The Sydney Memory and Ageing Study (MAS): methodology and baseline medical and neuropsychiatric characteristics of an elderly epidemiological non-demented cohort of Australians aged 70-90 years

Is Healthy Neuroticism Associated with Longevity? A Coordinated Integrative Data Analysis

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.

Participant and informant memory-specific cognitive complaints predict future decline and incident dementia: Findings from the Sydney Memory and Ageing Study

Subjective Cognitive Complaints (SCCs) may represent one of the earliest stages of preclinical dementia. The objective of the present study was to extend previous work by our group to examine the relationship between participant-reported and informant-reported memory and non-memory SCCs, cognitive decline and incident dementia, over a six-year period. Participants were 873 community dwelling older adults (M_age = 78.65, SD = 4.79) without dementia and 843 informants (close friends or family) from the Sydney Memory and Ageing Study. Comprehensive neuropsychological testing and diagnostic assessments were carried out at baseline and biennially for six years. Linear mixed models and Cox proportional hazard models were performed to determine the association of SCCs, rate of cognitive decline and risk of incident dementia, controlling demographics and covariates of mood and personality. Participant and informant memory-specific SCCs were associated with rate of global cognitive decline; for individual cognitive domains, participant memory SCCs predicted decline for language, while informant memory SCCs predicted decline for executive function and memory. Odds of incident dementia were associated with baseline participant memory SCCs and informant memory and non-memory SCCs in partially adjusted models. In fully adjusted models, only informant SCCs were associated with increased risk of incident dementia. Self-reported memory-specific cognitive complaints are associated with decline in global cognition over 6-years and may be predictive of incident dementia, particularly if the individual is depressed or anxious and has increased neuroticism or decreased openness. Further, if and where possible, informants should be sought and asked to report on their perceptions of the individual’s memory ability and any memory-specific changes that they have noticed as these increase the index of diagnostic suspicion.

Downregulated transferrin receptor in the blood predicts recurrent MDD in the elderly cohort: A fuzzy forests approach

BACKGROUND

At present, no predictive markers for Major Depressive Disorder (MDD) exist. The search for such markers has been challenging due to clinical and molecular heterogeneity of MDD, the lack of statistical power in studies and suboptimal statistical tools applied to multidimensional data. Machine learning is a powerful approach to mitigate some of these limitations.

METHODS

We aimed to identify the predictive markers of recurrent MDD in the elderly using peripheral whole blood from the Sydney Memory and Aging Study (SMAS) (N = 521, aged over 65) and adopting machine learning methodology on transcriptome data. Fuzzy Forests is a Random Forests-based classification algorithm that takes advantage of the co-expression network structure between genes; it allows to alleviate the problem of p >> n via reducing the dimensionality of transcriptomic feature space.

RESULTS

By adopting Fuzzy Forests on transcriptome data, we found that the downregulated TFRC (transferrin receptor) can predict recurrent MDD with an accuracy of 63%.

LIMITATIONS

Although we corrected our data for several important confounders, we were not able to account for the comorbidities and medication taken, which may be numerous in the elderly and might have affected the levels of gene transcription.

CONCLUSIONS

We found that downregulated TFRC is predictive of recurrent MDD, which is consistent with the previous literature, indicating the role of the innate immune system in depression. This study is the first to successfully apply Fuzzy Forests methodology on psychiatric condition, opening, therefore, a methodological avenue that can lead to clinically useful predictive markers of complex traits.

Mnemoscape: Supporting Older Adults' Event Memory Using Wearable Camera Photographs on an Immersive Interface

BACKGROUND

Wearable camera photographs have been shown to be an effective memory aid in people with and without memory impairment. Most studies using wearable cameras as a memory aid have presented photographs on a computer monitor and used a written diary or no review as a comparison. In this pioneering study, we took a new and innovative approach to wearable camera photograph review that embeds the photographs within a virtual landscape. This approach may enhance these benefits by reinstating the original environmental context to increase participants' sense of re-experiencing the event.

OBJECTIVE

We compare the traditional computer monitor presentation of wearable camera photographs and actively taken digital photographs with the presentation of wearable camera photographs in a new immersive interface that reinstates the spatiotemporal context.

METHODS

Healthy older adults wore wearable or took digital photographs during a staged event. The next day and 2 weeks later, they viewed wearable camera photographs on a computer monitor or in context on an immersive interface, or digital photographs.

RESULTS

Participants who viewed wearable camera photographs in either format recalled more details during photo viewing and subsequent free recall than participants who viewed digital photographs they had taken themselves.

CONCLUSION

Wearable camera photographs are an effective support for event memory, regardless of whether they are presented in context in an experience-near format.

International Mind, Activities and Urban Places (iMAP) study: methods of a cohort study on environmental and lifestyle influences on brain and cognitive health

INTRODUCTION

Numerous studies have found associations between characteristics of urban environments and risk factors for dementia and cognitive decline, such as physical inactivity and obesity. However, the contribution of urban environments to brain and cognitive health has been seldom examined directly. This cohort study investigates the extent to which and how a wide range of characteristics of urban environments influence brain and cognitive health via lifestyle behaviours in mid-aged and older adults in three cities across three continents.

METHODS AND ANALYSIS

Participants aged 50-79 years and living in preselected areas stratified by walkability, air pollution and socioeconomic status are being recruited in Melbourne (Australia), Barcelona (Spain) and Hong Kong (China) (n=1800 total; 600 per site). Two assessments taken 24 months apart will capture changes in brain and cognitive health. Cognitive function is gauged with a battery of eight standardised tests. Brain health is assessed using MRI scans in a subset of participants. Information on participants' visited locations is collected via an interactive web-based mapping application and smartphone geolocation data. Environmental characteristics of visited locations, including the built and natural environments and their by-products (e.g., air pollution), are assessed using geographical information systems, online environmental audits and self-reports. Data on travel and lifestyle behaviours (e.g., physical and social activities) and participants' characteristics (e.g., sociodemographics) are collected using objective and/or self-report measures.

