Increasing incidence of dementia in the oldest old: evidence and implications.
ABSTRACT The oldest old are the fastest growing segment of the US population but accurate estimates of the incidence of dementia in this age group have been elusive. Corrada and colleagues present data on the 5-year age-specific rates of dementia incidence in persons 90 years and older from The 90+ Study. Their findings show a continued exponential increase in dementia incidence after age 90 that mirrors the increase observed in persons aged 65 to 90, with a doubling every 5.5 years. This contrasts with previous smaller studies reporting a slowing of the increase in incidence after age 90. If confirmed, the continued increase, rather than a plateau, in the incidence of dementia in the oldest old has implications for proper healthcare planning. Strategies for prevention and treatment will require more information regarding risk factors and the etiopathogenesis of dementia in the oldest old.
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ABSTRACT: Vascular cognitive impairment (VCI) [vascular cognitive disorder (VCD), vascular dementia] describes a continuum of cognitive disorders ranging from mild cognitive impairment (MCI) to dementia, in which vascular brain injury involving regions important for memory, cognition and behavior plays an important role. Clinical diagnostic criteria show moderate sensitivity (ca 50%) and variable specificity (range 64-98%). In Western clinical series, VaD is suggested in 8-10% of cognitively impaired elderly subjects. Its prevalence in autopsy series varies from 0.03 to 58%, with means of 8 to 15% (in Japan 22-35%). Major types of sporadic VaD are multi-infarct encephalopathy, small vessel and strategic infarct type dementias, subcortical arteriosclerotic leukoencephalopathy (SAE) (Binswanger), multilacunar state, mixed cortico-subcortical type, granular cortical atrophy (rare), postischemic encephalopathy, and a mixture of cerebrovascular lesions (CVLs). They result from systemic, cardiac and local large or small vessel disease (SVD); their pathogenesis is multifactorial. Hereditary forms of VaD caused by gene mutations are rare. Cognitive decline is commonly associated with widespread small ischemic vascular lesions involving subcortical brain areas (basal ganglia and hemispheral white matter). The lesions affect neuronal networks involved in cognition, memory, and behavior (thalamo-cortical, striato-subfrontal, cortico-subcortical, limbic systems). CVLs often coexist with Alzheimer-type lesions and other pathologies; 25-80% of elderly demented show mixed pathologies. The lesion pattern of "pure" VaD differs from that in mixed dementia (AD + CVLs) suggesting different pathogenesis of both phenotypes. Minor CVLs, except for severe amyloid angiopathy, appear not essential for cognitive impairment in full-blown AD, while both mild AD-type pathology and SVD may interact synergistically in promoting dementia. However, in a large percentage of non-demented elderly individuals, both AD-related and vascular brain pathologies have been reported. Despite recent suggestions for staging and grading CVLs in specific brain areas, due to the high variability of CVLs associated with cognitive impairment, no validated neuropathological criteria are currently available for VaD and mixed dementia. Further clinico-pathological studies and harmonization of neuropathological procedures are needed to validate the diagnostic criteria for VaD and mixed dementia in order to clarify the impact of CVLs and other coexistent pathologies on cognitive impairment as a basis for further successful therapeutic options.Frontiers in Aging Neuroscience 01/2013; 5:17. · 5.20 Impact Factor
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ABSTRACT: IMPORTANCE While brain volume changes are used as surrogate markers for Alzheimer disease neuropathology in clinical studies, the extent to which these changes are due to pathologic features of Alzheimer disease in the aging brain is not well established. This study aims to clarify the neuropathologic correlates of longitudinal brain atrophy. OBJECTIVE To examine the association between brain atrophy during life and neuropathology in an elderly population. DESIGN Autopsy study of a cohort of elderly individuals. SETTING Community-based population. PARTICIPANTS Seventy-one healthy elderly individuals were selected from participants of the Oregon Brain Aging Study for having an autopsy, more than 1 magnetic resonance imaging scan, and the last magnetic resonance imaging scan within 36 months of death. MAIN OUTCOMES AND MEASURES The associations between brain volume trajectories (ventricular, total brain, and hippocampal) and time interaction terms for neurofibrillary tangles, neuritic plaques, gross infarcts, microinfarcts, amyloid angiopathy, Lewy bodies, APOE ϵ4 presence, and clinical diagnosis (no cognitive impairment, mild cognitive impairment, or dementia as time-varying covariates) were examined in mixed-effects models, adjusting for duration of follow-up and age at death. RESULTS Ventricular volume trajectory was significantly associated with age, presence of infarcts, neurofibrillary tangle and neuritic plaque scores, APOE ϵ4 allele presence, and dementia diagnosis. Total brain volume trajectory was significantly associated with age and mild cognitive impairment diagnosis. Hippocampal volume trajectory was significantly associated with amyloid angiopathy. CONCLUSIONS AND RELEVANCE Ventricular volume trajectory is more sensitive than total brain and hippocampal volume trajectories as a marker of accruing Alzheimer disease and vascular pathology in elderly individuals. The association between brain volume trajectories and cognitive impairment (mild cognitive impairment and dementia) remained after controlling for the degree of neuropathology and other covariates. This suggests that there may be other factors not measured in this study that could be contributing to brain atrophy in those with cognitive impairment.JAMA neurology. 03/2013;
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ABSTRACT: Informatics tools can help support the health and independence of older adults. In this paper, we present an approach towards integrating health-monitoring data and describe several techniques for the assessment and visualisation of integrated health and well-being of older adults. We present three different visualisation techniques to provide distinct alternatives towards display of the same information, focusing on reducing the cognitive load of data interpretation. We demonstrate the feasibility of integrating health-monitoring information into a comprehensive measure of wellness, while also highlighting the challenges of designing visual displays targeted at multiple user groups. These visual displays of wellness can be incorporated into personal health records and can be an effective support for informed decision-making.International Journal of Electronic Healthcare 01/2012; 7(2):89-104.
Th e oldest old, persons living into the 10th and 11th
decades of life, are the fastest growing segment of the
population, with numbers expected to quadruple to over
8 million by 2050 . Because advancing age is a major
risk factor for dementia, this demographic shift may
signifi cantly increase the burden of dementia borne by
our society. Indeed, the dementia incidence in persons
aged 65 to 90 has been reported to double every 5 years
. However, few studies have had suffi cient numbers of
partici pants older than 90 years of age to provide accurate
estimates in the oldest old and some studies have
suggested a slowing of the incidence in the oldest old
[3,4]. Further work is thus needed to determine the
incidence of dementia in the oldest old. Th e present work
not only has important implications for public health
planning, but is also relevant for studies of etiopatho-
genesis and strate gies for prevention and treatment.
In a pivotal study addressing this question, Corrada
and colleagues present data showing that the incidence of
dementia continues to exponentially rise in the oldest old
. Th e authors studied 330 persons from Th e 90+ Study,
a longitudinal cohort study of dementia in the oldest old.
Participants were originally members of an epidemio-
logical study of a retirement community in the 1980s ;
950 of the 1,150 persons at least 90 years old in 2003 were
enrolled. Analyses for this study included only non-
demented persons at baseline, as ascertained by in-
person evaluation, who had at least one follow-up over
4 years. Th e authors found that the incident rate of dementia
increased exponentially, from 12.7% per year for 90 to
94 year olds, to 21.2% per year for 95 to 99 year olds, to
40.7% per year for persons aged 100 years and older. Th e
estimated doubling time for incidence rates was 5.5 years
and is comparable with that observed for persons aged 65
Th e results of this study contrast with other studies that
showed a slowing of dementia incidence after age 90
[7-13]. Importantly, the study has a number of strengths
that strongly support the validity of the estimate. Having
a much larger sample size, particularly for the 95 to
100 year olds and centenarians, allows for more stable
estimates of incidence rates. Additionally, 6-month inter-
vals between assessments and high follow-up rates (96%)
make it unlikely that loss to follow-up could erro neously
result in an underestimate of incidence. Th ere were some
limitations, including the selective nature of the cohort,
raising questions about selection bias and generalizability.
Th e authors note that their study population –
predominantly female, white, with high education and
socioeconomic status – is representative of individuals
aged 90+ in the US. Nonetheless, participants were
originally recruited from one retirement community and
agreed to participate in not one but two cohort studies,
making selection bias still a potential issue. Epidemiologic
studies with more racially and ethnically diverse cohorts
will be important to confi rm and extend these fi ndings.
