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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
Education / cognitive reserve Sleep, mood and social life Prevention Benefit
why

Direction is for MORE education. Up to a quarter of the effect ran through midlife vascular risk factors, and the authors say treating those factors would not close the educational gap.

 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
Education / cognitive reserve Sleep, mood and social life Prevention Benefit
why

Education and job complexity each contributed independently; about 28% of the education effect ran through occupation.

 Dementia-free survival time meta-analysis 10,195 Education and occupational complexity independently associated with longer dementia-free survival (28% of education effect mediated by occupation) Journal of Alzheimer's Disease 2022
✓ Peer-reviewed PMID 34776437
Education / cognitive reserve Sleep, mood and social life Prevention Benefit
why

Effect held over and above measured Alzheimer's pathology, which is the point of the reserve idea.

 Incident MCI or dementia meta-analysis not stated "High CR was related to a 47% reduced relative risk of MCI or dementia (pooled-hazard ratio: 0.53 [0.35, 0.81]), with residual-based CR reducing risk by 62% and proxy-based CR by 48%." Neuropsychology Review 2021
✓ Peer-reviewed PMID 33415533
Music therapy Sleep, mood and social life Treatment Benefit
why

Improves depressive symptoms (moderate certainty) and overall behavioural problems (low certainty). No effect on agitation (SMD -0.05, 95% CI -0.27 to 0.17) and no evidence of long-term effects. Sits against the null MIDDEL trial on the same exposure.

 Depressive symptoms at end of treatment meta-analysis 1,720 Depressive symptoms SMD -0.23 (95% CI -0.42 to -0.04); agitation SMD -0.05 (95% CI -0.27 to 0.17) Cochrane Database of Systematic Reviews 2025
✓ Peer-reviewed PMID 40049590
Sleep Sleep, mood and social life Prevention Benefit
why

Direction is for normal sleep versus sleep deprivation, on a clearance measure — not on cognition, which this trial did not measure.

 Overnight brain-to-plasma clearance of amyloid-beta and tau randomised trial 39 Additional variance explained by the physiological predictor model in the sleep condition: "between 49.1% (Abeta40) to 56.0% (Abeta42)" in amyloid-positive participants and "between 71.3% (p-tau181) to 97.8% (Abeta40)" in amyloid-negative participants Nature Communications 2026
✓ Peer-reviewed PMID 41593094
Social isolation / loneliness Sleep, mood and social life Prevention Benefit
why

Significant only for contact measured at age 60, not at 50 or 70. The authors note that keeping up contact may itself be a marker of cognitive reserve rather than a cause of it.

 Incident dementia over 28 years cohort study 10,228 HR 0.88 per SD higher social contact frequency at age 60 (95% CI 0.79-0.98) PLoS Medicine 2019
✓ Peer-reviewed PMID 31374073

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