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Objective Handgrip strength, an indicator of overall muscle strength, has been found to be associated with slower rate of cognitive decline and decreased risk for cognitive impairment and dementia. However, evaluating the replicability of associations between aging-related changes in physical and cognitive functioning is challenging due to differences in study designs and analytical models. A multiple-study coordinated analysis approach was used to generate new longitudinal results based on comparable construct-level measurements and identical statistical models and to facilitate replication and research synthesis. Methods We performed coordinated analysis on 9 cohort studies affiliated with the Integrative Analysis of Longitudinal Studies of Aging and Dementia (IALSA) research network. Bivariate linear mixed models were used to examine associations among individual differences in baseline level, rate of change, and occasion-specific variation across grip strength and indicators of cognitive function, including mental status, processing speed, attention and working memory, perceptual reasoning, verbal ability, and learning and memory. Results were summarized using meta-analysis. Results After adjustment for covariates, we found an overall moderate association between change in grip strength and change in each cognitive domain for both males and females: Average correlation coefficient was 0.55 (95% CI = 0.44–0.56). We also found a high level of heterogeneity in this association across studies. Discussion Meta-analytic results from nine longitudinal studies showed consistently positive associations between linear rates of change in grip strength and changes in cognitive functioning. Future work will benefit from the examination of individual patterns of change to understand the heterogeneity in rates of aging and health-related changes across physical and cognitive biomarkers.

Background and Objectives There is an urgent need to better understand frailty and its predisposing factors. Although numerous cross-sectional studies have identified various risk and protective factors of frailty, there is a limited understanding of longitudinal frailty progression. Furthermore, discrepancies in the methodologies of these studies hamper comparability of results. Here, we use a coordinated analytical approach in 5 independent cohorts to evaluate longitudinal trajectories of frailty and the effect of 3 previously identified critical risk factors: sex, age, and education. Research Design and Methods We derived a frailty index (FI) for 5 cohorts based on the accumulation of deficits approach. Four linear and quadratic growth curve models were fit in each cohort independently. Models were adjusted for sex/gender, age, years of education, and a sex/gender-by-age interaction term. Results Models describing linear progression of frailty best fit the data. Annual increases in FI ranged from 0.002 in the Invecchiare in Chianti cohort to 0.009 in the Longitudinal Aging Study Amsterdam (LASA). Women had consistently higher levels of frailty than men in all cohorts, ranging from an increase in the mean FI in women from 0.014 in the Health and Retirement Study cohort to 0.046 in the LASA cohort. However, the associations between sex/gender and rate of frailty progression were mixed. There was significant heterogeneity in within-person trajectories of frailty about the mean curves. Discussion and Implications Our findings of linear longitudinal increases in frailty highlight important avenues for future research. Specifically, we encourage further research to identify potential effect modifiers or groups that would benefit from targeted or personalized interventions.

Background Substantial research is dedicated to understanding the aging-related dynamics among individual differences in level, change, and variation across physical and cognitive abilities. Evaluating replicability and synthesizing these findings has been limited by differences in measurements and samples, and by study design and statistical analyses confounding between-person differences with within-person changes. In this article, we conducted a coordinated analysis and summary meta-analysis of new results on the aging-related dynamics linking pulmonary function and cognitive performance. Methods We performed coordinated analysis of bivariate growth models in data from 20,586 participants across eight longitudinal studies to examine individual differences in baseline level, rate of change, and occasion-specific variability in pulmonary and cognitive functioning. Results were summarized using meta-analysis. Results We found consistent but weak baseline and longitudinal associations in levels of pulmonary and cognitive functioning, but no associations in occasion-specific variability. Conclusions Results provide limited evidence for a consistent link between simultaneous changes in pulmonary and cognitive function in a normal aging population. Further research is required to understand patterns of onset of decline and differences in rates of change within and across physical and cognitive functioning domains, both within-individuals and across countries and birth cohorts. Coordinated analysis provides an efficient and rigorous approach for replicating and comparing results across independent longitudinal studies.

