Each study has a usefulness score out of 100 (rubric version 4.0). Tap a score to see what makes it up.
Highest usefulness score first. Studies without a score come last.
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This randomized trial gave hearing aids plus counseling, or only general health education, to 977 older adults with untreated hearing loss, then tracked cognition for three years.
Why it matters
Across the whole group of 977 older adults with hearing loss, hearing treatment did not significantly slow cognitive decline over three years, but a planned higher-risk subgroup showed roughly 48% less decline with hearing treatment. Both the overall null result and the subgroup benefit are findings from the same randomized trial.
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Higher adherence to a MedDiet was associated with lower dementia risk, independent of genetic risk, underlining the importance of diet in dementia prevention interventions.
Why it matters
In this UK Biobank cohort, higher Mediterranean diet adherence was linked to lower dementia risk, and this was independent of genetic risk. Being observational, it shows an association and cannot prove that the diet prevents dementia.
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In this cohort study of a Korean population, decreased risk of dementia was associated with maintaining mild to moderate alcohol consumption, reducing alcohol consumption from a heavy to a moderate level, and the initiation of mild alcohol consumption, suggesting that the threshold of alcohol consumption for dementia risk reduction is low.
Why it matters
This South Korean cohort found that sustained mild or moderate drinking was linked to lower dementia risk, while sustained heavy drinking was linked to higher risk. It is observational, so it cannot prove that drinking protects against or causes dementia.
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Low SES substantially increased the risk of dementia and cognitive dysfunction, suggesting that public health strategies could reduce the dementia burden by reducing social inequalities.
Why it matters
This meta-analysis found that low socioeconomic status was associated with an elevated combined risk of cognitive impairment and dementia. It suggests that low education and low income are specifically linked to increased risk.
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We included randomized controlled trials (RCTs) and nonrandomized controlled studies at lower risk of bias comparing ChEI treatment with placebo or usual treatment, for 6 months or longer, in patients with dementia of any type.
Why it matters
This review of 24 studies covering 79,153 patients found that treatment with cholinesterase inhibitors was associated with lower all-cause mortality, a result consistent between randomized and nonrandomized studies. The authors note these findings may influence decisions to prescribe these drugs.
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Topic The magnitude and direction of the association between vision impairment and incident dementia and cognitive impairment in prospective cohort studies was estimated by systematic review and meta-analysis.
Why it matters
This review of many prospective studies found that people with vision impairment had a higher risk of developing dementia and cognitive impairment. Because much vision impairment can be treated, the authors suggest it may be a modifiable factor worth investigating for dementia prevention, but this review does not prove that treating vision problems prevents dementia.
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Current evidence on sex and gender differences in caregiving burden, mental and physical health is limited.
Why it matters
Across 22 studies of family caregivers of people with dementia, this registered systematic review found that "a majority of studies reported higher burden among females." But every study that found no sex or gender difference had adjusted for confounders, and results for caregivers' physical and mental health were "inconsistent." The authors call the evidence "limited." It is a narrative review with no pooled effect size, and it tests no support or treatment.
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During 1 110 831 person-years at risk, we recorded 245 573 hospitalisations in the Finnish cohorts; the corresponding numbers in the UK study were 60 946 hospitalisations in 186 572 person-years.
Why it matters
This multi-cohort study found that low socioeconomic status was associated with increased risk for 18 of 56 health conditions, with 16 diseases forming a cascade of interrelated conditions. It reports no treatment, cure or prevention of Alzheimer's disease.
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The overall conversion rate from iRBD to an overt neurodegenerative syndrome was 6.3% per year, with 73.5% converting after 12-year follow-up.
Why it matters
In this multicentre study, people with idiopathic REM sleep behaviour disorder converted to an overt neurodegenerative syndrome at 6.3% per year, with 73.5% converting after 12-year follow-up, and several markers predicted conversion. The findings are presented as a way to stratify patients for future neuroprotective trials, not as a treatment or cure.
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The study cohort included 568 patients (289 [50.9%] men; mean [SD] age, 70.5 [16.1] years) who died in the hospital or were discharged to hospice.