If confi rmed, these data suggest a looming public
health crisis. How can we prevent, delay, or treat dementia
The oldest old are the fastest growing segment of the
US population but accurate estimates of the incidence
of dementia in this age group have been elusive.
Corrada and colleagues present data on the 5-year
age-specifi c rates of dementia incidence in persons
90 years and older from The 90+ Study. Their fi ndings
show a continued exponential increase in dementia
incidence after age 90 that mirrors the increase
observed in persons aged 65 to 90, with a doubling
every 5.5 years. This contrasts with previous smaller
studies reporting a slowing of the increase in incidence
after age 90. If confi rmed, the continued increase,
rather than a plateau, in the incidence of dementia in
the oldest old has implications for proper healthcare
planning. Strategies for prevention and treatment will
require more information regarding risk factors and the
etiopathogenesis of dementia in the oldest old.
© 2010 BioMed Central Ltd
Increasing incidence of dementia in the oldest old:
evidence and implications
Bryan D James1* and Julie A Schneider2
1Rush Alzheimer’s Disease Center, Room 1038, 600 South Paulina Street, Chicago,
IL 60612, USA
Full list of author information is available at the end of the article
James and Schneider Alzheimer’s Research & Therapy 2010, 2:9
© 2010 BioMed Central Ltd
in the oldest old? To better address these questions, it
will be important to determine the pathogenesis of
dementia in the oldest old. Longitudinal clinicopathologic
epidemiologic studies suggest that dementia in older
persons is most commonly the result of mixed patholo-
gies; most commonly Alzheimer’s disease and vascular
pathology [14-16]. While there are few patho logic data
on the oldest old, a recent autopsy study in this group
showed that mixed Alzheimer’s disease and vascular
pathology continues to increase with age . Mean-
while, it has been suggested that the relationship between
Alzheimer’s disease pathology and dementia is attenuated
in the oldest old . Th is hypothesis may suggest a
greater role for vascular factors or even suggest additional
unrecognized pathologies. Further study of aging, dementia,
and pathology in longi tudinal community-based cohorts
will be needed to address these important questions.
As the fi rst major study to report that dementia
incidence continues to rise exponentially in the oldest
old, the present study has implications for how we
conceive of the relationship between aging and dementia.
It has been argued that a plateau in incidence in the
oldest old indicates that dementia is not an ‘aging-related’
process – that is, an inevitable part of aging  – but
rather an ‘age-related’ process, due to potentially
preventable age-related risk factors [4,12,13]. Yet the
distinction between these two concepts may be artifi cial.
Indeed, the continued rise in incidence could result from
the continued accumulation of age-related risk factors
eventually surpassing the brain’s compensatory facilities
(that is, reserve capacity). In addition, even if some
components of the pathologic process are inevitable,
given the possible continued accumulation of Alzheimer’s
disease and mixed pathologies, it remains quite feasible
that targeted strategies could prevent, delay, or treat at
least part of the dementing process in the oldest old.
After all, public health initiatives have dramatically
pushed back the average age of death, the most inevitable
conse quence of aging.
JAS is a neuropathology consultant for AVID Radiopharmaceuticals, Inc. and
is on the Alzheimer’s Medical Advisory Board for GE Healthcare. The authors
declare no other competing interests.
1Rush Alzheimer’s Disease Center, 600 South Paulina Street, Room 1038,
Chicago, IL 60612, USA. Department of Medicine, Rush University Medical
Center, Chicago, IL, USA. 2Rush Alzheimer’s Disease Center, 600 South Paulina
Street, Suite 1022F, Chicago IL 60612, USA. Departments of Pathology
(Neuropathology) and Neurological Sciences, Rush University Medical Center,
Chicago, IL, USA.
Published: 13 May 2010
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Cite this article as: James BD, Schneider JA: Increasing incidence of
dementia in the oldest old: evidence and implications. Alzheimer’s Research
& Therapy 2010, 2:9.
James and Schneider Alzheimer’s Research & Therapy 2010, 2:9
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