ETHICS AND DISSEMINATION

The study has been approved by the Human Research Ethics Committee of the Australian Catholic University, the Institutional Review Board of the University of Hong Kong and the Parc de Salut Mar Clinical Research Ethics Committee of the Government of Catalonia. Results will be communicated through standard scientific channels. Methods will be made freely available via a study-dedicated website.

TRIAL REGISTRATION NUMBER

ACTRN12619000817145.

Longitudinal Changes in Whole-Brain Functional Connectivity Strength Patterns and the Relationship With the Global Cognitive Decline in Older Adults

Aging is associated with changes in brain functional patterns as well as cognition. The present research sought to investigate longitudinal changes in whole brain functional connectivity strength (FCS) and cognitive performance scores in very old cognitively unimpaired individuals. We studied 34 cognitively normal elderly individuals at both baseline and 4-year follow-up (baseline age = 78 ± 3.14 years) with resting-state functional magnetic resonance imaging (r-fMRI), structural MRI scans, and neuropsychological assessments conducted. Voxel-based whole brain FCS was calculated and we found that bilateral superior parietal and medial frontal regions showed decreased FCS, while the supplementary motor area (SMA) and insula showed increased FCS with age, along with a decrease in bilateral prefrontal cortical thickness. The changes of FCS in left precuneus were associated with an aging-related decline in global cognition. Taken together, our results suggest changes in FCS with aging with the precuneus as a hub and this may underlie changes in global cognition that accompany aging. These findings help better understand the normal aging mechanism.

Reduced strength, poor balance and concern about falls mediate the relationship between knee pain and fall risk in older people

BACKGROUND

Pain is an independent risk factor for falling. One in two older community-dwelling people with musculoskeletal pain fall each year. This study examined physical, psychological and medical factors as potential mediators to explain the relationship between knee pain and falls.

METHODS

Three hundred and thirty-three community-dwelling people aged 70+ years (52% women) participated in this cohort study with a 1-year follow-up for falls. Participants completed questionnaires (medical history, general health and concern about falls) and underwent physical performance tests. Participants were classified into 'pain' and 'no pain' groups based on self-reported knee pain. Poisson Regression models were computed to determine the Relative Risk (RR) of having multiple falls and potential mediators for increased fall risk.

RESULTS

One hundred and eighteen (36%) participants were categorised as having knee pain. This group took more medications and had more medical conditions (P < 0.01) compared to the no pain group. The pain group had poorer balance, physical function and strength and reported increased concern about falls. Sixty one participants (20%) reported ≥2 falls, with the pain group twice as likely to experience multiple falls over the 12 month follow up (RR = 2.0, 95% confidence interval (CI) = 1.27-3.13). Concern about falls, knee extension torque and postural sway with eyes closed were identified as significant and independent mediators of fall risk, and when combined explained 23% of the relationship between knee pain and falls.

CONCLUSION

This study has identified several medical, medication, psychological, sensorimotor, balance and mobility factors to be associated with knee pain, and found the presence of knee pain doubles the risk of multiple falls in older community living people. Alleviating knee pain, as well as addressing associated risk factors may assist in preventing falls in older people with knee pain.

Differential longitudinal changes in structural complexity and volumetric measures in community-dwelling older individuals

Fractal geometry provides a method of analyzing natural and especially biological morphologies. To investigate the relationship between the complexity measure, which is indexed as fractal dimensionality (FD), and the traditional Euclidean metrics, such as the volume and thickness, of the brain in older age, we analyzed 483 MRI scans of 161 community-dwelling, nondemented individuals aged 70-90 years at the baseline and their 2-year and 6-year follow-ups. We quantified changes in neuroimaging metrics in cortical lobes and subcortical structures and investigated the effects of age, sex, hemisphere, and education on FD. We also analyzed the mediating effects of these metrics for further investigation. FD showed significant age-related decline in all structures, and its trajectory was best modeled quadratically in the bilateral frontal, parietal, and occipital lobes, as well as in the bilateral caudate, putamen, hippocampus, amygdala, and accumbens. FD showed specific mediating effects on aging and cognitive decline in some regions. Our findings suggest that FD is reliable yet shows a different pattern of decline compared with volumetric measures.

New avenue for the geriatric depression scale: Rasch transformation enhances reliability of assessment

BACKGROUND

Depression is a common problem in older adults. The 15-item Geriatric Depression Scale (GDS-15) is a widely used psychometric tool for measuring depression in the elderly, but its psychometric properties have not been yet rigorously investigated. The aim was to evaluate psychometric properties of the GDS-15 and improve precision of the instrument by applying Rasch analysis and deriving conversion tables for transformation of raw scores into interval level data.

METHODS

The data was extracted from the prospective cohort Sydney Memory and Ageing Study of initially not demented individuals aged 70 years and older. The GDS-15 items scores of 212 participants (47.2% males) were analysed using the dichotomous Rasch model.

RESULTS

Initially poor reliability of the GDS-15, Person Separation Index (PSI) = 0.68, was improved by combining locally dependent items into seven super-items. These modifications improved reliability of the GDS-15 (PSI = 0.78) and resulted in the best Rasch model fit (χ²(28)=37.72, p = =0.104), strict unidimensionality and scale invariance across personal factors such as gender, diagnostic and language background.

LIMITATIONS

Presence of participants with cognitive impairment may be a potential limitation.

CONCLUSIONS

Reliability and psychometric characteristics of the GDS-15 were improved by minor modifications and now satisfy expectations of the unidimensional Rasch model. By using Rasch transformation tables published here psychiatrists, psychologists and researchers can transform GDS raw scores into interval-level data, which improves reliability of the GDS-15 without the need to modify its original response format. These findings increase accuracy of clinical psychometric assessments, leading to more precise diagnosis of depression in the elderly.

Factors associated with odour identification in older Indonesian and white Australian adults

BACKGROUND AND AIMS

Among older adults, olfactory dysfunction is associated with cognitive impairment, lower quality of life, and increased mortality. While age is a risk factor for olfactory dysfunction, other risk factors are less well understood, and may vary between ethno-regional groups. This study investigated how associations between odour identification (OI) and various risk factors, as well as cognition and language ability, differed or were similar in two distinct ethno-regional groups of older adults.

METHODS

This cross-sectional study used data from two cohorts: 470 Indonesians (aged 67.4 ± 7.4 years) and 819 white Australians (aged 78.7 ± 4.8 years). Univariate and multivariate analyses explored whether OI test scores were associated with age, sex, education, cholesterol levels, apolipoprotein E ε4 status, smoking, diabetes, hypertension and depression scale scores, or with Mini-Mental State Examination (MMSE) and language test performance.

RESULTS

Univariate analyses identified some factors associated with OI scores in both Indonesians and white Australians, including older age and smoking with lower scores, and MMSE and language test performance with higher scores. Multivariate analyses yielded different and mutually exclusive patterns of associations in the two ethno-regional groups, with language test scores significantly associated with higher OI scores in Indonesians, and age, being male, smoking, having diabetes and higher depression scale scores significantly associated with lower OI scores in white Australians.

CONCLUSION

Ethno-regional differences may need consideration in the attempt to fully understand associations between OI and negative outcomes like dementia and mortality, and interventions for olfactory dysfunction might need to be tailored to specific ethno-regional groups. However, the difference in mean age between cohorts is a limitation of this study, and future studies should aim to compare populations with similar age distributions.

Is Healthy Neuroticism Associated with Health Behaviors? A Coordinated Integrative Data Analysis

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.

Investigation of antihypertensive class, dementia, and cognitive decline: A meta-analysis

OBJECTIVE

High blood pressure is one of the main modifiable risk factors for dementia. However, there is conflicting evidence regarding the best antihypertensive class for optimizing cognition. Our objective was to determine whether any particular antihypertensive class was associated with a reduced risk of cognitive decline or dementia using comprehensive meta-analysis including reanalysis of original participant data.

METHODS

To identify suitable studies, MEDLINE, Embase, and PsycINFO and preexisting study consortia were searched from inception to December 2017. Authors of prospective longitudinal human studies or trials of antihypertensives were contacted for data sharing and collaboration. Outcome measures were incident dementia or incident cognitive decline (classified using the reliable change index method). Data were separated into mid and late-life (>65 years) and each antihypertensive class was compared to no treatment and to treatment with other antihypertensives. Meta-analysis was used to synthesize data.

RESULTS

Over 50,000 participants from 27 studies were included. Among those aged >65 years, with the exception of diuretics, we found no relationship by class with incident cognitive decline or dementia. Diuretic use was suggestive of benefit in some analyses but results were not consistent across follow-up time, comparator group, and outcome. Limited data precluded meaningful analyses in those ≤65 years of age.

CONCLUSION

Our findings, drawn from the current evidence base, support clinical freedom in the selection of antihypertensive regimens to achieve blood pressure goals.

CLINICAL TRIALS REGISTRATION

The review was registered with the international prospective register of systematic reviews (PROSPERO), registration number CRD42016045454.

Development and validation of a rating scale for perivascular spaces on 3T MRI

BACKGROUND AND PURPOSE

To develop and validate a novel perivascular space rating scale, based on single axial slices in the basal ganglia and the centrum semiovale on T1-weighted and FLAIR images obtained on a 3T MRI scanner.

METHODS

414 community dwelling older adults age 70-90 were assessed. The number of perivascular spaces in the slices 2 mm (basal ganglia) and 37 mm (centrum semiovale) above the anterior commissure were counted. The construct validity of the scale was tested by examining associations with age, sex, vascular risk factors and neuroimaging markers of small vessel disease; white matter hyperintensities, lacunes and cerebral microbleeds. Associations with cross sectional global and domain specific cognition were also examined.

RESULTS

The rating scale had excellent inter-rater reliability (intraclass correlation coefficient in basal ganglia 0.82 and centrum semiovale 0.96), good intra-rater reliability (ICC in basal ganglia 0.72 and centrum semiovale 0.87) and reasonable concurrent validity with an existing perivascular spaces scale (Spearman rho = 0.49, p < .001). There was a median of four basal ganglia and zero centrum semiovale perivascular spaces. Basal ganglia perivascular spaces were more common in men and associated with the other neuroimaging markers. Perivascular spaces in either location were not independently associated with global or domain specific cognitive impairment.

CONCLUSION

The new rating scale is easy to use, quick, has good psychometric properties and performs better than existing scales in a community dwelling older cohort. Further studies are needed to validate the scale in more diverse cohorts with greater cerebrovascular burden.

The Meta VCI Map consortium for meta-analyses on strategic lesion locations for vascular cognitive impairment using lesion-symptom mapping: Design and multicenter pilot study

INTRODUCTION

The Meta VCI Map consortium performs meta-analyses on strategic lesion locations for vascular cognitive impairment using lesion-symptom mapping. Integration of data from different cohorts will increase sample sizes, to improve brain lesion coverage and support comprehensive lesion-symptom mapping studies.

METHODS

Cohorts with available imaging on white matter hyperintensities or infarcts and cognitive testing were invited. We performed a pilot study to test the feasibility of multicenter data processing and analysis and determine the benefits to lesion coverage.

RESULTS

Forty-seven groups have joined Meta VCI Map (stroke n = 7800 patients; memory clinic n = 4900; population-based n = 14,400). The pilot study (six ischemic stroke cohorts, n = 878) demonstrated feasibility of multicenter data integration (computed tomography/magnetic resonance imaging) and achieved marked improvement of lesion coverage.

DISCUSSION

Meta VCI Map will provide new insights into the relevance of vascular lesion location for cognitive dysfunction. After the successful pilot study, further projects are being prepared. Other investigators are welcome to join.

The role of concern about falling on stepping performance during complex activities

Background

There is limited understanding of the underlying mechanisms explaining the role of concern about falling on fall risk in older people. Anxiety is known to interact with cognitive resources and, as people get older, they require more cognitive resources to maintain balance. This might affect an individual’s ability to perform cognitive-motor tasks concurrently. The aim of this study was to investigate the effect of a visuospatial dual-task on stepping performance in older people with and without concern about falling and the impact of repeating this task in those with high concern about falling.

Methods

Three-hundred-eight community-dwelling older people, aged 70 to 90 years old, participated in the study. Participants were asked to perform a Choice Stepping Reaction Time (CSRT) task in two conditions; once without any other tasks (single task condition), and once while simultaneously performing a visuospatial task (dual-task condition). Participants were asked to rate their levels of concern and confidence specifically related to each of the 25 stepping trials (before/after). We also measured general concern about falling, affect, and sensorimotor and cognitive functioning.

Results

Total stepping reaction times increased when participants also performed the visuospatial task. The relation between general concern about falling and stepping reaction time, was affected by sensorimotor and executive functioning. Generalised linear mixed models showed that the group with moderate to high levels of general concern about falling had slower total stepping reaction times than those with lower levels of concern about falling, especially during the dual-task condition. Individuals with greater general concern about falling showed reduced confidence levels about whether they could do the stepping tasks under both conditions. Repeatedly performing the stepping task reduced the immediate task-specific concern about falling levels and increased confidence in all participants.

Conclusions

These findings reveal that people with higher general concern about falling experienced more difficulties during a dual-task condition than people with lower levels of concern. Of further interest, better sensorimotor and cognitive functioning reduced this effect. Graded exposure has potential to reduce concern about falling during fear-evoking activities, especially in conjunction with therapies that improve balance, mood and cognitive function.

The psychological health of 207 near-centenarians (95-99) and centenarians from the Sydney Centenarian Study

OBJECTIVE

While near-centenarians (95-99) and centenarians are the fastest growing sectors of the population in many countries, few studies have investigated their psychological health. We aimed to compare levels of psychological distress and life satisfaction in individuals aged 95 or above (95+) with younger age groups and identify the factors associated with psychological distress and life satisfaction in near-centenarians and centenarians.

METHODS

We assessed the physical, cognitive, social and psychological health of 207 participants aged 95+ in the Sydney Centenarian Study. Psychological distress and life satisfaction were rated on the Kessler Psychological Distress Scale (K10) and Satisfaction with Life Scale, respectively. Cross-sectional univariate comparisons were performed with participants aged 70-90 years from the Sydney Memory and Ageing Study. Factors associated with psychological distress and life satisfaction among Sydney Centenarian Study participants were examined using multiple regression analyses.

RESULTS

In Sydney Centenarian Study and Memory and Ageing Study, mean K10 scores were 15.3 (±5.9) and 13.4 (±3.6), and clinical levels of psychological distress (K10 ⩾ 20) were 19% and 7%, respectively. Sydney Centenarian Study participants demonstrated significantly higher levels and rates of psychological distress (t = 3.869, p < 0.001; χ² = 27.331, p < 0.001). In Sydney Centenarian Study, more psychotropic medications and having fewer relatives and friends were associated with higher psychological distress. Sydney Centenarian Study participants reported significantly higher levels of life satisfaction than Memory and Ageing Study participants, mean scores 6.0 (±1.5) and 5.6 (±1.3); t = 5.835, p < 0.001. Lower Mini-Mental State Examination scores and having fewer relatives and friends were associated with lower life satisfaction in Sydney Centenarian Study.

CONCLUSION

Despite showing higher levels of psychological distress in the prior 4 weeks than younger age groups, near-centenarians and centenarians remained highly satisfied with their overall lives. The identification of risk and protective factors for psychological distress and life satisfaction provides opportunities for interventions to maintain good psychological health in this vulnerable population.

Cross-sectional and prospective inter-relationships between depressive symptoms, vascular disease and cognition in older adults

BACKGROUND

It has been proposed that vascular disease is the mechanism linking depression and cognition, but prospective studies have not supported this hypothesis. This study aims to investigate the inter-relationships between depressive symptoms, cognition and cerebrovascular disease using a well-characterised prospective cohort.

METHOD

Data came from waves 1 (2005-2007) and 2 (2007-2009) of the Sydney Memory and Ageing Study (n = 462; mean age = 78.3 years).

RESULTS

At wave 1, there was an association between depressive symptoms and white matter hyperintensity (WMH) volume [b = 0.016, t(414) = 2.34, p = 0.020]. Both depressive symptoms [b = -0.058, t(413) = -2.64, p = 0.009] and WMH volume [b = -0.011, t(413) = -3.77, p < 0.001], but not stroke/transient ischaemic attack (TIA) [b = -0.328, t(413) = -1.90, p = 0.058], were independently associated with lower cognition. Prospectively, cerebrovascular disease was not found to predict increasing depressive symptoms [stroke/TIA: b = -0.349, t(374.7) = -0.76, p = 0.448; WMH volume: b = 0.007, t(376.3) = 0.875, p = 0.382]. Depressive symptoms predicted increasing WMH severity [b = 0.012, t(265.9) = -3.291, p = 0.001], but not incident stroke/TIA (odds ratio = 0.995; CI 0.949-1.043; p = 0.820). When examined in separate models, depressive symptoms [b = -0.027, t(373.5) = -2.16, p = 0.032] and a history of stroke/TIA [b = -0.460, t(361.2) = -4.45, p < 0.001], but not WMH volume [b = 0.001, t(362.3) = -0.520, p = 0.603], predicted declines in cognition. When investigated in a combined model, a history of stroke/TIA remained a predictor of cognitive decline [b = -0.443, t(360.6) = -4.28, p < 0.001], whilst depressive symptoms did not [b = -0.012, t(359.7) = -0.96, p = 0.336].

