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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.
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Showing 17 of 382 rows. One row per study per exposure: a study that tested two different things appears twice, once for each.
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| Exposure | Question | Direction | Outcome measured | Design | People | Effect size, as the source reported it | Source |
|---|---|---|---|---|---|---|---|
| Population burden (prevalence, incidence, lifetime risk) All modifiable factors together | Prevention |
No direction reported
whyA burden-of-disease decomposition: age-standardised rates rose slightly and population growth was the largest driver of the rise in cases. It compares no exposure, so no direction is recorded. |
Global prevalence, incidence, mortality and DALYs of young-onset dementia, 1990-2021 | modelling study | not stated | Global age standardized prevalence and incidence of dementia among people under 65 years increased from 93.39 and 16.24 per 100,000 persons in 1990 to 96.09 and 17.16 per 100,000 persons in 2021; mortality increased from 0.89 per 100,000 population to 0.91 per 100,000 population; and age standardized DALYs increased from 45.60 per 100,000 persons to 46.78 per 100,000 persons |
Translational Psychiatry
2025 ✓ Peer-reviewed PMID 39966345 |
| Population burden (prevalence, incidence, lifetime risk) All modifiable factors together | Prevention |
No direction reported
whyA lifetime-risk estimate (42% after age 55, higher in women, Black adults and APOE4 carriers) and a projection of new cases. It compares no exposure, so no direction is recorded. |
Lifetime risk of dementia from age 55, and projected annual US incident cases to 2060 | cohort study | 15,043 | The lifetime risk of dementia after age 55 years was 42% (95% confidence interval: 41-43). Rates were substantially higher in women, Black adults and APOE ε4 carriers, with lifetime risks ranging from approximately 45% to 60% in these populations. The number of US adults who will develop dementia each year was projected to increase from approximately 514,000 in 2020 to approximately 1 million in 2060 |
Nature Medicine
2025 ✓ Peer-reviewed PMID 39806070 |
| Population burden (prevalence, incidence, lifetime risk) All modifiable factors together | Prevention |
No direction reported
whyA pooled incidence and prevalence estimate with no exposure compared, so no direction is recorded. |
Pooled incidence and prevalence of frontotemporal dementia | meta-analysis | not stated | Pooled crude incidence for FTD was 2.28 (95% CI, 1.55-3.36) per 100 000 person-years and prevalence, 9.17 (95% CI, 3.59-23.42) per 100 000 people |
JAMA Neurology
2025 ✓ Peer-reviewed PMID 40920400 |
| Population burden (prevalence, incidence, lifetime risk) All modifiable factors together | Prevention |
No direction reported
whyA prevalence estimate and forecast: cases are projected to rise from 57.4 million to 152.8 million while age-standardised prevalence stays flat, with the rise attributed to population growth and ageing. It compares no exposure, so there is no direction to record. |
Number of people with dementia worldwide, 2019 and forecast to 2050 | modelling study | not stated | We estimated that the number of people with dementia would increase from 57·4 (95% uncertainty interval 50·4-65·1) million cases globally in 2019 to 152·8 (130·8-175·9) million cases in 2050. Despite large increases in the projected number of people living with dementia, age-standardised both-sex prevalence remained stable between 2019 and 2050 (global percentage change of 0·1% [-7·5 to 10·8]) |
The Lancet Public Health
2022 ✓ Peer-reviewed PMID 34998485 |
| Population burden (prevalence, incidence, lifetime risk) All modifiable factors together | Prevention |
No direction reported
whyA pooled prevalence estimate with no exposure compared, so there is no direction to record. |
Global prevalence of young-onset dementia (ages 30-64) | meta-analysis | 2,760,379 | Age-standardized prevalence estimates increased from 1.1 per 100 000 population in the group aged 30 to 34 years to 77.4 per 100 000 population in the group aged 60 to 64 years. This gives an overall global age-standardized prevalence of 119.0 per 100 000 population in the age range of 30 to 64 years, corresponding to 3.9 million people aged 30 to 64 years living with YOD in the world |
JAMA Neurology
2021 ✓ Peer-reviewed PMID 34279544 |
| Sex and gender differences (research agenda) All modifiable factors together | Prevention |
No direction reported
whyA position paper from an expert network. It sets out 12 priority research areas on sex and gender in Alzheimer's disease and reports no effect estimate. |
None measured (research agenda) | None | not stated | not established — position paper; the abstract reports no effect estimate. |
Alzheimer's & Dementia
2018 ✓ Peer-reviewed PMID 29907423 |
| APOE genotype Genes (not modifiable) | Prevention |
No direction reported
whyA descriptive proteomic mapping: APOE-linked protein changes were present before amyloid pathology and stable across age and disease stage, with ε2 tied to cellular-maintenance and anti-inflammatory pathways and ε4 to cell-cycle, oligodendrocyte-precursor and downstream vascular, immune and proteostatic proteins. It estimates no effect on a clinical outcome. |
Plasma and CSF proteomic signatures of APOE ε4 and ε2 across five cohorts | cross-sectional study | not stated | not established — pubmed abstract reports no numeric effect size. |
Nature Aging
2026 ✓ Peer-reviewed PMID 42141098 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyA transcriptome-wide association study prioritising nine genes (including BIN1, PTK2B and DMPK) with broadly consistent effects across populations; it reports no effect estimate for any exposure, so no direction is recorded. |