Coordinated analysis is a powerful form of integrative analysis, and is well suited in its capacity to promote cumulative scientific knowledge, particularly in subfields of psychology that focus on the processes of lifespan development and aging. Coordinated analysis uses raw data from individual studies to create similar hypothesis tests for a given research question across multiple datasets, thereby making it less vulnerable to common criticisms of meta-analysis such as file drawer effects or publication bias. Coordinated analysis can sometimes use random effects meta-analysis to summarize results, which does not assume a single true effect size for a given statistical test. By fitting parallel models in separate datasets, coordinated analysis preserves the heterogeneity among studies, and provides a window into the generalizability and external validity of a set of results. The current article achieves three goals: First, it describes the phases of a coordinated analysis so that interested researchers can more easily adopt these methods in their labs. Second, it discusses the importance of coordinated analysis within the context of the credibility revolution in psychology. Third, it encourages the use of existing data networks and repositories for conducting coordinated analysis, in order to enhance accessibility and inclusivity. Subfields of research that require time- or resource- intensive data collection, such as longitudinal aging research, would benefit by adopting these methods. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Early investigations of the neuroticism by conscientiousness interaction with regards to health have been promising, but to date, there have been no systematic investigations of this interaction that account for the various personality measurement instruments, varying populations, or aspects of health. The current study – the second of three – uses a coordinated analysis approach to test the impact of the neuroticism by conscientiousness interaction on the prevalence and incidence of chronic conditions. Using 15 pre-existing longitudinal studies (N > 49,375), we found that conscientiousness did not moderate the relationship between neuroticism and having hypertension (OR = 1.00,95%CI[0.98,1.02]), diabetes (OR = 1.02[0.99,1.04]), or heart disease (OR = 0.99[0.97,1.01]). Similarly, we found that conscientiousness did not moderate the prospective relationship between neuroticism and onset of hypertension (OR = 0.98[0.95,1.01]), diabetes (OR = 0.99[0.94,1.05]), or heart disease (OR = 0.98[0.94,1.03]). Heterogeneity of effect sizes was largely nonsignificant, with one exception, indicating that the effects are consistent between datasets. Overall, we conclude that there is no evidence that healthy neuroticism, operationalized as the conscientiousness by neuroticism interaction, buffers against chronic conditions.

Individual differences in the Big Five personality traits have emerged as predictors of health and longevity. Although there are robust protective effects for higher levels of conscientiousness, results are mixed for other personality traits. In particular, higher levels of neuroticism have significantly predicted an increased risk of mortality, no-risk at all, and even a reduced risk of dying. The current study hypothesizes that one potential reason for the discrepancy in these findings for neuroticism is that interactions among neuroticism and other key personality traits have largely been ignored. Thus, in the current study we focus on testing whether the personality traits neuroticism and conscientiousness interact to predict mortality. Specifically, we borrow from recent evidence of “healthy neuroticism” to explore whether higher levels of neuroticism are only a risk factor for increased mortality risk when conscientiousness levels are low. We conducted a pre-registered integrative data analysis using 12 different cohort studies (total N = 44,702). Although a consistent pattern emerged of higher levels of conscientiousness predicting a reduced hazard of dying, neuroticism did not show a consistent pattern of prediction. Moreover, no study provided statistical evidence of a neuroticism by conscientiousness interaction. The current findings do not support the idea that the combination of high conscientiousness and high neuroticism can be protective for longevity. Future work is needed to explore different protective factors that may buffer the negative effects of higher levels of neuroticism on health, as well as other behaviors and outcomes that may support the construct of healthy neuroticism.

This study assessed change in self–reported Big Five personality traits. We conducted a coordinated integrative data analysis using data from 16 longitudinal samples, comprising a total sample of over 60 000 participants. We coordinated models across multiple datasets and fit identical multi–level growth models to assess and compare the extent of trait change over time. Quadratic change was assessed in a subset of samples with four or more measurement occasions. Across studies, the linear trajectory models revealed declines in conscientiousness, extraversion, and openness. Non–linear models suggested late–life increases in neuroticism. Meta–analytic summaries indicated that the fixed effects of personality change are somewhat heterogeneous and that the variability in trait change is partially explained by sample age, country of origin, and personality measurement method. We also found mixed evidence for predictors of change, specifically for sex and baseline age. This study demonstrates the importance of coordinated conceptual replications for accelerating the accumulation of robust and reliable findings in the lifespan developmental psychological sciences. © 2020 European Association of Personality Psychology

