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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
Dietary pattern (general) Diet and supplements Prevention Benefit
why

Controls declined while the olive-oil arm held steady; the nut arm fell between the two. Cognitive follow-up was available for 334 of 447 enrolled.

 Global cognition composite at median 4.1 years randomised trial 447 Global cognition composite: +0.05 (95% CI -0.11 to 0.21) olive-oil arm vs -0.38 (-0.57 to -0.18) control; P=0.005 JAMA Internal Medicine 2015
✓ Peer-reviewed PMID 25961184
Mediterranean diet Diet and supplements Prevention Benefit
why

Controls declined while the olive-oil arm held steady; the nut arm fell between the two. Cognitive follow-up was available for 334 of 447 enrolled.

 Global cognition composite at median 4.1 years randomised trial 447 Global cognition composite: +0.05 (95% CI -0.11 to 0.21) olive-oil arm vs -0.38 (-0.57 to -0.18) control; P=0.005 JAMA Internal Medicine 2015
✓ Peer-reviewed PMID 25961184
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
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
Antihypertensives / BP lowering Medicines Prevention Benefit
why

Significant for MCI and for the MCI-or-dementia composite; not significant for probable dementia alone (HR 0.86, 95% CI 0.72-1.02).

 MCI and probable dementia over median 7 years randomised trial 9,361 Probable dementia: 8.5 vs. 10.2 per 1,000 person-years (HR 0.86, 95% CI 0.72-1.02); MCI: HR 0.87 (95% CI 0.76-1.00); composite MCI-or-dementia: HR 0.89 (95% CI 0.79-0.99) Neurology 2025
✓ Peer-reviewed PMID 39819096
Antihypertensives / BP lowering Medicines Prevention Benefit
why

A large drop in blood pressure (22/9 mmHg) and fewer serious adverse events in the intervention villages.

 All-cause dementia over 48 months randomised trial 33,995 All-cause dementia RR 0.85 (95% CI 0.76-0.95) Nature Medicine 2025
✓ Peer-reviewed PMID 40258956
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

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