Latent growth curve analyses of accelerating decline in cognitive abilities in late adulthood

Age-Related Difference in Cognitive Performance under Severe Whole-Body Hyperthermia Parallels Cortisol and Physical Strain Responses

Background and Objectives: To date, understanding age-related changes in cognitive processes during heat exposure still needs to be better-understood. Thus, the main aim of the current study was to evaluate the effects of whole-body hyperthermia (WBH), i.e., a ≈ 2.5 °C increase in rectal temperature (Tre) from overnight-fast baseline value, on cognitive functioning in old and young men and to explore factors, such as stress and thermophysiological strain, that could influence such changes. Materials and Methods: Ten young (19-21 years of age) and nine old (61-80 years of age) healthy men underwent an experimental trial with passive lower-body heating in hot water immersion (HWI) at 43 °C (HWI-43 °C) until Tre reached 39 °C in old adults and 39.5 °C in young adults. Cognitive performance and cortisol concentration were assessed before and after HWI, and the physiological strain index (PSI) was assessed during HWI-43 °C. Results: PSI was lower and cortisol concentration was greater after HWI-43 °C in the old group compared with the young group (p < 0.05). Surprisingly, hyperthermia improved cognitive flexibility only in old adults, whereas short-term and visual recognition memories were maintained in both age groups. Conclusions: A ≈ 2.5 °C increase in rectal temperature can improve executive function in old adults, and this increase parallels the increased cortisol concentration and the lower thermophysiological strain under severe WBH conditions.

Predictors of cognitive functioning trajectories among older Americans: A new investigation covering 20 years of age- and non-age-related cognitive change

Despite the extensive study of predictors of cognitive decline in older age, a key uncertainty is how much these predictors explain both the intercept and age- and non-age-related change in cognitive functioning (CF). We examined the contribution of a broad range of life course determinants to CF trajectories. Data came from 7,068 participants in the 1996-2016 Health and Retirement Study. CF was measured as a summary score on a 27-point cognitive battery of items. We estimated multilevel growth curve models to examine the CF trajectories in individuals ages 54-85. We found that the variation in CF level at age 54 was three times as much as the variation in age slope. All the observed individual predictors explained 38% of the variation in CF at age 54. Personal education was the most important predictor (25%), followed by race, household wealth and income, parental education, occupation, and depression. The contributions of activity limitations, chronic diseases, health behaviors (obesity, smoking, vigorous activity), childhood conditions (childhood health, nutrition, financial situation), gender, marital status, and religion were rather small (<5%). Even though the age slope varied with many adulthood factors, they only explained 5.6% of the between-person variation in age slope. Moreover, age explained 23% of within-person variation in CF from age 54 to 85. The rest non-age-related within-person variation could not be explained by the observed time-varying factors. These findings suggest that future research is urgently needed to discover the main determinants of the slope of cognitive decline to slow down the progression of cognitive impairment and dementia.

Turning Point of Cognitive Decline for Chinese Older Adults from a Longitudinal Analysis: Protective Factors and Risk Factors

OBJECTIVES

To explore the turning point of cognitive decline in Chinese older adults and to explore the influencing factors including covariates.

PARTICIPANTS

Aged 65 and older whose cognitive function was normal at their first test.

METHODS

a secondary analysis that identified participants from the database of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Cohort-sequential design was used to categorize the data by age (rather than study wave), including the follow-up data of Chinese older adults aged 65-79 years and spanning 14 years. Cognitive function in 1278 participants was assessed using the Chinese Mini-Mental State Examination (CMMSE) in five waves over 14 years. Piecewise latent growth curve modeling was used to analyze the data.

RESULTS

(1) The turning point of cognitive decline in Chinese older adults occurs between the ages of 68 and 70. (2) There are statistically significant individual differences in the initial level of cognitive function and the growth rate of cognitive function before and after the transition stage. (3) Factors influencing cognitive function include residence, education level, smoking, drinking, exercise, leisure activities, social activities, Activities of Daily Living (ADL), and Instrumental Activities for Daily Living (IADL). (4) Exercise and ADL are the main protective factors, while smoking and drinking are the main risk factors.

CONCLUSIONS

There is a transition stage (68-70) in the decline of cognitive function in Chinese older adults and four main factors (such as smoking, drinking, exercise and ADL) have impacts on the cognitive decline. We should strengthen these protective factors (exercise and ADL) for the cognitive decline of older adults and avoid these risk factors (smoking, drinking). To prevent the decline of the cognitive function of older adults, the government should build more places conducive to activities for older adults and actively encourage older adults to improve their physical activity level. Given our findings, public health interventions centered on alcohol and tobacco cessation in older adults should be governmentally endorsed.

Self-administered Web-Based Tests of Executive Functioning and Perceptual Speed: Measurement Development Study With a Large Probability-Based Survey Panel

BACKGROUND

Cognitive testing in large population surveys is frequently used to describe cognitive aging and determine the incidence rates, risk factors, and long-term trajectories of the development of cognitive impairment. As these surveys are increasingly administered on internet-based platforms, web-based and self-administered cognitive testing calls for close investigation.

OBJECTIVE

Web-based, self-administered versions of 2 age-sensitive cognitive tests, the Stop and Go Switching Task for executive functioning and the Figure Identification test for perceptual speed, were developed and administered to adult participants in the Understanding America Study. We examined differences in cognitive test scores across internet device types and the extent to which the scores were associated with self-reported distractions in everyday environments in which the participants took the tests. In addition, national norms were provided for the US population.

METHODS

Data were collected from a probability-based internet panel representative of the US adult population-the Understanding America Study. Participants with access to both a keyboard- and mouse-based device and a touch screen-based device were asked to complete the cognitive tests twice in a randomized order across device types, whereas participants with access to only 1 type of device were asked to complete the tests twice on the same device. At the end of each test, the participants answered questions about interruptions and potential distractions that occurred during the test.

RESULTS

Of the 7410 (Stop and Go) and 7216 (Figure Identification) participants who completed the device ownership survey, 6129 (82.71% for Stop and Go) and 6717 (93.08% for Figure Identification) participants completed the first session and correctly responded to at least 70% of the trials. On average, the standardized differences across device types were small, with the absolute value of Cohen d ranging from 0.05 (for the switch score in Stop and Go and the Figure Identification score) to 0.13 (for the nonswitch score in Stop and Go). Poorer cognitive performance was moderately associated with older age (the absolute value of r ranged from 0.32 to 0.61), and this relationship was comparable across device types (the absolute value of Cohen q ranged from 0.01 to 0.17). Approximately 12.72% (779/6123 for Stop and Go) and 12.32% (828/6721 for Figure Identification) of participants were interrupted during the test. Interruptions predicted poorer cognitive performance (P<.01 for all scores). Specific distractions (eg, watching television and listening to music) were inconsistently related to cognitive performance. National norms, calculated as weighted average scores using sampling weights, suggested poorer cognitive performance as age increased.

CONCLUSIONS

Cognitive scores assessed by self-administered web-based tests were sensitive to age differences in cognitive performance and were comparable across the keyboard- and touch screen-based internet devices. Distraction in everyday environments, especially when interrupted during the test, may result in a nontrivial bias in cognitive testing.

Examining the impact of socioeconomic status, demographic characteristics, lifestyle and other risk factors on adults' cognitive functioning in developing countries: an analysis of five selected WHO SAGE Wave 1 Countries

Background

Though extensive studies have been conducted on assessing the predictors of cognitive functioning among older adults in small community-based samples, very few studies have focused on understanding the impact of socioeconomic status (SES), demographic characteristics and other risk factors such as lifestyle and chronic diseases on the cognitive functioning among adults of all ages in a nationally representative population-based sample across low- and middle-income countries. This study, therefore, seeks to evaluate the impact of SES, demographic characteristics and risk factors on the cognitive functioning of adults across all ages in five selected developing countries.

Methods

Data from 12,430 observations obtained from the WHO Study on Global AGEing and Adult Health (SAGE) Wave 1; consisting of 2,486 observations each for China, Ghana, India, the Russian Federation, and South Africa, were used for the study. A meta-regression and a five-step hierarchical linear regression were used to analyze the data, with cognitive functioning as the dependent variable. Independent variables used in this study include SES; assessed by household income and education, demographic characteristics, other risk factors such as lifestyle, self-reported memory difficulty and chronic diseases.

