The Aging, Demographics, and Memory Study: Study Design and Methods

Pain and Cognitive Function Among Older Adults Living in the Community

BACKGROUND

Pain related to many age-related chronic conditions is a burdensome problem in elderly adults and may also interfere with cognitive functioning. The purpose of this study was to examine the cross-sectional relationship between measures of pain severity and pain interference and cognitive performance in community-living older adults.

METHODS

We studied 765 participants in the Maintenance of Balance Independent Living Intellect and Zest (MOBILIZE) Boston Study, a population-based study of persons aged 70 and older. Global pain severity and interference were measured using the Brief Pain Inventory subscales. The neuropsychological battery included measures of attentional capacity (Trail Making Test A, WORLD Test), executive function (Trail Making Test B and Delta, Clock-in-a-Box, Letter Fluency), memory (Hopkins Verbal Learning Test), and a global composite measure of cognitive function. Multivariable linear regression models were used to analyze the relationship between pain and cognitive functioning.

RESULTS

Elderly adults with more severe pain or more pain interference had poorer performance on memory tests and executive functioning compared to elders with none or less pain. Pain interference was also associated with impaired attentional capacity. Additional adjustment for chronic conditions, behaviors, and psychiatric medication resulted in attenuation of many of the observed associations. However, the association between pain interference and general cognitive function persisted.

CONCLUSIONS

Our findings point to the need for further research to understand how chronic pain may contribute to decline in cognitive function and to determine strategies that may help in preventing or managing these potential consequences of pain on cognitive function in older adults.

Mini-Mental State Examination (MMSE) for the detection of dementia in clinically unevaluated people aged 65 and over in community and primary care populations

BACKGROUND

The Mini Mental State Examination (MMSE) is a cognitive test that is commonly used as part of the evaluation for possible dementia.

OBJECTIVES

To determine the diagnostic accuracy of the Mini-Mental State Examination (MMSE) at various cut points for dementia in people aged 65 years and over in community and primary care settings who had not undergone prior testing for dementia.

SEARCH METHODS

We searched the specialised register of the Cochrane Dementia and Cognitive Improvement Group, MEDLINE (OvidSP), EMBASE (OvidSP), PsycINFO (OvidSP), LILACS (BIREME), ALOIS, BIOSIS previews (Thomson Reuters Web of Science), and Web of Science Core Collection, including the Science Citation Index and the Conference Proceedings Citation Index (Thomson Reuters Web of Science). We also searched specialised sources of diagnostic test accuracy studies and reviews: MEDION (Universities of Maastricht and Leuven, www.mediondatabase.nl), DARE (Database of Abstracts of Reviews of Effects, via the Cochrane Library), HTA Database (Health Technology Assessment Database, via the Cochrane Library), and ARIF (University of Birmingham, UK, www.arif.bham.ac.uk). We attempted to locate possibly relevant but unpublished data by contacting researchers in this field. We first performed the searches in November 2012 and then fully updated them in May 2014. We did not apply any language or date restrictions to the electronic searches, and we did not use any methodological filters as a method to restrict the search overall.

SELECTION CRITERIA

We included studies that compared the 11-item (maximum score 30) MMSE test (at any cut point) in people who had not undergone prior testing versus a commonly accepted clinical reference standard for all-cause dementia and subtypes (Alzheimer disease dementia, Lewy body dementia, vascular dementia, frontotemporal dementia). Clinical diagnosis included all-cause (unspecified) dementia, as defined by any version of the Diagnostic and Statistical Manual of Mental Disorders (DSM); International Classification of Diseases (ICD) and the Clinical Dementia Rating.

DATA COLLECTION AND ANALYSIS

At least three authors screened all citations.Two authors handled data extraction and quality assessment. We performed meta-analysis using the hierarchical summary receiver-operator curves (HSROC) method and the bivariate method.

MAIN RESULTS

We retrieved 24,310 citations after removal of duplicates. We reviewed the full text of 317 full-text articles and finally included 70 records, referring to 48 studies, in our synthesis. We were able to perform meta-analysis on 28 studies in the community setting (44 articles) and on 6 studies in primary care (8 articles), but we could not extract usable 2 x 2 data for the remaining 14 community studies, which we did not include in the meta-analysis. All of the studies in the community were in asymptomatic people, whereas two of the six studies in primary care were conducted in people who had symptoms of possible dementia. We judged two studies to be at high risk of bias in the patient selection domain, three studies to be at high risk of bias in the index test domain and nine studies to be at high risk of bias regarding flow and timing. We assessed most studies as being applicable to the review question though we had concerns about selection of participants in six studies and target condition in one study.The accuracy of the MMSE for diagnosing dementia was reported at 18 cut points in the community (MMSE score 10, 14-30 inclusive) and 10 cut points in primary care (MMSE score 17-26 inclusive). The total number of participants in studies included in the meta-analyses ranged from 37 to 2727, median 314 (interquartile range (IQR) 160 to 647). In the community, the pooled accuracy at a cut point of 24 (15 studies) was sensitivity 0.85 (95% confidence interval (CI) 0.74 to 0.92), specificity 0.90 (95% CI 0.82 to 0.95); at a cut point of 25 (10 studies), sensitivity 0.87 (95% CI 0.78 to 0.93), specificity 0.82 (95% CI 0.65 to 0.92); and in seven studies that adjusted accuracy estimates for level of education, sensitivity 0.97 (95% CI 0.83 to 1.00), specificity 0.70 (95% CI 0.50 to 0.85). There was insufficient data to evaluate the accuracy of the MMSE for diagnosing dementia subtypes.We could not estimate summary diagnostic accuracy in primary care due to insufficient data.

AUTHORS' CONCLUSIONS

The MMSE contributes to a diagnosis of dementia in low prevalence settings, but should not be used in isolation to confirm or exclude disease. We recommend that future work evaluates the diagnostic accuracy of tests in the context of the diagnostic pathway experienced by the patient and that investigators report how undergoing the MMSE changes patient-relevant outcomes.

2015 Alzheimer's disease facts and figures

This report discusses the public health impact of Alzheimer’s disease (AD), including incidence and prevalence, mortality rates, costs of care and the overall effect on caregivers and society. It also examines the challenges encountered by health care providers when disclosing an AD diagnosis to patients and caregivers. An estimated 5.3 million Americans have AD; 5.1 million are age 65 years, and approximately 200,000 are age <65 years and have younger onset AD. By mid-century, the number of people living with AD in the United States is projected to grow by nearly 10 million, fueled in large part by the aging baby boom generation. Today, someone in the country develops AD every 67 seconds. By 2050, one new case of AD is expected to develop every 33 seconds, resulting in nearly 1 million new cases per year, and the estimated prevalence is expected to range from 11 million to 16 million. In 2013, official death certificates recorded 84,767 deaths from AD, making AD the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age 65 years. Between 2000 and 2013, deaths resulting from heart disease, stroke and prostate cancer decreased 14%, 23% and 11%, respectively, whereas deaths from AD increased 71%. The actual number of deaths to which AD contributes (or deaths with AD) is likely much larger than the number of deaths from AD recorded on death certificates. In 2015, an estimated 700,000 Americans age 65 years will die with AD, and many of them will die from complications caused by AD. In 2014, more than 15 million family members and other unpaid caregivers provided an estimated 17.9 billion hours of care to people with AD and other dementias, a contribution valued at more than $217 billion. Average per-person Medicare payments for services to beneficiaries age 65 years with AD and other dementias are more than two and a half times as great as payments for all beneficiaries without these conditions, and Medicaid payments are 19 times as great. Total payments in 2015 for health care, long-term care and hospice services for people age 65 years with dementia are expected to be $226 billion. Among people with a diagnosis of AD or another dementia, fewer than half report having been told of the diagnosis by their health care provider. Though the benefits of a prompt, clear and accurate disclosure of an AD diagnosis are recognized by the medical profession, improvements to the disclosure process are needed. These improvements may require stronger support systems for health care providers and their patients.

Fuzzy-Trace Theory and Lifespan Cognitive Development

Fuzzy-trace theory (FTT) emphasizes the use of core theoretical principles, such as the verbatim-gist distinction, to predict new findings about cognitive development that are counterintuitive from the perspective of other theories or of common-sense. To the extent that such predictions are confirmed, the range of phenomena that are explained expands without increasing the complexity of the theory's assumptions. We examine research on recent examples of such predictions during four epochs of cognitive development: childhood, adolescence, young adulthood, and late adulthood. During the first two, the featured predictions are surprising developmental reversals in false memory (childhood) and in risky decision making (adolescence). During young adulthood, FTT predicts that a retrieval operation that figures centrally in dual-process theories of memory, recollection, is bivariate rather than univariate. During the late adulthood, FTT identifies a retrieval operation, reconstruction, that has been omitted from current theories of normal memory declines in aging and pathological declines in dementia. The theory predicts that reconstruction is a major factor in such declines and that it is able to forecast future dementia.

Effects of education and race on cognitive decline: An integrative study of generalizability versus study-specific results

The objective of the study was to examine variability across multiple prospective cohort studies in level and rate of cognitive decline by race/ethnicity and years of education. We compare data across studies, we harmonized estimates of common latent factors representing overall or general cognitive performance, memory, and executive function derived from the: (a) Washington Heights, Hamilton Heights, Inwood Columbia Aging Project (N = 4,115), (b) Spanish and English Neuropsychological Assessment Scales (N = 525), (c) Duke Memory, Health, and Aging study (N = 578), and (d) Neurocognitive Outcomes of Depression in the Elderly (N = 585). We modeled cognitive change over age for cognitive outcomes by race, education, and study. We adjusted models for sex, dementia status, and study-specific characteristics. The results found that for baseline levels of overall cognitive performance, memory, and executive function, differences in race and education tended to be larger than between-study differences and consistent across studies. This pattern did not hold for rate of cognitive decline: effects of education and race/ethnicity on cognitive change were not consistently observed across studies, and when present were small, with racial/ethnic minorities and those with lower education declining at faster rates. In this diverse set of datasets, non-Hispanic Whites and those with higher education had substantially higher baseline cognitive test scores. However, differences in the rate of cognitive decline by race/ethnicity and education did not follow this pattern. This study suggests that baseline test scores and longitudinal change have different determinants, and future studies to examine similarities and differences of causes of cognitive decline in racially/ethnically and educationally diverse older groups is needed.

Body mass index and cognitive function: the potential for reverse causation

OBJECTIVE

Higher late life body mass index (BMI) is unrelated to or even predicts lower risk of dementia in late life, a phenomenon that may be explained by reverse causation due to weight loss during preclinical phases of dementia. We aim to investigate the association of baseline BMI and changes in BMI with dementia in a large prospective cohort, and to examine whether weight loss predicts cognitive function.

METHODS

Using a national cohort of adults average age 58 years at baseline in 1994 (n=7029), we investigated the associations between baseline BMI in 1994 and memory scores from 2000 to 2010. We also examined the association of BMI change from 1994 to 1998 with memory scores from 2000 to 2010. Last, to investigate reverse causation, we examined whether memory scores in 1996 predicted BMI trajectories from 2000 to 2010.

RESULTS

Baseline overweight predicted better memory scores 6 to 16 years later (β=0.012, 95% confidence interval (CI)=0.001; 0.023). Decline in BMI predicted lower memory scores over the subsequent 12 years (β=-0.026, 95% CI= -0.041; -0.011). Lower memory scores at mean age 60 years in 1996 predicted faster annual rate of BMI decline during follow-up (β=-0.158 kg m(-2) per year, 95% CI= -0.223; -0.094).

CONCLUSION

Consistent with reverse causation, greater decline in BMI over the first 4 years of the study was associated with lower memory scores over the next decade and lower memory scores was associated with a decline in BMI. These findings suggest that preclinical dementia predicts weight loss for people as early as their late 50s.

Advance directives and nursing home stays associated with less aggressive end-of-life care for patients with severe dementia

The number of older adults with cognitive impairment is increasing, and such adults often require a surrogate to make decisions about health care. However, little is known about the aggressiveness of end-of-life care for these people, especially those who reside in the community. We found that cognitive impairment is common among older adults approaching the end of life, whether they live in the community or in a nursing home, and that nearly 30 percent of patients with severe dementia remained in the community until death. Among those patients, having an advance directive in the form of a living will was associated with significantly less aggressive care at the end of life, compared to similar patients without an advance directive-as measured by Medicare spending ($11,461 less per patient), likelihood of in-hospital death (17.9 percentage points lower), and use of the intensive care unit (9.4 percentage points lower). In contrast, advance directives were not associated with differences in care for people with normal cognition or mild dementia, whether they resided in the community or in a nursing home. Timely advance care planning after a diagnosis of cognitive impairment may be particularly important for older adults who reside in the community.

Estimating the cognitive effects of prevalent diabetes, recent onset diabetes, and the duration of diabetes among older adults

BACKGROUND

Little evidence is available on the effects of incident diabetes or diabetes duration on cognitive aging.

METHODS

We evaluated the effects of prevalent and incident diabetes on deteriorations in cognitive function, based on participants (n = 8,671) aged 65+ in the Health and Retirement Study in 2000. Inverse probability weighting was used to account for selective attrition and time-varying confounding of incident diabetes.

RESULTS

Prevalent diabetes predicted higher odds of dementia [odds ratio 1.27; 95% confidence interval (CI) 1.03-1.58] and worse memory (-0.06 in z-score units; 95% CI -0.10 to -0.02), but incident diabetes or diabetes duration up to 8 years of follow-up was not predictive.

CONCLUSION

Prevalent diabetes predicted lower cognition but not recent onset diabetes.

Predictors of Retest Effects in a Longitudinal Study of Cognitive Aging in a Diverse Community-Based Sample

Better performance due to repeated testing can bias long-term trajectories of cognitive aging and correlates of change. We examined whether retest effects differ as a function of individual differences pertinent to cognitive aging: race/ethnicity, age, sex, language, years of education, literacy, and dementia risk factors including apolipoprotein E ε4 status, baseline cognitive performance, and cardiovascular risk. We used data from the Washington Heights-Inwood Columbia Aging Project, a community-based cohort of older adults (n=4073). We modeled cognitive change and retest effects in summary factors for general cognitive performance, memory, executive functioning, and language using multilevel models. Retest effects were parameterized in two ways, as improvement between the first and subsequent testings, and as the square root of the number of prior testings. We evaluated whether the retest effect differed by individual characteristics. The mean retest effect for general cognitive performance was 0.60 standard deviations (95% confidence interval [0.46, 0.74]), and was similar for memory, executive functioning, and language. Retest effects were greater for participants in the lowest quartile of cognitive performance (many of whom met criteria for dementia based on a study algorithm), consistent with regression to the mean. Retest did not differ by other characteristics. Retest effects are large in this community-based sample, but do not vary by demographic or dementia-related characteristics. Differential retest effects may not limit the generalizability of inferences across different groups in longitudinal research.

Transitions in Care in a Nationally Representative Sample of Older Americans with Dementia

OBJECTIVES

To describe transitions in care for older adults with dementia identified from a nationally representative cohort and to describe transition rates in those with more-severe levels of cognitive and functional impairment.

DESIGN

Longitudinal cohort study.

SETTING

Health and Retirement Study (HRS).

PARTICIPANTS

HRS respondents aged 65 and older whose survey data were linked with Medicare claims from 1999 to 2008 (N = 16,186).

MEASUREMENTS

Transitions in care between home, home with formal services, hospital, and nursing facility care; cognitive function; activities of daily living; and mortality.

RESULTS

The 3,447 (21.3%) HRS subjects who were ever diagnosed with dementia experienced frequent transitions. Of subjects transitioning from a hospital stay, 52.2% returned home without home care services, and 33.8% transitioned to a nursing facility. Of subjects transitioning from a nursing facility, 59.2% transitioned to the hospital, and 25.3% returned home without services. There were 2,139 transitions to death, and 58.7% of HRS subjects with dementia died at home. Even in persons with moderate to severe dementia, multiple transitions in care were documented, including transitions from the hospital to home and back to the hospital.

