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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Why it matters
A Lancet report spanning dementia prevention, intervention and care. Its contribution is to pull together what is known across those areas, not to test a treatment.
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Dementia is a frequent problem encountered in advanced stages of Parkinson disease (PD).
Why it matters
This review describes cognitive decline in Parkinson's disease, noting that low cerebrospinal fluid amyloid-beta 42 predicts future cognitive decline and dementia, and that APOE epsilon4, GBA and SCNA mutations are linked to this decline. It states there is no convincing evidence that progression from mild cognitive impairment to dementia can be delayed or prevented, though some cognitive-enhancing medications have some effect in Parkinson's disease dementia.
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Comparing two nationally representative surveys of older Americans 12 years apart, researchers found the share of seniors with dementia fell substantially, from 11.6% in 2000 to 8.8% in 2012.
Why it matters
This study compared dementia prevalence in the United States in 2000 and 2012 using nationally representative survey data. It examines population trends in dementia prevalence and does not test any treatment, cure, or prevention.
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We recommend focusing on cognitive enhancement strategies, assessment and management of BPSD, and carer education and support to delay nursing home placement.
Why it matters
Pooling 26 controlled studies of older people with dementia, this review found that poorer memory and thinking and behavioral or psychological symptoms were consistently linked to moving into a nursing home, and most of its meta-analyses also linked difficulty with everyday activities to higher risk. Caregiver burden was associated with placement as well, while results for caregiver depression, physical health and the use of community support services were mixed or unclear. These are associations, not proof that changing any one factor will delay a move.
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Although both overt hyper- and hypothyroidism are known to lead to cognitive impairment, data on the association between subclinical thyroid dysfunction and cognitive function are conflicting.
Why it matters
This meta-analysis of prospective cohort studies examined whether subclinical thyroid dysfunction is linked to dementia and cognitive decline. The available text does not report the direction or significance of any association found.
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The relationship between sensory impairment and cognitive impairment was not unique to one sensory system, suggesting that sensorineural health may be a marker of brain aging.
Why it matters
This study found that hearing, vision and smell impairment were each linked to higher risk of cognitive impairment over 10 years. However, most participants with these impairments did not develop cognitive impairment, and the authors suggest sensory health may be a marker of brain aging rather than a cause.
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65/100
8 studies examined the association of sedentary behaviour with cognitive function. 6 studies reported significant negative associations between sedentary behaviour and cognitive function. 8 different measures of sedentary behaviour and 13 different measures of cognitive function were used across all eight studies.
Why it matters
This systematic review of 8 studies found emerging evidence that sedentary behaviour is associated with impaired cognitive function in adults aged 40 and over. It does not establish that reducing sedentary time prevents dementia, but it identifies sedentary behaviour as a factor worth studying further for healthy cognitive ageing.
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Population-based estimates for the epidemiology of FTD varied widely in the included studies.
Why it matters
This review found that estimates of how common frontotemporal dementia is varied widely between studies, partly because of differences in how the studies were done. It also found that frontotemporal dementia made up a larger share of dementia cases in people under 65 than in those 65 and older.
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DLB becomes more common with increasing age and accounts for about 5% of all dementia cases in older populations.
Why it matters
This systematic review of 22 studies found that dementia with Lewy bodies becomes more common with increasing age and accounts for about 5% of all dementia cases in older populations. It describes the prevalence and incidence of dementia with Lewy bodies, not treatment, cure, or prevention.
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The MetS was associated with an increased incidence of MCI and progression to dementia.
Why it matters
In this prospective study of 1519 cognitively normal adults, metabolic syndrome, central obesity, diabetes mellitus, dyslipidemia and having 3 or more component cardiovascular risk factors were associated with increased risk of incident mild cognitive impairment, and metabolic syndrome and diabetes mellitus with progression to dementia. These findings identify risk factors for cognitive decline rather than a treatment or cure.
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65/100
This meta-analysis suggests that hearing impairment is associated with cognitive problems.
Why it matters
This meta-analysis examined whether hearing impairment is linked to poorer cognition and faster cognitive decline, noting that some studies found increased risk of incident all-cause dementia but this finding was not universal. It does not establish that treating hearing loss prevents or cures Alzheimer's disease.
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Scope it has been suggested that overweight/obesity as a risk factor for incident dementia differs between mid-life and later life.
Why it matters
Pooling 21 long-term studies of people without cognitive impairment at the start, this review found that obesity before age 65 was linked to a higher risk of later dementia (risk ratio 1.41, 95% CI 1.20–1.66), while obesity at 65 or older was linked to a lower risk (0.83, 0.74–0.94). These are observational associations for dementia overall, not Alzheimer's specifically. The authors say whether losing weight in mid-life reduces risk still needs study, and the review covers literature only up to September 2014.
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65/100
Dietary patterns and some dietary components have been linked with dementia.
Why it matters
This meta-analysis found that the Mediterranean diet and higher intake of unsaturated fatty acids, antioxidants, and B vitamins were linked to lower dementia risk, while smoking, higher aluminum intake, and low vitamin D were linked to higher risk. It does not show that any diet prevents or cures dementia, only associations from observational studies.
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MoCA and MMSE were more similar for dementia cases, but MoCA distributes MCI cases across a broader score range with less ceiling effect.
Why it matters
In this cross-sectional analysis of 219 healthy controls, 299 mild cognitive impairment and 100 Alzheimer's dementia cases, most dementia cases scored abnormally while mild cognitive impairment and healthy control score distributions overlapped on both tests, and the ceiling effect was less using MoCA than MMSE. This describes how two cognitive tests relate to each other for assessment, and does not test any treatment, cure or prevention.