Results

This study found that SES and lifestyle significantly predicted cognitive functioning in all the five selected countries as obtained by the pooled results of the meta-regression analysis. The hierarchical linear regression results also revealed that demographic characteristics such as age, type of residency, and self-reported memory difficulty significantly impact cognitive functioning in China, Ghana, Russia, and South Africa.

Conclusion

The findings in this study provide new insights for policymakers, caregivers, parents, and individuals, especially those in developing countries, to implement policies and actions targeted at improving SES and eliminating risk factors associated with cognitive decline, as these measures could help improve the cognitive functioning among their populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12939-022-01622-7.

Swedish Normative Data for Mindmore: A Comprehensive Cognitive Screening Battery, Both Digital and Self-Administrated

OBJECTIVE

Cognitive impairment is a key element in most mental disorders. Its objective assessment at initial patient contact in primary care can lead to better adjusted and timely care with personalised treatment and recovery. To enable this, we designed the Mindmore self-administrative cognitive screening battery. What is presented here is normative data for the Mindmore battery for the Swedish population.

METHOD

A total of 720 healthy adults (17 to 93 years) completed the Mindmore screening battery, which consists of 14 individual tests across five cognitive domains: attention and processing speed, memory, language, visuospatial functions and executive functions. Regression-based normative data were established for 42 test result measures, investigating linear, non-linear and interaction effects between age, education and sex.

RESULTS

The test results were most affected by age and to a lesser extent by education and sex. All but one test displayed either linear or accelerated age-related decline, or a U-shaped association with age. All but two tests showed beneficial effects of education, either linear or subsiding after 12 years of educational attainment. Sex affected tests in the memory and executive domains. In three tests, an interaction between age and education revealed an increased benefit of education later in life.

CONCLUSION

This study provides normative models for 14 traditional cognitive tests adapted for self-administration through a digital platform. The models will enable more accurate interpretation of test results, hopefully leading to improved clinical decision making and better care for patients with cognitive impairment.

The Montreal Cognitive Assessment: Normative Data from a Large, Population-Based Sample of Cognitive Healthy Older Adults in Norway—The HUNT Study

Background: Several studies have found that normative scores on the Montreal Cognitive Assessment Scale (MoCA) vary depending on the person’s education and age. The evidence for different normative scores between sexes is poor. Objective: The main aim of the study was to determine normative scores on the MoCA for Norwegian older adults stratified by educational level, age, and sex. In addition, we aimed to explore sex differences in greater detail. Methods: From two population-based studies in Norway, we included 4,780 people age 70 years and older. People with a diagnosis of dementia or mild cognitive impairment, a history of stroke, and depression were excluded. Trained health personnel tested the participants with the MoCA. Results: The mean MoCA score varied between 22 and 27 and was highest among women 70–74 years with education >13 years and lowest among men age 85 and older with education ≤10 years. Education, age, and sex were significant predictors of MoCA scores. Conclusion: In the present study of cognitively healthy Norwegian adults 70 years and older, we found that the normative score on the MoCA varied between 22 and 27 depending on a person’s education, age, and sex. We suggest that normative scores should be determined taking these three variables into consideration.

Between-person and within-person associations of sleep and working-memory in the everyday lives of old and very old adults: initial level, learning, and variability

STUDY OBJECTIVES

Sleep duration affects various aspects of cognitive performance, such as working-memory and learning, among children and adults. However, it remains open, whether similar or even stronger associations exist in old and very old age when changes in sleep and cognitive decrements are common.

METHODS

Using repeated daily-life assessments from a sample of 121 young-old (66-69 years old) and 39 old-old adults (84-90 years old), we assessed links between sleep duration and different aspects of working-memory (initial level, practice-related learning, and residualized variability) between and within persons. Participants reported their sleep durations every morning and performed a numerical working-memory updating task six times a day for seven consecutive days.

RESULTS

Both people who slept longer and those who slept shorter than the sample average showed lower initial performance levels, but a stronger increase of WM over time (i.e. larger learning effects), relative to people with average sleep. Sleep duration did not predict performance variability. Within-person associations were found for people sleeping relatively little on average: For them, working-memory performance was lower on days with shorter than average sleep, yet higher on days with longer than average sleep. Except for lower initial levels of working-memory in old-old adults, no differences between young-old and old-old adults were observed.

CONCLUSION

We conclude that sufficient sleep remains important for working-memory performance in older adults and that it is relevant to include different aspects of working-memory performance, because effects differed for initial performance and learning.

Sex Differences on Montreal Cognitive Assessment and Mini-Mental State Examination Scores and the Value of Self-Report of Memory Problems among Community Dwelling People 70 Years and above: The HUNT Study

INTRODUCTION

The aims were to examine if the total and item scores on the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) and self-reported memory problems differed between older women and men, and if self-reported memory problems were associated with scores on the 2 tests.

METHODS

We included 309 home-dwelling people aged 70 years and older, 155 women, mean age 75.6 (SD 4.1) years, and 154 men, mean age 76.0 (SD 4.6) years. They were examined with MoCA and MMSE, and they answered 2 questions: "have you experienced any memory problems" and "have you experienced significant memory problems the last 5 years?"

RESULTS

The participants scored significantly higher on the MMSE (women 28.0 [1.8], men 28.4 [1.4]) than on MoCA (women 24.6 [3.3], men 24.3 [3.1]). Spearman's rho was 0.36 between the tests. Women scored significantly higher than men on delayed recall of MoCA (3.0 [1.6] vs. 2.4 [1.6]), whereas men scored significantly higher on visuoconstruction (3.8 [1.2] vs. 3.5 [1.0]) and serial subtraction on MoCA (2.7 [0.6] vs. 2.5 [0.8]) and serial sevens on MMSE (4.5 [0.8] vs. 4.1 [1.1]). Multivariate linear regression analyses revealed that female sex, younger age, and higher education were associated with a higher score on MoCA, whereas age and education were associated with a higher score on MMSE. About half of the participants (no sex difference) had experienced significant memory problems the last 5 years, and they had significantly lower scores on both tests.

CONCLUSIONS

The MoCA score was associated with sex, age, and education, whereas sex did not influence the MMSE score. The question "have you experienced significant memory problems the last 5 years?" may be useful to evaluate older people's cognition.

Measurement of individual differences in face-identity processing abilities in older adults

BACKGROUND

Face-identity processing declines with age. Few studies have examined whether face-identity processing abilities can be measured independently from general cognitive abilities in older adults (OA). This question has practical implications for the assessment of face-identity processing abilities in OA and theoretical implications for the notion of face processing as a specific ability. The present study examined the specificity of face memory and face matching abilities in OA aged 50 + .

METHODS

Performance of younger adults (YA) and OA was measured on face tasks: Cambridge Face Memory Task (CFMT), the Glasgow Face Matching Task (GFMT), holistic processing; and tasks of general cognition: fluid intelligence, selective attention, and mental rotation. Data were analyzed using multiple regression models encompassing (i) the CFMT/GFMT and measures of general cognition; and (ii) all face processing tasks.

RESULTS

Across the two age groups, models encompassing all face tasks were significant and accounted for more variance in the data than models encompassing the CFMT/GFMT and measures of general cognition. General cognitive abilities accounted for 17% of variance for the GFMT (p < 0.01) and 3% for the CFMT (p > 0.05).

DISCUSSION

Our results suggest that face memory can be measured independently from general cognition using the CFMT in OA. Implications for the notion of a general face processing factor across the adult lifespan are discussed.

The Association of Individual Changes in Stressful Life Events and Telomere Length Over Time in Twins 50 Years and Older

OBJECTIVE

Exposure to adverse stressors has been associated with shortening of leukocyte telomere length (LTL). The present longitudinal study investigates the time course of exposure to life events and LTL to determine whether increases in exposure to life events are related to subsequent accelerated LTL shortening.

METHODS

In the Swedish Adoption/Twin Study of Aging, we assessed late-life stressful events and LTL in 543 individual participants (mean age = 68.4 years, 40% men, including 48 complete monozygotic twin pairs and 167 complete dizygotic twin pairs) in up to five separate measurements over a period of 25 years. LTL was measured using quantitative polymerase chain reaction. Longitudinal analyses were conducted using time-varying mixed modeling, corrected for life-style factors and depressive symptoms.

RESULTS

When adjusting for differences in genetic makeup by looking only in monozygotic twins, we found that an increase in life stressors within an individual was related to decreased LTL over time (B = -0.02; 95% confidence interval = -0.04 to 0.01; p = .002). None of the findings were significant when only looking at dizygotic twins (all, p > .05).

CONCLUSIONS

Our findings in an older population show a causal relation between increase in life stress and accelerated LTL shortening by using intraindividual time-varying analysis.

Lack of association between proton pump inhibitor use and decline in cognitive performance in the ELSA-Brasil cohort

OBJECTIVE

The study aims to investigate the longitudinal association of use and time of use of proton pump inhibitors (PPIs) with decreased performance in three cognitive tests.

METHODS

Prospective cohort study included 7115 participants with mean age of 58.9 years at baseline (2008-2010) who participated in the second wave (2012-2014) of ELSA-Brasil (average interval between visits = 3.9 years (range: 1.7 to 6.0 years)). Cognitive performance was assessed by tests of memory, phonemic and semantic verbal fluency, and the trail making test, applied to both waves. Associations with the use and time of use of PPIs at baseline were investigated using linear models with mixed effects after adjusting for confounding factors.

RESULTS

At baseline, 7.4% (529) of the participants used PPIs on a regular basis. After all adjustments, the interaction term use of PPI × age was not statistically significant for the cognitive tests evaluated, indicating that the use of PPI at baseline was not associated with a more accelerated decline in cognitive performance between waves. The interaction term PPI use × age was not statistically significant, in any of the categories of medication use time, any of the cognitive function tests evaluated, indicating that PPI use time is not associated with decrease in cognitive scores as the time interval between visits increases.

CONCLUSION

In this cohort middle-aged and elderly adults, after average interval of 3.9 years (relatively short time to detect cognitive decline in a young cohort), the use and time of use of PPIs at the beginning of the study were not associated with a decline in cognitive performance in these tests between visits.

Change in cognition and body mass index in relation to preclinical dementia

INTRODUCTION

To study if declining cognition drives weight loss in preclinical dementia, we examined the longitudinal association between body mass index (BMI) and cognitive abilities in individuals who did or did not later develop dementia.

METHODS

Using data from individuals spanning age 50 to 89, we applied dual change score models separately in individuals who remained cognitively intact (n = 1498) and those who were diagnosed with dementia within 5 years of last assessment (n = 459).

RESULTS

Among the cognitively intact, there was a bidirectional association: Stable BMI predicted stable cognition and vice versa. Among individuals who were subsequently diagnosed with dementia, the association was unidirectional: Higher BMI predicted declining cognition but cognition did not predict change in BMI.

DISCUSSION

Although BMI and cognition stabilized each other when cognitive functioning was intact, this buffering effect was missing in the preclinical dementia phase. This finding indicates that weight loss in preclinical dementia is not driven by declining cognition.

Epigenome-wide association study of level and change in cognitive abilities from midlife through late life

Background

Epigenetic mechanisms are important in aging and may be involved in late-life changes in cognitive abilities. We conducted an epigenome-wide association study of leukocyte DNA methylation in relation to level and change in cognitive abilities, from midlife through late life in 535 Swedish twins.

Results

Methylation levels were measured with the Infinium Human Methylation 450 K or Infinium MethylationEPIC array, and all sites passing quality control on both arrays were selected for analysis (n = 250,816). Empirical Bayes estimates of individual intercept (age 65), linear, and quadratic change were obtained from latent growth curve models of cognitive traits and used as outcomes in linear regression models. Significant sites (p < 2.4 × 10^–7) were followed up in between-within twin pair models adjusting for familial confounding and full-growth modeling. We identified six significant associations between DNA methylation and level of cognitive abilities at age 65: cg18064256 (PPP1R13L) with processing speed and spatial ability; cg04549090 (NRXN3) with spatial ability; cg09988380 (POGZ), cg25651129 (-), and cg08011941 (ENTPD8) with working memory. The genes are involved in neuroinflammation, neuropsychiatric disorders, and ATP metabolism. Within-pair associations were approximately half that of between-pair associations across all sites. In full-growth curve models, associations between DNA methylation and cognitive level at age 65 were of small effect sizes, and associations between DNA methylation and longitudinal change in cognitive abilities of very small effect sizes.

Conclusions

Leukocyte DNA methylation was associated with level, but not change in cognitive abilities. The associations were substantially attenuated in within-pair analyses, indicating they are influenced in part by genetic factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01075-9.

Functional Aging Index Complements Frailty in Prediction of Entry Into Care and Mortality

BACKGROUND

The aim of this study was to develop a functional aging index (FAI) that taps four body systems: sensory (vision and hearing), pulmonary, strength (grip strength), and movement (gait speed) and to test the predictive value of FAI for entry into care and mortality.

METHOD

Growth curve models and Cox regression models were applied to data from 1,695 individuals from three Swedish longitudinal studies of aging. Participants were aged 45-93 at intake and data from up to eight follow-up waves were available.

RESULTS

The rate of change in FAI was twice as fast after age 75 as before, women demonstrated higher mean FAI, but no sex differences in rates of change with chronological age were identified. FAI predicted entry into care and mortality, even when chronological age and a frailty index were included in the models. Hazard ratios indicated that FAI was a more important predictor of entry into care for men than women, whereas it was a stronger predictor of mortality for men than women.

CONCLUSIONS

Measures of biological aging and functional aging differ in their predictive value for entry into care and mortality for men and women, suggesting that both are necessary for a complete picture of the aging process across genders.

The relation of poor mastication with cognition and dementia risk: a population-based longitudinal study

We investigated the effect of poor masticatory ability on cognitive trajectories and dementia risk in older adults. 544 cognitively intact adults aged ≥50 were followed for up to 22 years. Cognitive domains (verbal, spatial/fluid, memory, and perceptual speed) were assessed at baseline and follow-ups. Dementia was ascertained according to standard criteria. Masticatory ability was assessed using the Eichner Index and categorized according to the number of posterior occlusal zones: A (all four), B (3-1), and C (none).

At baseline, 147 (27.0%) participants were in Eichner category A, 169 (31.1%) in B and 228 (41.9%) in C. After the age of 65, participants in Eichner category B and C showed an accelerated decline in spatial/fluid abilities (β: -0.16, 95% CI: -0.30 to -0.03) and (β: -0.15, 95% CI: -0.28 to -0.02), respectively. Over the follow-up, 52 incident dementia cases were identified. Eichner categories B or C were not associated with an increased risk of dementia, compared to category A (Hazard Ratio [HR]: 0.83, 95% CI: 0.39 to 1.76 and HR: 0.63, 95% CI: 0.30 to 1.29, respectively).

Poor masticatory ability is associated with an accelerated cognitive decline in fluid/spatial abilities, however it was not related to a higher risk of dementia.

Longitudinal Characterization and Biomarkers of Age and Sex Differences in the Decline of Spatial Memory

The current longitudinal study examined factors (sex, physical function, response to novelty, ability to adapt to a shift in light/dark cycle, brain connectivity), which might predict the emergence of impaired memory during aging. Male and female Fisher 344 rats were tested at 6, 12, and 18 months of age. Impaired spatial memory developed in middle-age (12 months), particularly in males, and the propensity for impairment increased with advanced age. A reduced response to novelty was observed over the course of aging, which is inconsistent with cross-sectional studies. This divergence likely resulted from differences in the history of environmental enrichment/impoverishment for cross-sectional and longitudinal studies. Animals that exhibited lower level exploration of the inner region on the open field test exhibited better memory at 12 months. Furthermore, males that exhibited a longer latency to enter a novel environment at 6 months, exhibited better memory at 12 months. For females, memory at 12 months was correlated with the ability to behaviorally adapt to a shift in light/dark cycle. Functional magnetic resonance imaging of the brain, conducted at 12 months, indicated that the decline in memory was associated with altered functional connectivity within different memory systems, most notably between the hippocampus and multiple regions such as the retrosplenial cortex, thalamus, striatum, and amygdala. Overall, some factors, specifically response to novelty at an early age and the capacity to adapt to shifts in light cycle, predicted spatial memory in middle-age, and spatial memory is associated with corresponding changes in brain connectivity. We discuss similarities and differences related to previous longitudinal and cross-sectional studies, as well as the role of sex differences in providing a theoretical framework to guide future longitudinal research on the trajectory of cognitive decline. In addition to demonstrating the power of longitudinal studies, these data highlight the importance of middle-age for identifying potential predictive indicators of sexual dimorphism in the trajectory in brain and cognitive aging.

Gender Differences in Longitudinal Trajectories of Change in Physical, Social, and Cognitive/Sedentary Leisure Activities

Objective

We examined changes in participation in cognitive, social, and physical leisure activities across middle and older adulthood and tested moderation of trajectories of change in participation by gender.

Method

In all, 1,398 participants in the Swedish Adoption/Twin Study of Aging (SATSA) completed a 7-item leisure activity questionnaire up to 4 times over 17 years. Mean baseline age was 64.9 years (range = 36-91); 59% were women. Factor analysis identified physical, social, and cognitive/sedentary leisure activity participation factors. Age-based latent growth curve models adjusted for marital status, gender, education, depressive symptoms, and physical health were used.

Results

Overall, results indicated stability in social activities, increase in cognitive/sedentary activities, and decrease in physical activities, as well as accelerated decline in all three types of activities after about the age of 70 years. Social activity remained mostly stable for women and declined for men. Women reported higher levels of cognitive/sedentary leisure activity across the study. Both men and women declined in physical leisure activity. Variance in leisure activities increased with age; men demonstrated more variance in social activities and women in physical activities.

Conclusions

Understanding change in leisure activities with age and by gender can have important implications for interventions and for use of leisure activity data in epidemiological research.

The Role of Attitude Toward Own Aging for Fluid and Crystallized Functioning: 12-Year Evidence From the ILSE Study

Objectives

Aging attitudes have been shown to affect a variety of important developmental outcomes in old age, including memory. Extending previous research, the present study examined long-term effects of attitudes toward own aging (ATOA), relying on a broader range of cognitive abilities in later life.

Method

Data came from the Interdisciplinary Longitudinal Study of Adult Development and Aging (ILSE), with three measurement waves (1993/1994, 1997/1998, and 2005/2006) covering a 12-year interval. Drawing on the older of two available birth cohorts (1930-1932; n = 500), we analyzed the relationship between ATOA and change in fluid versus crystallized abilities based on overall and gender-specific latent change score models, while controlling for education and objective health.

Results

As expected, ATOA predicted change in fluid functioning-but not in crystallized performance-over 12 years. Gender-specific analyses revealed a stronger association between ATOA and decline in fluid abilities for men, even after controlling for health and education.

Discussion

This study adds to the understanding of long-term implications of aging attitudes for cognitive decline trajectories and shows that negative aging attitudes are a risk factor for age-vulnerable cognitive abilities, particularly among men. Further research is needed to better understand the underlying mechanisms of observed relationships.

Cognitive Trajectories of Older Adults With Prediabetes and Diabetes: A Population-Based Cohort Study

Background

Diabetes has been linked to dementia risk; however, the cognitive trajectories in older adults with diabetes remain unclear. We aimed to investigate the effect of prediabetes and diabetes on cognitive trajectories among cognitively intact older adults in a long-term follow-up study.

Methods

Within the Swedish Adoption/Twin Study of Aging, 793 cognitively intact older adults aged ≥50 were identified at baseline and followed for up to 23 years. Based on standardized scores from 11 cognitive tests, administered at baseline and up to seven follow-ups, four cognitive domains (verbal abilities, spatial/fluid, memory, perceptual speed) were identified by principal-component analysis. Prediabetes was defined according to blood glucose levels in diabetes-free participants. Diabetes was ascertained based on self-report, hypoglycemic medication use and blood glucose levels. Data were analyzed with linear mixed-effect models adjusting for potential confounders.

Results

At baseline, 68 participants (8.6%) had prediabetes and 45 (5.7%) had diabetes. Compared to diabetes-free individuals, people with diabetes had a steeper decline over time in perceptual speed and verbal abilities. The annual declines in these domains were greater than the annual decline in memory. Prediabetes was associated with lower performance in memory in middle-age, but also associated with a less steep memory decline over the follow-up.

Conclusions

Diabetes is associated with a faster decline in perceptual speed and verbal abilities, while prediabetes is associated with lower memory performance in middle-age. However, the detrimental effects of hyperglycemia seem to not affect memory over time.

Trajectories of Depressive Symptomatology and Loneliness in Older Adult Sexual Minorities and Heterosexual Groups

OBJECTIVES

This article examines whether sexual minority men and women experience greater increases in depressive symptoms and loneliness with age compared to heterosexual men and women.

METHODS

Using three waves of data from sexual minority (n_Men = 87 and n_Women = 62) and heterosexual (n_Men = 1,297 and n_Women = 1,362) older adults in the National Social Life, Health, and Aging Project, we used latent growth curve modeling to test whether change in depressive symptoms and loneliness varies across sexual orientation and whether annual household income and family support accounted for this change.

RESULTS

Although differences in the growth trajectories of depressive symptoms and loneliness across sexual orientation were not observed, gender differences were. Annual household income and family support more strongly influenced initial depressive symptoms and loneliness in sexual minority men and women than in heterosexual men and women.

CONCLUSIONS

Trajectories of depressive symptoms and loneliness in older adulthood do not vary by sexual orientation. Economic and family resources may allow sexual minorities to cope effectively with depressive symptoms and loneliness.

CLINICAL IMPLICATIONS

Clinicians should be cautious about assuming that older sexual minority group members are more susceptible to depressive symptoms and loneliness than heterosexual groups by virtue of their sexual preference.

Openness declines in advance of death in late adulthood

Openness to experience has been found to be a correlate of successful aging outcomes yet also has been found to decline from middle age onward. We hypothesized that decline in openness would be associated with death. Using longitudinal data from the Swedish Adoption/Twin Study of Aging (SATSA), the analytic sample encompassed 1954 individuals, approximately two-thirds of whom were deceased. We tested whether openness declines across late adulthood and, central to our hypothesis, whether the decline correlated with age at death. Multivariate modeling adjusted for age at study entry, sex, education, as well as the time-varying effects of physical illness, depressive symptoms, and cognitive ability. Correlations between change in neuroticism and extraversion and death were modeled for comparison. A follow-up cotwin control analysis adjusted for genetic and environmental familial confounders. Significant mean-level change was identified in all personality traits, but only for openness was change correlated with age at death, in support of our hypothesis. The findings were not explained by health factors or cognition. Cotwin control analyses indicated that the twin who died earlier showed a greater drop in openness prior to death, compared with their cotwin measured at the same time points. There was no cotwin finding for neuroticism or extraversion. We suggest that declines in openness may reflect a change in goal orientation due to the experience of a shortened time horizon, leading to an optimized selection of experiences as people approach the end of life. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Tracking the Epigenetic Clock Across the Human Life Course: A Meta-analysis of Longitudinal Cohort Data

Background

Epigenetic clocks based on DNA methylation yield high correlations with chronological age in cross-sectional data. Due to a paucity of longitudinal data, it is not known how Δage (epigenetic age - chronological age) changes over time or if it remains constant from childhood to old age. Here, we investigate this using longitudinal DNA methylation data from five datasets, covering most of the human life course.

Methods

Two measures of the epigenetic clock (Hannum and Horvath) are used to calculate Δage in the following cohorts: Avon Longitudinal Study of Parents and Children (ALSPAC) offspring (n = 986, total age-range 7-19 years, 2 waves), ALSPAC mothers (n = 982, 16-60 years, 2 waves), InCHIANTI (n = 460, 21-100 years, 2 waves), SATSA (n = 373, 48-99 years, 5 waves), Lothian Birth Cohort 1936 (n = 1,054, 70-76 years, 3 waves), and Lothian Birth Cohort 1921 (n = 476, 79-90 years, 3 waves). Linear mixed models were used to track longitudinal change in Δage within each cohort.

Results

For both epigenetic age measures, Δage showed a declining trend in almost all of the cohorts. The correlation between Δage across waves ranged from 0.22 to 0.82 for Horvath and 0.25 to 0.71 for Hannum, with stronger associations in samples collected closer in time.

Conclusions

Epigenetic age increases at a slower rate than chronological age across the life course, especially in the oldest population. Some of the effect is likely driven by survival bias, where healthy individuals are those maintained within a longitudinal study, although other factors like the age distribution of the underlying training population may also have influenced this trend.

Beyond health care: Volunteer work, social participation, and late-life general cognitive status in Taiwan

SIGNIFICANCE

In addition to the complexity associated with health care coverage and its utilization by older people, I hypothesize that social engagement promotes a better later-life general cognitive status beyond health care availability as is provided by Taiwan's National Health Insurance (NHI) system. The present study thus explores whether social engagement, specifically social participation and volunteer work, is independently associated with later-life general cognitive status after adjusting for health service utilization among older Taiwanese via the NHI system.

METHODS

Using a population-based natural experiment study design, data from the Taiwan Longitudinal Study on Aging (TLSA, 1993-2007) was analyzed. Mixed-effects models were conducted to estimate the relative effects of volunteer work, social participation, and NHI on general cognitive status over time, while taking health status, medical care utilization, community development, and social support into consideration.

RESULTS

The multivariate findings showed that a better general cognitive status is significantly associated with being actively involved in volunteer work (β = 0.14, p < 0.01) and social participation (β = 0.14, p < 0.01). In addition, NHI is also significantly associated with a higher level of general cognitive status (β = 0.10, p < 0.01).

DISCUSSION

This investigation suggests that social engagement has significant impacts on late-life general cognitive status, even taking into account the NHI system and its related utilization effects. The results highlight the importance of volunteer work and social participation among older Taiwanese because such social involvement produces a positive effect on their general cognitive status beyond health care itself. Furthermore, the contribution of productive activities to enhance late-life cognitive health is underscored.

Cognitive function trajectories and their determinants in older people: 8 years of follow-up in the English Longitudinal Study of Ageing

Background

Maintaining cognitive function is an important aspect of healthy ageing. In this study, we examined age trajectories of cognitive decline in a large nationally representative sample of older people in England. We explored the factors that influence such decline and whether these differed by gender.

Methods

Latent growth curve modelling was used to explore age-specific changes, and influences on them, in an 8-year period in memory, executive function, processing speed and global cognitive function among 10 626 participants in the English Longitudinal Study of Ageing. We run gender-specific models with the following exposures: age, education, wealth, childhood socioeconomic status, cardiovascular disease, diabetes, physical function, body mass index, physical activity, alcohol, smoking, depression and dementia.

Results

After adjustment, women had significantly less decline than men in memory (0.011, SE 0.006), executive function (0.012, SE 0.006) and global cognitive function (0.016, SE 0.004). Increasing age and dementia predicted faster rates of decline in all cognitive function domains. Depression and alcohol consumption predicted decline in some cognitive function domains in men only. Poor physical function, physical inactivity and smoking were associated with faster rates of decline in specific cognitive domains in both men and women. For example, relative to study members who were physically active, the sedentary experienced greater declines in memory (women −0.018, SE 0.009) and global cognitive function (men −0.015, SE 0.007 and women −0.016, SE 0.007).

Conclusions

The potential determinants of cognitive decline identified in this study, in particular modifiable risk factors, should be tested in the context of randomised controlled trials.

Cognitive trajectories and spectrum of neuropathology in SuperAgers: The first 10 cases

On average, memory capacity is significantly higher in populations of 50-60 year olds than in populations of 80 year olds. We define SuperAgers as individuals 80 or older whose episodic memory capacity is at least as good as that of cognitively average individuals in their 50s and 60s. SuperAgers therefore have memory capacity that is superior for age. Previous work showed that SuperAgers have greater cortical volumes and greater resistance to age-related cortical atrophy than "cognitively average" individuals of the same age. Here we report on the cognitive, personality, and neuropathologic characteristics of the first 10 autopsy cases in the Northwestern SuperAging Program. During the follow-up period, seven SuperAgers maintained episodic memory performance within or above the average range for 50-65 year-old norms and all 10 SuperAgers maintained episodic memory scores within normal limits for their own age. Extraversion scores tended to be high on the NEO-PI-R measure of personality. The 10 autopsy specimens showed variable findings within the spectrum of Alzheimer pathology. The hippocampus and entorhinal cortex contained neurofibrillary degeneration mostly in the Braak II-III stages. However, even these limbic areas contained many healthy appearing neurons and the neocortex was generally free of neurofibrillary degeneration. In contrast, neocortical areas in at least five of the cases contained moderate to high densities of neuritic plaques. These findings need to be placed in context by comparing them to the neuropathology of cognitively average individuals of the same age. Future research on SuperAgers is likely to offer insights into factors that either prevent the emergence of involutional changes in the brain or that makes cognitive function more resistant to their consequences.

Longitudinal decline of leukocyte telomere length in old age and the association with sex and genetic risk

Telomeres are DNA-protein structures at the ends of chromosomes. Leukocyte telomere length (LTL) shortening has been associated with advanced age. However, most studies use cross-sectional data, hence, the aim of our study was to model longitudinal trajectories of LTL attrition across 20 years at old age. Assessments of LTL were done by qPCR in SATSA (Swedish Adoption/Twin Study of Aging; N=636 individuals). Cross-sectional and longitudinal associations with age were estimated, the latter using latent growth curve analysis. A genetic risk score (GRS) for LTL was further assessed and included in the models. We confirmed an inverse cross-sectional association of LTL with age (B=−0.0022 T/S-ratio; 95% CI: −0.0035, −0.0009, p-value=0.0008). Longitudinal LTL analyses adjusted for sex (1598 samples; ≤5 measurements) suggested modest average decline until 69 years of age but accelerating decline after 69 years, with significant inter-individual variation. Women had on average ∼6% T/S-ratio units longer LTL at baseline, and inclusion of the GRS improved the model where four risk alleles was equivalent to the effect size difference between the sexes. In this cohort of old individuals, baseline LTL varied with age, sex and genetic background. The rate of change of LTL accelerated with age and varied considerably between individuals.

Examining the influence of perceived stress on developmental change in memory and perceptual speed for adopted and nonadopted individuals

The present study prospectively evaluated cumulative early life perceived stress in relation to differential change in memory and perceptual speed from middle childhood to early adulthood. We aimed to identify periods of cognitive development susceptible to the effects of perceived stress among both adopted and nonadopted individuals. The sample consisted of participants in the Colorado Adoption Project (CAP, N = 690). Structured latent growth curves were fit to 4 memory outcomes as well as 1 perceptual speed outcome, which described nonlinear change between ages 9 and 30. Both adoption status and cumulative perceived stress indices served as predictors of the latent curves. The perceived stress indices were constructed from the Brooks-Gunn Life Events Scale for Adolescents, and reflected "upsettingness" ratings associated with the occurrence of particular life events during middle childhood (ages 9 to 12) and adolescence (ages 13 to 16). For memory and perceptual speed, cumulative perceived stress did not predict differential cognitive gains. However, differences in perceptual speed trajectories between nonadopted and adopted individuals were observed, with adopted individuals showing smaller gains. Although these findings provide no evidence that emergent variability in memory and perceptual speed trajectories by age 30 are explained by cumulative perceptions of stress in childhood and adolescence, further investigations regarding potential vulnerability across the life span are warranted. (PsycINFO Database Record

Sex differences in exercise efficacy to improve cognition: A systematic review and meta-analysis of randomized controlled trials in older humans

Exercise is a non-pharmacological strategy to mitigate the deleterious effects of aging on brain health. However, a large amount of variation exists in its efficacy. Sex of participants and exercise type are two possible factors contributing to this variation. To better understand this, we conducted a concurrent systematic review and meta-analysis of cognitively healthy older adults. Executive functions, episodic memory, visuospatial function, word fluency, processing speed and global cognitive function were examined for exercise- and sex-dependent effects. For executive functions, three types of exercise interventions - aerobic training, resistance training, and multimodal training (i.e., both aerobic and resistance training) - were associated with larger effect sizes in studies comprised of a higher percentage of women compared to studies with a lower percentage of women. This suggests that women's executive processes may benefit more from exercise than men. Regardless of sex, compared to control, all three exercise training approaches enhanced visuospatial function, but only multimodal training enhanced episodic memory. Overall, aerobic training led to greater benefits than resistance training in global cognitive function and executive functions, while multimodal combined training led to greater benefits than aerobic training for global cognitive function, episodic memory, and word fluency. Possible underlying mechanisms, including brain-derived neurotrophic factor and sex steroid hormones, are discussed.

Childhood social class and cognitive aging in the Swedish Adoption/Twin Study of Aging

In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social class based on the Swedish socioeconomic index. Cognitive ability included a general factor and the four domains of verbal, fluid, memory, and perceptual speed. Latent growth curve models of the longitudinal data tested whether level and change in cognitive performance differed as a function of childhood social class. Between-within twin-pair analyses were performed on twins reared apart to assess familial confounding. Childhood social class was significantly associated with mean-level cognitive performance at age 65 y, but not with rate of cognitive change. The association decreased in magnitude but remained significant after adjustments for level of education and the degree to which the rearing family was supportive toward education. A between-pair effect of childhood social class was significant in all cognitive domains, whereas within-pair estimates were attenuated, indicating genetic confounding. Thus, childhood social class is important for cognitive performance in adulthood on a population level, but the association is largely attributable to genetic influences.

Cognitive Variability during Middle-Age: Possible Association with Neurodegeneration and Cognitive Reserve

Objective: Increased variability in cognition with age has been argued as an indication of pathological processes. Focusing on early detection of neurodegenerative disorders, we investigated variability in cognition in healthy middle-aged adults. In order to understand possible determinants of this variability, we also investigated associations with cognitive reserve, neuroimaging markers, subjective memory complaints, depressive symptomatology, and gender.

Method: Thirty-one 50 ± 2 years old individuals were investigated as target group and deviation was studied in comparison to a reference younger group of 30 individuals 40 ± 2 years old. Comprehensive neuropsychological and structural imaging protocols were collected. Brain regional volumes and cortical thickness were calculated with FreeSurfer, white matter hyperintensities with CASCADE, and mean diffusivity with FSL.

Results: Across-individuals variability showed greater dispersion in lexical access, processing speed, executive functions, and memory. Variability in global cognition correlated with, reduced cortical thickness in the right parietal-temporal-occipital association cortex, and increased mean diffusivity in the cingulum bundle and right inferior fronto-occipital fasciculus. A trend was also observed for the correlation between global cognition and hippocampal volume and female gender. All these associations were influenced by cognitive reserve. No correlations were found with subjective memory complaints, white matter hyperintensities and depressive symptomatology. Across-domains and across-tasks variability was greater in several executive components and cognitive processing speed.

Conclusion: Variability in cognition during middle-age is associated with neurodegeneration in the parietal–temporal–occipital association cortex and white matter tracts connecting this to the prefrontal dorsolateral cortex and the hippocampus. Moreover, this effect is influenced by cognitive reserve. Studying variability offers valuable information showing that differences do not occur in the same magnitude and direction across individuals, cognitive domains and tasks. These findings may have important implications for early detection of subtle cognitive impairment and clinical interpretation of deviation from normality.

The development of multitasking in children aged 7-12years: Evidence from cross-sectional and longitudinal data

This study investigated the development of multitasking ability across childhood. A sample of 65 typically developing children aged 7, 9, and 11years completed two multitasking tests across three time points within a year. Cross-sectional and longitudinal data consistently indicated continuous linear growth in children's multitasking ability. By the age of 12years, children could effectively perform a simple multitasking scenario comprising six equally important tasks, although their ability to strategically organize assorted tasks with varied values and priorities in a complex multitasking setting had not reached proficiency yet. Cognitive functions underlying a complex multitasking scenario varied in their developmental trajectories. Retrospective memory developed continuously from 7 to 12years of age, suggesting its supporting role in the development of multitasking. Planning skills developed slowly and showed practice effects for older children but not for younger children. The ability to adhere to plans also developed slowly, and children of all age groups benefited from practice. This study offers a preliminary benchmark for future comparison with clinical populations and may help to inform the development of targeted interventions.

Temporal dynamics of cognitive performance and anxiety across older adulthood

Cognitive decline and anxiety symptoms commonly co-occur in later life, but the temporal order of changes on these two attributes is unclear. Specifically, it is unknown if greater anxiety leads to subsequent declines in cognitive performance or if worse cognitive performance leads to increased anxiety. In this study, we sought to elucidate the temporal dynamics between anxiety symptoms and cognitive performance across old age-that is, the extent to which level and change in one variable influence subsequent changes in a second variable. We examined data from 721 nondemented participants from the Swedish Adoption/Twin Study of Aging. Participants completed as many as eight assessments of cognitive performance and anxiety over a 26-year period. Bivariate dual-change score models were fit to examine the dynamic association between anxiety and cognitive performance. Bidirectional associations between anxiety and cognitive performance were found among measures of processing speed, attention, and memory but not visuospatial abilities. Higher anxiety was associated with greater declines in processing speed over the duration of 6 years and worsening attention over a span of 3 years. The reverse direction was also significant in that slower processing speed, worse attention, and poorer nonverbal and working memory performance were associated with larger increases in anxiety 3 years later. These findings highlight that in cognitively intact older adults, the association between anxiety and worse cognitive performance is bidirectional and complex. (PsycINFO Database Record

A longitudinal twin study of general cognitive ability over four decades

In this longitudinal study we examined the stability of general cognitive ability (GCA), as well as heterogeneity and genetic and environmental influences underlying individual differences in change. We investigated GCA from young adulthood through late midlife in 1,288 Vietnam Era Twin Study of Aging participants at ages ∼20, ∼56, and ∼62 years. The correlations among the 3 occasions ranged from .73 to .85, reflecting substantial stability. The heritability was significant on each of the 3 occasions and ranged from .59 to .66. The influence of the shared environment was not significant at any of the ages. The genetic correlations across the 3 occasions ranged from .95 to .99 and did not differ significantly from 1.0. The nonshared environmental correlations ranged from .21 to .47. Latent growth curve analysis was applied to characterize trajectories over the 42-year period. Slope was significantly different from 0 and indicated that there was modest change over time. There was a significant genetic influence on initial level of GCA (h2 = .67), but not change (h2 = .23). Genetic factors primarily contribute to stability, while change reflects the influence of nonshared environmental influences. There was a significant negative correlation between initial level of GCA and change (r = -.31). Latent class growth analysis identified 4 trajectories. In general, the 4 groups followed parallel trajectories and were differentiated mainly by differences in AFQT performance level at the time of military induction. (PsycINFO Database Record

The Relationship between Body Mass Index and 10-Year Trajectories of Physical Functioning in Middle-Aged and Older Russians: Prospective Results of the Russian HAPIEE Study

OBJECTIVE

To investigate the associations of overweight and obesity with longitudinal decline in physical functioning (PF) among middle-aged and older Russians.

DESIGN

Prospective cohort study.

SETTING

Four rounds of data collection in the Russian Health, Alcohol and Psychosocial factors In Eastern Europe study with up to 10 years of follow-up.

PARTICIPANTS

9,222 men and women aged 45-69 years randomly selected from the population of two districts of Novosibirsk, Russia.

MEASUREMENTS

PF score (range 0-100) was measured by the Physical Functioning Subscale (PF-10) of the 36-item Short Form Health Survey (SF-36) at baseline and three subsequent occasions. Body mass index (BMI), derived from objectively measured body height and weight at baseline, was classified into normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), obesity class I (BMI 30.0-34.9), and obesity class II+ (BMI≥35.0).

RESULTS

The mean annual decline in the PF score during the follow-up was -1.92 (95% confidence interval -2.17; -1.68) in men and -1.91 (-2.13; -1.68) in women. At baseline, compared with normal weight, obesity classes I and II+ (but not overweight) were associated with significantly lower PF in both sexes. In prospective analyses, the decline in PF was faster in overweight men (difference from normal weight subjects -0.38 [-0.63; -0.14]), class I obese men and women (-0.49 [-0.82; -0.17] and -0.44 [-0.73; -0.15] respectively) and class II+ obese men and women (-1.13 [-1.73; -0.53] and -0.43 [-0.77; -0.09] respectively). Adjustment for physical activity and other covariates did not materially change the results.

CONCLUSIONS

PF decreased more rapidly in obese men and women than among those with normal weight. The adverse effect of high BMI on PF trajectories appeared to be more pronounced in men than in women, making more extremely obese Russian men an important target population to prevent/slow down the process of decline in PF.

Shared and unique influences on age-related cognitive change

OBJECTIVE

Decompose cognitive change into influences unique to particular cognitive domains, and influences shared across different cognitive domains.

METHOD

A total of 2,546 adults between 18 and 95 years of age performed a battery of 12 cognitive tests on 2 occasions separated by an average of 3 years. An estimate of general cognitive functioning based on the first principal factor was regressed from the observed cognitive scores to derive an estimate of specific influences on each measure, and this value was subtracted from the observed score to provide an estimate of general influences on the measure. Longitudinal change was assessed by the (T2 - T1) difference between scores on the 2 occasions.

RESULTS

Although increased age was associated with specific influences on speed in cross-sectional comparisons, and in memory change in longitudinal comparisons among older adults, most of the relations between age and cognitive functioning in both cross-sectional and longitudinal comparisons were manifested as general influences shared with other cognitive measures.