CONCLUSIONS

This study is contrasted with previous prospective studies which indicate that depressive symptoms predict cognitive decline independently of vascular disease. Future research should focus on further exploring the vascular mechanisms underpinning the relationship between depressive symptoms and cognition.

Comparison of Single Phase and Biphasic Extraction Protocols for Lipidomic Studies Using Human Plasma

Lipidomic profiling of plasma is an emerging field, given the importance of lipids in major cellular pathways, and is dependent on efficient lipid extraction protocols. Recent attention has turned to plasma lipidomics as a means to identify potential diagnostic and prognostic biomarkers related to dementia, neuropsychiatric health and disease. Although several solvent-based lipid extraction protocols have been developed and are currently in use, novel and more efficient methods could greatly simplify lipid analysis in plasma and warrant investigation. Human plasma from normolipidemic adult volunteers was collected to evaluate three different solvent extraction protocols, including the classical Folch method, the methanol/tert-butyl methyl ether (MTBE) (Matyash) method, and a recent single-phase methanol/1-butanol (Alshehry) method. Extracted lipids were analyzed using liquid chromatography mass spectrometry (LC-MS) in positive and negative ion mode. Overall, more than 500 different lipids were identified in positive and negative ion mode combined. Our data show that the single phase Alshehry method was as effective as the Folch and Matyash methods in extracting most lipid classes and was more effective in extraction of polar lipids. Normalized peak areas of the Alshehry method were highly and positively correlated with both the Folch and Matyash methods (r 2 = 0.99 and 0.97, respectively). Within- and between- subject correlations were r = 0.99 and 0.96, respectively. Median intra-assay coefficient of variation (CV%) in positive mode was 14.1, 15.1, and 21.8 for the Alshehry, Folch and Matyash methods, respectively. Median Alshehry inter-assay CV (collected over 5 separate days) was 14.4%. In conclusion, the novel Alshehry method was at least as good as, if not better than the established biphasic extraction methods in detecting a wide range of lipid classes, using as little as 10 μL of plasma, and was highly reproducible, safer and more environmentally-friendly as it doesn't require chloroform.

Validation and Normative Data for the Modified Telephone Interview for Cognitive Status: The Sydney Memory and Ageing Study

OBJECTIVES

Telephone-based cognitive screens, such as the Telephone Interview for Cognitive Status (TICS), can potentially reduce the barriers and costs of assessing older adults. However, validation of clinically relevant psychometric properties is lacking in a large and comprehensively assessed sample of older adults. Furthermore, published normative data may lack sensitivity as they have not used regression-based demographic corrections or accounted for cases with subsequent dementia. We address these gaps using the modified TICS (TICS-M; a modified, 13-item, 39-point version) and provide an online norms calculator for clinicians and researchers.

DESIGN

Prospective longitudinal study.

SETTING

Sydney, Australia.

PARTICIPANTS

A total of 617 community-living older adults, aged from 71 to 91 years.

MEASUREMENTS

The measures used included the TICS-M, the Mini-Mental State Examination (MMSE), Addenbrooke's Cognitive Examination-Revised (ACE-R), and a comprehensive neuropsychological test battery. Descriptive statistics, correlations, area under the curve, and regression analyses were used to determine the validity and normative properties of the TICS-M.

RESULTS

TICS-M total scores (mean = 24.20; SD = 3.76) correlated well with the MMSE (0.70) and ACE-R (0.80) and moderately with neuropsychological tests tested noncontemporaneously. A cutoff score of 21 or lower reliably distinguished between those with and without incident dementia after 1 year (sensitivity = 77%; specificity = 88%) but was less reliable at distinguishing mild cognitive impairment from normal cognition. TICS-M scores decreased with age and increased with higher education levels. The robust normative sample, which excluded incident dementia cases, scored higher on the TICS-M and with less variability than the whole sample. An online calculator is provided to compute regression-based norms and reliable change statistics.

CONCLUSIONS

In a large sample of community-dwelling older adults, the TICS-M performed well in terms of construct validity against typical screening tools and neuropsychological measures and diagnostic validity for incident dementia. The comprehensive, regression-based, and robust normative data provided will help improve the sensitivity, accessibility, and cost-effectiveness of cognitive testing with older adults. J Am Geriatr Soc 67:2108-2115, 2019.

Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study

BACKGROUND

With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups.

METHODS AND FINDINGS

We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54-105 (mean = 72.7) years and without dementia at baseline. Studies had 2-15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = -0.1, SE = 0.01), APOE*4 carriage (B = -0.31, SE = 0.11), depression (B = -0.11, SE = 0.06), diabetes (B = -0.23, SE = 0.10), current smoking (B = -0.20, SE = 0.08), and history of stroke (B = -0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = -0.07, SE = 0.01), APOE*4 carriage (B = -0.41, SE = 0.18), and diabetes (B = -0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = -0.24, SE = 0.12), and between diabetes and cognitive decline (B = -0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife.

CONCLUSIONS

These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.

The role of cognitive function and physical activity in physical decline in older adults across the cognitive spectrum

OBJECTIVES

The aim of this study was to investigate physical decline over 1-year in a cohort of older people across the cognitive spectrum.

METHODS

Physical function was assessed using the Physiological Profile Assessment (PPA) in 593 participants (cognitively normal [CN]: n = 342, mild cognitive impairment [MCI]: n = 77, dementia: n = 174) at baseline and in 490 participants available for reassessment 1-year later. Neuropsychological performance and physical activity (PA) were assessed at baseline.

RESULTS

Median baseline PPA scores for CN, MCI and dementia groups were 0.41 (IQR = -0.09-1.02), 0.66 (IQR = -0.06-1.15) and 2.37 (IQR = 0.93-3.78) respectively. All baseline neuropsychological domains and PA were significantly associated with baseline PPA. There were significant interaction terms (Time × Cognitive Group, Global Cognition, Processing Speed, Executive Function and PA) in the models investigating PPA decline. In multivariate analysis the Time × Executive Function and PA interaction terms were significant, indicating that participants with poorer baseline executive function and reduced PA demonstrated greater physical decline when compared to individuals with better executive function and PA respectively.

DISCUSSION

Having MCI or dementia is associated with greater physical decline compared to CN older people. Physical inactivity and executive dysfunction were associated with physical decline in this sample, which included participants with MCI and dementia. Both factors influencing physical decline are potentially amenable to interventions e.g. exercise.

Visual memory tests enhance the identification of amnestic MCI cases at greater risk of Alzheimer's disease

OBJECTIVES

To investigate whether amnestic mild cognitive impairment (aMCI) identified with visual memory tests conveys an increased risk of Alzheimer's disease (risk-AD) and if the risk-AD differs from that associated with aMCI based on verbal memory tests.

PARTICIPANTS

4,771 participants aged 70.76 (SD = 6.74, 45.4% females) from five community-based studies, each a member of the international COSMIC consortium and from a different country, were classified as having normal cognition (NC) or one of visual, verbal, or combined (visual and verbal) aMCI using international criteria and followed for an average of 2.48 years. Hazard ratios (HR) and individual patient data (IPD) meta-analysis analyzed the risk-AD with age, sex, education, single/multiple domain aMCI, and Mini-Mental State Examination (MMSE) scores as covariates.

RESULTS

All aMCI groups (n = 760) had a greater risk-AD than NC (n = 4,011; HR range = 3.66 - 9.25). The risk-AD was not different between visual (n = 208, 17 converters) and verbal aMCI (n = 449, 29 converters, HR = 1.70, 95%CI: 0.88, 3.27, p = 0.111). Combined aMCI (n = 103, 12 converters, HR = 2.34, 95%CI: 1.13, 4.84, p = 0.023) had a higher risk-AD than verbal aMCI. Age and MMSE scores were related to the risk-AD. The IPD meta-analyses replicated these results, though with slightly lower HR estimates (HR range = 3.68, 7.43) for aMCI vs. NC.

CONCLUSIONS

Although verbal aMCI was most common, a significant proportion of participants had visual-only or combined visual and verbal aMCI. Compared with verbal aMCI, the risk-AD was the same for visual aMCI and higher for combined aMCI. Our results highlight the importance of including both verbal and visual memory tests in neuropsychological assessments to more reliably identify aMCI.

Deep white matter hyperintensities, microstructural integrity and dual task walking in older people

To examine neural, physiological and cognitive influences on gait speed under single and dual-task conditions. Sixty-two community-dwelling older people (aged 80.0 ± 4.2 years) participated in our study. Gait speed was assessed with a timed 20-meter walk under single and dual-task (reciting alternate letters of the alphabet) conditions. Participants also underwent tests to estimate physiological fall risk based on five measures of sensorimotor function, cognitive function across five domains, brain white matter (WM) hyperintensities and WM microstructural integrity by measuring fractional anisotropy (FA). Univariate linear regression analyses showed that global physiological and cognitive measures were associated with single (β = 0.594 and β=-0.297, respectively) and dual-task gait speed (β = 0.306 and β=-0.362, respectively). Deep WMHs were associated with dual-task gait speed only (β = 0.257). Multivariate mediational analyses showed that global and executive cognition reduced the strength of the association between deep WMHs and dual-task gait speed by 27% (β = 0.188) and 44% (β = 0.145) respectively. There was a significant linear association between single-task gait speed and mean FA values of the genu (β=-0.295) and splenium (β=-0.326) of the corpus callosum, and between dual-task gait speed and mean FA values of Superior Cerebellar Peduncle (β=-0.284), splenium of the Corpus Callosum (β=-0.286) and Cingulum (β=-0.351). Greater deep WMH volumes are associated with slower walking speed under dual-task conditions, and this relationship is mediated in part by global cognition and executive abilities specifically. Furthermore, both cerebellum and cingulum are related to dual-task walking due to their role in motor skill performance and attention, respectively.

Plasma lipidome variation during the second half of the human lifespan is associated with age and sex but minimally with BMI

Recent advances in mass spectrometry-based techniques have inspired research into lipidomics, a subfield of ‘–omics’, which aims to identify and quantify large numbers of lipids in biological extracts. Although lipidomics is becoming increasingly popular as a screening tool for understanding disease mechanisms, it is largely unknown how the lipidome naturally varies by age and sex in healthy individuals. We aimed to identify cross-sectional associations of the human lipidome with ‘physiological’ ageing, using plasma from 100 subjects with an apolipoprotein E (APOE) E3/E3 genotype, and aged between 56 to 100 years. Untargeted analysis was performed by liquid chromatography coupled-mass spectrometry (LC-MS/MS) and data processing using LipidSearch software. Regression analyses confirmed a strong negative association of age with the levels of various lipid, which was stronger in males than females. Sex-related differences include higher LDL-C, HDL-C, total cholesterol, particular sphingomyelins (SM), and docosahexaenoic acid (DHA)-containing phospholipid levels in females. Surprisingly, we found a minimal relationship between lipid levels and body mass index (BMI). In conclusion, our results suggest substantial age and sex-related variation in the plasma lipidome of healthy individuals during the second half of the human lifespan. In particular, globally low levels of blood lipids in the ‘oldest old’ subjects over 95 years could signify a unique lipidome associated with extreme longevity.

Exceptional Longevity and Polygenic Risk for Cardiovascular Health

Studies investigating exceptionally long-lived (ELL) individuals, including genetic studies, have linked cardiovascular-related pathways, particularly lipid and cholesterol homeostasis, with longevity. This study explored the genetic profiles of ELL individuals (cases: n = 294, 95–106 years; controls: n = 1105, 55–65 years) by assessing their polygenic risk scores (PRS) based on a genome wide association study (GWAS) threshold of p < 5 × 10⁻⁵. PRS were constructed using GWAS summary data from two exceptional longevity (EL) analyses and eight cardiovascular-related risk factors (lipids) and disease (myocardial infarction, coronary artery disease, stroke) analyses. A higher genetic risk for exceptional longevity (EL) was significantly associated with longevity in our sample (odds ratio (OR) = 1.19–1.20, p = 0.00804 and 0.00758, respectively). Two cardiovascular health PRS were nominally significant with longevity (HDL cholesterol, triglycerides), with higher PRS associated with EL, but these relationships did not survive correction for multiple testing. In conclusion, ELL individuals did not have significantly lower polygenic risk for the majority of the investigated cardiovascular health traits. Future work in larger cohorts is required to further explore the role of cardiovascular-related genetic variants in EL.

Subjective cognitive decline and rates of incident Alzheimer's disease and non-Alzheimer's disease dementia

Introduction:

In this multicenter study on subjective cognitive decline (SCD) in community-based and memory clinic settings, we assessed the (1) incidence of Alzheimer’s disease (AD) and non-AD dementia and (2) determinants of progression to dementia.

Methods:

Eleven cohorts provided 2978 participants with SCD and 1391 controls. We estimated dementia incidence and identified risk factors using Cox proportional hazards models.

Results:

In SCD, incidence of dementia was 17.7 (95% Poisson confidence interval 15.2–20.3)/1000 person-years (AD: 11.5 [9.6–13.7], non-AD: 6.1 [4.7–7.7]), compared with 14.2 (11.3–17.6) in controls (AD: 10.1 [7.7–13.0], non-AD: 4.1 [2.6–6.0]). The risk of dementia was strongly increased in SCD in a memory clinic setting but less so in a community-based setting. In addition, higher age (hazard ratio 1.1 [95% confidence interval 1.1–1.1]), lower Mini-Mental State Examination (0.7 [0.66–0.8]), and apolipoprotein E ε4 (1.8 [1.3–2.5]) increased the risk of dementia.

Discussion:

SCD can precede both AD and non-AD dementia. Despite their younger age, individuals with SCD in a memory clinic setting have a higher risk of dementia than those in community-based cohorts.

Co-expression network analysis of peripheral blood transcriptome identifies dysregulated protein processing in endoplasmic reticulum and immune response in recurrent MDD in older adults

The molecular factors involved in the pathophysiology of major depressive disorder (MDD) remain poorly understood. One approach to examine the molecular basis of MDD is co-expression network analysis, which facilitates the examination of complex interactions between expression levels of individual genes and how they influence biological pathways affected in MDD. Here, we applied an unsupervised gene-network based approach to a prospective experimental design using microarray genome-wide gene expression from the peripheral whole blood of older adults. We utilised the Sydney Memory and Ageing Study (sMAS, N = 521) and the Older Australian Twins Study (OATS, N = 186) as discovery and replication cohorts, respectively. We constructed networks using Weighted Gene Co-expression Network Analysis (WGCNA), and correlated identified modules with four subtypes of depression: single episode, current, recurrent, and lifetime MDD. Four modules of highly co-expressed genes were associated with recurrent MDD (N = 27) in our discovery cohort (FDR<0.2), with no significant findings for a single episode, current or lifetime MDD. Functional characterisation of these modules revealed a complex interplay between dysregulated protein processing in the endoplasmic reticulum (ER), and innate and adaptive immune response signalling, with possible involvement of pathogen-related pathways. We were underpowered to replicate findings at the network level in an independent cohort (OATS), however; we found a significant overlap for 9 individual genes with similar co-expression and dysregulation patterns associated with recurrent MDD in both cohorts. Overall, our findings support other reports on dysregulated immune response and protein processing in the ER in MDD and provide novel insights into the pathophysiology of depression.

Altered functional connectivity strength in informant-reported subjective cognitive decline: A resting-state functional magnetic resonance imaging study

Introduction

Informant-reported subjective cognitive decline (iSCD) has been associated with a higher risk of conversion to dementia, but the findings of whole brain functional connectivity strength (FCS) changes in iSCD are limited.

Methods

The sample comprised 39 participants with iSCD and 39 age- and sex- matched healthy controls. The global absolute (aFCS) and relative functional connectivity strengths were estimated using weighted degree centrality and the z-scores of the weighted degree centrality respectively. FreeSurfer was used for measuring cortical thickness.

Results

The aFCS was lower in iSCD primarily in left medial superior frontal, left precuneus, left parietal, right cuneus, and bilateral calcarine; while relative functional connectivity strength was higher in posterior cingulate cortex/precuneus compared with healthy controls. No significant differences in cortical thickness were observed.

