Outcomes of mild cognitive impairment by definition: a population study

BACKGROUND

Mild cognitive impairment (MCI) has been defined in several ways.

OBJECTIVE

To determine the 1-year outcomes of MCI by different definitions at the population level.

DESIGN

Inception cohort with 1-year follow-up. Participants were classified as having MCI using the following definitions operationalized for this study: amnestic MCI by Mayo criteria, expanded MCI by International Working Group criteria, Clinical Dementia Rating (CDR) = 0.5, and a purely cognitive classification into amnestic and nonamnestic MCI.

SETTING

General community.

PARTICIPANTS

Stratified random population-based sample of 1982 individuals 65 years and older.

MAIN OUTCOME MEASURES

For each MCI definition, there were 3 possible outcomes: worsening (progression to dementia [CDR ≥ 1] or severe cognitive impairment), improvement (reversion to CDR = 0 or normal cognition), and stability (unchanged CDR or cognitive status).

RESULTS

Regardless of MCI definition, over 1 year, a small proportion of participants progressed to CDR > 1 (range, 0%-3%) or severe cognitive impairment (0%-20%) at rates higher than their cognitively normal peers. Somewhat larger proportions of participants improved or reverted to normal (6%-53%). Most participants remained stable (29%-92%). Where definitions focused on memory impairment and on multiple cognitive domains, higher proportions progressed and lower proportions reverted on the CDR.

CONCLUSIONS

As ascertained by several operational definitions, MCI is a heterogeneous entity at the population level but progresses to dementia at rates higher than in normal elderly individuals. Proportions of participants progressing to dementia are lower and proportions reverting to normal are higher than in clinical populations. Memory impairments and impairments in multiple domains lead to greater progression and lesser improvement. Research criteria may benefit from validation at the community level before incorporation into clinical practice.

Terminal decline and practice effects in older adults without dementia: the MoVIES project

OBJECTIVE

To track cognitive change over time in dementia-free older adults and to examine terminal cognitive decline.

METHODS

A total of 1,230 subjects who remained free from dementia over 14 years of follow-up were included in a population-based epidemiologic cohort study. First, we compared survivors and decedents on their trajectories of 5 cognitive functions (learning, memory, language, psychomotor speed, executive functions), dissociating practice effects which can mask clinically significant decline from age-associated cognitive decline. We used longitudinal mixed-effects models with penalized linear spline. Second, limiting the sample to 613 subjects who died during follow-up, we identified the inflection points at which the rate of cognitive decline accelerated, in relation to time of death, controlling for practice effects. We used mixed-effects model with a change point.

RESULTS

Age-associated cognitive trajectories were similar between decedents and survivors without dementia. However, substantial differences were observed between the trajectories of practice effects of survivors and decedents, resembling those usually observed between normal and mildly cognitively impaired elderly. Executive and language functions showed the earliest terminal declines, more than 9 years prior to death, independent of practice effects.

CONCLUSIONS

Terminal cognitive decline in older adults without dementia may reflect presymptomatic disease which does not cross the clinical threshold during life. Alternatively, cognitive decline attributed to normal aging may itself represent underlying neurodegenerative or vascular pathology. Although we cannot conclude definitively from this study, the separation of practice effects from age-associated decline could help identify preclinical dementia.

Replication study of genome-wide associated SNPs with late-onset Alzheimer's disease

Late-onset Alzheimer's disease (LOAD) is a multifactorial disease with the potential involvement of multiple genes. Four recent genome-wide association studies (GWAS) have found variants showing significant association with LOAD on chromosomes 6, 10, 11, 12, 14, 18, 19, and on the X chromosome. We examined a total of 12 significant SNPs from these studies to determine if the results could be replicated in an independent large case-control sample. We genotyped these 12 SNPs as well the E2/E3/E4 APOE polymorphisms in up to 993 Caucasian Americans with LOAD and up to 976 age-matched healthy Caucasian Americans. We found no statistically significant associations between the 12 SNPs and the risk of AD. Stratification by APOE*4 carrier status also failed to reveal statistically significant associations. Additional analyses were performed to examine potential associations between the 12 SNPs and age-at-onset (AAO) and disease duration among AD cases. Significant associations were observed between AAO and ZNF224/rs3746319 (P = 0.002) and KCNMA1/rs16934131 (P = 0.0066). KCNMA1/rs16934131 also demonstrated statistically significant association with disease duration (P = 0.0002). Although we have been unable to replicate the reported GWAS association with AD risk in our sample, we have identified two new associations with AAO and disease duration that need to be confirmed in additional studies.

Assessment of cognition in early dementia

Better tools for assessing cognitive impairment in the early stages of Alzheimer's disease (AD) are required to enable diagnosis of the disease before substantial neurodegeneration has taken place and to allow detection of subtle changes in the early stages of progression of the disease. The National Institute on Aging and the Alzheimer's Association convened a meeting to discuss state of the art methods for cognitive assessment, including computerized batteries, as well as new approaches in the pipeline. Speakers described research using novel tests of object recognition, spatial navigation, attentional control, semantic memory, semantic interference, prospective memory, false memory and executive function as among the tools that could provide earlier identification of individuals with AD. In addition to early detection, there is a need for assessments that reflect real-world situations in order to better assess functional disability. It is especially important to develop assessment tools that are useful in ethnically, culturally and linguistically diverse populations as well as in individuals with neurodegenerative disease other than AD.

Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer's disease

The Alzheimer Disease Genetics Consortium (ADGC) performed a genome-wide association study of late-onset Alzheimer disease using a three-stage design consisting of a discovery stage (stage 1) and two replication stages (stages 2 and 3). Both joint analysis and meta-analysis approaches were used. We obtained genome-wide significant results at MS4A4A (rs4938933; stages 1 and 2, meta-analysis P (P(M)) = 1.7 × 10(-9), joint analysis P (P(J)) = 1.7 × 10(-9); stages 1, 2 and 3, P(M) = 8.2 × 10(-12)), CD2AP (rs9349407; stages 1, 2 and 3, P(M) = 8.6 × 10(-9)), EPHA1 (rs11767557; stages 1, 2 and 3, P(M) = 6.0 × 10(-10)) and CD33 (rs3865444; stages 1, 2 and 3, P(M) = 1.6 × 10(-9)). We also replicated previous associations at CR1 (rs6701713; P(M) = 4.6 × 10(-10), P(J) = 5.2 × 10(-11)), CLU (rs1532278; P(M) = 8.3 × 10(-8), P(J) = 1.9 × 10(-8)), BIN1 (rs7561528; P(M) = 4.0 × 10(-14), P(J) = 5.2 × 10(-14)) and PICALM (rs561655; P(M) = 7.0 × 10(-11), P(J) = 1.0 × 10(-10)), but not at EXOC3L2, to late-onset Alzheimer's disease susceptibility.

