Research into dementia prevention is of paramount importance if the dementia epidemic is to be halted. Observational studies have identified several potentially modifiable risk factors for dementia, including hypertension, dyslipidaemia and obesity at midlife, diabetes mellitus, smoking, physical inactivity, depression and low levels of education. Randomized clinical trials are needed that investigate whether interventions targeting these risk factors can reduce the risk of cognitive decline and dementia in elderly adults, but such trials are methodologically challenging. To date, most preventive interventions have been tested in small groups, have focused on a single lifestyle factor and have yielded negative or modest results. Given the multifactorial aetiology of dementia and late-onset Alzheimer disease, multidomain interventions that target several risk factors and mechanisms simultaneously might be necessary for an optimal preventive effect. In the past few years, three large multidomain trials (FINGER, MAPT and PreDIVA) have been completed. The FINGER trial showed that a multidomain lifestyle intervention can benefit cognition in elderly people with an elevated risk of dementia. The primary results from the other trials did not show a statistically significant benefit of preventive interventions, but additional analyses among participants at risk of dementia showed beneficial effects of intervention. Overall, results from these three trials suggest that targeting of preventive interventions to at-risk individuals is an effective strategy. This Review discusses the current knowledge of lifestyle-related risk factors and results from novel trials aiming to prevent cognitive decline and dementia. Global initiatives are presented, including the World Wide FINGERS network, which aims to harmonize studies on dementia prevention, generate high-quality scientific evidence and promote its implementation.

Lifestyle interventions to prevent cognitive impairment, dementia and Alzheimer disease.

Post-stroke dementia (PSD) or post-stroke cognitive impairment (PSCI) may affect up to one third of stroke survivors. Various definitions of PSCI and PSD have been described. We propose PSD as a label for any dementia following stroke in temporal relation. Various tools are available to screen and assess cognition, with few PSD-specific instruments. Choice will depend on purpose of assessment, with differing instruments needed for brief screening (e.g., Montreal Cognitive Assessment) or diagnostic formulation (e.g., NINDS VCI battery). A comprehensive evaluation should include assessment of pre-stroke cognition (e.g., using Informant Questionnaire for Cognitive Decline in the Elderly), mood (e.g., using Hospital Anxiety and Depression Scale), and functional consequences of cognitive impairments (e.g., using modified Rankin Scale). A large number of biomarkers for PSD, including indicators for genetic polymorphisms, biomarkers in the cerebrospinal fluid and in the serum, inflammatory mediators, and peripheral microRNA profiles have been proposed. Currently, no specific biomarkers have been proven to robustly discriminate vulnerable patients (‘at risk brains’) from those with better prognosis or to discriminate Alzheimer’s disease dementia from PSD. Further, neuroimaging is an important diagnostic tool in PSD. The role of computerized tomography is limited to demonstrating type and location of the underlying primary lesion and indicating atrophy and severe white matter changes. Magnetic resonance imaging is the key neuroimaging modality and has high sensitivity and specificity for detecting pathological changes, including small vessel disease. Advanced multi-modal imaging includes diffusion tensor imaging for fiber tracking, by which changes in networks can be detected. Quantitative imaging of cerebral blood flow and metabolism by positron emission tomography can differentiate between vascular dementia and degenerative dementia and show the interaction between vascular and metabolic changes. Additionally, inflammatory changes after ischemia in the brain can be detected, which may play a role together with amyloid deposition in the development of PSD. Prevention of PSD can be achieved by prevention of stroke. As treatment strategies to inhibit the development and mitigate the course of PSD, lowering of blood pressure, statins, neuroprotective drugs, and anti-inflammatory agents have all been studied without convincing evidence of efficacy. Lifestyle interventions, physical activity, and cognitive training have been recently tested, but large controlled trials are still missing.

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Post-stroke dementia - a comprehensive review

BACKGROUND
After the double-blind, placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial ended in February 1997, randomized patients were offered active study medication for a further period of observation.


OBJECTIVE
To refine the estimates of the long-term effects of antihypertensive therapy on the incidence of dementia.


METHODS
Eligible patients had no dementia and were at least 60 years old. Their systolic blood pressure at entry was 160 to 219 mm Hg, with diastolic blood pressure below 95 mm Hg. Antihypertensive therapy was started immediately after randomization in the active treatment group, but only after termination of the double-blind trial in the control patients. Treatment consisted of nitrendipine (10-40 mg/d), with the possible addition of enalapril maleate (5-20 mg/d), hydrochlorothiazide (12.5-25 mg/d), or both add-on drugs.