Current literature suggests that neuroticism is positively associated with maladaptive life choices, likelihood of disease, and mortality. However, recent research has identified circumstances under which neuroticism is associated with positive outcomes. The current project examined whether “healthy neuroticism”, defined as the interaction of neuroticism and conscientiousness, was associated with the following health behaviors: smoking, alcohol consumption, and physical activity. Using a pre-registered multi-study coordinated integrative data analysis (IDA) approach, we investigated whether “healthy neuroticism” predicted the odds of engaging in each of the aforementioned activities. Each study estimated identical models, using the same covariates and data transformations, enabling optimal comparability of results. These results were then meta-analyzed in order to estimate an average (N-weighted) effect and to ascertain the extent of heterogeneity in the effects. Overall, these results suggest that neuroticism alone was not related to health behaviors, while individuals higher in conscientiousness were less likely to be smokers or drinkers, and more likely to engage in physical activity. In terms of the healthy neuroticism interaction of neuroticism and conscientiousness, significant interactions for smoking and physical activity suggest that the association between neuroticism and health behaviors was smaller among those high in conscientiousness. These findings lend credence to the idea that healthy neuroticism may be linked to certain health behaviors and that these effects are generalizable across several heterogeneous samples.

OBJECTIVES: Very few studies looking at slow gait speed as early marker of cognitive decline investigated the competing risk of death. The current study examines associations between slow gait speed and transitions between cognitive states and death in later life.METHODS: We performed a coordinated analysis of three longitudinal studies with 9 to 25 years of follow-up. Data were used from older adults participating in H70 (Sweden; n = 441; aged ≥70 years), InCHIANTI (Italy; n = 955; aged ≥65 years), and LASA (the Netherlands; n = 2824; aged ≥55 years). Cognitive states were distinguished using the Mini-Mental State Examination. Slow gait speed was defined as the lowest sex-specific quintile at baseline. Multistate models were performed, adjusted for age, sex and education.RESULTS: Most effect estimates pointed in the same direction, with slow gait speed predicting forward transitions. In two cohort studies, slow gait speed predicted transitioning from mild to severe cognitive impairment (InCHIANTI: HR = 2.08, 95%CI = 1.40-3.07; LASA: HR = 1.33, 95%CI = 1.01-1.75) and transitioning from a cognitively healthy state to death (H70: HR = 3.30, 95%CI = 1.74-6.28; LASA: HR = 1.70, 95%CI = 1.30-2.21).CONCLUSIONS: Screening for slow gait speed may be useful for identifying older adults at risk of adverse outcomes such as cognitive decline and death. However, once in the stage of more advanced cognitive impairment, slow gait speed does not seem to predict transitioning to death anymore.

Existing literature indicates a relatively consistent relationship between neuroticism and cognitive functioning (CF). Interindividually, high levels of neuroticism may predispose individuals to cognitive aging and dementia-related neuropathology. Intraindividually, increases in neuroticism may be intrinsic to the aging process or to dementia pathology. These hypotheses are not mutually exclusive, though the relationships are rarely examined using the same individuals, which may contribute to publication bias and confusion regarding the hypotheses as mutually exclusive. Data were drawn from the Origins of Variance in the Oldest-Old (Sweden, Mage=83.6, 67% female), Swedish Adoption/Twin Study of Aging (Sweden, Mage=60.4, 59% female), and Longitudinal Aging Study Amsterdam (Netherlands; Mage=68.1, 52% female). Controlling for age, sex, education, and depressive symptoms, parallel process latent growth models were fit independently in each sample (NT=3293) to simultaneously estimate growth parameters of neuroticism with three measures of CF (processing speed, learning/memory, and reasoning). Multilevel meta-analysis estimated the pooled covariation between neuroticism and CF at baseline and overtime, revealing a significantly negative intercept-intercept relationship across datasets (covariance= -0.46, 95% CIs [-0.90,-0.02], z=-2.02, p=0.04, τ2=0.06). The slope-slope covariances were consistently negative, but the meta-analytic pooled estimate was not significant despite some significant individual estimates across studies. Overall, results provide some evidence for intraindividual and interindividual relationships between neuroticism and CF, such that higher neuroticism is associated with lower CF, and neuroticism tends to increase as CF decreases. Identification of the early indicators and risk factors for cognitive decline may facilitate development of screening assessments and aid in treatment strategies for dementia care services.