Passive case-finding for Alzheimer's disease and dementia in two U.S. communities

Passive surveillance for disease is a public health approach that relies on documentation available within existing health records for the region or community being studied. Its two primary advantages over active case-finding are the lower cost of research and the lower burden on the population under study. The effectiveness of passive case-finding depends on the comprehensiveness of the healthcare coverage in a given community and the adequacy of the available medical records. The Rochester Epidemiology Project has permitted dementia case detection for Olmsted County, Minnesota, using a medical records-linkage system. These data were compared with case ascertainment using direct assessment of individuals in an epidemiological study of the same community. At the Group Health Research Institute, investigators compared dementia and Alzheimer's disease cases detected using an electronic medical record database search with those identified by a parallel active case-finding study. In this article, the advantages and disadvantages of passive case-finding were discussed, and the following conclusion was drawn: the purpose of the study being conducted should determine the case-finding approach that is to be used.

Engagement in reading and hobbies and risk of incident dementia: the MoVIES project

OBJECTIVE

To examine whether there is an association between engagement in reading and hobbies and dementia risk in late life.

METHODS

A total of 942 members of a population-based, prospective cohort study were followed biennially to identify incident dementia cases. Cox proportional hazards models were used to estimate the risk of dementia in relation to baseline total number of activities and time commitment to reading and hobbies.

RESULTS

A lower risk for dementia was found for a greater number of activities and for a high (about 1 hour each day) compared with low (less than 30 minutes each day) weekly time commitment to hobbies, independent of covariates. Only the protective effect of hobbies remained after methods were used to minimize bias due to potential preclinical dementia.

CONCLUSION

Engaging in hobbies for 1 or more hours every day might be protective against dementia in late life.

Cognitive test performance predicts change in functional status at the population level: the MYHAT Project

In the community at large, many older adults with minimal cognitive and functional impairment remain stable or improve over time, unlike patients in clinical research settings, who typically progress to dementia. Within a prospective population-based study, we identified neuropsychological tests predicting improvement or worsening over 1 year in cognitively driven everyday functioning as measured by Clinical Dementia Rating (CDR). Participants were 1682 adults aged 65+ and dementia-free at baseline. CDR change was modeled as a function of baseline test scores, adjusting for demographics. Among those with baseline CDR = 0.5, 29.8% improved to CDR = 0; they had significantly better baseline scores on most tests. In a stepwise multiple logistic regression model, tests which remained independently associated with subsequent CDR improvement were Category Fluency, a modified Token Test, and the sum of learning trials on Object Memory Evaluation. In contrast, only 7.1% with baseline CDR = 0 worsened to CDR = 0.5. They had significantly lower baseline scores on most tests. In multiple regression analyses, only the Mini-Mental State Examination, delayed memory for visual reproduction, and recall susceptible to proactive interference, were independently associated with CDR worsening. At the population level, changes in both directions are observable in functional status, with different neuropsychological measures predicting the direction of change.

Prevalence of mild cognitive impairment by multiple classifications: The Monongahela-Youghiogheny Healthy Aging Team (MYHAT) project

OBJECTIVES

To estimate and compare the frequency and prevalence of mild cognitive impairment (MCI) and related entities using different classification approaches at the population level.

DESIGN

Cross-sectional epidemiologic study of population-based cohort recruited by age-stratified random sampling from electoral rolls.

SETTING

Small-town communities in western Pennsylvania.

PARTICIPANTS

Of 2,036 individuals aged 65 years and older, 1,982 participants with normal or mildly impaired cognition (age-education-corrected Mini-Mental State scores ≥ 21).

MEASUREMENTS

Demographics, neuropsychological assessment expressed as cognitive domains, functional ability, and subjective reports of cognitive difficulties; based on these measurements, operational criteria for the Clinical Dementia Rating (CDR) scale, the 1999 criteria for amnestic MCI, the 2004 Expanded criteria for MCI, and new, purely cognitive criteria for MCI.

RESULTS

A CDR rating of 0.5 (uncertain/very mild dementia) was obtained by 27.6% of participants, whereas 1.2% had CDR ≥ 1 (mild or moderate dementia). Among those with CDR <1, 2.27% had amnestic MCI and 17.66% had expanded MCI, whereas 35.17% had MCI by purely cognitive classification. Isolated executive function impairment was the least common, whereas impairment in multiple domains including executive function was the most common. Prevalence estimates weighted against the U.S. Census are also provided.

CONCLUSIONS

The manner in which criteria for MCI are operationalized determines the proportion of individuals who are thus classified and the degree of overlap with other criteria. Prospective follow-up is needed to determine progression from MCI to dementia and thus empirically develop improved MCI criteria with good predictive value.

Association of CLU and PICALM variants with Alzheimer's disease

Two recent large genome-wide association studies have reported significant associations in the CLU (APOJ), CR1, and PICALM genes with the risk of Alzheimer's disease (AD). In order to replicate these findings, we examined 7 single nucleotide polymorphisms (SNPs) most significantly implicated by these studies in a large case-control sample comprising 2707 individuals. Principle components analysis revealed no population substructure in our sample. While no association was observed with CR1 SNPs (p = 0.30-0.457), a trend of association was seen with the PICALM (p = 0.071-0.086) and CLU (p = 0.148-0.258) SNPs. A meta-analysis of 3 studies revealed significant associations with all 3 genes. Our data from an independent and large case-control sample suggest that these gene regions should be followed up by comprehensive resequencing to find functional variants.

A histopathological study of liver and biliary remnants with clinical outcome in cases of extrahepatic biliary atresia

CONTEXT

The indicators of poor prognosis in cases of extrahepatic biliary atresia (EHBA) continue to remain controversial.

AIMS

To correlate the histopathological findings of wedge biopsy from liver and tissue obtained from the shaving at the porta hepatis, during hepatic portoenterostomy, with the clinical outcome.