RESULTS
Median follow-up increased from 2.0 years in the double-blind trial to 3.9 years overall. The incidence of dementia doubled from 32 to 64 cases, 41 of whom had Alzheimer disease. Throughout follow-up, systolic/diastolic blood pressure was 7.0/3.2 mm Hg higher in the 1417 control patients than in the 1485 subjects randomized to active treatment. At the last examination, the blood pressure difference was still 4.2/2.9 mm Hg; 48.1%, 26.4%, and 11.4% of the control patients were taking nitrendipine, enalapril, and/or hydrochlorothiazide, whereas in the active treatment group these proportions were 70.2%, 35.4%, and 18.4%, respectively. Compared with the controls, long-term antihypertensive therapy reduced the risk of dementia by 55%, from 7.4 to 3.3 cases per 1000 patient-years (43 vs 21 cases, P<.001). After adjustment for sex, age, education, and entry blood pressure, the relative hazard rate associated with the use of nitrendipine was 0.38 (95% confidence interval, 0.23-0.64; P<.001). Treatment of 1000 patients for 5 years can prevent 20 cases of dementia (95% confidence interval, 7-33).


CONCLUSION
The extended follow-up of Syst-Eur patients reinforces the evidence that blood pressure-lowering therapy initiated with a long-acting dihydropyridine protects against dementia in older patients with systolic hypertension.

The prevention of dementia with antihypertensive treatment. New evidence from the systolic hypertension in europe (Syst-Eur) study☆

Stroke is a major cause of death in the elderly, and risk of dementia increases after stroke. Poststroke dementia （PSD） covers all types of dementia after stroke, and is an important cause of disability in the elderly. The prevalence of PSD varies from 31.4% to 21.5% in 3 months to 4 years after the stroke. Its incidence increases with time after the stroke. Stroke and dementia share a number of risk factors. Stroke can be the direct cause of dementia and may also produce dementia by precipitating the onset of degenerative disease.

Key words: 
stroke ;  dementia ;  Alzheimer＇s disease ; risk factor

Poststroke Dementia

Cerebrovascular disease typically manifests with stroke, cognitive impairment, or both. Vascular cognitive impairment refers to all forms of cognitive disorder associated with cerebrovascular disease, regardless of the specific mechanisms involved. It encompasses the full range of cognitive deficits from mild cognitive impairment to dementia. In principle, any of the multiple causes of clinical stroke can cause vascular cognitive impairment. Recent work further highlights a role of microinfarcts, microhemorrhages, strategic white matter tracts, loss of microstructural tissue integrity, and secondary neurodegeneration. Vascular brain injury results in loss of structural and functional connectivity and, hence, compromise of functional networks within the brain. Vascular cognitive impairment is common both after stroke and in stroke-free individuals presenting to dementia clinics, and vascular pathology frequently coexists with neurodegenerative pathology, resulting in mixed forms of mild cognitive impairment or dementia. Vascular dementia is now recognized as the second most common form of dementia after Alzheimer's disease, and there is increasing awareness that targeting vascular risk may help to prevent dementia, even of the Alzheimer type. Recent advances in neuroimaging, neuropathology, epidemiology, and genetics have led to a deeper understanding of how vascular disease affects cognition. These new findings provide an opportunity for the present reappraisal of vascular cognitive impairment. We further briefly address current therapeutic concepts.

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Vascular Cognitive Impairment

Background and Purpose—Cognitive impairment occurs in ≤30% of all stroke survivors. However, effective therapies aimed at preventing poststroke cognitive decline are lacking. We assessed the efficacy of a multidomain intervention on preventing cognitive decline after stroke. Methods—In this randomized, observer-blind trial patients were recruited within 3 months after an acute stroke in 5 Austrian neurological centers. Patients were assigned to a 24-month lifestyle-based multidomain intervention or standard stroke care. Primary outcomes were the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-cog) and occurrence of cognitive decline in the composite scores of at least 2 of 5 cognitive domains at 24 months. Results—A total of 101 patients were randomized into multi-intervention and 101 into standard care during June 2010 and November 2012. Of them, 76 patients in the intervention group and 83 in the control group were included in the final intention-to-treat analysis. At 24 months, 8 of ...

Multidomain Lifestyle Interventions for the Prevention of Cognitive Decline After Ischemic Stroke Randomized Trial

BackgroundCognitive impairment after stroke is a considerable burden to patients and their caregivers and occurs in one-third of stroke survivors. No strategy to prevent cognitive decline after str...

Prevention of Poststroke Cognitive Decline: ASPIS – a Multicenter, Randomized, Observer-Blind, Parallel Group Clinical Trial to Evaluate Multiple Lifestyle Interventions – Study Design and Baseline Characteristics:

Berthold Kepplinger

Papers

Multidomain Lifestyle Interventions for the Prevention of Cognitive Decline After Ischemic Stroke Randomized Trial

Prevention of Poststroke Cognitive Decline: ASPIS – a Multicenter, Randomized, Observer-Blind, Parallel Group Clinical Trial to Evaluate Multiple Lifestyle Interventions – Study Design and Baseline Characteristics: