Cognitive impairment assessed by Mini-Mental State Examination predicts all-cause and CVD mortality in Chinese older adults: A 10-year follow-up study

Objective

Cognitive impairment (CI) has been demonstrated as a useful proxy measure of mortality in Western populations. However, the predictive value of CI in Chinese populations is unknown. We aimed to explore whether CI is independently associated with increased long-term all-cause and cardiovascular disease (CVD) mortality in Chinese older adults and the association of performance in specific MMSE sub-domains to subsequent mortality.

Methods and results

A total of 4,499 older adults [mean (SD) age, 70.3(6.7) years] who received a sample investigation from 2011 to 2014 were followed up till 2021 for mortality. The Mini-Mental State Examination was used to assess cognitive function, and Cox's proportional hazard models were used to evaluate the effects of cognitive function on the risk of all-cause and CVD mortality. Demographic characteristics, lifestyle, and health status were included as covariates. During a 10-year follow-up, a total of 667 (14.8%) died. In the fully adjusted model, compared with cognitively normal participants with CI had a 1.33-fold [HR, 1.33; (95% CI, 1.10-1.61)] greater risk of all-cause mortality and a 1.45-fold [HR, 1.45; (95% CIs, 1.11-1.92)] greater risk of CVD mortality. After a similar multivariable adjustment, a per-SD increase in MMSE scores was associated with a reduced risk of all-cause mortality [HR, 0.85; (95% CI, 0.78-0.93)] and CVD mortality [HR, 0.74; (95% CI, 0.65-0.84)]. In the unadjusted model, MMSE sub-domains (apart from immediate recall) were associated with mortality. But only orientation and calculation and attention were still independently associated with all-cause and CVD mortality in a multivariable model.

Conclusion

These findings confirmed that CI is a marker of all-cause and CVD mortality risk in Chinese older adults, independently of other commonly assessed risk factors, and some sub-domains of the MMSE may have stronger associations with mortality. Further research is needed to identify the mechanisms underlying the observed associations.

System Complexity in Influenza Infection and Vaccination: Effects upon Excess Winter Mortality

Unexpected outcomes are usually associated with interventions in complex systems. Excess winter mortality (EWM) is a measure of the net effect of all competing forces operating each winter, including influenza(s) and non-influenza pathogens. In this study over 2400 data points from 97 countries are used to look at the net effect of influenza vaccination rates in the elderly aged 65+ against excess winter mortality (EWM) each year from the winter of 1980/81 through to 2019/20. The observed international net effect of influenza vaccination ranges from a 7.8% reduction in EWM estimated at 100% elderly vaccination for the winter of 1989/90 down to a 9.3% increase in EWM for the winter of 2018/19. The average was only a 0.3% reduction in EWM for a 100% vaccinated elderly population. Such outcomes do not contradict the known protective effect of influenza vaccination against influenza mortality per se—they merely indicate that multiple complex interactions lie behind the observed net effect against all-causes (including all pathogen causes) of winter mortality. This range from net benefit to net disbenefit is proposed to arise from system complexity which includes environmental conditions (weather, solar cycles), the antigenic distance between constantly emerging circulating influenza clades and the influenza vaccine makeup, vaccination timing, pathogen interference, and human immune diversity (including individual history of host-virus, host-antigen interactions and immunosenescence) all interacting to give the observed outcomes each year. We propose that a narrow focus on influenza vaccine effectiveness misses the far wider complexity of winter mortality. Influenza vaccines may need to be formulated in different ways, and perhaps administered over a shorter timeframe to avoid the unanticipated adverse net outcomes seen in around 40% of years.

Trajectories of Pain in Very Old Age: The Role of Eudaimonic Wellbeing and Personality

Pain is common in very old age and in the last years prior to death. However, little is known regarding longitudinal trajectories of pain in very old age and at the end of life. Moreover, whereas medical and morbidity-related factors contributing to pain are established, the role of psychosocial factors, such as eudaimonic wellbeing or personality as potential determinants of late-life pain trajectories has so far not been sufficiently investigated. We used data from the LateLine project. The sample consisted of n = 118 very old adults (M = 90.5 years, SD = 2.8 years) who were living alone at baseline and who had died between 2009 and 2021. They took part in up to 16 measurement occasions (M = 5.2, SD = 4.7, range 1–16) within an observational interval of 7 years. Assessment of pain was based on the SF-36 bodily pain subscale. Key indicators of eudaimonic wellbeing (autonomy, environmental mastery, and purpose in life) as well two of the Big Five personality traits (neuroticism and extraversion) were included as predictors. We controlled in all analyses for gender, education, subjective health, and depressive symptoms. Contrasting pain trajectories over chronological age (time since birth) vs. time to death, a time-to-death-related model resulted in a better model fit and accounted for a larger amount of pain variability than the age-related model. Mean-level change in pain, both over age and time to death, was not significant, but there was substantial interindividual variability in intraindividual trajectories. Age-related change in pain was significantly predicted by autonomy and neuroticism, with increasing pain among those who had lower initial autonomy scores and higher initial neuroticism scores. With regard to time-to-death-related trajectories of pain, higher purpose in life as well as lower extraversion at baseline predicted less increase or even steeper decrease in pain with approaching death. Our findings suggest that, despite overall mean-level stability in pain both over age and time to death, there is a substantial proportion of individuals who reveal deterioration in pain over time. Regarding the role of psychosocial predictors, personality traits and eudaimonic wellbeing are related with late-life pain trajectories both over age and time-to-death.

Is simple reaction time or choice reaction time an indicator of all-cause mortality or CVD mortality?

OBJECTIVES

Simple reaction time (SRT) and choice reaction time (CRT) have been shown to be good indicators for quantitatively assessing the level of human cognitive impairment, but these parameters have also been linked to the risk of human death. This study aimed to quantitatively assess the independent predictive value of SRT or CRT for all-cause mortality or cardiovascular disease (CVD) mortality by conducting a meta-analysis of prospective studies.

STUDY DESIGN

The study design of this study is a prospective cohort study.

METHODS

We conducted a meta-analysis by combining hazard ratios (HRs) and 95% confidence intervals (95% CIs) of SRT or CRT with all-cause mortality or CVD mortality in healthy community residents aged 18 and over. Heterogeneity was evaluated by using Q statistics and Cochrane's I² statistics.