MATERIALS AND METHODS

All cases of EHBA surgically treated in our hospital from 1995 to 2006 have been reviewed. Wedge biopsies of the liver and biopsies from the porta hepatis were analyzed with hemotoxylin-eosin stains and immunohistochemistry. The parameters correlated with clinical outcomes were--presence of large bile ducts ( > 150microm diameter) in the portal tissue plaque, degree of fibrosis (semi-quantitative; graded as mild, moderate and severe), presence of ductal plate malformation (DPM) and age at operation.

RESULTS

The proportions of patients with small or large ductal diameter who remained clinically controlled (serum bilirubin < 1.5mg/dl with no evidence of end stage liver failure) were 39% and 66.6% respectively (P=0.44). There was a highly significant correlation between the extent of fibrosis and clinical outcome. Mild, moderate and severe fibrosis resulted in clinical control rates of 78.5%, 34.4% and 24% respectively (P=0.001). Ductal plate malformation was seen in 15% of our cases and was uniformly associated with poor outcome. A non-significant trend towards poorer outcome was seen with increasing age at surgery.

CONCLUSIONS

Histopathological correl ations with clinical outcome in EHBA have been rarely reported from the Indian subcontinent. A greater degree of fibrosis at the time of hepatic portoenterostomy and presence of ductal plate malformation is associated with a significantly poorer clinical outcome.

Age and education effects and norms on a cognitive test battery from a population-based cohort: the Monongahela-Youghiogheny Healthy Aging Team

OBJECTIVES

Performance on cognitive tests can be affected by age, education, and also selection bias. We examined the distribution of scores on several cognitive screening tests by age and educational levels in a population-based cohort.

METHOD

An age-stratified random sample of individuals aged 65+ years was drawn from the electoral rolls of an urban US community. Those obtaining age and education-corrected scores > or = 21/30 on the Mini-Mental State Examination (MMSE) were designated as cognitively normal or only mildly impaired, and underwent a full assessment including a battery of neuropsychological tests. Participants were also rated on the Clinical Dementia Rating (CDR) scale. The distribution of neuropsychological test scores within demographic strata, among those receiving a CDR of 0 (no dementia), are reported here as cognitive test norms. After combining individual test scores into cognitive domain composite scores, multiple linear regression models were used to examine associations of cognitive test performance with age and education.

RESULTS

In this cognitively normal sample of older adults, younger age and higher education were associated with better performance in all cognitive domains. Age and education together explained 22% of the variation of memory, and less of executive function, language, attention, and visuospatial function.

CONCLUSION

Older age and lesser education are differentially associated with worse neuropsychological test performance in cognitively normal older adult representatives of the community at large. The distribution of scores in these participants can serve as population-based norms for these tests, and can be especially useful to clinicians and researchers assessing older adults outside specialty clinic settings.

How much do depressive symptoms affect cognition at the population level? The Monongahela-Youghiogheny Healthy Aging Team (MYHAT) study

OBJECTIVE

To examine the impact of subjective depressive symptoms on objective performance on tests of several cognitive domains, in a community-based sample of older adults.

METHODS

An age-stratified sample of 2036 individuals aged 65+ years was drawn from the electoral rolls of a U.S. community, excluding individuals with moderate to severe cognitive impairment. A cognitive test battery and a modified Center for Epidemiologic Studies-Depression scale (mCES-D) were completed by 1982 participants. Cognitive test scores were compared across levels of depressive symptoms, and composite scores created to represent cognitive domains of attention, language, memory, visuospatial, and executive function. Multivariable regression models tested the association of depressive symptoms with cognitive domain composite scores, adjusting for age, sex, race, and education.

RESULTS

Most participants reported no depressive symptoms. Small differences in cognitive scores were observed on all tests among those with 0, 1-2, and > or = 3 symptoms. Adjusting for demographic variables, depressive symptoms remained associated with lower performance on all cognitive composites except attention, most strongly with executive function. Depressive symptoms explained <2% of the variance in test scores, less than that explained by age or education.

CONCLUSION

In this population-based sample of older adults, restricted to those with normal or only mildly impaired cognition, a relatively small proportion reported any depressive symptoms. The number of depressive symptoms had strong statistically significant associations with performance in most cognitive domains. However, depressive symptoms explained little of the variance in cognitive performance, with relatively small differences in scores among those with and without symptoms.

Minimizing attrition bias: a longitudinal study of depressive symptoms in an elderly cohort

BACKGROUND

Attrition from mortality is common in longitudinal studies of the elderly. Ignoring the resulting non-response or missing data can bias study results.

METHODS

1260 elderly participants underwent biennial follow-up assessments over 10 years. Many missed one or more assessments over this period. We compared three statistical models to evaluate the impact of missing data on an analysis of depressive symptoms over time. The first analytic model (generalized mixed model) treated non-response as data missing at random. The other two models used shared parameter methods; each had different specifications for dropout but both jointly modeled both outcome and dropout through a common random effect.

RESULTS

The presence of depressive symptoms was associated with being female, having less education, functional impairment, using more prescription drugs, and taking antidepressant drugs. In all three models, the same variables were significantly associated with depression and in the same direction. However, the strength of the associations differed widely between the generalized mixed model and the shared parameter models. Although the two shared parameter models had different assumptions about the dropout process, they yielded similar estimates for the outcome. One model fitted the data better, and the other was computationally faster.

CONCLUSIONS

Dropout does not occur randomly in longitudinal studies of the elderly. Thus, simply ignoring it can yield biased results. Shared parameter models are a powerful, flexible, and easily implemented tool for analyzing longitudinal data while minimizing bias due to nonrandom attrition.

Modifiable Midlife Risk Factors for Late-Life Cognitive Impairment and Dementia

The baby boom generation is approaching the age of greatest risk for cognitive impairment and dementia. There is growing interest in strategies to modify the environment in midlife to increase the probability of maintaining cognitive health in late life. Several potentially modifiable risk factors have been studied in relation to cognitive impairment and dementia in late life, but methodological limitations of observational research have resulted in some inconsistencies across studies. The most promising strategies are maintaining cardiovascular health, engagement in mental, physical, and social activities, using alcohol in moderation, abstaining from tobacco use, and following a heart-healthy diet. Other factors that may influence cognitive health are occupational attainment, depression, personality, exposure to general anesthesia, head injury, postmenopausal hormone therapy, non-steroidal anti-inflammatory medications, and nutritional supplements such as antioxidants. Some long-term observational studies initiated in midlife or earlier, and some randomized controlled trials, have examined the effects of specific cognitive health promotion behaviors in midlife on the risk of cognitive impairment in late life. Overall, these studies provide limited support for risk reduction at this time. Recommendations and challenges for developing effective strategies to reduce the burden of cognitive impairment and dementia in the future are discussed.

Sustained benzodiazepine use in a community sample of older adults

OBJECTIVES

To identify factors associated with sustained benzodiazepine use in older adults.

DESIGN

Twelve-year cohort study.

SETTING

Community-based epidemiological survey.

PARTICIPANTS

One thousand three hundred forty-two individuals aged 65 and older.

MEASUREMENTS

Demographics, medication use, depressive symptoms, sleep complaints, alcohol use, and smoking assessed at 2-year intervals; descriptive analysis to characterize benzodiazepine users and identify factors associated with sustained benzodiazepine use (use at two consecutive waves); and longitudinal lag-time analysis to determine characteristics that predicted sustained use.

RESULTS

Initially, 5.5% of men and 9.8% of women were using benzodiazepines. Users were significantly more likely than nonusers to be female and less educated, report more depressive and anxiety symptoms, use more prescription medications, have lower self-rated health, have difficulty maintaining sleep, and be less likely to consume alcohol. Approximately 50%, 44%, and 25% of these users aged 65 to 74, 75 to 84, and 85 and older, respectively, were sustained users at follow-up. Being female, using two or more nonbenzodiazepine prescription medications, and smoking were independently associated with subsequent sustained benzodiazepine use.

CONCLUSION

At the population level, women, smokers, and users of at least two prescription drugs have higher probabilities of sustaining benzodiazepine use once started. This information can facilitate risk assessment and counseling of older adults before prescribing benzodiazepines.

Depression, cognitive impairment and dementia: Why should clinicians care about the web of causation?

Depression, cognitive impairment and dementia are all common in older adults. The relationship between them is bi-directional and complex. The literature on the subject is growing and fascinating but also riddled with apparent inconsistencies. This brief review attempts to clarify and integrate information from clinical, laboratory, and community studies and to draw some inferences of potential relevance to clinicians.

Healthy cognitive aging and leisure activities among the oldest old in Japan: Takashima study

BACKGROUND

Little is known regarding the normative levels of leisure activities among the oldest old and the factors that explain the age-associated decline in these activities.

METHODS

The sample included 303 cognitively intact community-dwelling elderly persons with no disability in Activities of Daily Living (ADL) and minimal dependency in Instrumental ADL (IADL) in Shiga prefecture, Japan. We examined (i) the nature and frequency of leisure activities, comparing the oldest old versus younger age groups; (ii) factors that explain the age-associated differences in frequencies of engagement in these activities; and (iii) domain-specific cognitive functions associated with these activities, using three summary index scores: physical and nonphysical hobby indexes and social activity index.

RESULTS

The oldest old (85 years old or older) showed significantly lower frequency scores in all activity indexes, compared with the youngest old (age 65-74 years). Gait speed or overall mobility consistently explained the age-associated reduction in levels of activities among the oldest old, whereas vision or hearing impairment and depressive symptoms explained only the decline in social activity. Frequency of engagement in nonphysical hobbies was significantly associated with all cognitive domains examined.

CONCLUSIONS

Knowing the factors that explain age-associated decline in leisure activities can help in planning strategies for maintaining activity levels among elderly persons.

Cognitive decline and mortality in a community-based cohort: the Monongahela Valley Independent Elders Survey

OBJECTIVES

To compare, in a longitudinal cohort study, declines in specific cognitive domains on their ability to predict time to death, in the presence and absence of dementia, and to explore an explanatory role for vascular disease.

DESIGN

Prospective population-based epidemiological study.

SETTING

The mid-Monongahela valley of southwestern Pennsylvania from 1987 to 2002.

PARTICIPANTS

Nine hundred eighty-nine community-dwelling adults aged 65 and older enrolled in the Monongahela Valley Independent Elders Survey.

MEASUREMENTS

Biennial assessments of a range of cognitive domains for up to 12 years. Mortality was modeled as a function of decline in each domain, adjusting for vascular diseases and stratified according to age (< or =75 (younger-old) and >75 (older-old)) using Cox proportional hazards modeling.

RESULTS

Average annual declines in almost all cognitive domains were significant predictors of mortality in the cohort as a whole. However, after adjustment for dementia, only general cognition, processing speed, the language composite, and the executive function composite remained significant. Adjustment for vascular diseases did not alter the results. In the younger-old group, decline in memory (hazard ratio (HR)=21.4) and executive function (HR=25.5) remained strong predictors after adjustment for dementia and vascular disease. In the older-old group, decline in processing speed was a strong predictor of mortality before (HR=7.4) and after (HR=5.3) controlling for dementia and vascular diseases.

CONCLUSION

Decline in most cognitive domains predicted mortality across the cohort, but declines in memory and learning were not independent of dementia. Different domains predicted mortality in the younger and older subgroups.

Simple balance and mobility tests can assess falls risk when cognition is impaired

To examine the ability of the Romberg test and the original untimed version of the Get-Up-and-Go test (GUG) to elders at risk for falls. At baseline and two annual follow-up visits, nurses administered the Romberg and GUG tests to 358 primary care patients aged 65+ years. Logistic regression models examined cross-sectional and longitudinal associations between abnormal balance tests and self-reported falls over the preceding year. Models were adjusted for age, sex, education and self-rated health (and, in the longitudinal models, for baseline falls), and the Mini-Mental State Examination (MMSE) as a measure of cognitive status. In cross-sectional analyses, falls reported at baseline were significantly associated with concurrently abnormal Romberg and GUG tests, after adjustment for covariates. In longitudinal analyses, abnormal GUG remained significantly associated with future falls, adjusting for covariates. Among those with low MMSE, GUG remained a significant predictor of future falls. Both balance tests were associated with low MMSE among those reporting no falls. Simple balance tests can help assess falls risk, particularly in cognitively impaired elderly who have elevated falls risk and might not accurately recall previous falls.

No advantage of A beta 42-lowering NSAIDs for prevention of Alzheimer dementia in six pooled cohort studies

INTRODUCTION

Observational studies show reduced incidence of Alzheimer dementia (AD) in users of nonsteroidal anti-inflammatory drugs (NSAIDs). One hypothesis holds that the subset of NSAIDs known as selective A beta(42)-lowering agents (SALAs) is responsible for this apparent reduction in AD risk.