BackgroundInternational comparisons of trajectories of depressive symptoms in older adults are scarce and longitudinal associations with co-morbid conditions not fully understood.ObjectiveTo compare trajectories of depressive symptoms from participants living in 10 European Countries and identify ages at which the associations of co-morbid conditions with these trajectories become more relevant.MethodsLatent growth curve models were fitted to depressive symptoms scores from participants of the Survey of Health and Retirement in Europe (SHARE) initiative (combined n = 21,253) and co-morbid conditions modelled as time varying covariates. To identify the ages at which the association between co-morbid conditions and depressive symptoms was significant the Johnson-Neyman (JN) technique was used.ResultsThe shape of depressive symptoms trajectories varied between countries, and was highly dependent on modelling decisions. The association between the average number of co-morbidities reported over time and depressive symptoms was consistent and positive across countries and ages.ConclusionInternational differences in ageing-related trajectories of depressive symptoms emerged. The longitudinal association of co-morbid conditions with trajectories of depressive symptoms was found, but the results overall suggest that modelling decisions could greatly influence the outcomes, and should thus be interpreted with caution.

Previous cross-sectional research suggests that age-related decreases in Rapid-Eye Movement (REM) sleep may contribute to poorer cognitive functioning (CF); however, few studies have examined the relationship at the intraindividual level by measuring habitual sleep over multiple days. Applying a 14-day daily diary design, the current study examines the dynamic relationship between REM sleep and CF in 69 healthy older adults (M age=70.8 years, SD=3.37; 73.9% female; 66.6% completed at least an undergraduate degree). A Fitbit device provided actigraphy indices of REM sleep (minutes and percentage of total sleep time), while CF was measured four times daily on a smartphone via ambulatory cognitive tests that captured processing speed and working memory. This research addressed the following questions: At the within-person level, are fluctuations in quantity of REM sleep associated with fluctuations in next day cognitive measures across days? Do individuals who spend more time in REM sleep on average, perform better on cognitive tests than adults who spend less time in REM sleep? A series of multilevel models were fit to examine the extent to which each index of sleep accounted for daily fluctuations in performance on next day cognitive tests. Results indicated that during nights when individuals had more REM sleep minutes than was typical, they performed better on the working memory task the next morning (estimate = -.003, SE = .002, p = .02). These results highlight the impact of REM sleep on CF, and further research may allow for targeted interventions for earlier treatment of sleep-related cognitive impairment.

Substantial research has focused on aging-related dynamics among individual differences in level, change, and variation across physical and cognitive functioning. Evaluating replicability and synthesizing these findings has been limited by differences in measurements and samples, and by study design and statistical analyses confounding between-person differences with within-person changes. We used coordinated analysis to examine individual differences in level, rate of change, and occasion-specific variability in pulmonary and cognitive functioning using data from 20,482 participants across eight longitudinal studies. Results were summarized using meta-analysis. The coordinated analysis found consistent baseline associations in levels of pulmonary and cognitive functioning. Associations of rates of change and occasion-specific variability in pulmonary function and cognition were inconsistent across studies. Meta-analysis by cognitive domain showed small associations linking changes in pulmonary functioning with changes in processing speed and attention/working memory. We found limited evidence for a link between simultaneous changes in pulmonary and cognitive function.

We investigated the heterogeneity in end of life cognitive decline in two European longitudinal studies of the oldest old: the OCTO-Twin and the Newcastle 85+ Study. Using a coordinated analytical approach, we identified unobserved groups of individuals with similar trajectories of cognitive decline at the end of life by fitting Tobit Growth Mixture Models to Mini-Mental State Examination scores. In both studies, the current analyses consistently identified two groups of individuals whose cognitive decline at the end of life were distinct: one group did not exhibit an ostensible rate of decline, another group experienced steep decline in measures of global cognition within each study. In OCTO-Twin, accelerated decline was found in only one group. Our results showed heterogeneity in cognitive decline at the end of life in the oldest old across two different European countries and suggest that terminal decline is not necessarily a normative process.

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. Many issues are encountered when conducting integrative multi-study research for understanding aging-related change and prediction of health risk and for the synthesis of results across complex longitudinal studies. We emphasize the necessity of longitudinal designs for understanding developmental and aging changes and discuss methodological issues that should be considered for achieving reproducible research on within-person processes and in an international context.

