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 long-running Massachusetts study tracked dementia rates over more than 30 years and found that a given person's chance of developing dementia at a given age has been steadily falling since the late 1970s. The decline was seen mainly in people with at least a high school education.
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68/100
Major postoperative complications and delirium are separately associated with adverse events and demonstrate a combined effect.
Why it matters
In 566 older adults (mean age 76.7) having elective surgery, delirium alone was linked to longer hospital stays (RR 1.9), discharge to an institution (RR 1.5) and 30-day readmission (RR 2.3), while major complications alone were linked only to longer stays. Delirium had the highest population-level attributable risk (5.8%) of any adverse event studied. These are observational associations about complications around surgery, not a test of any Alzheimer's treatment.
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The cumulative incidence of cognitive impairment was 8.5% at year 1, increasing to 47.4% by year 6.
Why it matters
In 141 people with Parkinson disease who started with normal thinking, 8.5% had cognitive impairment after one year and 47.4% by year six, and every new case of mild cognitive impairment had become dementia by year five. Men, people with worse movement scores and people with lower baseline cognitive scores were more likely to decline. That is an association, not a cause. This is a natural-history study of Parkinson disease: it tests no treatment, and its rates should not be applied to Alzheimer's disease.
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In the oldest-old, the presence of multiple pathologies is associated with increased likelihood and severity of dementia.
Why it matters
In 183 members of The 90+ Study who were followed during life and examined at autopsy, having more than one brain pathology was common and was found in 45% of those with dementia versus 14% of those without; more pathologies went with more severe dementia. Adding a second pathology was linked to a four-fold rise in the likelihood of dementia among people with intermediate/high Alzheimer pathology, but not among those with other pathologies, which the authors say suggests "pathologies may interrelate in different ways." These are autopsy-based associations in people aged 90 and over; the study does not test any treatment or prevention.
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Under circumstances emulating routine clinical practice, the positive predictive value of an MCI diagnosis is in line with previous clinical studies and the external validity of the concept is strengthened.
Why it matters
This large database study found an annual progression rate from mild cognitive impairment to Alzheimer's disease dementia of 13.7% per person-year, higher for amnestic than nonamnestic mild cognitive impairment. It describes progression in routine practice and does not test treatment or prevention.
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In older women, habitual sleep duration predicts the future risk for cognitive impairments including dementia, independent of vascular risk factors.
Why it matters
In 7,444 women aged 65–80 followed in the Women's Health Initiative Memory Study, those who reported sleeping 6 hours or less a night had about a 36% higher adjusted risk of mild cognitive impairment or dementia than 7-hour sleepers, and those sleeping 8 hours or more had about a 35% higher risk if they did not have cardiovascular disease. Sleep was self-reported and the study shows an association only: it does not show that changing how long you sleep lowers dementia risk.
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In the seven longitudinal studies assessing the effect of antihypertensive medication on cognitive impairment or cognitive decline, antihypertensive drugs appeared to be beneficial.
Why it matters
Across the reviewed longitudinal studies, antihypertensive drugs generally appeared beneficial for cognitive decline and dementia incidence, though three of eleven studies on dementia incidence found no significant protective effect. The review does not establish that these drugs prevent dementia.
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In a study of nearly 190,000 older US military veterans, those who had experienced a traumatic brain injury were about 57% more likely to develop dementia over the next 9 years than veterans without a brain injury history.
Why it matters
Veterans with a traumatic brain injury history were about 57% more likely to develop dementia over 9 years than those without. This identifies brain injury as a risk factor, but it is an observational finding and does not show that preventing injuries would prevent dementia.
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Pre- and postoperative orthogeriatric care given in an acute geriatric ward was not effective in reducing delirium or long-term cognitive impairment in patients with hip fracture.
Why it matters
In this randomized controlled trial of 329 hip fracture patients, a pre- and postoperative orthogeriatric service produced no significant difference in cognitive function four months after surgery compared with standard orthopedic care. There was also no significant difference in delirium rates, so the intervention did not prevent delirium or longer-term cognitive decline in this trial.
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Over follow-up, 449 (18.3%) participants developed dementia.