METHODS

We pooled individual-level data from six prospective studies to obtain a sufficient sample to examine AD risk in users of SALA vs non-SALA NSAIDs.

RESULTS

Of 13,499 initially dementia-free participants (70,863 person-years), 820 developed incident AD. Users of NSAIDs (29.6%) showed reduced risk of AD (adjusted hazard ratio [aHR] 0.77, 95% CI 0.65-0.91). The point estimates were similar for SALAs (aHR 0.87, CI 0.72-1.04) and non-SALAs (aHR 0.75, CI 0.56-1.01). Because 573 NSAID users (14.5%) reported taking both a SALA and non-SALA, we examined their use alone and in combination. Resulting aHRs were 0.82 (CI 0.67-0.99) for SALA only, 0.60 (CI 0.40-0.90) for non-SALA only, and 0.87 (CI 0.57-1.33) for both NSAIDs (Wald test for differences, p = 0.32). The 40.7% of participants who used aspirin also showed reduced risk of AD, even when they used no other NSAIDs (aHR 0.78, CI 0.66-0.92). By contrast, there was no association with use of acetaminophen (aHR 0.93, CI 0.76-1.13).

CONCLUSIONS

In this pooled dataset, nonsteroidal anti-inflammatory drug (NSAID) use reduced the risk of Alzheimer dementia (AD). However, there was no apparent advantage in AD risk reduction for the subset of NSAIDs shown to selectively lower A beta(42), suggesting that all conventional NSAIDs including aspirin have a similar protective effect in humans.

Application of the Pattern-Mixture Latent Trajectory Model in an Epidemiological Study with Non-Ignorable Missingness

In longitudinal studies where the same individuals are followed over time, bias caused by unobserved data raises a serious concern, particularly when the data are missing in a non-ignorable manner. One approach to deal with non-ignorable missing data is a pattern mixture model. In this paper, we combine the pattern mixture model with latent trajectory analysis using the SAS TRAJ procedure, which offers a practical solution to many problems of the same nature. Our model assumes a stochastic process that categorizes a relative large number of missing-data patterns into several latent groups, each of which has unique outcome trajectory, which allows patterns with missing values to share information with patterns with more data points. We estimated the longitudinal trajectories of a memory test over 12 years of follow-up, using data from the prospective epidemiological study of dementia. Missing data patterns were created conditional on survival, and final marginal response was obtained by excluding those who had died at each time point. The approach presented here is appealing since it can be easily implemented using common software.

Psychogeriatric research comes of age in developing countries

Psychogeriatrics and psychogeriatric research have been particularly slow to take hold in developing countries. In part this is because the elderly constitute relatively small proportions of those countries' populations, and are thus of low priority for specialized services. A recent report in Science (Miller, 2006) addresses mental health needs in developing countries worldwide but does not include old-age mental disorders other than dementia. Similarly, an article from Brazil (Garcez-Leme et al., 2005), in another international journal, provides an overview of that country's resources and needs in geriatrics, but neglects to mention mental disorders or mental health professionals. Yet, these countries are aging faster than the industrialized world and have fewer resources with which to care for their mentally ill elderly. High-quality, locally acquired information will be essential for planning appropriate mental health services.

Cognitive assessment of older primary care patients with and without memory complaints

BACKGROUND

Dementia screening is currently recommended only for symptomatic patients.

OBJECTIVE

To evaluate memory complaints, a mental status test, and several cognitive tests as dementia screens in primary care.

DESIGN

Cross-sectional clinical epidemiologic study.

PARTICIPANTS

Three hundred thirty-nine comprehensively assessed, primary care patients aged > or = 65 years.

MEASUREMENTS

Memory complaints were abstracted from chart review. Scores on Mini-Mental State Examination (MMSE) and domain-specific cognitive testing were compared to a dementia diagnosis based on Clinical Dementia Rating score > or = 1, and areas under the receiver operating characteristic curves (AUC) were calculated. Classification and regression tree analyses were performed on memory complaints and tests with the highest AUCs.

RESULTS

Of 33 patients with dementia, only 5 had documented memory complaints. In 25 patients with documented memory complaints, no cognitive tests further improved identification of the 5 with dementia. In 28 patients with dementia but without memory complaints, an MMSE score < 20 identified 8 cases; among those with MMSE scores 20-21, a visual memory test identified a further 11 cases. Further cognitive testing could not detect 9 dementia cases without memory complaints and with MMSE scores > or = 22.

CONCLUSIONS

In older primary care patients with memory complaints, cognitive screening does not help identify those who require further examination for dementia. Most patients with dementia do not report memory complaints. In these asymptomatic individuals, general mental status testing, supplemented by a memory test when the mental status score is equivocal, will identify lower-scoring patients who need dementia assessment. However, high-scoring asymptomatic dementia cases will remain undetected.

The association between congestive heart failure and cognitive performance in a primary care population of elderly adults: the Steel Valley Seniors Survey

BACKGROUND

Evidence suggests an association between congestive heart failure (CHF) and cognitive function, particularly in heart transplant patients and patients hospitalized for CHF. We examined the association between CHF and cognitive performance in stable outpatients recruited from primary care.

METHODS

This is a cross-sectional secondary data analysis of the Steel Valley Seniors Survey, an epidemiological study of elderly primary care outpatients. Participants aged >/= 65 years were recruited in primary care clinics. The study cohort (n = 354) is a subgroup, composed of subjects with Mini-mental State Examination score < 25, and a random sample of the remaining, who underwent a baseline assessment in the home. The assessment included demographics, comorbid illnesses, depressive symptoms, functional status, a neurological examination and a neuropsychological battery. CHF is defined by self-report and/or chart review, and stable CHF as not being hospitalized in the year prior to the assessment. The associations between CHF and specific cognitive tests were examined by bivariate analysis and logistic regression, controlling for demographic variables.

RESULTS

Subjects with CHF performed worse on tests of visual memory [10.1 (S.D. 5.4) vs. 12.7 (S.D. 5.2), p = 0.007], Trailmaking B [0.1 (0.1) vs. 0.2 (0.1), p = 0.002], category fluency [11.1 (4.4) vs. 13.4 (4.5), p = 0.008], and clock drawing [5.6 (1.9) vs. 6.7 (1.4), p < 0.001] compared to subjects without CHF, after adjustment for relevant demographic variables.

CONCLUSION

CHF is associated with lower cognitive functioning in a population of patients with stable heart failure in primary care settings.