Introduction: This study examines the role of educational attainment, an indicator of cognitive reserve, on transitions in later life between cognitive states (normal Mini-Mental State Examination (MMSE), mild MMSE impairment, and severe MMSE impairment) and death.Methods: Analysis of six international longitudinal studies was performed using a coordinated approach. Multistate survival models were used to estimate the transition patterns via different cognitive states. Life expectancies were estimated.Results: Across most studies, a higher level of education was associated with a lower risk of transitioning from normal MMSE to mild MMSE impairment but was not associated with other transitions. Those with higher levels of education and socioeconomic status had longer nonimpaired life expectancies.Discussion: This study highlights the importance of education in later life and that early life experiences can delay later compromised cognitive health. This study also demonstrates the feasibility and benefit in conducting coordinated analysis across multiple studies to validate findings.

Objectives Grip strength and cognitive function reflect upper body muscle strength and mental capacities. Cross-sectional research has suggested that in old age these two processes are moderately to highly associated, and that an underlying common cause drives this association. Our aim was to synthesize and evaluate longitudinal research addressing whether changes in grip strength are associated with changes in cognitive function in healthy older adults. Methods We systematically reviewed English-language research investigating the longitudinal association between repeated measures of grip strength and of cognitive function in community-dwelling older adults to evaluate the extent to which the two indices decline concurrently. We used four search engines: Embase, PsychINFO, PubMed, and Web of Science. Results Of 459 unique citations, 6 met our full criteria: 4 studies reported a longitudinal association between rates of change in grip strength and cognitive function in older adults, 2 of which reported the magnitudes of these associations as ranging from low to moderate; 2 studies reported significant cross-sectional but not longitudinal associations among rates of change. All studies concluded that cognitive function and grip strength declined, on average, with increasing age, although with little to no evidence for longitudinal associations among rates of change. Conclusions Future research is urged to expand the study of physical and cognitive associations in old age using a within-person and multi-study integrative approach to evaluate the reliability of longitudinal results with greater emphasis on the magnitude of this association. Systematic review registration number CRD42016038544.

BACKGROUND: We aimed to identify the hierarchy of rates of decline in 16 physical functioning measures in U.S. and English samples, using a systematic and integrative coordinated data analysis approach.METHODS: The U.S. sample consisted of 13,612 Health and Retirement Study participants, and the English sample consisted of 5,301 English Longitudinal Study of Ageing participants. Functional loss was ascertained using self-reported difficulties performing 6 activities of daily living and 10 mobility tasks. The variables were standardized, rates of decline were computed, and mean rates of decline were ranked. Mann-Whitney U tests were performed to compare rates of decline between studies.RESULTS: In both studies, the rates of decline followed a similar pattern; difficulty with eating was the activity that showed the slowest decline and climbing several flights of stairs and stooping, kneeling, or crouching the fastest declines. There were statistical differences in the speed of decline in all 16 measures between countries. American women had steeper declines in 10 of the measures than English women. Similar differences were found between American and English men.CONCLUSIONS: Reporting difficulties climbing several flights of stairs without resting, and stooping, kneeling, or crouching are the first indicators of functional loss reported in both populations.

Maintaining independence in older age depends on adequate levels of physical and cognitive functioning. Numerous studies, both longitudinal and cross-sectional, describe progressive declines although few studies report on the dynamics within and across these domains of functioning. In a coordinated analysis of 12 longitudinal studies, we examined associations between changes in physical functioning (i.e., grip strength, pulmonary function) and changes in cognitive functioning (i.e., speed, memory, reasoning, executive functioning) using multivariate latent growth curve models analyses with adjustment for baseline age, sociodemographic factors, health behaviors, diabetes, and cardiovascular disease. Overall, initial levels of pulmonary and cognitive functioning were related across many measures of cognitive functioning for both men and women. Multivariate patterns of change across physical and cognitive variables were less consistent. We provide a research synthesis of the findings across studies and describe study-level differences in terms of country, cohort, and measurements.

The earliest stage of Alzheimer’s disease (AD) pathology begins in one of the main components of the olfactory pathway, the entorhinal cortex, making deficits in smell a potential prospective biomarker for the early detection of AD. A bivariate longitudinal coupling model was used to determine whether assessment-to-assessment variation in olfaction mirrors variation in cognition over time. The model included terms for age, sex, education, ApoE e4 allele, and autopsy diagnosed AD pathology.

