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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 7 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, 7 rows. Every row links to its source.
Exposure Question Direction Outcome measured Design People Effect size, as the source reported it Source
Antihypertensives / BP lowering Medicines Prevention Mixed
why

Antihypertensive treatment improved cognitive scores by a small amount (SMD 0.06, moderate certainty) but the reduction in dementia incidence was not statistically significant (OR 0.89, low certainty). The drug-class rankings rest on one trial per class and are described as highly uncertain.

 Cognitive function scores and incident dementia in hypertensive older adults (four RCTs) meta-analysis 16,823 Antihypertensive treatment significantly improved cognitive function scores (SMD, 0.06; 95% CI, 0.03-0.09; P < .001, GRADE moderate certainty) and showed a nonsignificant trend toward reduced dementia incidence (OR, 0.89; 95% CI, 0.76-1.05; P = .172, GRADE low certainty) Journal of the American Medical Directors Association 2026
✓ Peer-reviewed PMID 41962914
Antihypertensives / BP lowering Medicines Prevention Mixed
why

Antihypertensive use tracked lower Alzheimer's risk but not lower non-Alzheimer dementia risk, where treated and untreated hypertension looked the same. A single baseline blood pressure reading predicted neither.

 Alzheimer's and non-Alzheimer dementia meta-analysis 31,250 Untreated vs treated hypertension: Alzheimer's dementia HR 1.42 (95% CI 1.08-1.87) Neurology 2024
✓ Peer-reviewed PMID 39141884
Antihypertensives / BP lowering Medicines Prevention Benefit
why

Individual participant data from five double-blind placebo-controlled trials, which is the strongest design in this table for this exposure.

 Incident dementia over a median 4.3 years meta-analysis 28,008 Adjusted OR 0.87 (95% CI 0.75-0.99) for incident dementia European Heart Journal 2022
✓ Peer-reviewed PMID 36282295
Antihypertensives / BP lowering Medicines Prevention Benefit
why

Consistent across 14 trials (I-squared 0%) but small in absolute terms: 0.39 percentage points over about 4 years.

 Incident dementia or cognitive impairment meta-analysis 96,158 OR 0.93 (95% CI 0.88-0.98); absolute risk reduction 0.39% over 4.1 years JAMA 2020
✓ Peer-reviewed PMID 32427305
Hormone therapy Medicines Prevention No effect MCI or dementia meta-analysis 1,016,055 No evidence that MHT use either increases or decreases the risk of dementia in post-menopausal women (10 studies, 1,016,055 participants; certainty of evidence moderate to very low) The Lancet Healthy Longevity 2025
✓ Peer-reviewed PMID 41448220
Metformin / antidiabetic Medicines Prevention Benefit
why

Heterogeneity was near-total (I-squared 98.9%) and the estimate went to null in people newly diagnosed with diabetes (HR 1.01), which is where prevalent-user bias would be smallest.

 Incident dementia meta-analysis 3,463,100 HR 0.76 (95% CI 0.65-0.91) vs non-users overall; HR 1.01 (0.81-1.27) in newly diagnosed diabetes Diabetes, Obesity and Metabolism 2025
✓ Peer-reviewed PMID 39780315
Metformin / antidiabetic Medicines Prevention Mixed
why

The split inside this one paper is the finding: the 41 observational studies show large benefits (SGLT2i OR 0.56, GLP-1RA OR 0.58) while the 23 randomised trials show no difference. When design and result disagree this cleanly, the trials are the ones to believe.

 Incident dementia meta-analysis 3,462,926 Observational: SGLT2i OR 0.56 (95% CI 0.45-0.69), GLP-1RA OR 0.58 (0.46-0.73) vs non-users; RCTs: no difference Alzheimer's Research & Therapy 2024
✓ Peer-reviewed PMID 39716328

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