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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
GLP-1 receptor agonist Medicines Prevention No effect
why

The authors state the data are compatible with anything from a 39% decrease to a 5% increase in risk, against DPP-4 inhibitors rather than no treatment.

 Incident dementia at 30 months cohort study 7,254 Dementia RR 0.83 (95% CI 0.61-1.05) at 30 months; risk difference -0.93 percentage points (95% CI -2.33 to 0.23) Annals of Internal Medicine 2025
✓ Peer-reviewed PMID 40690769
GLP-1 receptor agonist Medicines Prevention No effect
why

For GLP-1 receptor agonists specifically: HR 0.95 (95% CI 0.87-1.04) against DPP4 inhibitors in the intention-to-treat analysis. Only the continuous-use analysis reached significance (HR 0.79).

 Incident dementia cohort study not stated SGLT2i vs DPP4i HR 0.86 (95% CI 0.79-0.94); GLP1-RA vs DPP4i HR 0.95 (0.87-1.04) Alzheimer's Research & Therapy 2025
✓ Peer-reviewed PMID 41420258
GLP-1 receptor agonist Medicines Prevention Benefit
why

Seven separate comparisons against seven other antidiabetic drugs, so the comparator is always another drug rather than no treatment.

 First-time Alzheimer's diagnosis over 3 years cohort study 1,094,761 HR 0.33 (95% CI 0.21-0.51) vs. insulin; HR 0.59 (95% CI 0.37-0.95) vs. other GLP-1 agonists Alzheimer's & Dementia 2024
✓ Peer-reviewed PMID 39445596
Metformin / antidiabetic Medicines Prevention No effect
why

Designed around new diabetes diagnoses with a landmark analysis and a one-year lag, which removes the prevalent-user advantage that inflates metformin's apparent benefit in the pooled cohorts.

 Incident dementia cohort study 34,700 Adjusted HR 1.05 (95% CI 0.96-1.15), no association Journal of Internal Medicine 2024
✓ Peer-reviewed PMID 37747779
Metformin / antidiabetic Medicines Prevention Benefit
why

Comparator is other oral antidiabetic drugs, not no treatment.

 All-cause dementia and Parkinson's disease cohort study 358,862 All-cause dementia aHR 0.79 (95% CI 0.69-0.90) for SGLT2 inhibitor vs other oral antidiabetic drugs Neurology 2024
✓ Peer-reviewed PMID 39292986
Metformin / antidiabetic Medicines Prevention Benefit
why

The exposure actually studied is STOPPING metformin early, which carried 21% higher dementia incidence than staying on it. Read as indirect support for metformin, not as a trial of it.

 Incident dementia cohort study 41,346 HR 1.21 (95% CI 1.12-1.30) for dementia after early metformin termination JAMA Network Open 2023
✓ Peer-reviewed PMID 37878309
SGLT2 inhibitor Medicines Prevention Benefit
why

For SGLT2 inhibitors specifically: HR 0.86 (95% CI 0.79-0.94) against DPP4 inhibitors, and HR 0.70 in the as-treated analysis.

 Incident dementia cohort study not stated SGLT2i vs DPP4i HR 0.86 (95% CI 0.79-0.94); GLP1-RA vs DPP4i HR 0.95 (0.87-1.04) Alzheimer's Research & Therapy 2025
✓ Peer-reviewed PMID 41420258
Statins / lipid-lowering Medicines Prevention No effect
why

After the first year the data rule out more than a 3% change either way. Diagnoses were 46% higher in the first year, which the authors attribute to people being seen more often just after starting a statin. This sits against the Chicago cohort, which found benefit in APOE4 carriers.

 Incident Alzheimer's disease and related dementias cohort study 322,358 HR 1.00 (95% CI 0.99-1.01) for dementia after the first year of statin initiation Neurology 2025
✓ Peer-reviewed PMID 40577672
Statins / lipid-lowering Medicines Prevention Benefit
why

Benefit was confined to APOE4 carriers (HR 0.60) and absent in non-carriers (HR 0.96). Observational, and it disagrees with the larger target-trial emulation that found nothing.

 Incident clinical Alzheimer's disease and cognitive decline cohort study 4,807 Alzheimer's HR 0.81 (95% CI 0.70-0.94) overall; 0.60 (0.49-0.74) in APOE ε4 carriers; 0.96 (0.82-1.12) in non-carriers Neurology 2024
✓ Peer-reviewed PMID 38447103

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