Genes whose blood expression is genetically associated with Alzheimer's disease across three populations | cross-sectional study | 751 | not established — pubmed abstract reports gene counts and a correlation (r2 ≈ 0.34 between two bin1 variants), no effect estimate. |
American Journal of Human Genetics
2026 ✓ Peer-reviewed PMID 42066773 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyLocus-discovery genome-wide association study: it reports which genetic regions reached significance and no effect estimate for any exposure, so no direction is recorded. Nine signals (HP1BP3, SLC50A1, PTPRC, NPAS3, DDHD1, CHST9, SMYD2, PRAMEF1, GFRA1) appeared only in APOE-stratified analyses; DDHD1 was protective in ε4 carriers. |
New genome-wide risk loci for AD found when stratifying by APOE ε4 and ε2 carrier status | case-control study | not stated | not established — the abstract names nine new loci and prints no effect estimate. |
Nature genetics
2026 ✓ Peer-reviewed PMID 42736378 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyLocus-discovery genome-wide association study: it reports which genetic regions reached significance and no effect estimate for any exposure, so no direction is recorded. The study reports 14 new loci for clinically diagnosed AD and two from AD-by-proxy. |
Genome-wide significant loci for clinically diagnosed AD and AD-by-proxy | meta-analysis | 432,374 | not established — pubmed abstract lists the loci by name and reports no effect estimate. |
Alzheimer's & Dementia
2025 ✓ Peer-reviewed PMID 39998322 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyLocus-discovery genome-wide association study: it reports which genetic regions reached significance and no effect estimate for any exposure, so no direction is recorded. The study reports eight new loci (six ancestry-specific, two trans-ancestry) and nominates eight genes in microglial activation, glutamate production and signalling. |
Genome-wide significant loci for early-onset Alzheimer's disease (onset before 70) | case-control study | 25,236 | not established — pubmed abstract reports locus counts and pathways, no effect estimate. |
Alzheimer's & Dementia
2025 ✓ Peer-reviewed PMID 40556318 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyLocus-discovery genome-wide association study: it reports which genetic regions reached significance and no effect estimate for any exposure, so no direction is recorded. Beyond APOE, the study reports TREM2 R47H and variants near RAB3B, SPOCK3/ANXA10 and SMAP2, and a gene-based association with GIPR. |
Genome-wide and exome-wide loci for Alzheimer's disease in Ashkenazi Jews | case-control study | not stated | not established — pubmed abstract reports p-values for the loci and no effect estimate. |
Alzheimer's & Dementia
2023 ✓ Peer-reviewed PMID 37260021 |
| Polygenic risk / GWAS loci Genes (not modifiable) | Prevention |
No direction reported
whyLocus-discovery genome-wide association study: it reports which genetic regions reached significance and no effect estimate for any exposure, so no direction is recorded. Two signals at 17p13.2 and 18q21.33 are reported; the authors state that African ancestry at 17p13.2 went with lower AD risk and that overall African ancestry did not differ between cases and controls, without an effect estimate. |
Admixture-mapping loci for Alzheimer's disease in African Americans | case-control study | 10,271 | not established — pubmed abstract reports p-values for the two loci and no effect estimate. |
Alzheimer's & Dementia
2023 ✓ Peer-reviewed PMID 36539198 |
| Rare protective or risk variant (APOE3 Christchurch, APOE R145C, RELN, FN1) Genes (not modifiable) | Prevention |
No direction reported
whyA single case report: one man with the PSEN1 E280A mutation stayed cognitively intact until 67 despite very heavy amyloid, and carried a gain-of-function RELN variant. With one case and no comparison group beyond the earlier Christchurch case, no direction can be recorded. |
Cognitive status and amyloid/tau burden in one PSEN1 E280A carrier heterozygous for RELN-COLBOS | None | not stated | not established — case report; the abstract reports no effect estimate. |
Nature Medicine
2023 ✓ Peer-reviewed PMID 37188781 |
| Rare protective or risk variant (APOE3 Christchurch, APOE R145C, RELN, FN1) Genes (not modifiable) | Prevention |
No direction reported
whyAmong 37 heterozygous carriers (ages 56.6-82.1) none had developed AD or MCI by the March 2022 data freeze and apolipoprotein B was lower than in non-carriers, but the authors say continued follow-up is necessary and no homozygotes were found, so protection could not be tested. No incidence comparison is reported, so no direction is recorded. |
Alzheimer's disease or MCI diagnoses and blood lipid biomarkers in heterozygous APOE Christchurch carriers | cohort study | 455,306 | not established — research letter with no pubmed abstract; the full text at pmc10685495 reports carrier counts and p-values (apob p = 0.004; p = 0.036… |
Molecular Neurodegeneration
2023 ✓ Peer-reviewed PMID 38017580 |
| Brain insulin resistance ('type 3 diabetes') Heart and metabolic health | Prevention |
No direction reported
whyA narrative review arguing that Alzheimer's disease is a brain-specific form of diabetes; it states that type 2 diabetes alone "fall[s] far short of mimicking AD" and reports no effect estimate. |
Alzheimer-type neurodegeneration (mechanistic argument) | None | not stated | not established — review; the abstract reports no effect estimate. |
Journal of Diabetes Science and Technology
2008 ✓ Peer-reviewed PMID 19885299 |
| Sleep Sleep, mood and social life | Prevention |
No direction reported
whyA narrative review proposing glymphatic failure as a final common pathway to dementia. It reports no effect estimate. |
Dementia pathogenesis (glymphatic clearance of protein waste) | None | not stated | not established — review; the abstract reports no effect estimate. |
Science
2020 ✓ Peer-reviewed PMID 33004510 |