CONCLUSION

In this nationally representative sample of older adults, subjects diagnosed with dementia experience frequent transitions. Persons with dementia who are cared for at home and who transition back to home often have moderate to severe impairments in function and cognition.

Chronic obstructive pulmonary disease, cognitive impairment, and development of disability: the health and retirement study

RATIONALE

The relationship between chronic obstructive pulmonary disease (COPD) and cognitive impairment in leading to disability has not been characterized.

OBJECTIVES

We aimed to investigate the prevalence and cumulative incidence of disability among adults with and without COPD and the association of COPD and cognitive impairment with disability.

METHODS

We analyzed 2006-2008 waves of the Health and Retirement Study, a nationally representative longitudinal health survey. COPD was self-reported. Prevalent disability was defined as baseline dependency in one or more activities of daily living (ADLs) and incident disability as one or more additional ADL dependencies. We used a validated performance-based measure of cognition to identify dementia and mild cognitive impairment. Covariates included seven chronic diseases, four geriatric syndromes, and sociodemographics. We used logistic regression to test associations between COPD, cognitive status, and prevalent/incident disability.

MEASUREMENTS AND MAIN RESULTS

Of 17,535 participants at least 53 years of age in wave 2006 (representing 77.7 million Americans), 9.5% reported COPD and 13.5% mild cognitive impairment; 17.5% of those with COPD had mild cognitive impairment. Prevalent disability for COPD was 12.8% (5.2% for no-COPD, P < 0.001). An additional 9.2% with COPD developed incident disability at 2 years (4.0% for no-COPD, P < 0.001). In adjusted models, COPD was associated with baseline (odds ratio, 2.0) and incident disability (odds ratio, 2.1; adjusted for baseline disability). Cognitive impairment had an additive effect to COPD. The COPD-disability association, prevalent/incident, was of similar or greater magnitude than that of other chronic diseases (e.g., stroke, diabetes). The associations were maintained in sensitivity analyses using alternative definitions of disability (dependency in two or more ADLs, dependency in instrumental ADLs), and in analysis excluding respondents with dementia.

CONCLUSIONS

Both COPD and mild cognitive impairment increase the risk of disability. The risk conferred by COPD is significant and similar or higher than other chronic diseases.

Contemporary Modeling of Gene × Environment Effects in Randomized Multivariate Longitudinal Studies

There is a great deal of interest in the analysis of Genotype × Environment interactions (G×E). There are some limitations in the typical models for the analysis of G×E, including well-known statistical problems in identifying interactions and unobserved heterogeneity of persons across groups. The impact of a treatment may depend on the level of an unobserved variable, and this variation may dampen the estimated impact of treatment. Some researchers have noted that genetic variation may sometimes account for unobserved, and hence unaccounted for, heterogeneity. The statistical power associated with the G×E design has been studied in many different ways, and most results show that the small effects expected require relatively large or nonrepresentative samples (i.e., extreme groups). In this article, we describe some alternative approaches, such as randomized designs with multiple measures, multiple groups, multiple occasions, and analyses, to identify latent (unobserved) classes of people. These approaches are illustrated with data from the Aging, Demographics, and Memory Study (part of the Health and Retirement Study) examining the relations among episodic memory (based on word recall), APOE4 genotype, and educational attainment (as a proxy for an environmental exposure). Randomized clinical trials (RCTs) and randomized field trials (RFTs) have multiple strengths in the estimation of causal influences, and we discuss how measured genotypes can be incorporated into these designs. Use of these contemporary modeling techniques often requires different kinds of data be collected and encourages the formation of parsimonious models with fewer overall parameters, allowing specific G×E hypotheses to be investigated with a reasonable statistical foundation.

The role of early-life educational quality and literacy in explaining racial disparities in cognition in late life

OBJECTIVES

Racial disparities in late-life cognition persist even after accounting for educational attainment. We examined whether early-life educational quality and literacy in later life help explain these disparities.

METHOD

We used longitudinal data from the Washington Heights-Inwood Columbia Aging Project (WHICAP). Educational quality (percent white students; urban/rural school; combined grades in classroom) was operationalized using canonical correlation analysis. Late-life literacy (reading comprehension and ability, writing) was operationalized using confirmatory factor analysis. We examined whether these factors attenuated race-related differences in late-life cognition.

RESULTS

The sample consisted of 1,679 U.S.-born, non-Hispanic, community-living adults aged 65-102 (71% black, 29% white; 70% women). Accounting for educational quality and literacy reduced disparities by 29% for general cognitive functioning, 26% for memory, and 32% for executive functioning but did not predict differences in rate of cognitive change.

DISCUSSION

Early-life educational quality and literacy in late life explain a substantial portion of race-related disparities in late-life cognitive function.