Cognitive domains and trajectories of functional independence in nondemented elderly persons

BACKGROUND

Cognitive impairment in general is known to predict functional disability, but it is not clear whether performance on specific cognitive domains predicts future disability trends among nondemented elderly persons.

METHODS

In a representative elderly community-based cohort over up to 10 years of follow-up, we examined predictors of longitudinal trajectories in ability to perform Instrumental Activities of Daily Living (IADL) among nondemented elderly persons. We used trajectory analyses to identify homogeneous groups with respect to trends over time in the numbers of IADL disabilities and their association with baseline demographics, social engagement, depression, physical well-being, and general and domain-specific cognitive functions. We excluded from these analyses those individuals found to have dementia at baseline or at any time during follow-up.

RESULTS

Trajectory analysis revealed three homogeneous latent groups which we characterized as No Decline (no decline in abilities to perform IADL tasks over the course of study), Moderate Decline (some functional decline), and Sharp Decline (steep functional decline followed by death). Compared to the Sharp Decline group, the No Decline group was associated with higher baseline functions in all cognitive domains, and the Moderate Decline group was associated with higher baseline functions in all cognitive domains except psychomotor speed and naming. The Moderate and No Decline groups did not differ on any cognitive measure.

CONCLUSION

Among community dwelling elderly persons who remained free from dementia throughout the study, poorer scores in all cognitive domains predicted sharp functional decline followed by death.

Distal support and community living among individuals diagnosed with schizophrenia and schizoaffective disorder

Community integration for individuals diagnosed with schizophrenia is essential to successful community tenure. Most of the research and clinical emphasis on the process of integration has been focused on the successes in normative goals (e.g., employment, support networks). Little research has focused on how individuals diagnosed with schizophrenia and schizoaffective disorder integrate in the realm of public life involving the casual routine interactions with other community members, termed "distal support" in this study. This was a cross-sectional study specifically designed to develop a measure of distal support and to identify clinical and sociodemographic factors associated with fostering distal supports. Findings suggest that personality factors, specifically extroversion and openness, play a role in the process of fostering community distal supports. It was also found that a greater number of distal supports were associated with higher quality of life satisfaction ratings and sense of belonging scores with the participants who were diagnosed with schizophrenia. A greater number of distal supports were associated with higher hospitalization rates and emergency contacts among the participants diagnosed with schizoaffective disorder, but not among those diagnosed with schizophrenia.

Mild cognitive impairment and the 7 uses of epidemiology

In 1907, Alzheimer's single case report of presenile dementia led to the condition being recognized as a rare disease of middle-aged people. In 1964, Roth and colleagues reported an epidemiologic survey showing that the same condition was in fact a relatively common disease of the elderly. In 1987, Katzman introduced the concept of brain reserve, suggesting how individuals could have Alzheimer disease pathology in their brains without clinically manifesting the disease. In 1999, Petersen described mild cognitive impairment (MCI) as an amnestic state, since broadened to include other cognitive deficits, which, in the majority of patients, was a prelude to the development of full-blown Alzheimer disease or other dementia. MCI today is in some ways analogous to Alzheimer disease a century ago. We recognize and describe MCI clinically, among patients with memory complaints, but we do not know its distribution, outcomes, and risk factors in the elderly population at large. All population-based studies to date have found MCI to be an unstable and heterogeneous entity with a far wider range of outcomes than in the clinical setting, including reversion to normal in a substantial proportion. However, these studies thus far have been purely descriptive, and retro-fitted on to existing studies of dementia, using measurements not necessarily appropriate for the assessment of MCI. This review will address what is known and what has yet to be determined about MCI from the perspectives of the classic 7 uses of epidemiology.

Discrepancies in information provided to primary care physicians by patients with and without dementia: the Steel Valley Seniors Survey

OBJECTIVE

The objective of this study was to examine associations between discrepancies in health information provided to primary care providers and severity of impairment in older patients with and without dementia.

METHODS

This study included brief assessment and medical record review of 1,107 patients with a mean (standard deviation) age of 76.3 (6.6) years (range: 65-100 years) in seven small-town primary care practices. In 358 patients, detailed in-home assessment included demographics; dementia by Clinical Dementia Rating (CDR) scale; and frequencies of memory complaints, falls, and inadvertent medication nonadherence determined from medical records and standardized in-home research assessments. Main outcome variables were trends in discrepancies between chart reviews and research assessments. Main explanatory variable was CDR box total scores.

RESULTS

Proportions of patients reporting memory complaints and falls, and evidence of inadvertent nonadherence, in the charts and by research assessment increased with CDR. Discrepancies between medical record and research assessment, were also associated with CDR, showing linear trends for memory complaints and inadvertent nonadherence and a quadratic trend for falls.

CONCLUSION

Memory complaints, falls, and inadvertent medication nonadherence increase with dementia severity. The levels of discrepancy between information patients provided to their physicians and information they provided in response to detailed, standardized assessments, also varied with dementia severity. Physicians should be alert to the possibility of receiving unreliable health information from even mildly demented patients, whether or not dementia has been detected.

Mild cognitive impairment

Mild cognitive impairment is a syndrome defined as cognitive decline greater than expected for an individual's age and education level but that does not interfere notably with activities of daily life. Prevalence in population-based epidemiological studies ranges from 3% to 19% in adults older than 65 years. Some people with mild cognitive impairment seem to remain stable or return to normal over time, but more than half progress to dementia within 5 years. Mild cognitive impairment can thus be regarded as a risk state for dementia, and its identification could lead to secondary prevention by controlling risk factors such as systolic hypertension. The amnestic subtype of mild cognitive impairment has a high risk of progression to Alzheimer's disease, and it could constitute a prodromal stage of this disorder. Other definitions and subtypes of mild cognitive impairment need to be studied as potential prodromes of Alzheimer's disease and other types of dementia.

Alcohol consumption and cognitive function in late life: a longitudinal community study

OBJECTIVE

To examine the association between alcohol use and cognitive decline in a longitudinal study of a representative elderly community sample free of dementia at baseline.

METHODS

Cognitive functions and self-reported drinking habits were assessed at 2-year intervals over an average of 7 years of follow-up. Cognitive measures, grouped into composites, were examined in association with alcohol consumption. Trajectory analyses identified latent homogeneous groups with respect to alcohol use frequency over time, and their association with average decline over the same period in each cognitive domain. Models controlled for age, sex, education, depression, smoking, general mental status (Mini-Mental State Examination [MMSE]), performance on the given test at baseline, and subsequent new-onset dementia during follow-up.