Why it matters
Among 2,457 dementia-free older adults in Pittsburgh and Memphis followed for 12 years, 20.7% of black participants and 16.6% of white participants developed dementia. The researchers then tested whether income, financial adequacy, education, literacy and health factors could account for that difference, and concluded that differences in these risk factors, "especially socioeconomic status, may contribute" to the gap. This is an observational study, so it shows an association rather than proof that reducing socioeconomic disparities would lower dementia rates.
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Where feasible, we combined data to obtain an overall estimate of effect.
Why it matters
This review of 38 studies in low- and middle-income countries found that non-specialist health workers probably slightly improve behavioral symptoms in people with dementia and probably improve the mental well-being, burden and distress of their carers. These findings are about care delivered by non-specialists, not about curing or preventing Alzheimer's disease.
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Purpose of the study During aging, musical activities can help maintain physical and mental health and cognitive abilities, but their rehabilitative use has not been systematically explored in persons with dementia (PWDs).
Why it matters
In this randomized study of 89 people with dementia and their caregivers, ten weeks of singing or music listening coaching improved mood, orientation and remote episodic memory, and to a lesser extent attention, executive function and general cognition, compared with usual care. These are benefits in daily functioning and wellbeing rather than a treatment, cure or prevention of Alzheimer's disease.
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Overall estimates of treatment effect were calculated using a fixed-effect model, and statistical heterogeneity was measured using a standard Chi(2) statistic.
Why it matters
This review found that cognitive training was not associated with any positive or negative effects on the outcomes reported, and the overall quality of the trials was low to moderate. A single trial of cognitive rehabilitation showed promising results, but the authors describe these as preliminary.
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68/100
Neuropsychiatric symptoms in MCI are associated with significantly an increased risk of incident dementia and AD.
Why it matters
Among 1821 people with mild cognitive impairment, having symptoms of depression or other neuropsychiatric symptoms at baseline was associated with a higher risk of progressing to dementia or Alzheimer's disease. This identifies these symptoms as risk markers, but it does not show that treating them prevents or cures the disease.
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Study objectives To examine the association of sleep complaints reported at baseline (insomnia complaints and excessive daytime sleepiness (EDS)) and medication, with cognitive decline in community-dwelling elderly.
Why it matters
In 4,894 older people without dementia, excessive daytime sleepiness reported at the start predicted later cognitive decline on the Mini-Mental State Examination. This shows an association only and does not show that treating sleepiness prevents or cures Alzheimer's disease.
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Recommendations for practice include development of standardized guidelines that address caregiver assessment, education, and resources; identification of "caregiver champions" in practice settings; provision of referrals to established support organizations for caregivers (eg, Cancer Support Community, Cancer Care); and collaboration among caregiving, professional, and cancer-related organizations to advocate policy and practice changes for family caregivers.
Why it matters
This review reports that caregiver stress can lead to psychological and sleep disturbances and changes in caregivers' physical health, immune function and financial well-being, and that research-tested interventions can reduce many of these negative effects and improve caregivers' coping, knowledge and quality of life. It notes these interventions also reduce patients' symptoms and mortality in non-dementia patients, but it is about supporting caregivers rather than treating or preventing Alzheimer's disease.
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Our results suggest that diet may be a powerful environmental factor that modulates Alzheimer disease risk through its effects on central nervous system concentrations of Aβ42, lipoproteins, oxidative stress, and insulin.
Why it matters
In people with amnestic mild cognitive impairment, a 4-week low-saturated-fat/low-glycemic-index diet raised levels of a cerebrospinal fluid Alzheimer marker in the direction opposite to the pattern usually seen in the disease. The authors suggest diet may influence Alzheimer risk through effects on these central nervous system markers, but this was a short 4-week study of 49 people and does not show whether diet changes dementia outcomes.
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The rising prevalence of dementia will have an impact on acute hospitals.
Why it matters
Many older people admitted to hospital for emergency care had dementia, often undiagnosed before admission, and those with severe cognitive impairment had higher death rates during admission. This describes hospital outcomes and does not test any treatment or cure for dementia.
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The dual primary efficacy endpoint was not reached.
Why it matters
In this 48-week placebo-controlled trial in people with mild cognitive impairment, donepezil did not meet its main test of success: it gave "small but significant" gains on a cognitive test but no change on the primary measure of everyday/global function. The authors suggest standard measures may be "insensitive to change in MCI", and patients rated themselves as better on donepezil — a subjective signal, not proof of benefit. The trial does not show that donepezil slows or prevents progression to Alzheimer's.