Demographic and Socioenvironmental Characteristics of Black and White Community-Dwelling Caregivers and Care Recipients' Behavioral and Psychological Symptoms of Dementia

The purpose of the current study was to compare the association between caregiver background characteristics and care recipients' behavioral and psychological symptoms of dementia (BPSD) in Black and White community-dwelling family caregivers. Using logistic regression models, caregiver/care recipient dyad data from the Aging Demographics and Memory Study were used to describe associations between caregiver background characteristics (i.e., demographic and socioenvironmental variables) and care recipients' BPSD (i.e., hallucinations, delusions, agitation, depression) (N = 755). Results showed that Black caregivers were more likely to be female, younger, an adult child, have less education, and live in the South (p ≤ 0.05); they were less likely to be married. Several caregiver background characteristics were associated with care recipients' depression and agitation, but not with other BPSD. Caregiver background characteristics may play a role in the recognition and reporting of BPSD and should be considered when working with families of individuals with dementia.

Who has undiagnosed dementia? A cross-sectional analysis of participants of the Aging, Demographics and Memory Study

BACKGROUND

delays in diagnosing dementia may lead to suboptimal care, yet around half of those with dementia are undiagnosed. Any strategy for case finding should be informed by understanding the characteristics of the undiagnosed population. We used cross-sectional data from a population-based sample with dementia aged 71 years and older in the United States to describe the undiagnosed population and identify factors associated with non-diagnosis.

METHODS

the Aging, Demographics and Memory Study (ADAMS) Wave A participants (N = 856) each underwent a detailed neuropsychiatric investigation. Informants were asked whether the participant had ever received a doctor's diagnosis of dementia. We used multiple logistic regression to identify factors associated with informant report of a prior dementia diagnosis among those with a study diagnosis of dementia.

RESULTS

of those with a study diagnosis of dementia (n = 307), a prior diagnosis of dementia was reported by 121 informants (weighted proportion = 42%). Prior diagnosis was associated with greater clinical dementia rating (CDR), from 26% (CDR = 1) to 83% (CDR = 5). In multivariate analysis, those aged 90 years or older were less likely to be diagnosed (P = 0.008), but prior diagnosis was more common among married women (P = 0.038) and those who had spent more than 9 years in full-time education (P = 0.043).

CONCLUSIONS

people with dementia who are undiagnosed are older, have fewer years in education, are more likely to be unmarried, male and have less severe dementia than those with a diagnosis. Policymakers and clinicians should be mindful of the variation in diagnosis rates among subgroups of the population with dementia.

Antidepressant Use and Cognitive Decline: The Health and Retirement Study

BACKGROUND

Depression is associated with cognitive impairment and dementia, but whether treatment for depression with antidepressants reduces the risk for cognitive decline is unclear. We assessed the association between antidepressant use and cognitive decline over 6 years.

METHODS

Participants were 3714 adults aged 50 years or more who were enrolled in the nationally representative Health and Retirement Study and had self-reported antidepressant use. Depressive symptoms were assessed using the 8-item Center for Epidemiologic Studies Depression Scale. Cognitive function was assessed at 4 time points (2004, 2006, 2008, 2010) using a validated 27-point scale. Change in cognitive function over the 6-year follow-up period was examined using linear growth models, adjusted for demographics, depressive symptoms, comorbidities, functional limitations, and antidepressant anticholinergic activity load.

RESULTS

At baseline, cognitive function did not differ significantly between the 445 (12.1%) participants taking antidepressants and those not taking antidepressants (mean, 14.9%; 95% confidence interval, 14.3-15.4 vs mean, 15.1%; 95% confidence interval, 14.9-15.3). During the 6-year follow up period, cognition declined in both users and nonusers of antidepressants, ranging from -1.4 change in mean score in those with high depressive symptoms and taking antidepressants to -0.5 change in mean score in those with high depressive symptoms and not taking antidepressants. In adjusted models, cognition declined in people taking antidepressants at the same rate as those not taking antidepressants. Results remained consistent across different levels of baseline cognitive function, age, and duration of antidepressant use (prolonged vs short-term).

CONCLUSIONS

Antidepressant use did not modify the course of 6-year cognitive change in this nationally representative sample.

Does Stroke Contribute to Racial Differences in Cognitive Decline?

BACKGROUND AND PURPOSE

It is unknown whether blacks' elevated risk of dementia is because of racial differences in acute stroke, the impact of stroke on cognitive health, or other factors. We investigated whether racial differences in cognitive decline are explained by differences in the frequency or impact of incident stroke between blacks and whites, controlling for baseline cognition.

METHODS

Among 4908 black and white participants aged ≥65 years free of stroke and cognitive impairment in the nationally representative Health and Retirement Study with linked Medicare data (1998-2010), we examined longitudinal changes in global cognition (modified version of the Telephone Interview for Cognitive Status) by race, before and after adjusting for time-dependent incident stroke followed by a race-by-incident stroke interaction term, using linear mixed-effects models that included fixed effects of participant demographics, clinical factors, and cognition, and random effects for intercept and slope for time.

RESULTS

We identified 34 of 453 (7.5%) blacks and 300 of 4455 (6.7%) whites with incident stroke over a mean (SD) of 4.1 (1.9) years of follow-up (P=0.53). Blacks had greater cognitive decline than whites (adjusted difference in modified version of the Telephone Interview for Cognitive Status score, 1.47 points; 95% confidence interval, 1.21 to 1.73 points). With further adjustment for cumulative incidence of stroke, the black-white difference in cognitive decline persisted. Incident stroke was associated with a decrease in global cognition (1.21 points; P<0.001) corresponding to ≈7.9 years of cognitive aging. The effect of incident stroke on cognition did not statistically differ by race (P=0.52).