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The best cluster solution found was based on orthostatic hypotension, mild cognitive impairment, rapid eye movement sleep behavior disorder (RBD), depression, anxiety, and Unified Parkinson's Disease Rating Scale Part II and Part III scores at baseline.
Why it matters
This study identified clinical subtypes of Parkinson disease based on features including orthostatic hypotension, mild cognitive impairment, REM sleep behavior disorder, depression and anxiety. It concerns Parkinson disease subtyping and reports no treatment, cure or prevention for Alzheimer's disease.
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Older adults with diabetes and dementia are at increased risk for hypoglycemia and other adverse events associated with tight glycemic control and are unlikely to experience long-term benefits.
Why it matters
Many older veterans with diabetes and dementia had tight blood sugar control and were at high risk of hypoglycemia from intensive diabetes treatment. The authors suggest these patients may be candidates for reducing or changing diabetes medications, but the study did not test whether this affects dementia itself.
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No systematic review of epidemiological evidence has examined risk factors for sleep disturbances among older adults.
Why it matters
This review of 21 studies found that female gender, depressed mood and physical illness were the most consistent risk factors for future sleep disturbances in older adults. It does not address treating, curing or preventing Alzheimer's disease.
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There are commonalities in the prevalence of problems across cancer and non-cancer patients, highlighting the need for palliative care to be provided irrespective of diagnosis.
Why it matters
This systematic review compared the prevalence of palliative care problems in people with advanced cancer and eight non-cancer conditions, including dementia. It concerns symptom burden and palliative care, not treating, curing, or preventing Alzheimer's disease.
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Aerobic training significantly increased hippocampal volume in older women with probable MCI.
Why it matters
In this trial of 86 women aged 70-80 with probable mild cognitive impairment, aerobic training significantly improved left, right and total hippocampal volumes compared with the balance and tone control group. Increased left hippocampal volume was independently associated with reduced verbal memory and learning performance.
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This Cochrane systematic review looked for solid evidence that respite care (temporary relief for caregivers) helps caregivers or people with dementia.
Why it matters
Only 4 small trials with 753 total participants met inclusion criteria, and the 3 trials comparing respite care to no respite care found no significant benefit on any caregiver outcome. The review concluded there is currently no reliable evidence that respite care helps, reflecting a shortage of well-designed studies rather than proof that it does not help.
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Broad consensus emerged on the protective role against dementia of leisure activities.
Why it matters
Reviewing 75 papers from 33 long-term cohort studies published up to December 2013, the authors found broad agreement that people with more social, physical and mental leisure activities had lower dementia risk. Results conflicted for smoking, mild-to-moderate alcohol, dietary antioxidants, the Mediterranean diet and living with others. Studies measured lifestyle very differently ("intensity, frequency and duration of exposure") and adjusted for different confounders, so the authors call for standardized measurement. These are associations only and do not show that changing a habit prevents dementia.
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Professional caregivers may initiate ACP early if strategies carefully consider timing and family and patient receptiveness or reluctance, and are family and patient-centered.
Why it matters
This systematic review identified factors associated with starting advance care planning in dementia, with family factors dominating and ethnic minority status and family distance acting as possible barriers. It concerns end-of-life planning rather than treating, curing or preventing Alzheimer's disease.
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Researchers re-ran the same detailed dementia survey in the same three parts of England twenty years apart.
Why it matters
Researchers re-ran the same detailed dementia survey in the same three parts of England twenty years apart and found notably fewer people with dementia than expected, about 670,000 in 2011 versus a projected 884,000 based on aging alone. This was strong UK evidence that a person's chance of developing dementia at a given age has genuinely fallen over the past generation, not just that population aging looks different.
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DLB currently accounts for around one in 25 dementia cases diagnosed in the community and one in 13 cases in secondary care.
Why it matters
Earlier studies put dementia with Lewy bodies anywhere from 0% to 22.8% of dementia cases; this review of population and clinic studies found it accounted for about 1 in 25 diagnosed dementias in the community (4.2%), 1 in 13 in specialist care (7.5%), and 3.8% of new dementia cases. Using the revised 2005 diagnostic criteria picked up significantly more cases than the original 1996 criteria. The authors say the true figure is likely much higher because the diagnosis is often missed.
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This longitudinal study examined whether insulin resistance among late middle-aged, cognitively healthy individuals was associated with 1) less gray matter in Alzheimer disease-sensitive brain regions and 2) worse cognitive performance.
Why it matters
In this longitudinal study of 372 cognitively healthy late middle-aged people, insulin resistance was examined for links to less gray matter in Alzheimer disease-sensitive brain regions and worse cognitive performance. The findings suggest insulin resistance may play a role in how Alzheimer's disease develops, but the study does not show that treating insulin resistance prevents or cures the 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.
- Blood-Based Biomarkers and Risk of Onset of Mild Cognitive Impairment Over the Short and Long Term
- Associations of cigarette smoking with gray and white matter in the UK Biobank
- Distinguishing Early from Late Mild Cognitive Impairment Using Magnetic Resonance Free-Water Diffusion Tensor Imaging
- People with dementia living alone: what are their needs and what kind of support are they receiving?
- CSF biomarkers in Olmsted County: Evidence of 2 subclasses and associations with demographics
- Metformin Use Associated with Reduced Risk of Dementia in Patients with Diabetes: A Systematic Review and Meta-Analysis
- Rate of memory decline in AD is related to education and occupation: cognitive reserve?
- Comorbidity in arthritis
- Regional specificity of hippocampal volume reductions in first-episode schizophrenia
- Attempted suicide in the elderly: characteristics of suicide attempters 70 years and older and a general population comparison group