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68/100
The prevalence of DSM-IV dementia varied widely, from 0.3% (95% CI 0.1-0.5) in rural India to 6.3% (5.0-7.7) in Cuba.
Why it matters
In surveys of 14,960 people aged 65 and older at 11 sites in seven low- and middle-income countries, dementia measured by the DSM-IV definition ranged from 0.3% in rural India to 6.3% in Cuba, while the "culturally and educationally sensitive" 10/66 algorithm gave higher, more consistent figures (5.6% to 11.7%). Of 1,345 people with 10/66 dementia, 847 were missed by DSM-IV but had high levels of disability, and the authors conclude DSM-IV "might underestimate dementia prevalence, especially in regions with low awareness". This measures how common dementia is, not what causes it or how to treat it.
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Treatment of dementia with cholinesterase inhibitors and memantine can result in statistically significant but clinically marginal improvement in measures of cognition and global assessment of dementia.
Why it matters
This evidence review found that cholinesterase inhibitors and memantine produced statistically significant but clinically marginal improvement in cognition and global assessment for patients with dementia. It does not suggest these drugs cure or prevent Alzheimer's disease.
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These analyses give a population based estimated median survival for incident dementia of 4.5 years.
Why it matters
Among 438 people aged 65+ in England and Wales who developed dementia during a 13,004-person population study, median survival after onset was 4.5 years overall (4.1 for men, 4.6 for women), but it varied widely with age at onset: 10.7 years for onset at 65–69 versus 3.8 years at 90 or older. Sex, age at onset and disability predicted mortality, and the authors say these estimates "can be used for prognosis and planning for patients, carers, service providers, and policy makers." These are group averages from a 1991–2005 UK cohort. They show associations, not causes, and the study tested no treatment.
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Pulse pressure and pulse wave velocity, markers of arterial stiffness, have been associated with stroke, dementia, and lowered levels of cognitive function.
Why it matters
This study found that higher pulse pressure and pulse wave velocity, markers of arterial stiffness, were associated with prospective decline in several cognitive domains in people without dementia. It suggests that treating risk factors for arterial stiffness may help preserve cognition, but it does not prove that this prevents Alzheimer's disease.
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Use of NSAIDs was associated with a lower risk of dementia (adjusted hazard ratio or aHR 0.76, 95% CI or CI 0.60-0.96) and, in particular, AD (aHR 0.63, CI 0.45-0.88), but not VaD (aHR 0.92, CI 0.65-1.28).
Why it matters
In the Cardiovascular Health Study, NSAID use was associated with lower risk of dementia and Alzheimer's disease, particularly in participants carrying an APOE epsilon4 allele, while acetaminophen showed no such trend. This is an observational association and does not establish that NSAIDs prevent Alzheimer's disease.
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We have previously performed detailed clinical and neuropsychological assessments in a community-based cohort of patients with newly diagnosed parkinsonism, and through analysis of a subcohort with idiopathic Parkinson's disease (PD), we have demonstrated that cognitive dysfunction occurs even at the time of PD diagnosis and is heterogeneous.
Why it matters
In this community-based Parkinson's disease cohort, 10% developed dementia within about 3.5 years of diagnosis and a further 57% showed cognitive impairment. This concerns cognitive decline in Parkinson's disease, not Alzheimer's disease treatment, cure or prevention.
From across this topic
9 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 9. The same 9 appear here every time.
- The treatment of hyperhomocysteinemia
- Is the risk of Alzheimer's disease and dementia declining?
- Effects of Exercise on Vascular Function, Structure, and Health in Humans
- Ethnicity, stress, and cortisol function in Hispanic and non-Hispanic white women: A preliminary study of family dementia caregivers and noncaregivers
- Cardiometabolic multimorbidity, genetic risk, and dementia: a prospective cohort study
- Increased risk for dementia in neurofibromatosis type 1
- Motor cortex and gait in mild cognitive impairment: a magnetic resonance spectroscopy and volumetric imaging study
- Montreal Cognitive Assessment 5-minute protocol is a brief, valid, reliable, and feasible cognitive screen for telephone administration
- Impact of Kolb’s experiential learning theory-based nursing on caregiver burden and psychological state of caregivers of dementia patients