CONCLUSIONS

In this population-based cohort of older adults, incident stroke did not explain black-white differences in cognitive decline or impact cognition differently by race.

Awareness of Memory Ability and Change: (In)Accuracy of Memory Self-Assessments in Relation to Performance

Little is known about subjective assessments of memory abilities and decline among middle-aged adults or their association with objective memory performance in the general population. In this study we examined self-ratings of memory ability and change in relation to episodic memory performance in two national samples of middle-aged and older adults from the Midlife in the United States study (MIDUS II in 2005-06) and the Health and Retirement Study (HRS; every two years from 2002 to 2012). MIDUS (Study 1) participants (N=3,581) rated their memory compared to others their age and to themselves five years ago; HRS (Study 2) participants (N=14,821) rated their current memory and their memory compared to two years ago, with up to six occasions of longitudinal data over ten years. In both studies, episodic memory performance was the total number of words recalled in immediate and delayed conditions. When controlling for demographic and health correlates, self-ratings of memory abilities, but not subjective change, were related to performance. We examined accuracy by comparing subjective and objective memory ability and change. More than one third of the participants across the studies had self-assessments that were inaccurate relative to their actual level of performance and change, and accuracy differed as a function of demographic and health factors. Further understanding of self-awareness of memory abilities and change beginning in midlife may be useful for identifying early warning signs of decline, with implications regarding policies and practice for early detection and treatment of cognitive impairment.

Measuring cognition: the Chicago Cognitive Function Measure in the National Social Life, Health and Aging Project, Wave 2

OBJECTIVES

To describe the development of a multidimensional test of cognition for the National Social life, Health and Aging Project (NSHAP), the Chicago Cognitive Function Measure (CCFM).

METHOD

CCFM development included 3 steps: (a) A pilot test of the Montreal Cognitive Assessment (MoCA) to create a standard protocol, choose specific items, reorder items, and improve clarity; (b) integration into a CAPI-based format; and (c) evaluation of the performance of the CCFM in the field. The CCFM was subsequently incorporated into NSHAP, Wave 2 (n = 3,377).

RESULTS

The pre-test (n = 120) mean age was 71.35 (SD 8.40); 53% were female, 69% white, and 70% with college or greater education. The MoCA took an average of 15.6min; the time for the CCFM was 12.0 min. CCFM scores (0-20) can be used as a continuous outcome or to adjust for cognition in a multivariable analysis. CCFM scores were highly correlated with MoCA scores (r = .973). Modeling projects MoCA scores from CCFM scores using the equation: MoCA = (1.14 × CCFM) + 6.83. In Wave 2, the overall weighted mean CCFM score was 13.9 (SE 0.13).

DISCUSSION

A survey-based adaptation of the MoCA was successfully integrated into a nationally representative sample of older adults, NSHAP Wave 2.

Factors associated with cognitive evaluations in the United States

OBJECTIVE

We aimed to explore factors associated with clinical evaluations for cognitive impairment among older residents of the United States.

METHODS

Two hundred ninety-seven of 845 subjects in the Aging, Demographics, and Memory Study (ADAMS), a nationally representative community-based cohort study, met criteria for dementia after a detailed in-person study examination. Informants for these subjects reported whether or not they had ever received a clinical cognitive evaluation outside of the context of ADAMS. Among subjects with dementia, we evaluated demographic, socioeconomic, and clinical factors associated with an informant-reported clinical cognitive evaluation using bivariate analyses and multivariable logistic regression.

RESULTS

Of the 297 participants with dementia in ADAMS, 55.2% (representing about 1.8 million elderly Americans in 2002) reported no history of a clinical cognitive evaluation by a physician. In a multivariable logistic regression model (n = 297) controlling for demographics, physical function measures, and dementia severity, marital status (odds ratio for currently married: 2.63 [95% confidence interval: 1.10-6.35]) was the only significant independent predictor of receiving a clinical cognitive evaluation among subjects with study-confirmed dementia.

CONCLUSIONS

Many elderly individuals with dementia do not receive clinical cognitive evaluations. The likelihood of receiving a clinical cognitive evaluation in elderly individuals with dementia associates with certain patient-specific factors, particularly severity of cognitive impairment and current marital status.

2014 Alzheimer's disease facts and figures

This report discusses the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality rates, costs of care, and overall effect on caregivers and society. It also examines the impact of AD on women compared with men. An estimated 5.2 million Americans have AD. Approximately 200,000 people younger than 65 years with AD comprise the younger onset AD population; 5 million are age 65 years or older. By mid-century, fueled in large part by the baby boom generation, the number of people living with AD in the United States is projected to grow by about 9 million. Today, someone in the country develops AD every 67 seconds. By 2050, one new case of AD is expected to develop every 33 seconds, or nearly a million new cases per year, and the total estimated prevalence is expected to be 13.8 million. In 2010, official death certificates recorded 83,494 deaths from AD, making AD the sixth leading cause of death in the United States and the fifth leading cause of death in Americans aged 65 years or older. Between 2000 and 2010, the proportion of deaths resulting from heart disease, stroke, and prostate cancer decreased 16%, 23%, and 8%, respectively, whereas the proportion resulting from AD increased 68%. The actual number of deaths to which AD contributes (or deaths with AD) is likely much larger than the number of deaths from AD recorded on death certificates. In 2014, an estimated 700,000 older Americans will die with AD, and many of them will die from complications caused by AD. In 2013, more than 15 million family members and other unpaid caregivers provided an estimated 17.7 billion hours of care to people with AD and other dementias, a contribution valued at more than $220 billion. Average per-person Medicare payments for services to beneficiaries aged 65 years and older with AD and other dementias are more than two and a half times as great as payments for all beneficiaries without these conditions, and Medicaid payments are 19 times as great. Total payments in 2014 for health care, long-term care, and hospice services for people aged 65 years and older with dementia are expected to be $214 billion. AD takes a stronger toll on women than men. More women than men develop the disease, and women are more likely than men to be informal caregivers for someone with AD or another dementia. As caregiving responsibilities become more time consuming and burdensome or extend for prolonged durations, women assume an even greater share of the caregiving burden. For every man who spends 21 to more than 60 hours per week as a caregiver, there are 2.1 women. For every man who lives with the care recipient and provides around-the-clock care, there are 2.5 women. In addition, for every man who has provided caregiving assistance for more than 5 years, there are 2.3 women.