CONCLUSIONS

Differences in cognitive functioning associated with aging are often attributed to domain-specific effects, but results from this and other recent studies suggest that large proportions of the age differences are associated with general influences shared across different types of cognitive measures. (PsycINFO Database Record

Brain Biomarkers of Vulnerability and Progression to Psychosis

Identifying predictors and elucidating the fundamental mechanisms underlying onset of psychosis are critical for the development of targeted preemptive interventions. This article presents a selective review of findings on risk prediction algorithms and potential mechanisms of onset in youth at clinical high-risk for psychosis, focusing principally on recent findings of the North American Prodrome Longitudinal Study (NAPLS). Multivariate models incorporating risk factors from clinical, demographic, neurocognitive, and psychosocial assessments achieve high levels of predictive accuracy when applied to individuals who meet criteria for a prodromal risk syndrome. An individualized risk calculator is available to scale the risk for newly ascertained cases, which could aid in clinical decision making. At risk individuals who convert to psychosis show elevated levels of proinflammatory cytokines, as well as disrupted resting state thalamo-cortical functional connectivity at baseline, compared with those who do not. Further, converters show a steeper rate of gray matter reduction, most prominent in prefrontal cortex, that in turn is predicted by higher levels of inflammatory markers at baseline. Microglia, resident immune cells in the brain, have recently been discovered to influence synaptic plasticity in health and impair plasticity in disease. Processes that modulate microglial activation may represent convergent mechanisms that influence brain dysconnectivity and risk for onset of psychosis and thus may be targetable in developing and testing preventive interventions.

Mid-life socioeconomic status, depressive symptomatology and general cognitive status among older adults: inter-relationships and temporal effects

Background

Few longitudinal studies have analyzed how socioeconomic status (SES) influences both depressive and cognitive development over an individual’s life course. This study investigates the change trajectories of both depressive symptomatology and general cognitive status, as well as their associations over time, focusing on the effects of mid-life SES.

Methods

Data were obtained from the Taiwan Longitudinal Study on Aging (1993–2007), a nationally representative cohort study of older adults in Taiwan. The short form of the Center of Epidemiological Studies-Depression (CES-D) scale that measures depressive symptomatology in two domains (negative affect and lack of positive affect) was used. General cognitive status was assessed using the brief Short Portable Mental Status Questionnaire scale. Assessments of the subjects’ mid-life SES included measurement of the participant’s education and occupation. Analyses were conducted by the parallel latent growth curve modeling.

Results

The participants’ initial levels of depressive symptomatology and general cognitive status were significantly and negatively correlated; furthermore, any changes in these two outcomes were also correlated over time. The initial assessment of general cognitive status significantly contributed to any advancement towards more severe depressive symptomatology over time, particularly when this occurred in a negative manner. Furthermore, a mid-life SES advantage resulted in a significant reduction in late-life depressive symptomatology and also produced a slower decline in general cognitive status during later life. In contrast, lower mid-life SES exacerbated depressive symptomatology during old age, both at the initial assessment and in terms of the change over time. In addition, female gender was significantly associated with lower general cognitive status and more severe depressive symptomatology in negative affect.

Conclusions

These findings suggest a complex and longitudinal association between depressive symptomatology and general cognitive status in later life and this complicated relationship seems to be affected by mid-life SES over time.

Sex differences in cognitive impairment in Alzheimer’s disease

Sex differences in neurocognitive abilities have been extensively explored both in the healthy population and in many disorders. Until recently, however, little work has examined such differences in people with Alzheimer’s disease (AD). This is despite clear evidence that AD is more prevalent in women, and converging lines of evidence from brain imaging, post-mortem analyses, hormone therapy and genetics suggesting that AD affects men and women differently. We provide an overview of evidence attesting to the poorer cognitive profiles in women than in men at the same stage of AD. Indeed, men significantly outperform women in several cognitive domains, including: Language and semantic abilities, visuospatial abilities and episodic memory. These differences do not appear to be attributable to any differences in age, education, or dementia severity. Reasons posited for this female disadvantage include a reduction of estrogen in postmenopausal women, greater cognitive reserve in men, and the influence of the apolipoprotein E ε4 allele. Assessment of cognitive abilities contributes to the diagnosis of the condition and thus, it is crucial to identify the role of sex differences if potentially more accurate diagnoses and treatments are to emerge.

Sex differences in cognitive trajectories in clinically normal older adults

Age effects on cognitive functioning are well-documented, but effects of sex on trajectories of cognitive aging are less clear. We examined cognitive ability across a variety of measures for 1,065 to 2,127 participants (mean baseline age 64.1 to 69.7 years) from the Baltimore Longitudinal Study of Aging who were repeatedly tested over a mean follow-up interval of 3.0 to 9.0 years with a mean of 2.3 to 4.4 assessments. Memory and other cognitive tests were administered at each visit, assessing mental status, verbal learning and memory, figural memory, language, attention, perceptuomotor speed and integration, executive function, and visuospatial ability. Importantly, participants free from cognitive impairment at all time points were used in the analyses. Results showed that for all tests, higher age at baseline was significantly associated with lower scores, and performance declined over time. In addition, advancing age was associated with accelerated longitudinal declines in performance (trend for mental status). After adjusting for age, education, and race, sex differences were observed across most tests of specific cognitive abilities examined. At baseline, males outperformed females on the 2 tasks of visuospatial ability, and females outperformed males in most other tests of cognition. Sex differences in cognitive change over time indicated steeper rates of decline for men on measures of mental status, perceptuomotor speed and integration, and visuospatial ability, but no measures on which women showed significantly steeper declines. Our results highlight greater resilience to age-related cognitive decline in older women compared with men.

Regional brain shrinkage and change in cognitive performance over two years: The bidirectional influences of the brain and cognitive reserve factors

We examined relationships between regional brain shrinkage and changes in cognitive performance, while taking into account the influence of chronological age, vascular risk, Apolipoprotein E variant and socioeconomic status. Regional brain volumes and cognitive performance were assessed in 167 healthy adults (age 19-79 at baseline), 90 of whom returned for the follow-up after two years. Brain volumes were measured in six regions of interest (ROIs): lateral prefrontal cortex (LPFC), prefrontal white matter (PFw), hippocampus (Hc), parahippocampal gyrus (PhG), cerebellar hemispheres (CbH), and primary visual cortex (VC), and cognitive performance was evaluated in three domains: episodic memory (EM), fluid intelligence (Gf), and vocabulary (V). Average volume loss was observed in Hc, PhG and CbH, but reliable individual differences were noted in all examined ROIs. Average positive change was observed in EM and V performance but not in Gf scores, yet only the last evidenced individual differences in change. We observed reciprocal influences among neuroanatomical and cognitive variables. Larger brain volumes at baseline predicted greater individual gains in Gf, but differences in LPFC volume change were in part explained by baseline level of cognitive performance. In one region (PFw), individual change in volume was coupled with change in Gf. Larger initial brain volumes did not predict slower shrinkage. The results underscore the complex role of brain maintenance and cognitive reserve in adult development.

How Schizophrenia Develops: Cognitive and Brain Mechanisms Underlying Onset of Psychosis

Identifying cognitive and neural mechanisms involved in the development of schizophrenia requires longitudinal observation of individuals prior to onset. Here recent studies of prodromal individuals who progress to full psychosis are briefly reviewed in relation to models of schizophrenia pathophysiology. Together, this body of work suggests that disruption in brain connectivity, driven primarily by a progressive reduction in dendritic spines on cortical pyramidal neurons, may represent a key triggering mechanism. The earliest disruptions appear to be in circuits involved in referencing experiences according to time, place, and agency, which may result in a failure to recognize particular cognitions as self-generated or to constrain interpretations of the meaning of events based on prior experiences, providing the scaffolding for faulty reality testing.

Dietary Patterns and Cognitive Decline Among Chinese Older Adults

BACKGROUND

Prospective evidence of associations of dietary patterns with cognitive decline is limited and inconsistent. We examined how cognitive changes among Chinese older adults relate to either an adapted Mediterranean diet score or factor analysis-derived dietary patterns.

METHODS

This prospective cohort study comprised 1,650 adults ≥55 years of age, who completed a cognitive screening test at two or more waves of the China Health and Nutrition Survey in 1997, 2000, or 2004. Outcomes were repeated measures of global cognitive scores, composite cognitive z scores (standardized units [SU]), and standardized verbal memory scores (SU). Baseline diet was measured by 24-hour recalls over 3 days. We used linear mixed effects models to evaluate how changes in cognitive scores were associated with adapted Mediterranean diet score and two dietary pattern scores derived from factor analysis.