Why it matters
This study describes a cohort of patients who died in the hospital or were discharged to hospice as part of research on sepsis-associated mortality. It does not address treating, curing, or preventing Alzheimer's disease.
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It has been suggested that various different vitamin and mineral supplements might be useful in maintaining cognitive function and delaying the onset of dementia.
Why it matters
This review of five trials with 879 participants found no significant effect of three years of vitamin E supplementation on overall cognitive function or other outcomes, and none of the trials reported dementia incidence. The evidence on overall cognitive function was of very low quality.
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Five RCTs of the Mediterranean diet and cognition have been published to date.
Why it matters
In a systematic review of 5 randomized controlled trials with 1,888 participants, only 8 of 66 individual cognitive outcomes significantly favored a Mediterranean diet, while 2 favored controls. Data limitations prevented a meta-analysis, and the prescribed Mediterranean diets varied considerably between studies.
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It has been reported that social engagement may be associated with dementia risk.
Why it matters
This meta-analysis found that poor social engagement, such as a poor social network or poor social support, was associated with increased dementia risk, while loneliness was not significantly associated with increased risk. The authors suggest interventions targeting social isolation for dementia prevention, but this review does not test such interventions.
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73/100
The association between BMI and dementia is likely to be attributable to two different processes: a harmful effect of higher BMI, which is observable in long follow-up, and a reverse-causation effect that makes a higher BMI to appear protective when the follow-up is short.
Why it matters
In 1.3 million people from 39 cohort studies, the link between body mass index and dementia depended on when weight was measured. Each 5-unit higher BMI went with higher dementia risk when measured more than 20 years before diagnosis (hazard ratio 1.16), but with lower risk when measured nearer to diagnosis (0.71). The authors attribute the second pattern to reverse causation, weight loss in the years before dementia is diagnosed. This is an observational study of all-cause dementia: it suggests midlife weight may matter, but it does not show that changing weight changes dementia risk.
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This study found no evidence of a neuroprotective effect of physical activity.
Why it matters
In this 28-year follow-up of over 10,000 people, physical activity was not associated with later cognitive decline or with risk of dementia. The study found no evidence that midlife physical activity reduces dementia risk.
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Of 5687 unique abstracts, 255 were selected for full-text review, and 57 studies, representing 20 892 patients, met all inclusion criteria.
Why it matters
Pooling 57 studies of 20,892 people with mild cognitive impairment, this review estimated that about 1 in 3 (32%) have depression. The figure was 25% in community samples and 40% in clinic samples, and estimates varied widely between studies. It measures how common depression is, not what causes it, and it does not test any treatment, cure or prevention for Alzheimer's disease.
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Cohort studies have reported that midlife high total serum cholesterol (TC) is associated with increased risk of Alzheimer's disease (AD) in late-life but findings have been based on few studies and previous reviews have been limited by a lack of compatible data.
Why it matters
This review and meta-analysis synthesized cohort study data on the association between total serum cholesterol and late-life cognitive outcomes including Alzheimer's disease, vascular dementia, any dementia, mild cognitive impairment, and cognitive decline. It examines a risk association only and does not test any treatment, cure, or prevention for Alzheimer's disease.
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White matter hyperintensities are frequent on neuroimaging of older people and are a key feature of cerebral small vessel disease.
Why it matters
This systematic review and meta-analysis found that cerebral blood flow was lower in subjects with more white matter hyperintensity cross-sectionally, but these differences were attenuated by excluding studies in dementia or that lacked age-matching. Four longitudinal studies gave differing results, so whether low cerebral blood flow is cause or effect remains unclear.
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This systematic review and meta-analyses covering a wide range of observational studies and diverse settings provides robust support for the CR hypothesis.
Why it matters
This 2012 systematic review pooled observational studies (133 articles covering 437,477 people) and found that low education was linked to higher dementia risk, with pooled odds ratios of 2.61 in prevalence studies and 1.88 in incidence studies. The authors, treating education as a stand-in for cognitive reserve, call this "robust support for the CR hypothesis." Because every study was observational, it shows an association, not that more schooling prevents dementia.