Two studies suggest that personality change may be an early indicator of dementia (Balsis et al, 2005; Smith-Gamble et al, 2001); however, these studies did not assess personality trait change. Although Yoneda et al (2015) prospectively examined personality traits, the nature of the analyses did not allow comparison between trajectories in normal and abnormal aging. The current study includes comparison of trajectories of extraversion and neuroticism personality traits in individuals who did and did not receive a dementia diagnosis.

Although existing research shows that physical activity (PA) protects against cognitive decline, it is unclear if maintenance of PA throughout older adulthood influences the timing of onset or transitions through cognitive states. Further understanding of modifiable lifestyle factors that protect against cognitive changes characteristic of both normal aging and pathological aging, such as Alzheimer’s disease and other dementias, is imperative. Data were drawn from fourteen longitudinal studies of aging from Europe and America (total N=53,069). Controlling for demographics and chronic conditions, multi-state models were independently fit between datasets to investigate the impact of PA (computed based on Metabolic Equivalent of Task Method) on the likelihood of transitioning through three cognitive states, while also accounting for death as a competing risk factor. Random effects meta-analysis of transition probabilities indicated that more PA was associated with a reduced risk of transitioning from normal cognition to mildly impaired cognition (HR=0.90, CI’s=0.84, 0.97, p=0.007) and death (HR=0.24, CI’s=0.06, 0.92, p=0.04), as well as an increased likelihood of transitioning from severe impairment back to mild impairment (HR=1.09, CI’s=1.01, 1.17, p=0.03). Engagement in national minimum recommendations for PA (~150 minutes/week) increased total life expectancy for 70 year old males and females by 4.08 and 5.47 years, respectively. These results suggest that engaging in at least 150 minutes of physical activity per week in older adulthood contributes to delays in onset of mild cognitive impairment, substantially increases life expectancy, and may also diminish the symptoms that contribute to poor cognitive performance at the severely impaired stage.

Objectives. We describe and compare the expected performance trajectories of older adults on the Mini-Mental Status Examination (MMSE) across six independent studies from four countries in the context of a collaborative network of longitudinal studies of aging. A coordinated analysis approach is used to compare patterns of change conditional on sample composition differences related to age, sex, and education. Such coordination accelerates evaluation of particular hypotheses. In particular, we focus on the effect of educational attainment on cognitive decline.Method. Regular and Tobit mixed models were fit to MMSE scores from each study separately. The effects of age, sex, and education were examined based on more than one centering point.Results. Findings were relatively consistent across studies. On average, MMSE scores were lower for older individuals and declined over time. Education predicted MMSE score, but, with two exceptions, was not associated with decline in MMSE over time.Conclusion. A straightforward association between educational attainment and rate of cognitive decline was not supported. Thoughtful consideration is needed when synthesizing evidence across studies, as methodologies adopted and sample characteristics, such as educational attainment, invariably differ. © 2012 The Author.

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed-mediation hypothesis at both the within-and between-person levels in two longitudinal studies, Longitudinal Aging Study Amsterdam (LASA) and Origins of Variance in the Oldest-Old (OCTO-Twin). We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed, which in turn relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin which is not unexpected given the age homogeneous nature of the OCTO-Twin data. A more in-depth examination through measures of effect size suggests that, for the LASA study, the within-person indirect effects were small and between-person indirect effects were consistently larger. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. © 2013 American Psychological Association.

Social activity is 1 aspect of an active lifestyle and some evidence indicates it is related to preserved cognitive function in older adulthood. However, the potential mechanisms underlying this association remain unclear. We investigate 4 potential mediational pathways through which social activity may relate to cognitive performance. A multilevel structural equation modeling approach to mediation was used to investigate whether cognitive activity, physical activity, depressive symptoms, and vascular health conditions mediate the association between social activity and cognitive function in older adults. Using data from the Victoria Longitudinal Study, we tested 4 cognitive outcomes: fluency, episodic memory, reasoning, and vocabulary. Three important findings emerged. First, the association between social activity and all 4 domains of cognitive function was significantly mediated by cognitive activity at the within-person level. Second, we observed a significant indirect effect of social activity on all domains of cognitive function through cognitive activity at the between-person level. Third, we found a within-person indirect relationship of social activity with episodic memory performance through physical activity. For these older adults, engagement in social activities was related to participation in everyday cognitive activities and in turn to better cognitive performance. This pattern is consistent with the interpretation that a lifestyle of social engagement may benefit cognitive performance by providing opportunities or motivation to participate in supportive cognitively stimulating activities. (PsycINFO Database Record