RESULTS

Among adults ≥65 years of age, compared with participants in the lowest tertile of adapted Mediterranean diet, those in the highest tertile had a slower rate of cognitive decline (difference in mean SU change/year β = 0.042; 95% confidence interval [CI]: 0.002, 0.081). A wheat-based diverse diet derived by factor analysis shared features of the adapted Mediterranean diet, with the top tertile associated with slower annual decline in global cognitive function (β = 0.069 SU/year; 95% CI: 0.023, 0.114). We observed no associations among adults <65 years of age.

CONCLUSIONS

Our findings suggest that an adapted Mediterranean diet or a wheat-based, diverse diet with similar components may reduce the rate of cognitive decline in later life in the Chinese population.

Temporal Dynamics of Motor Functioning and Cognitive Aging

BACKGROUND

Because of the possible implications for intervention and thus successful aging, researchers have striven to determine whether the age changes in physical and cognitive functioning are coincident or does functioning in one domain change before, and possibly contribute to, functioning in the other.

METHODS

Bivariate dual change score models were applied to four cognitive factors and three motor functioning factors available from 813 adults who participated in the Swedish Adoption/Twin Study of Aging. Participants were aged 50-88 at the first of six waves of testing covering a 19-year follow-up period; 68% participated in at least three waves.

RESULTS

Model comparisons indicated dynamic coupling relationships between Balance and Fine Motor factors and the Speed cognitive factor. Decline in motor function precedes decline in performance on processing speed tasks, even though the motor function tasks were not timed. Results indicated possible bidirectional coupling between Fine Motor and Speed.

CONCLUSIONS

Combined with other dual change score model analyses of cognition and physical function, a picture is beginning to emerge of the cascade of events that may lead to cognitive aging.

A meta-analysis of heritability of cognitive aging: minding the "missing heritability" gap

The etiologies underlying variation in adult cognitive performance and cognitive aging have enjoyed much attention in the literature, but much of that attention has focused on broad factors, principally general cognitive ability. The current review provides meta-analyses of age trends in heritability of specific cognitive abilities and considers the profile of genetic and environmental factors contributing to cognitive aging to address the 'missing heritability' issue. Our findings, based upon evaluating 27 reports in the literature, indicate that verbal ability demonstrated declining heritability, after about age 60, as did spatial ability and perceptual speed more modestly. Trends for general memory, working memory, and spatial ability generally indicated stability, or small increases in heritability in mid-life. Equivocal results were found for executive function. A second meta-analysis then considered the gap between twin-based versus SNP-based heritability derived from population-based GWAS studies. Specifically, we considered twin correlation ratios to agnostically re-evaluate biometrical models across age and by cognitive domain. Results modestly suggest that nonadditive genetic variance may become increasingly important with age, especially for verbal ability. If so, this would support arguments that lower SNP-based heritability estimates result in part from uncaptured non-additive influences (e.g., dominance, gene-gene interactions), and possibly gene-environment (GE) correlations. Moreover, consistent with longitudinal twin studies of aging, as rearing environment becomes a distal factor, increasing genetic variance may result in part from nonadditive genetic influences or possible GE correlations. Sensitivity to life course dynamics is crucial to understanding etiological contributions to adult cognitive performance and cognitive aging.

Fish intake is associated with slower cognitive decline in Chinese older adults

Modifiable lifestyle changes, including dietary changes, could translate into a great reduction in the global burden of cognitive impairment and dementia. Few studies evaluated the benefits of fish intake for delaying cognitive decline, and no studies were conducted in a Chinese population, which may differ with respect to types, amounts, and correlates of fish consumption compared with Western populations. We hypothesized that higher consumption of fish would predict slower decline in cognitive function, independent of a wide range of potential confounders. This prospective cohort study comprised 1566 community-dwelling adults aged ≥ 55 y who completed a cognitive screening test at ≥2 waves of the China Health and Nutrition Survey in 1997, 2000, or 2004, with a mean follow-up of 5.3 y [age at entry (mean ± SD): 63 ± 6 y]. Diet was measured by 3-d 24-h recalls at baseline. Outcomes included repeated measures of global cognitive scores (baseline mean ± SD: 19 ± 6 points), composite cognitive Z-scores (standardized units), and standardized verbal memory scores (standardized units). Multivariable-adjusted linear mixed-effects models were used to evaluate the relation of fish intake with changes in cognitive scores. Age was found to significantly modify the association between fish consumption and cognitive change (P = 0.007). Among adults aged ≥ 65 y, compared with individuals who consumed <1 serving/wk (i.e., 100 g) fish, the mean annual rate of global cognitive decline was reduced by 0.35 point (95% CI: 0.13, 0.58) among those consuming ≥ 1 serving/wk, equivalent to the disparity associated with 1.6 y of age. Fish consumption was also associated with a slower decline in composite and verbal memory scores. No associations were observed among adults aged 55-64 y. Our findings suggest a potential role of fish consumption as a modifiable dietary factor to reduce the rate of cognitive decline in later life.

Blood glucose, diet-based glycemic load and cognitive aging among dementia-free older adults

BACKGROUND

Although evidence indicates that Type II Diabetes is related to abnormal brain aging, the influence of elevated blood glucose on long-term cognitive change is unclear. In addition, the relationship between diet-based glycemic load and cognitive aging has not been extensively studied. The focus of this study was to investigate the influence of diet-based glycemic load and blood glucose on cognitive aging in older adults followed for up to 16 years.

METHODS

Eight-hundred and thirty-eight cognitively healthy adults aged ≥50 years (M = 63.1, SD = 8.3) from the Swedish Adoption/Twin Study of Aging were studied. Mixed effects growth models were utilized to assess overall performance and change in general cognitive functioning, perceptual speed, memory, verbal ability, and spatial ability as a function of baseline blood glucose and diet-based glycemic load.

RESULTS

High blood glucose was related to poorer overall performance on perceptual speed as well as greater rates of decline in general cognitive ability, perceptual speed, verbal ability, and spatial ability. Diet-based glycemic load was related to poorer overall performance in perceptual speed and spatial ability.

CONCLUSION

Diet-based glycemic load and, in particular, elevated blood glucose appear important for cognitive performance/cognitive aging. Blood glucose control (perhaps through low glycemic load diets) may be an important target in the detection and prevention of age-related cognitive decline.

Life-course socio-economic disadvantage and late-life cognitive functioning in Taiwan: results from a national cohort study

BACKGROUND

Declines in late-life cognitive functioning differ greatly between socio-economic status (SES) groups, but little is known about whether these effects are related to child and adult SES versus SES effects that accumulate over the individual's life course.

METHODS

An 18-year longitudinal national sample of older adults from Taiwan (n=2944) was used to estimate the effect of socio-economic disadvantage over the individual's life course on cognitive functioning during late life. Cognitive functioning was assessed using the brief Short Portable Mental Status Questionnaire scale. Life-course socio-economic disadvantage, as accrued during childhood and adulthood, included measures of paternal education and occupation and participant's education and occupation.

RESULTS

Multivariate analyses using various mixed-effects models showed that the effects of childhood SES could be largely explained by adult SES and that disadvantageous SES in adulthood further exacerbated declines in late-life cognitive functioning (β=-0.02; p<0.001), even controlling for aging, practice and other covariates. Possible factors that are associated with life-course socio-economic disadvantage and late-life cognitive decline included household income and perception of economic strain.

CONCLUSIONS

The results suggest a critical role for life-course socio-economic disadvantage in late-life cognitive decline and that this may be manifested via the inequitable distribution of socio-economic resources over the individual's life course.

Correlates of cognitive change

Although there has been considerable interest in identifying potential correlates of cognitive change, results of past studies have been inconsistent. The present study incorporated a number of methodological features intended to maximize sensitivity to detect characteristics of individuals with different amounts of cognitive change. Cognitive change in 5 cognitive abilities was analyzed with 2nd-order latent growth curve models applied to data from a moderately large sample of healthy adults ranging from 18 to 99 years of age (Ns of 4,802 with 1 occasion, 2,265 with 2 occasions, and 1,128 with 3 occasions). There was significant individual difference variance in the longitudinal changes in several cognitive abilities, even in separate analyses of individuals between 18 years of age and 39, between 40 and 64, and 65 and over. Potential correlates of change included measures of self-rated health, vision, mood, personality, and lifestyle. Most of the potential correlates of change had high reliability, and several analyses were based on even more reliable factors determined by the variance common to multiple measures. Despite favorable conditions for detecting correlates of change, there was little evidence that cognitive change was moderated by any of the variables examined. Possible reasons for the inconsistent results regarding correlates of cognitive change are discussed.