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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 10 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, 10 rows. Every row links to its source.
Exposure Question Direction Outcome measured Design People Effect size, as the source reported it Source
Coffee, tea and flavonoid-rich foods Diet and supplements Prevention Benefit
why

The association was strongest at moderate intake rather than the highest.

 Incident dementia over a median 36.8 years cohort study 131,821 HR 0.82 (95% CI 0.76-0.89) for highest vs lowest quartile of caffeinated coffee JAMA 2026
✓ Peer-reviewed PMID 41661604
Coffee, tea and flavonoid-rich foods Diet and supplements Prevention Benefit
why

882 cases across five quintiles and several interaction strata, so the subgroup estimates rest on small numbers.

 Incident dementia over a mean 9.2 years cohort study 121,986 AHR 0.72 (95% CI 0.57-0.89) for highest vs lowest flavodiet quintile JAMA Network Open 2024
✓ Peer-reviewed PMID 39292460
Dietary pattern (general) Diet and supplements Prevention Benefit
why

The association is reported in people who already have elevated Alzheimer's blood markers, which is the point of the study.

 Incident dementia over a mean 8.4 years cohort study 1,865 Dementia HR 0.71 (95% CI 0.58-0.88) per SD of anti-inflammatory diet adherence among participants with elevated p-tau217 JAMA Network Open 2026
✓ Peer-reviewed PMID 42348207
Dietary pattern (general) Diet and supplements Prevention Benefit
why

Independent of overall diet quality. Substituting olive oil for margarine or mayonnaise was also associated with lower risk; substituting for butter or other vegetable oils was not.

 Dementia-related death over 28 years cohort study 92,383 HR 0.72 (95% CI 0.64-0.81) for dementia-related death with ≥7 g/day olive oil vs never/rarely JAMA Network Open 2024
✓ Peer-reviewed PMID 38709531
Dietary pattern (general) Diet and supplements Prevention Benefit
why

Significant on one adherence score (MEDAS, HR 0.77) but not the other (PYRAMID, HR 0.86, 95% CI 0.73-1.02).

 Incident dementia over a mean 9.1 years cohort study 60,298 HR 0.77 (95% CI 0.65-0.91) for highest vs lowest MEDAS tertile BMC Medicine 2023
✓ Peer-reviewed PMID 36915130
Mediterranean diet Diet and supplements Prevention Benefit
why

Significant on one adherence score (MEDAS, HR 0.77) but not the other (PYRAMID, HR 0.86, 95% CI 0.73-1.02).

 Incident dementia over a mean 9.1 years cohort study 60,298 HR 0.77 (95% CI 0.65-0.91) for highest vs lowest MEDAS tertile BMC Medicine 2023
✓ Peer-reviewed PMID 36915130
Omega-3 / fish and fish oil Diet and supplements Prevention No effect
why

Risk ratios close to one across every intake strategy, including substituting fish for meat. This is the one study here that emulates a trial rather than comparing eaters with non-eaters, and it disagrees with the pooled cohorts.

 21-year Alzheimer's disease risk cohort study 2,012 21-year Alzheimer's risk 10.33% (no fish) vs 9.98% (3+ servings/week); risk ratios near 1 American Journal of Epidemiology 2026
✓ Peer-reviewed PMID 42506897
Ultra-processed food Diet and supplements Prevention Harm
why

The dementia-only estimate barely cleared significance (HR 1.58, 95% CI 1.003-2.48) and its test for trend did not (P=0.50).

 Cognitive impairment or dementia cohort study 5,370 Cognitive impairment or dementia HR 1.47 (95% CI 1.16-1.87) for highest vs lowest quintile of ultra-processed food American Journal of Public Health 2026
✓ Peer-reviewed PMID 42233196
Ultra-processed food Diet and supplements Prevention Harm Rate of global cognitive decline over a median 8 years cohort study 10,775 28% faster global cognitive decline above the lowest quartile (beta -0.004; 95% CI -0.006 to -0.001) JAMA Neurology 2023
✓ Peer-reviewed PMID 36469335
Ultra-processed food Diet and supplements Prevention Harm
why

518 cases. Replacing 10% of ultra-processed food with minimally processed food was associated with 19% lower risk.

 Incident dementia over a median 10 years cohort study 72,083 HR 1.25 per 10% increase in ultra-processed food share (95% CI 1.14-1.37) Neurology 2022
✓ Peer-reviewed PMID 36219796

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