Objective: The association between patterns of change in self-rated health (SRH) and memory trajectories in older adults was examined using a systematic approach. Method: Data from the Health and Retirement Study ( n = 6,016) and the English Longitudinal Study of Ageing ( n = 734) were analyzed. Individuals were grouped into five categories according to their pattern of change in SRH over 8 years: stable excellent/very good/good, stable fair/poor, improvement, decline, and fluctuating pattern without a trend. Memory was measured using immediate and delayed recall tests. Kruskal–Wallis, chi-squares tests, and linear mixed models were used to examine the association. Results: Different rates of decline in memory can be identified in the different patterns of change in SRH. Those who had a stable excellent/very good/good pattern had the slowest rate of decline. Discussion: Our findings suggest that SRH status and patterns of change could be used as a marker of cognitive decline in prevention screening programs.

Background Education, a marker for cognitive reserve, is thought to be associated with low risks of dementia, but less is known about its association with cognitive decline in preclinical stages of dementia. This study aimed to see whether higher education level could have a protective effect against faster cognitive decline in preclinical stages of dementia and whether this protection is consistent across six different studies around the world. Methods We assessed the association between education and change in mini-mental state examination (MMSE) in people who developed dementia during the study period before the time of dementia diagnosis in six international studies of ageing: Newcastle 85+, UK; Three-City (3C), France; Leiden 85+ and Longitudinal Aging Study Amsterdam (LASA), the Netherlands; Octogenarian Twins (OCTO-Twin), Sweden; and Memory and Ageing Study (MAS), Australia. Using a coordinated analysis approach, we used multilevel models to investigate the role of education in the change in MMSE independently within each cohort, while controlling for common covariates such as age at baseline, sex, and time to dementia diagnosis from study entry within each cohort. Each individual's cognitive scores were aligned according to distance (years) to dementia diagnosis. Findings High levels of education (>12 years) were associated with steeper linear rates of decline in MMSE scores from study entry to time of dementia diagnosis in most cohorts—3C, Leiden 85+, LASA, OCTO-Twin, and MAS. However, in one cohort (Newcastle 85+), higher education was associated with a slow rate of decline in the preclinical stages of dementia (β=0·93, 95% CI 0·09–1·77) compared with lower education, suggesting perhaps a difference in the educational system between the UK and the rest of Europe or Australia during the early 1990s. A random-effects meta-analysis across data from all six studies showed a non-significant steeper cognitive decline with time for those with higher education (β=–0·08, 95% CI –0·17 to 0·003; see appendix for forest plot). Interpretation This coordinated approach analysis revealed no consistent protection for people with higher education in terms of lowering the rate of cognitive decline in the preclinical stages of dementia, which is a major public health burden. This work only partly supports the cognitive reserve hypothesis—ie, the clinical manifestation of dementia is delayed in people with higher education but that a steeper decline occurs once a certain threshold has been reached. Funding The funding sources of this work were the Alzheimer's Society (grant number 144) and the Medical Research Council (unit programme number MC_UU_12019/1).

The current study examines the role of social contact intensity, cognitive activity, and depressive symptoms as within- and between-person mediators for the relationships between physical activity and cognitive functioning. All three types of mediators were considered simultaneously using multilevel structural equations modeling with longitudinal data. The sample consisted of 470 adults ranging from 79.37 to 97.92 years of age (M = 83.4; SD = 3.2) at the first occasion. Between-person differences in cognitive activity mediated the relationship between physical activity and cognitive functioning, such that individuals who participated in more physical activities, on average, engaged in more cognitive activities and, in turn, showed better cognitive functioning. Mediation of between-person associations between physical activity and memory through social contact intensity was also significant. At the within-person level, only cognitive activity mediated the relationship between physical activity and change in cognition; however, the indirect effect was small. Depressive symptomatology was not found to significantly mediate within- or between-person effects on cognitive change. Our findings highlight the implications of physical activity participation for the prevention of cognitive decline and the importance of meditational processes at the between-person level. Physical activity can provide older adults with an avenue to make new friendships and engage in more cognitive activities which, in turn, attenuates cognitive decline.