Calibrating longitudinal cognition in Alzheimer's disease across diverse test batteries and datasets

BACKGROUND

We sought to identify optimal approaches by calibrating longitudinal cognitive performance across studies with different neuropsychological batteries.

METHODS

We examined four approaches to calibrate cognitive performance in nine longitudinal studies of Alzheimer's disease (AD) (n = 10,875): (1) common test, (2) standardize and average available tests, (3) confirmatory factor analysis (CFA) with continuous indicators, and (4) CFA with categorical indicators. To compare precision, we determined the minimum sample sizes needed to detect 25% cognitive decline with 80% power. To compare criterion validity, we correlated cognitive change from each approach with 6-year changes in average cortical thickness and hippocampal volume using available MRI data from the AD Neuroimaging Initiative.

RESULTS

CFA with categorical indicators required the smallest sample size to detect 25% cognitive decline with 80% power (n = 232) compared to common test (n = 277), standardize-and-average (n = 291), and CFA with continuous indicators (n = 315) approaches. Associations with changes in biomarkers changes were the strongest for CFA with categorical indicators.

CONCLUSIONS

CFA with categorical indicators demonstrated greater power to detect change and superior criterion validity compared to other approaches. It has wide applicability to directly compare cognitive performance across studies, making it a good way to obtain operational phenotypes for genetic analyses of cognitive decline among people with AD.

The Value of Delaying Alzheimer's Disease Onset

Alzheimer's disease (AD) extracts a heavy societal toll. The value of medical advances that delay onset of AD could be significant. Using data from nationally representative samples from the Health and Retirement Study (1998-2008) and Aging Demographics and Memory Study (2001-2009), we estimate the prevalence and incidence of AD and the formal and informal health care costs associated with it. We use microsimulation to project future prevalence and costs of AD under different treatment scenarios. We find from 2010 to 2050, the number of individuals ages 70+ with AD increases 153%, from 3.6 to 9.1 million, and annual costs increase from $307 billion ($181B formal, $126B informal costs) to $1.5 trillion. 2010 annual per person costs were $71,303 and double by 2050. Medicare and Medicaid are paying 75% of formal costs. Medical advances that delay onset of AD for 5 years result in 41% lower prevalence and 40% lower cost of AD in 2050. For one cohort of older individuals, who would go on to acquire AD, a 5-year delay leads to 2.7 additional life years (about 5 AD-free), slightly higher formal care costs due to longer life but lower informal care costs for a total value of $511,208 per person. We find Medical advances delaying onset of AD generate significant economic and longevity benefits. The findings inform clinicians, policymakers, businesses and the public about the value of prevention, diagnosis, and treatment of AD.

Functional disability and cognitive impairment after hospitalization for myocardial infarction and stroke

BACKGROUND

We assessed the acute and long-term effect of myocardial infarction (MI) and stroke on postevent functional disability and cognition while controlling for survivors' changes in functioning over the years before the event.

METHODS AND RESULTS

Among participants in the nationally representative Health and Retirement Study with linked Medicare data (1998-2010), we determined within-person changes in functional limitations (basic and instrumental activities of daily living) and cognitive impairment after hospitalization for stroke (n=432) and MI (n=450), controlling for premorbid functioning using fixed-effects regression. In persons without baseline impairments, an acute MI yielded a mean acute increase of 0.41 functional limitations (95% confidence interval [CI], 0.18-0.63) with a linear increase of 0.14 limitations/year in the following decade. These increases were 0.65 limitations (95% CI, 0.07-1.23) and 0.27 limitations/year afterward for those with mild-to-moderate impairment at baseline. Stroke resulted in an acute increase of 2.07 (95% CI, 1.51-2.63) limitations because of the acute event and an increase of 0.15 limitations/year afterward for those unimpaired at baseline. There were 2.65 new limitations (95% CI, 1.86-3.44) and 0.19/year afterward for those with baseline mild-to-moderate impairment. Stroke hospitalization was associated with greater odds of moderate-to-severe cognitive impairment (odds ratio, 3.86; 95% CI, 2.10-7.11) at the time of the event, after adjustment for premorbid cognition but MI hospitalization was not.

CONCLUSIONS

In this population-based cohort, most MI and stroke hospitalizations were associated with significant increases in functional disability at the time of the event and in the decade afterward. Survivors of MI and stroke warrant screening for functional disability over the long-term.

