolipoprotein E ε4 (HR, 1.22 [95% CI, 1.02-1.45]; P = .03)	JAMA network open 2026 ✓ Peer-reviewed PMID 41854616
Ultra-processed food Diet and supplements	Prevention	Harm why Heterogeneity was extreme (I-squared 97%), so the pooled figure hides large differences between the 10 studies.	Dementia	meta-analysis	867,316	Pooled RR 1.44 (95% CI 1.09-1.90) for high vs low ultra-processed food intake	Journal of Neurology 2024 ✓ Peer-reviewed PMID 37831127
Air pollution Environment	Prevention	Harm why Heterogeneity was high (I-squared 95%). Reaches a firmer conclusion than the earlier BMJ meta-analysis of largely the same literature.	Incident dementia	meta-analysis	24,030,527	PM2.5 HR 1.08 per 5 ug/m3 (95% CI 1.02-1.14); NO2 HR 1.03 per 10 ug/m3 (1.01-1.05)	Lancet Planetary Health 2025 ✓ Peer-reviewed PMID 40716448
Polygenic risk / GWAS loci Genes (not modifiable)	Prevention	Harm why Direction is for a high polygenic score (excluding APOE): people in the top decile had a twofold risk of Braak stage >4 tangles and of moderate-to-severe amyloid plaque pathology at death. 91 loci identified, 16 new; 18 further loci await validation.	Genome-wide risk loci and a polygenic score's association with tau and amyloid pathology at death	meta-analysis	978,514	We identified 91 genetic loci associated with ADRD risk, of which 16 are new and 56 are specifically detected in clinically diagnosed AD cases ... Individuals in the tenth decile of the score exhibited a twofold increased risk of presenting with Braak neurofibrillary tangles stage of >4 and moderate-to-severe neuritic amyloid plaque pathology at death compared to individuals in the median score group	Nature Genetics 2026 ✓ Peer-reviewed PMID 42237039
Polygenic risk / GWAS loci Genes (not modifiable)	Prevention	Harm why Direction is for carrying a higher genetic risk score: risk of AD rose 1.6- to 1.9-fold from the lowest to the highest decile, over and above age and APOE4. The main output is 75 risk loci, 42 new.	Genome-wide risk loci and a genetic risk score for future AD/dementia	meta-analysis	788,989	We found 75 risk loci, of which 42 were new at the time of analysis ... The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele	Nature Genetics 2022 ✓ Peer-reviewed PMID 35379992
Hearing loss / hearing aids Hearing and vision	Prevention	Harm why Direction is for having the impairment. Dual sensory impairment carried the highest risk (HR 1.63 for all-cause dementia, 2.55 for Alzheimer's).	All-cause and cause-specific dementia	meta-analysis	937,908	Hearing impairment: pooled HR 1.30 (95% CI 1.21-1.40); dual sensory impairment HR 1.63 (1.14-2.12) for all-cause dementia	BMC Medicine 2024 ✓ Peer-reviewed PMID 39506811
Vision impairment / cataract surgery Hearing and vision	Prevention	Harm why Direction is for having a vision impairment. Single vision impairment raised all-cause dementia risk but not Alzheimer's specifically; having both hearing and vision impairment carried the highest risk.	All-cause and cause-specific dementia	meta-analysis	937,908	UK Biobank cohort: vision impairment and all-cause dementia HR 1.55 (95% CI 1.18-2.04) and non-Alzheimer non-vascular dementia HR 1.51 (1.07-2.13). Meta-analysis of 31 cohorts: single vision impairment and all-cause dementia HR 1.43 (95% CI 1.16-1.71), not significant for Alzheimer's. Mendelian randomisation: vision impairment and non-AD non-VD OR 1.62 (95% CI 1.13-2.33). Dual sensory impairment: all-cause dementia HR 1.63 (1.14-2.12)	BMC Medicine 2024 ✓ Peer-reviewed PMID 39506811
Type 2 diabetes Heart and metabolic health	Prevention	Harm	Incident all-cause, vascular and non-vascular dementia	meta-analysis	2,310,330	All-cause dementia: women RR 1.62 (95% CI 1.45-1.80), men RR 1.58 (95% CI 1.38-1.81); vascular dementia: women RR 2.34 (95% CI 1.86-2.94), men RR 1.73 (95% CI 1.61-1.85); non-vascular dementia: women RR 1.53 (95% CI 1.35-1.73), men RR 1.49 (95% CI 1.31-1.69)	Diabetes Care 2016 ✓ Peer-reviewed PMID 26681727
Sleep Sleep, mood and social life	Prevention	Harm why Eight kinds of sleep disturbance were analysed; both short and long sleep carried higher risk, as did excessive daytime sleepiness and insomnia.	Cognitive decline or dementia	meta-analysis	not stated	Excessive daytime sleepiness RR 1.41 for all-cause dementia; long sleep RR 1.66 for Alzheimer's disease	Journal of Neurology 2025 ✓ Peer-reviewed PMID 41081870
Sleep Sleep, mood and social life	Prevention	Harm why No significant association with vascular dementia, and none of the 11 studies used biomarkers to confirm the diagnoses.	Any neurocognitive disorder; Alzheimer's disease	meta-analysis	1,333,424	HR 1.43 (95% CI 1.26-1.62) for any neurocognitive disorder; Alzheimer's HR 1.28 (1.16-1.41)	Journal of Sleep Research 2022 ✓ Peer-reviewed PMID 35366021
Social isolation / loneliness Sleep, mood and social life	Prevention	Harm why Persisted after controlling for depression and social isolation.	Incident all-cause dementia	meta-analysis	608,561	All-cause dementia HR 1.306 (95% CI 1.197-1.426); Alzheimer's disease HR 1.393 (95% CI 1.290-1.504, 5 samples); vascular dementia HR 1.735 (95% CI 1.483-2.029, 3 samples); cognitive impairment HR 1.150 (95% CI 1.113-1.189, 16 samples)	Nature Mental Health 2024 ✓ Peer-reviewed PMID 39802418

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