RESULTS

The authors found three homogeneous trajectories that they characterized as no drinking, minimal drinking, and moderate drinking. Few heavy drinkers were identified in this elderly cohort. Compared to no drinking, both minimal and moderate drinking were associated with lesser decline on the MMSE and Trailmaking tests. Minimal drinking was also associated with lesser decline on tests of learning and naming. These associations were more pronounced when comparing current drinkers to former drinkers (quitters) than to lifelong abstainers.

CONCLUSION

In a representative elderly cohort over an average of 7 years, a pattern of mild-to-moderate drinking, compared to not drinking, was associated with lesser average decline in cognitive domains over the same period.

Screening for cognitive impairment and depression in ethnically diverse older populations

Considerable advances have been made over the past decade in developing and adapting instruments to measure cognitive functioning in individuals with a wide range of educational and racial/ethnic backgrounds in different countries. Similar approaches can be used to extend these assessments to groups that have not yet been studied. The critical issues are to ensure that methods are appropriately harmonized to the local context, that local norms are established, and that local expertise is brought to bear in instrument development/adaptation. Effective instruments are also available to screen for depression in the elderly but closer attention should be made to possible ethnic differences in item response on these scales. The ideal screening tool should be quick, inexpensive, painless, and socially/culturally acceptable to the population. It should also have desirable psychometric properties. Examples are provided from several international studies. The context, costs, and objectives of screening a given population should be considered when selecting a screening instrument and a threshold on the scale, whether for clinical or research purposes.

Depressive symptoms and cognitive decline in late life: a prospective epidemiological study

CONTEXT

Depression is associated with cognitive impairment and dementia. It is less clear whether depression contributes to further cognitive decline over time, independently of incipient dementia.

OBJECTIVE

To examine the relationship between depressive symptoms and subsequent cognitive decline in a cohort of nondemented older adults, some of whom remained dementia free during follow-up and others in whom incident dementia eventually developed.

DESIGN

Twelve-year prospective epidemiological study, including biennial measurement of cognition and depressive symptoms, biennial assessment of dementia, and comparison of cognitive function at baseline and over time in persons with and without baseline depressive symptoms in the dementia-free and eventual-dementia groups, using random-effects models.

SETTING

A largely blue-collar rural community.

PARTICIPANTS

Population-based sample of 1265 adults 67 years and older without dementia at baseline.

MAIN OUTCOME MEASURES

Scores over time on each of several cognitive test composites.

RESULTS

Among 1094 participants who remained dementia free, those with baseline depressive symptoms had significantly lower baseline scores on all cognitive composites than the nondepressed participants. Among the 171 individuals in whom dementia later developed, depression was associated with worse performance in some but not all baseline cognitive composites. Cognitive decline over time was minimal in the dementia-free group, whereas marked decline was seen in the eventual-dementia group. Depressive symptoms were not associated with rate of cognitive decline over time in either group.

CONCLUSIONS

Depressive symptoms are cross-sectionally associated with cognitive impairment but not subsequent cognitive decline. Substantial cognitive decline over time cannot be explained by depression and most likely reflects incipient dementia.

Perspectives on Depression, Mild Cognitive Impairment, and Cognitive Decline

CONTEXT

The public health implications of depression and cognitive impairment in late life are enormous. Cognitive impairment and late-life depression are associated with increased risk for subsequent dementia; however, investigations of these phenomena appear to be proceeding along separate tracks. OBJECTIVES AND DATA SOURCE: The National Institute of Mental Health organized the conference "Perspectives on Depression, Mild Cognitive Impairment, and Cognitive Decline" to consider how the varied perspectives might be better integrated to examine the associations among depression, mild cognitive impairment, and cognitive decline and to illuminate the common or distinct mechanisms involved in these associations.

DATA SYNTHESIS

The following 2 broad questions were addressed: (1) What gaps in our knowledge have the greatest public health significance? (2) Can we more efficiently use our research dollars and participant resources to fill these gaps? Meeting participants included grantees from the National Institute of Mental Health and the National Institute on Aging and program staff from the National Institute of Mental Health, the National Institute on Aging, and the National Institute of Neurological Disorders and Stroke.

CONCLUSIONS

One of the most important recommendations to emerge from the meeting discussions is for increased collaboration among clinical and epidemiological investigators whose work focuses in the area of depression with those working primarily in the area of memory disorders. Directions for future research were identified.

Global prevalence of dementia: a Delphi consensus study

BACKGROUND

100 years after the first description, Alzheimer's disease is one of the most disabling and burdensome health conditions worldwide. We used the Delphi consensus method to determine dementia prevalence for each world region.

METHODS

12 international experts were provided with a systematic review of published studies on dementia and were asked to provide prevalence estimates for every WHO world region, for men and women combined, in 5-year age bands from 60 to 84 years, and for those aged 85 years and older. UN population estimates and projections were used to estimate numbers of people with dementia in 2001, 2020, and 2040. We estimated incidence rates from prevalence, remission, and mortality.

FINDINGS

Evidence from well-planned, representative epidemiological surveys is scarce in many regions. We estimate that 24.3 million people have dementia today, with 4.6 million new cases of dementia every year (one new case every 7 seconds). The number of people affected will double every 20 years to 81.1 million by 2040. Most people with dementia live in developing countries (60% in 2001, rising to 71% by 2040). Rates of increase are not uniform; numbers in developed countries are forecast to increase by 100% between 2001 and 2040, but by more than 300% in India, China, and their south Asian and western Pacific neighbours.

INTERPRETATION

We believe that the detailed estimates in this paper constitute the best currently available basis for policymaking, planning, and allocation of health and welfare resources.

Alzheimer Disease and Mortality

BACKGROUND

Alzheimer disease (AD) is considered a leading cause of death, but few studies have examined the contribution of AD to mortality based on follow-up of representative US cohorts.

OBJECTIVE

To examine mortality rates, duration of survival, causes of death, and the contribution of AD to the risk of mortality in an aging community-based cohort, controlling for other predictors.

DESIGN

Fifteen-year prospective epidemiological study. Mortality rates per 1000 person-years and the population-attributable risk of mortality were determined. Cox proportional hazards models were used to estimate relative risk of mortality due to AD, adjusting for relevant covariates. Death certificates were abstracted for listed causes of death.

SETTING

A largely blue-collar rural community in southwestern Pennsylvania.