Development and validation of a brief dementia screening indicator for primary care

BACKGROUND

Detection of "any cognitive impairment" is mandated as part of the Medicare annual wellness visit, but screening all patients may result in excessive false positives.

METHODS

We developed and validated a brief Dementia Screening Indicator using data from four large, ongoing cohort studies (the Cardiovascular Health Study [CHS]; the Framingham Heart Study [FHS]; the Health and Retirement Study [HRS]; the Sacramento Area Latino Study on Aging [SALSA]) to help clinicians identify a subgroup of high-risk patients to target for cognitive screening.

RESULTS

The final Dementia Screening Indicator included age (1 point/year; ages, 65-79 years), less than 12 years of education (9 points), stroke (6 points), diabetes mellitus (3 points), body mass index less than 18.5 kg/m(2) (8 points), requiring assistance with money or medications (10 points), and depressive symptoms (6 points). Accuracy was good across the cohorts (Harrell's C statistic: CHS, 0.68; FHS, 0.77; HRS, 0.76; SALSA, 0.78).

CONCLUSIONS

The Dementia Screening Indicator is a simple tool that may be useful in primary care settings to identify high-risk patients to target for cognitive screening.

Validation of a polygenic risk score for dementia in black and white individuals

OBJECTIVE

To determine whether a polygenic risk score for Alzheimer's disease (AD) predicts dementia probability and memory functioning in non-Hispanic black (NHB) and non-Hispanic white (NHW) participants from a sample not used in previous genome-wide association studies.

METHODS

Non-Hispanic white and NHB Health and Retirement Study (HRS) participants provided genetic information and either a composite memory score (n = 10,401) or a dementia probability score (n = 7690). Dementia probability score was estimated for participants' age 65+ from 2006 to 2010, while memory score was available for participants age 50+. We calculated AD genetic risk scores (AD-GRS) based on 10 polymorphisms confirmed to predict AD, weighting alleles by beta coefficients reported in AlzGene meta-analyses. We used pooled logistic regression to estimate the association of the AD-GRS with dementia probability and generalized linear models to estimate its effect on memory score.

RESULTS

Each 0.10 unit change in the AD-GRS was associated with larger relative effects on dementia among NHW aged 65+ (OR = 2.22; 95% CI: 1.79, 2.74; P < 0.001) than NHB (OR=1.33; 95% CI: 1.00, 1.77; P = 0.047), although additive effect estimates were similar. Each 0.10 unit change in the AD-GRS was associated with a -0.07 (95% CI: -0.09, -0.05; P < 0.001) SD difference in memory score among NHW aged 50+, but no significant differences among NHB (β = -0.01; 95% CI: -0.04, 0.01; P = 0.546). [Correction added on 29 July 2014, after first online publication: confidence intervalshave been amended.] The estimated effect of the GRS was significantly smaller among NHB than NHW (P < 0.05) for both outcomes.

CONCLUSION

This analysis provides evidence for differential relative effects of the GRS on dementia probability and memory score among NHW and NHB in a new, national data set.

Does Dementia Caregiving Accelerate Frailty? Findings From the Health and Retirement Study

PURPOSE OF THE STUDY

Numerous studies have discovered negative health consequences associated with spousal caregiving at the end of life; however, little is known about how care-recipient cognitive status impacts caregiver health outcomes, specifically in the area of frailty, and whether health consequences remain over time. This study examines differences in frailty between spousal caregivers of persons with and without a dementia diagnosis.

DESIGN AND METHODS

Using 7 biannual waves of the Health and Retirement Study data (1998-2010), we examined odds of becoming frailer among surviving spouses of individuals who died between 2000 and 2010 (N = 1,246) with and without dementia. To assess increased frailty, we used a Frailty Index, which assesses chronic diseases, mobility, functional status, depressive symptoms, and subjective health. Logistic regression was used to examine the relationship between care-recipient cognitive status and whether, compared with the wave prior to death of the care-recipient, spousal caregivers were frailer: (1) in the wave the death was reported and (2) 2 years after the death was reported.

RESULTS

Dementia caregivers had 40.5% higher odds of experiencing increased frailty by the time the death was reported and 90% higher odds in the following wave compared with non-dementia caregivers.

IMPLICATIONS

Given our findings, we discuss public health implications regarding the health and well-being of caregivers of persons with dementia. Given projected increases in dementia diagnoses as the population ages, we propose a need for interventions that provide enhanced support for dementia caregivers.

Hospital and nursing home use from 2002 to 2008 among U.S. older adults with cognitive impairment, not dementia in 2002

Little is known about health care use in the cognitive impairment, not dementia (CIND) subpopulation. Using a cohort of 7130 persons aged 71 years or over from the Health and Retirement Survey, we compared mean and total health care use from 2002 to 2008 for those with no cognitive impairment, CIND, or dementia in 2002. Cognitive status was determined using a validated method based on self or proxy interview measures. Health care use was also based on self or proxy reports. On the basis of the Health and Retirement Survey, the CIND subpopulation in 2002 was 5.3 million or 23% of the total population 71 years of age or over. Mean hospital nights was similar and mean nursing home nights was less in persons with CIND compared with persons with dementia. The CIND subpopulation, however, had more total hospital and nursing home nights--71,000 total hospital nights and 223,000 total nursing home nights versus 32,000 hospital nights and 138,000 nursing home nights in the dementia subpopulation. A relatively large population and high health care use result in a large health care impact of the CIND subpopulation.