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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 2 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, 2 rows. Every row links to its source.
Exposure Question Direction Outcome measured Design People Effect size, as the source reported it Source
Alcohol Alcohol, tobacco and cannabis Prevention Harm
why

The key point: the observational analysis showed light drinking looking protective, but the genetic (Mendelian randomisation) analysis did not, which the authors read as the protective appearance coming from people cutting down in early dementia.

 Incident dementia cohort study 559,559 Mendelian randomisation OR 1.15 per SD increase in log drinks/week (95% CI 1.03-1.27); alcohol use disorder HR 1.51 (1.42-1.60) BMJ Evidence-Based Medicine 2026
✓ Peer-reviewed PMID 40987604
Cannabis use Alcohol, tobacco and cannabis Prevention Harm
why

The exposure is cannabis use severe enough to need hospital care, not cannabis use in general, and the comparison is against other acute-care patients as well as the general population.

 New dementia diagnosis cohort study 6,086,794 Adjusted HR 1.23 (95% CI 1.09-1.39) vs all-cause acute care; 1.72 (95% CI 1.38-2.15) vs general population JAMA Neurology 2025
✓ Peer-reviewed PMID 40227745

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