PARTICIPANTS

A community-based cohort of 1670 adults 65 years and older at study enrollment.

MAIN OUTCOME MEASURE

Mortality.

RESULTS

In the overall cohort, AD was a significant predictor of mortality, with a hazard ratio of 1.4 after adjusting for covariates. The population-attributable risk of mortality from AD was 4.9% based on the same model. Examining the sexes separately, AD increased mortality risk only among women. Death certificates of AD subjects were more likely to list dementia/AD, other brain disorders, pneumonia, and dehydration, and less likely to include cancer.

CONCLUSIONS

Alzheimer disease was responsible for 4.9% of the deaths in this elderly cohort. Alzheimer disease increased the risk of mortality 40% in the cohort as a whole and separately in women but not in men. The mean (SD) duration of survival with AD was 5.9 (3.7) years, and longer with earlier age at onset.

Detection and management of cognitive impairment in primary care: The Steel Valley Seniors Survey

OBJECTIVES

To identify characteristics of older primary care patients who were cognitively impaired and who underwent mental status testing by their physicians.

DESIGN

Cross-sectional and retrospective analysis.

SETTING

Seven small-town primary care practices.

PARTICIPANTS

A total of 1,107 patients with a mean+/-standard deviation age of 76.3+/-6.6, screened using the Mini-Mental State Examination (MMSE); medical records reviewed.

MEASUREMENTS

Demographics, MMSE, medical record information. Odds ratios (OR) with 95% confidence intervals (CI), adjusted for age, sex, and education.

RESULTS

Thirty-one percent of the sample had MMSE scores of less than 25. Among these patients, physicians documented memory loss in only 23% which was significantly more often than in the higher scoring group (OR=1.9, 95% CI=1.3-2.8), basic activity of daily living (ADL) impairment in 7.9% (OR=2.4, 95% CI=1.3-4.4), instrumental ADL (IADL) impairment in 6.7% (OR=2.2, 95% CI=1.1=4.2), dementia in 12.2% (OR=3.7, 95% CI=2.0-6.8), and prescription of cholinesterase inhibitors in 7.6% (OR=4.4, 95% CI=1.9-10.2). Physicians recorded mental status testing largely in patients with research MMSE scores of 24 to 28, significantly more often when they also documented memory loss (OR=3.8, 95% CI=2.5-5.6) or impaired IADLs (OR=2.7, 95% CI=1.4-5.2), diagnosed dementia (OR=4.9, 95% CI=2.8-8.6), referred to specialists (OR=6.3, 95% CI=2.5-16.2) or social services (OR=3.6, 95% CI=1.8-7.3), or prescribed cholinesterase inhibitors (OR=8.5, 95% CI=4.2-17.5).

CONCLUSION

Physicians noted impairment in a minority of impaired patients. They tested mental status in those with documented cognitive and functional difficulties, in very mildly impaired patients, and in those for whom they intervened.

Exercise level and cognitive decline: the MoVIES project

Growing evidence suggests that physical exercise may be protective against cognitive impairment and decline. A prospective study of a representative rural community sample (N = 1,146) aged 65+ years examined self-reported exercise habits and measured global cognitive function using the Mini-Mental State Examination (MMSE). A composite variable "exercise level" combining type, frequency, and duration of exercise was created with three levels: "high exercise" (aerobic exercise of > or = 30 minute duration > or = 3 times a week), "low exercise" (all other exercise groups), and "no exercise." Cognitive decline was defined as being in the 90 percentile of decline in this cohort, ie, declining by 3 or more MMSE points during the 2-year interval between two assessments. In a multiple regression model, high exercise level at the baseline assessment was negatively associated with, ie, was protective against, being in the group with the greatest amount of decline at the follow-up assessment, after adjusting for likely confounders (odds ratio = 0.39; 95% confidence interval, 0.19, 0.78). When high exercise was redefined using frequency as > or = 5 days per week as the threshold, as per the Surgeon General's guidelines, both low exercise and high exercise were negatively associated with cognitive decline. Exercise may have implications for prevention of cognitive decline.

Hemoglobin levels and Alzheimer disease: an epidemiologic study in India

OBJECTIVE

Anemia is common in developing countries, where populations are aging rapidly. The authors explored the cross-sectional relationship between hemoglobin concentration and Alzheimer disease (AD) in a rural elderly sample in Ballabgarh, India.

METHODS

A clinical diagnostic evaluation for dementia and a hemoglobin estimation were performed in 605 persons selected by screening a larger community-based sample age 55+ years. Twenty-six participants met criteria for AD.

RESULTS

Hemoglobin was inversely associated with AD after adjustment for age, sex, and literacy.

CONCLUSION

Low hemoglobin is associated with AD and should be investigated further as a modifiable risk factor.

Mild cognitive impairment, amnestic type: an epidemiologic study

OBJECTIVE

To estimate the prevalence and examine the course of mild cognitive impairment (MCI), amnestic type, using current criteria, within a representative community sample.

METHODS

Retroactive application of MCI criteria to data collected during a prospective epidemiologic study was performed. The subjects were drawn from voter registration lists, composing a cohort of 1,248 individuals with mean age of 74.6 (5.3) years, who were nondemented at entry and who were assessed biennially over 10 years of follow-up. The Petersen amnestic MCI criteria were operationalized as 1) impaired memory: Word List Delayed Recall score of <1 SD below mean; 2) normal mental status: Mini-Mental State Examination score of 25+; 3) normal daily functioning: no instrumental impairments; 4) memory complaint: subjective response to standardized question; 5) not demented: Clinical Dementia Rating Scale score of <1.

RESULTS

At the five assessments, amnestic MCI criteria were met by 2.9 to 4.0% of the cohort. Of 40 persons with MCI at the first assessment, 11 (27%) developed dementia over the next 10 years. Over each 2-year interval, MCI persons showed increased risk of dementing (odds ratio = 3.9, 95% CI = 2.1 to 7.2); 11.1 to 16.7% progressed to Alzheimer disease and 0 to 5.0% progressed to other dementias. Over the same intervals, 11.1 to 21.2% of those with MCI remained MCI; of 33.3 to 55.6% who no longer had MCI, half had reverted to normal.

CONCLUSIONS

In this community-based sample, 3 to 4% of nondemented persons met MCI operational criteria; despite increased risk of progressing to dementia, a substantial proportion also remained stable or reverted to normal during follow-up. Amnestic MCI as currently defined is a high-risk but unstable and heterogeneous group.