RESULTS

A total of seven prospective studies that examined all-cause mortality and CVD mortality were included. The pooled HR of all-cause mortality in SRT was 1.099 (1.065-1.134, I² = 11.9%), and an increased risk of CVD mortality was associated with lower SRT (HR = 1.186, 95% CI = 1.137-1.236; I² = 52.4%). Similarly, the pooled HR of all-cause mortality in CRT was 1.140 (95% CI = 1.085-1.197, I² = 33.7%). However, lower CRT was not statistically associated with an increased risk of CVD mortality.

CONCLUSION

SRT may be a predictor of all-cause-mortality and CVD mortality, and CRT is significantly associated with an increased risk of all-cause mortality.

Healthy Aging-Relevant Goals: The Role of Person-Context Co-construction

OBJECTIVES

This article considers how individuals' motivation for healthy aging manifests within the myriad of different contexts that older adults are embedded in as they move through later life.

METHODS

Drawing on the concept of co-construction, we argue that persons and contexts both contribute to the emergence, maintenance, and disengagement from healthy aging relevant goals in adulthood and old age.

RESULTS

To promote the understanding of such co-constructive dynamics, we propose four conceptual refinements of previous healthy aging models. First, we outline various different, often multidirectional, ways in which persons and contexts conjointly contribute to how people set, pursue, and disengage from health goals. Second, we promote consideration of context as involving unique, shared, and interactive effects of socio-economic, social, physical, care/service, and technology dimensions. Third, we highlight how the relevance, utility, and nature of these context dimensions and their role in co-constructing health goals change as individuals move through the Third Age, the Fourth Age, and a terminal stages of life. Finally, we suggest that these conceptual refinements be linked to established (motivational) theories of lifespan development and aging.

DISCUSSIONS

In closing, we outline a set of research questions that promise to advance our understanding of the mechanisms by which contexts and aging persons co-construct healthy aging relevant goals and elaborate on the applied significance of this approach for common public health practices.

Exploring Quality of Life Reported by Norwegian Older Adults Using Classification Tree Approach on Group Profiles

This study aims to explore the variation between- and within subgroups of older adults with regard to low, medium, and high levels of self-reported quality of life (QoL) measured by the WHOQOL-BREF scale. The contribution of interacting personal and contextual life conditions to QoL was examined in a sample of 1,910 (sample frame 6,000) Norwegian men and women aged 62 to 99 years. The data collected by a postal questionnaire were analyzed using the Chi-square Automatic Interaction Detection (CHAID) classification method in order to detect unique profiles of groups who shared common characteristics. The CHAID model revealed 15 relatively homogenous groups, but distinct from one another, whose profiles were defined by unique constellations of several interacting variables significantly related to a given QoL level. Mental functioning was predominantly linked to perception of life meaning along with health status, and/or in some cases living arrangement, loneliness, neighborhood quality, and satisfaction with income, and placed an individual at different likelihood levels of reporting low, medium, or high QoL. Socio-demographics had no statistically significant impact on QoL for any subgroup. Through this individual-oriented approach, a periodically ongoing assessment of subjective quality of life (QoL) may be sufficiently powerful to allow detecting and addressing personal concerns and specific needs that detract from quality of life in advancing age.

Advanced old age as a developmental dilemma: An in-depth comparison of established fourth age conceptualizations

Distinguishing the Fourth Age (FoA) from the Third Age (ThA) has become a common practice in aging research. In this theoretical paper, we focus on four established conceptualizations of the ThA-FoA distinction, i.e., (1) Neugarten's work on the young-old vs. the old-old; (2) Laslett's concept of the innovative life period of the ThA; (3) Erikson's 9th life stage approach; and (4) Baltes' approach considering the FoA as the most radical incompleteness of the human condition. After a comparative descriptive analysis, we extract evaluative elements inherent in the four approaches according to six categories: (1) fundamental values; (2) positive evaluative elements; (3) negative evaluative elements; (4) the decline vs. growth view; (5) the continuity vs. discontinuity view; and (6) values related to practical issues. As an overarching result of our analysis, we conclude that all conceptions face - in different ways - dilemmas that seem difficult to solve. One option may be to give up all ambitions toward agency for the FoA and indeed qualify this phase as the "aging without agency" phase of life. Doing so, however, seems ethically questionable, because it would give up acknowledged values connected with a good human life such as human goal-directed autonomy and freedom. In conclusion, the ThA-FoA distinction, although arguably a needed and helpful roadmap for the recent decades of aging science, comes with enduring disadvantages and eventually even risks. Therefore, in future aging science, we recommend avoiding the ThA-FoA distinction or at least using it only in combination with a critical attitude.

The Mental Landscape of Imagining Life Beyond the Current Life Span: Implications for Construal and Self-Continuity

Background and Objectives

With rapid advancements in medicine, technology, and nutrition, the future holds the possibility of longer and healthier lives. Despite garnering attention from myriad disciplines, psychological perspectives on life extension are scarce. In three studies, we addressed this gap by exploring key mental characteristics and psychological variables associated with simulating an expanded life span and thus an extremely distant future self.

Research Design and Methods

Three studies investigated the construal (i.e., valence, vividness, and visual perspective) of extremely distant future simulations and the extent to which participants felt connected to their future selves (i.e., self-continuity). Studies 1 and 2 investigated the characteristics of imagery associated with different ages ranging from near the current species maximum (e.g., 120, 150) to more highly hypothetical ages (e.g., 201, 501). Study 3 probed the mental construal of extreme aging among different populations (i.e., life-extension supporters, students, and Mechanical Turk workers). Studies also assessed participants’ general feelings about the ethicality and likelihood of techniques that halt or reverse biological aging to help individuals live beyond the current life expectancy.

Results

Participants in all studies reported being able to vividly imagine expanded aging scenarios (increased chronological, without biological, and aging), but these simulations were characterized by a decreased sense of connection to one’s future self (i.e., self-continuity) compared to a control condition. Temporal distance did not, however, impact ratings of self-continuity when comparing experimental conditions (i.e., imagining one’s self 120 vs 150 or 201 vs 501). Curiously, a sense of self-continuity (when simulating oneself well beyond the current life expectancy) remained intact for individuals who belonged to a community of life-extension supporters. The perceived likelihood and ethicality of extended life-span scenarios also varied significantly across different populations.

Discussion and Implications

The current work is the first to quantify the disconnect between one’s current and extremely distant (i.e., beyond the current life expectancy) future self. Given the behavioral implications of feeling disconnected from one’s future self (e.g., failing to save for retirement or care for one’s own physical health), these findings inform a critical barrier of extended life spans and provide insight into potential remedies (e.g., enhancing the perceived likelihood of living longer). Theoretical implications of hypotheticality and temporal distance, two key dimensions of Construal Level Theory, and their impact on the construal and self-continuity associated with future simulations are also discussed.

Person–Environment Resources for Aging Well: Environmental Docility and Life Space as Conceptual Pillars for Future Contextual Gerontology

A variety of different disciplines in the study of aging have long acknowledged that individual functioning and development are profoundly shaped by the contexts people live in. The Gerontologist has played a central role in publishing and fostering theoretical and empirical work geared toward better understanding many of the questions that revolve around the how and the why. To illustrate, we consider in a first step the environmental docility hypothesis and the life space construct as two landmark concepts published in The Gerontologist and review how these—in conjunction with the later introduced proactivity perspective—have shaped for decades and continue to shape the larger field of (contextual) gerontology. In a second step, we discuss how these two entirely separate conceptualizations could be integrated in a late pas-de-deux. In doing so, we also make use of Wahl & Gerstorf's conceptual framework for studying COntext Dynamics in Aging (CODA) to discuss how these classic concepts can promote future gerontological research.

Well-Being at the End of Life

This review proposes that the end of life is a uniquely contemporary life course stage. Epidemiologic, technological, and cultural shifts over the past two centuries have created a context in which dying has shifted from a sudden and unexpected event to a protracted, anticipated transition following an incurable chronic illness. The emergence of an end-of-life stage lasting for months or even years has heightened public interest in enhancing patient well-being, autonomy, and the receipt of medical care that accords with patient and family members' wishes. We describe key components of end-of-life well-being and highlight socioeconomic and race disparities therein, drawing on fundamental cause theory. We describe two practices that are critical to end-of-life well-being (advance care planning and hospice) and identify limitations that may undermine their effectiveness. We conclude with recommendations for future sociological research that could inform practices to enhance patient and family well-being at the end of life.

Understanding the relationship between cognition and death: a within cohort examination of cognitive measures and mortality

Despite several studies demonstrating an independent and inverse association between cognition and mortality, the nature of this association still remains unclear. To examine the association of cognition and mortality after accounting for sociodemographic, health and lifestyle factors and to explore both test and population characteristics influencing this relationship. In a population based cohort of 8585 men and women aged 48-92 years, who had cognitive assessments in 2006-2011 and were followed up till 2016 for mortality, we examined the relationship between individual cognitive tests as well as a global cognition score to compare their ability in predicting mortality and whether these differed by population characteristics. Risk of death was estimated using Cox proportional hazard regression models including sociodemographic, lifestyle and health variables, and self-reported comorbidities, as covariates in the models. Poor cognitive performance (bottom quartile of combined cognition score) was associated with higher risk of mortality, Hazard Ratio = 1.32 (95% Confidence Interval 1.09, 1.60); individual cognitive tests varied in their mortality associations and also performed differently in middle-age and older age groups. Poor cognitive performance is independently associated with higher mortality. This association is observed for global cognition and for specific cognitive abilities. Associations vary depending on the cognitive test (and domain) as well as population characteristics, namely age and education.

Loneliness and depression symptoms among the elderly in nursing homes: A moderated mediation model of resilience and social support

Loneliness has been identified as a risk factor for depressive symptoms. Resilience and social support have been regarded as underlying protective factors. Little is known about the complex relations among these factors in the nursing home elderly. This study aimed to assess the prevalence of depressive symptoms, explore whether resilience mediated the association between loneliness and depressive symptoms, and investigate whether social support moderated the indirect or direct effect of mediation model. A total of 323 nursing home elderly were recruited in Jinan City, China. Loneliness, resilience, social support and depressive symptoms were measured. Results shown the association between loneliness and depressive symptoms was partially mediated by resilience. Besides, the indirect effect of the mediation model was moderated by social support. When the level of social support was higher, the indirect effect of loneliness on depressive symptoms through resilience was weaker. The incidence of depressive symptoms among the nursing home elderly could not be neglected. The findings suggest that interventions, such as improving resilience and social support, may help break the link between loneliness and depressive symptoms among the elderly in nursing homes.

The connection between subjective nearness-to-death and depressive symptoms: The mediating role of meaning in life

Depression is characterized by a wide range of emotional, cognitive, and physical symptoms. Two prominent features of depressive symptoms are a sense that life has no meaning on the one hand, and that life is not worth living on the other hand. In recent years, the subjective perception of how close one feels to his/her death has gained importance as a significant factor associated with various aspects of physical and psychological well-being. Thus, the current study examined the connection between subjective nearness-to-death, meaning in life, and depressive symptoms, and assessed whether meaning in life mediates the connection between subjective nearness-to-death and depressive symptoms. Data was collected from 268 participants between the ages of 28 and 74 (mean age = 46.75), who completed measures of subjective nearness-to-death, meaning in life, and depressive symptoms. Results yielded a significant positive connection between subjective nearness-to-death and depressive symptoms, as well as a negative connection between meaning in life and depressive symptoms. Moreover, meaning in life was found to mediate the connection between subjective nearness-to-death and depressive symptoms. Findings are discussed in light of the Terror Management Theory, and potential clinical implications are suggested.

Decline in Memory, Visuospatial Ability, and Crystalized Cognitive Abilities in Older Adults: Normative Aging or Terminal Decline?

The aim of this study is to explore the pattern of change in multiple measures of cognitive abilities in a sample of oldest-old adults, comparing two different time metrics (chronological age and time to death) and therefore examining both underlying conceptual assumptions (age-related change and terminal decline). Moreover, the association with individual characteristics as sex, education, and dementia diagnosis was also examined. Measures of cognitive status (Mini-Mental State Examination and the Swedish Clock Test) and tests of crystallized (knowledge and synonyms), memory (verbal memory, nonverbal long-term memory, recognition and correspondence, and short-term memory), and visuospatial ability were included. The sample consisted of 671 older Swedish adult participants of the OCTO Twin Study. Linear mixed models with random coefficients were used to analyse change patterns and BIC indexes were used to compare models. Results showed that the time to death model was the best option in analyses of change in all the cognitive measures considered (except for the Information Test). A significant cognitive decline over time was found for all variables. Individuals diagnosed with dementia had lower scores at the study entrance and a faster decline. More educated individuals performed better in all the measures of cognition at study entry than those with poorer education, but no differences were found in the rate of change. Differences were found in age, sex, or time to death at baseline across the different measures. These results support the terminal decline hypothesis when compared to models assuming that cognitive changes are driven by normative aging processes.

Think Fast, Feel Fine, Live Long: A 29-Year Study of Cognition, Health, and Survival in Middle-Aged and Older Adults

In a 29-year study of 6,203 individuals ranging in age from 41 to 96 years at initial assessment, we evaluated the relative and combined influence of 65 mortality risk factors, which included sociodemographic variables, lifestyle attributes, medical indices, and multiple cognitive abilities. Reductions in mortality risk were most associated with higher self-rated health, female gender, fewer years as a smoker, and smaller decrements in processing speed with age. Thus, two psychological variables-subjective health status and processing speed-were among the top predictors of survival. We suggest that these psychological attributes, unlike risk factors that are more narrowly defined, reflect (and are influenced by) a broad range of health-related behaviors and characteristics. Information about these attributes can be obtained with relatively little effort or cost and-given the tractability of these measures in different cultural contexts-may prove expedient for prevention, diagnosis, and treatment of conditions related to increased mortality risk in diverse human populations.

Selective attrition and intraindividual variability in response time moderate cognitive change

OBJECTIVES

Selection of a developmental time metric is useful for understanding causal processes that underlie aging-related cognitive change and for the identification of potential moderators of cognitive decline. Building on research suggesting that time to attrition is a metric sensitive to non-normative influences of aging (e.g., subclinical health conditions), we examined reason for attrition and intraindividual variability (IIV) in reaction time as predictors of cognitive performance.

METHOD

Three hundred and four community dwelling older adults (64-92 years) completed annual assessments in a longitudinal study. IIV was calculated from baseline performance on reaction time tasks. Multilevel models were fit to examine patterns and predictors of cognitive change.

RESULTS

We show that time to attrition was associated with cognitive decline. Greater IIV was associated with declines on executive functioning and episodic memory measures. Attrition due to personal health reasons was also associated with decreased executive functioning compared to that of individuals who remained in the study.

DISCUSSION

These findings suggest that time to attrition is a useful metric for representing cognitive change, and reason for attrition and IIV are predictive of non-normative influences that may underlie instances of cognitive loss in older adults.

Cognition and mortality in older people: the Sydney Memory and Ageing Study

BACKGROUND

Both cognitive ability and cognitive decline have been shown to predict mortality in older people. As dementia, a major form of cognitive decline, has an established association with shorter survival, it is unclear the extent to which cognitive ability and cognitive decline predict mortality in the absence of dementia.

OBJECTIVE

To determine whether cognitive ability and decline in cognitive ability predict mortality in older individuals without dementia.

DESIGN

The Sydney Memory and Ageing Study is an observational population-based cohort study. Participants completed detailed neuropsychological assessments and medical examinations to assess for risk factors such as depression, obesity, hypertension, diabetes, hypercholesterolaemia, smoking and physical activity. Participants were regularly assessed at 2-year intervals over 8 years.

SETTING

A community sample in Sydney, Australia.

SUBJECTS

One thousand and thirty-seven elderly people without dementia.

RESULTS

Overall, 236 (22.8%) participants died within 8 years. Both cognitive ability at baseline and decline in cognitive ability over 2 years predicted mortality. Decline in cognitive ability, but not baseline cognitive ability, was a significant predictor of mortality when depression and other medical risk factors were controlled for. These relationships also held when excluding incident cases of dementia.

CONCLUSIONS

The findings indicate that decline in cognition is a robust predictor of mortality in older people without dementia at a population level. This relationship is not accounted for by co-morbid depression or other established biomedical risk factors.

Changes in Optimism Are Associated with Changes in Health Over Time Among Older Adults

Little is known about how optimism differs by age and changes over time, particularly among older adults. Even less is known about how changes in optimism are related to changes in physical health. We examined age differences and longitudinal changes in optimism in 9,790 older adults over a four-year period. We found an inverted U-shaped pattern between optimism and age both cross-sectionally and longitudinally, such that optimism generally increased in older adults before decreasing. Increases in optimism over a four-year period were associated with improvements in self-rated health and fewer chronic illnesses over the same time frame. The findings from the current study are consistent with changes in emotion regulation strategies employed by older adults and age-related changes in well-being.

The utility of estimating population-level trajectories of terminal wellbeing decline within a growth mixture modelling framework

PURPOSE

Mortality-related decline has been identified across multiple domains of human functioning, including mental health and wellbeing. The current study utilised a growth mixture modelling framework to establish whether a single population-level trajectory best describes mortality-related changes in both wellbeing and mental health, or whether subpopulations report quite different mortality-related changes.

METHODS

Participants were older-aged (M = 69.59 years; SD = 8.08 years) deceased females (N = 1,862) from the dynamic analyses to optimise ageing (DYNOPTA) project. Growth mixture models analysed participants' responses on measures of mental health and wellbeing for up to 16 years from death.

RESULTS

Multi-level models confirmed overall terminal decline and terminal drop in both mental health and wellbeing. However, modelling data from the same participants within a latent class growth mixture framework indicated that most participants reported stability in mental health (90.3 %) and wellbeing (89.0 %) in the years preceding death.

CONCLUSIONS

Whilst confirming other population-level analyses which support terminal decline and drop hypotheses in both mental health and wellbeing, we subsequently identified that most of this effect is driven by a small, but significant minority of the population. Instead, most individuals report stable levels of mental health and wellbeing in the years preceding death.

A framework for studying mechanisms underlying terminal decline in well-being

Multiple facets of well-being are known to show steep end-of-life deteriorations. However, the underlying mechanisms and pathways are vague. Capitalizing on an earlier review of the existing empirical literature on terminal decline, we present a conceptual/methodological framework that can be used as a tool to structure future inquiry aimed at refining the precision and specificity of the terminal decline concept. Specifically, we propose a model of terminal decline in well-being in which within-person mean levels of, inconsistencies in, or couplings among multiple domains of functioning serve as indicators or sources of well-being. The model, based on time-varying dynamic factor analysis of intensive longitudinal data, provides for concise articulation and testing of central tenets of theories of successful aging, including hypotheses regarding shifts in goals away from some domains and towards others (e.g. secondary control). We conclude by suggesting routes for empirical research.

The dynamic relationship between cognitive function and walking speed: the English Longitudinal Study of Ageing

Cross-sectional studies show that older people with better cognition tend to walk faster. Whether this association reflects an influence of fluid cognition upon walking speed, vice versa, a bidirectional relationship or the effect of common causes is unclear. We used linear mixed effects models to examine the dynamic relationship between usual walking speed and fluid cognition, as measured by executive function, verbal memory and processing speed, in 2,654 men and women aged 60 to over 90 years from the English Longitudinal Study of Ageing. There was a bidirectional relationship between walking speed and fluid cognition. After adjusting for age and sex, better performance on executive function, memory and processing speed was associated with less yearly decline in walking speed over the 6-year follow-up period; faster walking speed was associated with less yearly decline in each cognitive domain; and less yearly decline in each cognitive domain was associated with less yearly decline in walking speed. Effect sizes were small. After further adjustment for other covariates, effect sizes were attenuated but most remained statistically significant. We found some evidence that walking speed and the fluid cognitive domains of executive function and processing speed may change in parallel with increasing age. Investigation of the association between walking speed and cognition earlier in life is needed to better understand the origins of this relation and inform the development and timing of interventions.

Donepezil and life expectancy in Alzheimer's disease: a retrospective analysis in the Tajiri Project

Background

Cholinesterase inhibitors (ChEIs) such as donepezil have the effect of delaying progression of Alzheimer’s disease (AD), but their effect on life expectancy is unclear. We analyzed the influence of donepezil on life expectancy after onset of AD, together with the effects of antipsychotic drugs and residency in a nursing home.

Methods

All outpatients at the Tajiri Clinic from 1999–2012 with available medical records and death certificates were included in a retrospective analysis. The entry criteria were a dementia diagnosis based on DSM-IV criteria and diagnosis of AD using NINCDS-ADRDA criteria; medical treatment for more than 3 months; and follow up until less than 1 year before death.

Results

We identified 390 subjects with medical records and death certificates, of whom 275 had a diagnosis of dementia that met the entry criteria. Of 100 patients diagnosed with AD, 52 had taken donepezil and 48 patients had not received the drug due to treatment prior to the introduction of donepezil in 1999 in Japan. The lifetime expectancies after onset were 7.9 years in the donepezil group and 5.3 years in the non-donepezil group. There was a significant drug effect with a significant covariate effect of nursing home residency. Other covariates did not reach a significant level.

Conclusions

Although this report has the limitation of all retrospective analyses: the lack of randomization, we found a positive effect of donepezil on lifetime expectancy after onset of AD. This may be due to a decreased mortality rate caused by reduction of concomitant diseases such as pneumonia. The similar life expectancies in patients taking donepezil at home and those not taking donepezil in a nursing home indicated a positive health economic effect of the drug.

Apolipoprotein E ε4 and later-life decline in cognitive function and grip strength

OBJECTIVES

Presence of the apolipoprotein E (APOE) ε4 allele is a risk factor for dementia, whereas the ε2 allele offers protection against dementia. There is also evidence for a relationship between APOE genotype and changes in cognitive function. It is not clear, however, whether this relationship stems from undetected disease in persons genetically more vulnerable to dementia. This study examined whether APOE genotype was associated with either initial performance or change in performance on a range of cognitive and noncognitive tasks, after accounting for possible preclinical dementia.

DESIGN

A population-based cohort was assessed up to four times over 12 years.

PARTICIPANTS

The sample was an Australian cohort of 590 participants age 70 years and older who were genotyped for APOE.

MEASUREMENTS

The outcomes were processing speed, verbal fluency, episodic memory, word recognition, face recognition, grip strength, and reaction time.

RESULTS

Adjusted latent growth models indicated that ε4 carriers had significantly poorer initial memory performance and greater declines in processing speed and word recognition than ε2 and ε3 carriers. In addition, ε2 carriers exhibited significantly less decline in right grip strength than ε3 carriers. However, after excluding 125 participants with low global cognition scores, all genotype effects became nonsignificant.

CONCLUSIONS

Over a 12-year period, findings indicate that APOE ε4-related cognitive decline in older community-dwelling populations is due to a higher likelihood of preclinical dementia among ε4 carriers. When possible dementia cases are removed from the analyses, ε4 associations with cognitive decline become statistically unreliable.

Selectivity of attrition in longitudinal studies of cognitive functioning

OBJECTIVES

Identify characteristics distinguishing people who do and do not continue to participate in a longitudinal study and determine whether the longitudinal changes for people who continue are representative of the changes that would have occurred had longitudinal data been available from all of the initial participants.

METHOD

Moderately large samples of returning (N = 2,082) and nonreturning (N = 1,698) participants across a wide age range (i.e., 18-97 years of age) performed a battery of cognitive tests and completed personality and mood questionnaires. Differences between the groups were examined with multiple regression analyses with age, returner status, and their interaction as predictors.

RESULTS

Compared with participants who did not return, returning participants at the initial occasion had higher levels of each cognitive ability and of certain personality characteristics (e.g., agreeableness and openness), but many of the differences were only apparent among adults older than 50 years of age. Importantly, there was no evidence that the longitudinal change for nonreturning participants would have been different from that among the participants who did return.

DISCUSSION

The phenomenon of selective attrition is more complex than often assumed, and it may not necessarily limit the generalizability of longitudinal comparisons.

Inquiry into terminal decline: five objectives for future study

Notions of terminal decline propose that late-life change is primarily driven by processes closely tied to pathology and mortality rather than chronological age. We use the rationales of longitudinal research as outlined by Baltes and Nesselroade (Baltes, P., & Nesselroade, J. [1979]. History and rationale of longitudinal research. In J. R. Nesselroade & P. Baltes (Eds.), Longitudinal research in the study of behavior and development [pp. 1-39]. San Diego, CA: Academic Press) as a framework for organizing research on terminal decline. In doing so, we note that there are relatively robust descriptions of terminal decline across a variety of different domains, as well as the extent of interindividual differences in the levels of function, rates of change, and timing of terminal decline (research rationales 1 and 2). However, there is much more to learn about the interrelations among change in different domains, the underlying mechanisms of change, and the factors that contribute to interindividual differences in change (research rationales 3-5). Needed are new study designs and analytical models that better address the structural, temporal, and causal interrelations that contribute to and protect against terminal decline.

Mini-Mental Status Examination as predictors of mortality in the elderly

OBJECTIVE

Because the number of elderly is increasing worldwide, cognitive dysfunction becomes important health care issue. This study investigated the association between cognitive dysfunction and mortality in the elderly.

METHOD

Data were analyzed from a longitudinal mortality follow-up study of 2712 Korean elderly aged 60 and over, examined in 2002 with complete data followed an average 6.03 years. Measurements included socio-demographic and clinical factors and Mini-Mental State Examination (MMSE). MMSE was categorized into groups with no, mild, or moderate cognitive dysfunction, and the subscores of MMSE domains were categorized into no dysfunction or dysfunction. The Cox proportional hazards models were conducted to examine the association between MMSE score and mortality, after adjusting for age, gender, education and other socio-demographic factors.

RESULTS

Death during follow-up occurred in 318 subjects. The mortality risk was significantly associated with the elderly with mild cognitive dysfunction [hazard ratio (HR) = 1.93] and with moderate cognitive dysfunction (HR = 2.66). 'Orientation-to-time' (HR = 1.39) and 'Attention' (HR = 1.48) domains of MMSE were independently associated with mortality.

CONCLUSION

This study showed that cognitive dysfunction independently predicted mortality in the elderly. Cognitive dysfunction should be considered part of identifying the elderly at high risk for mortality.

Depression, anxiety and cognition in community-dwelling adults aged 70 years and over

Although there is evidence of associations between anxiety, depression and cognitive function in old age, there is little work investigating relations between those variables over an extended period of time. Therefore, we used data from the Canberra Longitudinal Study to investigate 12-year cognitive change over four measurement points in relation to anxiety and depression symptoms. Latent growth models on over 836 community-dwelling persons aged 70 years and over, recruited from the electoral roll suggested that higher depression symptom scores were associated with poorer initial performance in processing speed, verbal fluency and episodic memory while higher anxiety symptom scores were associated with verbal fluency. We found no evidence that mental health variables affected change in cognition over time. Importantly, when possible mild cognitive impairment or dementia cases were removed from the models, associations between the cognitive variables and depression symptoms disappeared while those for anxiety symptoms strengthened. The findings are consistent with the possibility that depression-related cognitive deficits represent a prodrome or risk factor for dementia while associations between anxiety and cognition may be more characteristic of normal aging.

Practice-oriented retest learning as the basic form of cognitive plasticity of the aging brain

It has been well documented that aging is associated with declines in a variety of cognitive functions. A growing body of research shows that the age-related cognitive declines are reversible through cognitive training programs, suggesting maintained cognitive plasticity of the aging brain. Retest learning represents a basic form of cognitive plasticity. It has been consistently demonstrated for adults in young-old and old-old ages. Accumulated research indicates that retest learning is effective, robust, endurable and could occur at a more conceptual level beyond item-specific memorization. Recent studies also demonstrate promisingly broader transfer effects from retest practice of activities involving complex executive functioning to other untrained tasks. The results shed light on the development of self-guided mental exercise programs to improve cognitive performance and efficiency of the aging brain. The relevant studies were reviewed, and the findings were discussed in light of their limitations, implications, and future directions.

Linking biological and cognitive aging: toward improving characterizations of developmental time

OBJECTIVES

Chronological age is the most frequently employed predictor in life-span developmental research, despite repeated assertions that it is best conceived as a proxy for true mechanistic changes that influence cognition across time. The present investigation explores the potential that selected functional biomarkers may contribute to the more effective conceptual and operational definitions of developmental time.

METHODS

We used data from the Victoria Longitudinal Study to explore both static and dynamic biological or physiological markers that arguably influence process-specific mechanisms underlying cognitive changes in late life. Multilevel models were fit to test the dynamic coupling between change in theoretically relevant biomarkers (e.g., grip strength, pulmonary function) and change in select cognitive measures (e.g., executive function, episodic and semantic memory).

RESULTS

Results showed that, independent of the passage of developmental time (indexed as years in study), significant time-varying covariation was observed linking corresponding declines for select cognitive outcomes and biological markers.

DISCUSSION

Our findings support the interpretation that cognitive decline is not due to chronological aging per se but rather reflects multiple causal factors from a broad range of biological and physical health domains that operate along the age continuum.

Trajectories of cognitive decline following dementia onset: what accounts for variation in progression?

BACKGROUND

Delineating the natural history of dementia progression has important clinical implications, including reducing caregiver burden and targeting effective drug trials. We examined whether trajectories of cognitive change differed reliably after diagnosis, and whether diverse predictors of such differences (demographic, psychological, biological, genetic, social) could be identified.

METHODS

Cognitive change was examined for incident dementia cases (mild: n = 156; moderate: n = 77; severe: n = 73) and controls (n = 249) from the Kungsholmen Project, a community-based study of adults 75 years and older.

RESULTS

For those with dementia, total variance attributed to between-person differences in cognitive decline was modest and linked to but a single predictor (history of cardiovascular disease). Although less variance in cognitive decline was observed for the similarly aged controls, numerous significant predictors of these differences were identified.

CONCLUSION

The neurodegenerative process underlying dementia overshadows formerly significant predictors of cognitive change.

Losing one's grip: a bivariate growth curve model of grip strength and nonverbal reasoning from age 79 to 87 years in the Lothian Birth Cohort 1921

OBJECTIVES

Grip strength and reasoning are associated in old age. This is one of the few longitudinal studies addressing whether aging of one causes decline in the other or whether they share causal influences.

METHODS

The Lothian Birth Cohort 1921 were assessed for grip strength and nonverbal reasoning at ages M = 79 (N = 550), M = 83 (N = 321), and M = 87 (N = 207). Associations among intercepts and slopes for grip strength and reasoning and covariates were examined by fitting a bivariate growth curve structural equation model.

RESULTS

Grip strength and reasoning declined with age. They were each significantly correlated on each occasion. Their intercepts were significantly correlated (.20) but not their slopes. Neither intercept was significantly associated with its own or the other's slope. Better reasoning was associated with higher childhood intelligence, more professional occupations, male sex, and being taller. There were no significant reasoning slope associations. Stronger grip strength was associated with male sex, being taller, and drinking less alcohol. Women showed less age-related decline in grip strength.

DISCUSSION

Physical and mental "grips" declined in the ninth decade of life. Their levels were significantly correlated; their slopes were not. There was no evidence for reciprocal dynamic influences nor for shared associations.

Consequences of age-related cognitive declines

Adult age differences in a variety of cognitive abilities are well documented, and many of those abilities have been found to be related to success in the workplace and in everyday life. However, increased age is seldom associated with lower levels of real-world functioning, and the reasons for this lab-life discrepancy are not well understood. This article briefly reviews research concerned with relations of age to cognition, relations of cognition to successful functioning outside the laboratory, and relations of age to measures of work performance and achievement. The final section discusses several possible explanations for why there are often little or no consequences of age-related cognitive declines in everyday functioning.

Terminal decline from within- and between-person perspectives, accounting for incident dementia

OBJECTIVE

The terminal cognitive decline hypothesis has been debated for almost 50 years. This hypothesis implies a change in rate of decline within an individual. Therefore, we examine the hypothesis from a within-person perspective using a time to death chronological structure.

METHOD

Scores on a Swedish version of the Wechsler Adult Intelligence Scale Information and Block Design scores from 461 OCTO-Twin Study participants with confirmed death dates were modeled using quadratic growth curve models including both age and distance from death at study entry, sex, education, and dementia diagnosis as covariates of initial performance and of linear and quadratic change over time.

RESULTS

Information scores showed statistically significant evidence of slight within-person acceleration of declines in the no dementia group. Individuals with incident dementia declined more quickly, and those who were closer to death at study baseline had a stronger acceleration. Block Design scores declined but did not show evidence of such acceleration either within or across individuals. Decline was faster in incident cases closer to death at study entry.

DISCUSSION

Within-person evidence of terminal decline is not as strong as previously published between-person results. Strategies for focusing models on longitudinal aspects of available data and the extent to which lack of within-person evidence for terminal decline may stem from common data limitations are discussed.

Personality and personal control make a difference for life satisfaction in the oldest-old: findings in a longitudinal population-based study of individuals 80 and older

This study investigates life satisfaction in relation to impending death among the oldest-old using overall disease load, self-rated health, and personality as interacting covariates of level and change. We used data from a sample of 370 healthy individuals who completed the Life Satisfaction Index-Z at four measurement occasions during a 6-year period in the Swedish OCTO-Twin study of individuals aged 80 and older. Growth curve analyses showed a linear decrease in life satisfaction as individuals approached death. The decrease was not related to level or change in self-rated health and disease load. High disease load was, however, related to lower levels of life satisfaction, but, this association was moderated by locus of control, such that those with high disease load and high locus of control did not show lower life satisfaction. Poor self-rated health was also associated with lower life satisfaction, but, this association was moderated by neuroticism, such that those with poor-rated health and low neuroticism did not show lower live satisfaction. Personality factors such as locus of control and neuroticism can influence the association between health and life satisfaction. The findings suggest further investigations of the role of personality characteristics in late life satisfaction and whether interventions aimed to increase personal control can improve life satisfaction in old age.

Aging and the shape of cognitive change before death: terminal decline or terminal drop?

OBJECTIVES

Relative to typical age-related cognitive decrements, the terms "terminal decline" and "terminal drop" refer to the phenomenon of increased cognitive decline in proximity to death. Given that these terms are not necessarily synonymous, we examined the important theoretical distinction between the two alternative trajectories or shapes of changes they imply.

METHODS

We used 12-year (5-wave) data from the Victoria Longitudinal Study to directly test whether pre-death cognitive decrements follow a terminal decline (generally gradual) or a terminal drop (more abrupt) shape. Pre-death trajectories of cognitive decline for n=265 decedents (Mage = 72.67 years, SD = 6.44) were examined separately for 5 key cognitive constructs (verbal speed, working memory, episodic memory, semantic memory, and crystallized ability).

RESULTS

Several classes of linear mixed models evaluated whether cognitive decline increased per additional year closer to death. Findings indicated that the shape of pre-death cognitive change was predominantly characterized by decline that is steeper as compared with typical aging-related change, but still best described as slow and steady decline, especially as compared with precipitous drop.

DISCUSSION

The present findings suggest that terminal decline and terminal drop trajectories may not be mutually exclusive but could rather reflect distinct developmental trajectories within the same individual.

Toward an integrative science of life-span development and aging

The study of aging demands an integrative life-span developmental framework, involving interdisciplinary collaborations and multiple methodological approaches for understanding how and why individuals change, in both normative and idiosyncratic ways. We highlight and summarize some of the issues encountered when conducting integrative research for understanding aging-related change, including, the integration of results across different levels of analysis; the integration of theory, design, and analysis; and the synthesis of results across studies of aging. We emphasize the necessity of longitudinal designs for understanding development and aging and discuss methodological issues that should be considered for achieving reproducible research on within-person processes. It will be important that current and future studies permit opportunities for quantitative comparison across populations given the extent to which historical shifts and cultural differences influence life-span processes and aging-related outcomes.

Aging, Disablement, and Dying: Using Time-as-Process and Time-as-Resources Metrics to Chart Late-Life Change

Time is a vehicle that can be used to represent aging-related processes and to index the amount of aging-related resources or burdens individuals have accumulated. Using data on cognitive (memory) performance from two Swedish studies of the elderly (OCTO and OCTO-TWIN), we illustrate how time-as-process and time-as-resources/burdens time metrics can be articulated and incorporated within a growth curve modeling framework. Our results highlight the possibilities for representing the contributions of primary, secondary, and tertiary aspects of aging to late-life changes in cognitive and other domains of functioning.

Delineating terminal change in subjective well-being and subjective health

The present study investigated whether several evaluative indicators of subjective well-being (SWB) and subjective health decline as death approaches and which of them shows a stronger decline. Using three-wave longitudinal data from deceased participants of the Cross-Sectional and Longitudinal Aging Study (N = 1,360; age range 75-94 at T1= Time 1), we found a stronger decline in most evaluative indicators when plotted by distance-to-death relative to distance from birth. After controlling for background characteristics and physical and cognitive functioning, death-related decline was still found for SWB but not for subjective health. Implications are discussed regarding the well-being paradox and the yet unclear mechanisms that link evaluative indicators to the dying process.