Social activity is typically viewed as part of an engaged lifestyle that may help mitigate the deleterious effects of advanced age on cognitive function. As such, social activity has been examined in relation to cognitive abilities later in life. However, longitudinal evidence for this hypothesis thus far remains inconclusive. The current study sought to clarify the relationship between social activity and cognitive function over time using a coordinated data analysis approach across four longitudinal studies. A series of multilevel growth models with social activity included as a covariate is presented. Four domains of cognitive function were assessed: reasoning, memory, fluency, and semantic knowledge. Results suggest that baseline social activity is related to some, but not all, cognitive functions. Baseline social activity levels failed to predict rate of decline in most cognitive abilities. Changes in social activity were not consistently associated with cognitive functioning. Our findings do not provide consistent evidence that changes in social activity correspond to immediate benefits in cognitive functioning, except perhaps for verbal fluency.

Engagement in cognitively stimulating activities has been considered to maintain or strengthen cognitive skills, thereby minimizing age-related cognitive decline. While the idea that there may be a modifiable behavior that could lower risk for cognitive decline is appealing and potentially empowering for older adults, research findings have not consistently supported the beneficial effects of engaging in cognitively stimulating tasks. Using observational studies of naturalistic cognitive activities, we report a series of mixed effects models that include baseline and change in cognitive activity predicting cognitive outcomes over up to 21 years in four longitudinal studies of aging. Consistent evidence was found for cross-sectional relationships between level of cognitive activity and cognitive test performance. Baseline activity at an earlier age did not, however, predict rate of decline later in life, thus not supporting the concept that engaging in cognitive activity at an earlier point in time increases one's ability to mitigate future age-related cognitive decline. In contrast, change in activity was associated with relative change in cognitive performance. Results therefore suggest that change in cognitive activity from one's previous level has at least a transitory association with cognitive performance measured at the same point in time.

The present study used a coordinated analyses approach to examine the association of physical activity and cognitive change in four longitudinal studies. A series of multilevel growth models with physical activity included both as a fixed (between-person) and time-varying (within-person) predictor of four domains of cognitive function (reasoning, memory, fluency, and semantic knowledge) was used. Baseline physical activity predicted fluency, reasoning and memory in two studies. However, there was a consistent pattern of positive relationships between time-specific changes in physical activity and time-specific changes in cognition, controlling for expected linear trajectories over time, across all four studies. This pattern was most evident for the domains of reasoning and fluency.

We illustrate the use of the parallel latent growth curve model using data from OCTO-Twin. We found a significant intercept-intercept and slope-slope association between processing speed and visuospatial ability. Within-person correlations among the occasion-specific residuals were significant, suggesting that the occasion-specific fluctuations around individual’s trajectories, after controlling for intraindividual change, are related between both outcomes. Random and fixed effects for visuospatial ability are reduced when we include structural parameters (directional growth curve model) providing information about changes in visuospatial abilities after controlling for processing speed. We recommend this model to researchers interested in the analysis of multivariate longitudinal change, as it permits decomposition and directly interpretable estimates of association among initial levels, rates of change, and occasion-specific variation.

Joint longitudinal-survival models are useful when repeated measures and event time data are available and possibly associated. The application of this joint model in aging research is relatively rare, albeit particularly useful, when there is the potential for nonrandom dropout. In this article we illustrate the method and discuss some issues that may arise when fitting joint models of this type. Using prose recall scores from the Swedish OCTO-Twin Longitudinal Study of Aging, we fitted a joint longitudinal-survival model to investigate the association between risk of mortality and individual differences in rates of change in memory. A model describing change in memory scores as following an accelerating decline trajectory and a Weibull survival model was identified as the best fitting. This model adjusted for random effects representing individual variation in initial memory performance and change in rate of decline as linking terms between the longitudinal and survival models. Memory performance and change in rate of memory decline were significant predictors of proximity to death. Joint longitudinal-survival models permit researchers to gain a better understanding of the association between change functions and risk of particular events, such as disease diagnosis or death. Careful consideration of computational issues may be required because of the complexities of joint modeling methodologies.