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The relationships between alcohol consumption and dementia and cognitive decline were investigated in a systematic review including meta-analyses of 15 prospective studies.
Why it matters
Pooling 15 prospective studies with 2–8 years of follow-up, this meta-analysis found that light to moderate drinkers had lower relative risks than nondrinkers of Alzheimer disease (RR 0.72, 95% CI 0.61–0.86), vascular dementia (0.75, 0.57–0.98) and any dementia (0.74, 0.61–0.91). Drinkers did not show a lower risk of cognitive decline. The finding that heavy drinkers had no increased dementia risk "may reflect sampling bias," according to the authors. Because the cohorts began in late life, the authors say it is unclear whether the pattern reflects "selection effects," a lifelong effect of alcohol, or a late-life benefit, so the study does not show that drinking prevents dementia.
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Central obesity in midlife increases risk of dementia independent of diabetes and cardiovascular comorbidities.
Why it matters
This study found that people with the highest midlife central obesity had nearly a threefold increased risk of dementia about three decades later. It identifies a possible risk factor but does not test any treatment, cure, or prevention for Alzheimer's disease.
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We found that more intensive follow-up of individuals in a placebo-controlled clinical trial of Ginkgo biloba for treating mild-moderate dementia resulted in a better outcome than minimal follow-up, as measured by their cognitive functioning.
Why it matters
In a dementia trial, participants given more intensive follow-up scored better on cognitive function and self-rated quality of life than those with minimal follow-up, but there was no significant difference in carer-rated quality of life. This shows that how often people are assessed can itself affect trial results, which matters for interpreting treatment studies.
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The majority of community-dwelling older persons have brain pathology.
Why it matters
Most dementia cases in this community sample had more than one brain pathology, and having multiple pathologies made dementia almost three times more likely. This means treatment and prevention may need to address several disease processes at once, not just Alzheimer's alone.
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73/100
This randomized trial of 406 spouse caregivers of people with Alzheimer's tested whether counseling and support (six counseling sessions, mandatory support groups, and on-call phone counseling) could delay nursing home placement.
Why it matters
Spouse caregivers who received counseling and support kept their partners at home significantly longer, with a 28.3% lower rate of nursing home placement. This shows a caregiver support program can delay nursing home placement for people with Alzheimer's disease.
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73/100
Greater access to effective programs of counseling and support could yield considerable benefits for caregivers, patients with Alzheimer disease, and society.
Why it matters
Spouse caregivers who received counseling and support kept their partners at home significantly longer, with a 28.3% lower rate of nursing home placement. This shows a caregiver support program can delay nursing home placement for people with Alzheimer's disease.
From across this topic
10 of the 7,967 studies in this topic, picked by a fixed rule (a hash of each study's address), not by score or date; each page of this list shows a different 10. The same 10 appear here every time.
- Efficacy of Cognitive Training in Older Adults with and without Subjective Cognitive Decline Is Associated with Inhibition Efficiency and Working Memory Span, Not with Cognitive Reserve
- No Association between Dietary Patterns and Risk for Cognitive Decline in Older Women with 9-Year Follow-Up: Data from the Women's Health Initiative Memory Study
- Effects of intensive lifestyle changes on the progression of mild cognitive impairment or early dementia due to Alzheimer’s disease: the need for rigor
- A Comparison of the Prevalence of Dementia in the United States in 2000 and 2012
- Geographic Variation in Diagnosis Frequency and Risk of Death Among Medicare Beneficiaries
- Incidence of dementia in a population older than 75 years in the United Kingdom
- Age- and Sex-Specific Prevalence and Modifiable Risk Factors of Mild Cognitive Impairment Among Older Adults in China: A Population-Based Observational Study
- Under-recruitment and nonselective recruitment: dissociable neural mechanisms associated with aging
- From Mandates to Mechanisms: Institutional Vulnerability, Decentralized Governance, and the Challenges of Local Disaster Risk Reduction Implementation
- Preserved neural correlates of priming in old age and dementia