Age-related changes in memory and fluid reasoning in a sample of healthy old people

Participants in the Healthy Old People in Edinburgh (HOPE) study (N = 398) were assessed on Raven's Progressive Matrices and Logical Memory on up to three occasions. Covariates included education, social class, disease and medication status, blood pressure and study outcome. Raven's score declined linearly with age, whereas decline in Logical Memory was accelerating. There was significant variation in individuals' rates of decline for Ravens but not Logical Memory. Slope-intercept covariances were not significant. Those who later developed dementia already exhibited lower scores, more so for Logical Memory than Raven's. Death and study attrition were related to performance, again greater for Logical Memory.

CONCLUSIONS

The HOPE approach of progressive screening is a feasible and practical method for studying healthy cognitive ageing. As predicted for an initially healthy sample, rates of decline were relatively homogeneous. The hypothesis of differential decline was not supported, nor was a strict interpretation of the hypothesis that cognitive ageing is entirely pathology driven.

Methods for the Study of Development - Developing Methods: Introduction to a Special Issue of Research in Human Development

This collection of articles explores how contemporary methods interface with and can be used effectively to test developmental perspectives and hypotheses. The authors review some of the latest advancements in measurement and scale equating, multilevel models of change, growth mixture models, longitudinal models of mediation, and survival models and illustrate how these methods can be applied to developmental data. In this introduction, we present the data-box as a useful heuristic for both assessing the conceptual assumptions and implications of a given research approach and selecting the appropriately aligned statistical models for measurement, change, and interindividual differences. Together, the articles provide accessible introductions, illustrations, and discussions of how some of the recent methodological innovations might be applied in the study of development.

Application of a joint multivariate longitudinal-survival analysis to examine the terminal decline hypothesis in the Swiss Interdisciplinary Longitudinal Study on the Oldest Old

In this work I aim at extending current knowledge on the terminal decline hypothesis by applying a joint multivariate longitudinal-survival analysis to the cognitive data of the Swiss Interdisciplinary Longitudinal Study on the Oldest Old. (In that study, 529 individuals between 79 and 85 years of age at study inception were assessed up to five times on a task of perceptual speed and one of verbal fluency.) I simultaneously estimated a multivariate, multilevel longitudinal model and a Weibull survival model to test whether individual performance and change in speed and fluency predict survival, controlling for retest effects, initial age, gender, overall health, socioeconomic status, and sensory functioning. Results revealed that age and performance level in fluency predicted survival, whereas level in speed and change in both cognitive variables did not. I discuss the relevance of fluency tasks in predicting mortality.

Cognitive impairment as assessed by a short form of MMSE was predictive of mortality

OBJECTIVE

This study explores the association between cognitive impairment and mortality in late senescence. A specific purpose was to validate the ability of a short form of the Mini-Mental State Examination (MMSE) in predicting mortality.

STUDY DESIGN AND SETTING

The cognition-mortality link, as assessed by the original MMSE and D-MMSE (a subscale associated to dementia) was estimated on a community sample of 1,111 older people using Cox proportional hazards models.

RESULTS

Impaired cognitive function as assessed by both the original MMSE and D-MMSE predicted mortality in older men and women over long intervals. The association persisted after controlling for sociodemographic variables, Body Mass Index, mobility, and comorbidity and was unaffected by self-reported specific chronic diseases in both men and women. In addition, disease related risk of mortality was substantially reduced by sociodemographic and health variables including cognitive functioning. Only in women, stroke and diabetes remained statistically significant associated with mortality.

CONCLUSION

The association between cognitive impairment and mortality reflects processes different from those underlying a simple relation between chronic diseases and mortality. A short, valid MMSE subscale, which was a powerful predictor of mortality especially among men, is attractive for research and clinical practice.

Factors predicting mortality in midlife adults with and without Down syndrome living with family

BACKGROUND

Little is known about the mortality of individuals with Down syndrome who have lived at home with their families throughout their lives. The current study evaluates the predictors, causes and patterns of mortality among co-residing individuals in midlife with Down syndrome as compared with co-residing individuals with ID owing to other causes.

METHOD

This paper examines mortality in 169 individuals with and 292 individuals without Down syndrome from 1988 to 2007. Dates and causes of death were obtained from maternal report, the Social Security Death Index and the National Death Index. Risk factors predicting mortality, including demographic variables, transition variables, and initial and change measures of health, functional abilities and behaviour problems, were obtained from maternal report.

RESULTS

Having Down syndrome is a risk factor of mortality, net of other risk factors including older age, poorer functional abilities, worsening behaviour problems, residential relocation and parental death. The causes of death among individuals with and without Down syndrome who are in midlife and co-residing with their families are similar, and are most commonly due to cardiovascular or respiratory problems.

CONCLUSIONS

The findings indicate that midlife adults with Down syndrome who co-reside with their families generally exhibit similar causes of mortality as do midlife adults with intellectual disability owing to other causes, but show an elevated risk of mortality in midlife net of other variables, such as age and changes in functional abilities and behaviour problems.

Association between mortality and cognitive change over 7 years in a large representative sample of UK residents

OBJECTIVE

To examine the association between change in reaction time and cognitive performance over 7 years and the risk of death from all causes and some specific causes after controlling for known risk factors.

METHODS

The sample comprised members of the Health and Lifestyle Survey (HALS) of community-dwelling adults in England, Scotland, and Wales. Baseline testing (HALS1), involving 9003 people, took place in 1985 and 1986. Sociodemographic, lifestyle, health, and physiological information was collected. Cognitive functioning was measured using tests of simple and choice reaction time, a short memory test, and a test of visual-spatial reasoning. Follow-up testing (HALS2) took place in 1991 and 1992, when 5352 members of the study were administered the same questionnaires, physiological examinations, and cognitive tests. The sample has been followed for mortality up to June 2005.

RESULTS

After controlling for age, gender, and the relevant baseline cognitive test scores, greater declines between HALS1 and HALS2 on simple reaction time mean and variability, choice reaction time mean and variability, memory and visual-spatial reasoning were associated with significantly increased risks of death from all causes, all cardiovascular diseases (CVDs), coronary heart disease (CHD), stroke, and respiratory disease. These associations were only slightly attenuated after adjusting for occupational social class, educational, smoking, alcohol consumption, physical activity, body mass index, blood pressure, and lung function.

CONCLUSIONS

Decline in performance of reaction times and simple cognitive tasks across a 7-year period was associated with an increased risk of death from all causes, all CVDs, CHD, stroke, and respiratory disease up to 13 years later, even after adjustment for known risk factors.