Discussion

There are detectable changes of FCS in iSCD, with the precuneus possibly playing a compensatory role. FCS could therefore have a potential role to serve as one of the earliest neuroimaging markers of neurodegenerative disease.

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Functional connectivity strength was examined in informant-reported subjective cognitive decline.

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Absolute functional connectivity strength was lower in the default mode network in informant-reported subjective cognitive decline.

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Individuals with informant-reported subjective cognitive decline showed higher relative functional connectivity strength in precuneus.

Study protocol for a randomised, double-blind, placebo-controlled 12-week pilot phase II trial of Sailuotong (SLT) for cognitive function in older adults with mild cognitive impairment

Background

Mild cognitive impairment (MCI) is a syndrome characterised by a decline in cognition but relatively intact activities of daily living. People with MCI have an increased risk of developing dementia, and MCI is often referred to as a transitional stage between healthy ageing and dementia. Currently, there are no pharmaceutical therapies approved by the US Federal Drug Administration for MCI. Randomised controlled trials on the two major classes of anti-dementia pharmaceuticals, cholinesterase inhibitors and glutamate receptor antagonists, have produced poor results in MCI cohorts. There is a need to test and evaluate new and promising treatments for MCI that target multiple aspects of the syndrome’s multi-faceted pathophysiology. The primary aim of this study is to evaluate the efficacy of 12 weeks of treatment with a standardised herbal formula, Sailuotong (SLT), compared to placebo, on cognition in older adults with MCI. Secondary aims are to assess SLT’s mechanisms of action via electroencephalography (EEG), autonomic function, brain blood flow, and inflammation, as well as its safety in this cohort.

Methods/design

The target cohort for this trial is community-dwelling older adults over the age of 60 years who meet the National Institute of Aging-Alzheimer’s Association working group core clinical criteria for MCI due to Alzheimer’s disease. Eighty participants will be recruited and randomly allocated via a permuted block strategy at a 1:1 ratio to either the treatment or placebo group. The co-primary cognitive outcome measures are Logical Memory Story A delayed recall (episodic memory), Letter Number Sequencing (perceptual processing speed), and both the Trail Making Test and Rey Complex Figure Test (executive function). Secondary outcome measures are EEG activity, autonomic function (via electrocardiogram, skin conductance, and peripheral pulse pressure), brain blood flow (via common carotid artery ultrasound), and serum concentrations of inflammatory cytokines. Analyses will be performed blind to group allocation.

Discussion

This study is a 12-week, randomised, double-blind, placebo-controlled trial. Primary and secondary outcome measures will be compared between treatment and placebo groups at baseline and endpoint. Data from this pilot study will inform a larger, more highly powered clinical trial if the findings are positive.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000371392 Registered on 10 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2912-0) contains supplementary material, which is available to authorized users.

World dementia: One approach does not fit all

OBJECTIVE

To highlight the broad global diversity in the diagnosis, management, and research of dementia in different regions of the world.

METHODS

A critical review of the limited literature from the global South compared with advances that have emerged from key studies in the West and observations from the authors' experiences.

RESULTS

The last several decades have witnessed major advances in dementia research and include an understanding of epidemiologic trends in the global burden of disease, the development of biomarkers for Alzheimer disease, the identification of novel therapeutic targets, and the recognition of the role of protective life-course experiential factors. For the effective translation of these research advances into societies, a "world approach" to dementia is vital. Developing societies substantially differ from Western countries in their attitudes toward dementia, as well as their clinical manifestations and risk factor profiles, marked by lower education and socioeconomic status, a higher cardiovascular disease burden, and genetic variability. Emerging evidence emphasizes the interaction among ethnicity, genetics, epigenetics, environment, culture, and neurobiology in influencing manifestations of dementia. Therefore, the investigation of dementia in diverse settings, including a more global perspective, is crucial for a comprehensive understanding of the condition as well as the identification of novel solutions.

CONCLUSIONS

A world approach to dementia provides an opportunity to understand, manage, coordinate, and begin to prevent dementia through an integrated approach based on firm scientific evidence.

Review and meta-analysis of genetic polymorphisms associated with exceptional human longevity

BACKGROUND

Many factors contribute to exceptional longevity, with genetics playing a significant role. However, to date, genetic studies examining exceptional longevity have been inconclusive. This comprehensive review seeks to determine the genetic variants associated with exceptional longevity by undertaking meta-analyses.

METHODS

Meta-analyses of genetic polymorphisms previously associated with exceptional longevity (85+) were undertaken. For each variant, meta-analyses were performed if there were data from at least three independent studies available, including two unpublished additional cohorts.

RESULTS

Five polymorphisms, ACE rs4340, APOE ε2/3/4, FOXO3A rs2802292, KLOTHO KL-VS and IL6 rs1800795 were significantly associated with exceptional longevity, with the pooled effect sizes (odds ratios) ranging from 0.42 (APOE ε4) to 1.45 (FOXO3A males).

CONCLUSION

In general, the observed modest effect sizes of the significant variants suggest many genes of small influence play a role in exceptional longevity, which is consistent with results for other polygenic traits. Our results also suggest that genes related to cardiovascular health may be implicated in exceptional longevity. Future studies should examine the roles of gender and ethnicity and carefully consider study design, including the selection of appropriate controls.

Body mass index and waist circumference predict health-related quality of life, but not satisfaction with life, in the elderly

OBJECTIVES

While obesity has been linked with lower quality of life in the general adult population, the prospective effects of present obesity on future quality of life amongst the elderly is unclear. This article investigates the cross-sectional and longitudinal relationships between obesity and aspects of quality of life in community-dwelling older Australians.

METHOD

A 2-year longitudinal sample of community dwellers aged 70-90 years at baseline, derived from the Sydney Memory and Ageing Study (MAS), was chosen for the study. Of the 1037 participants in the original MAS sample, a baseline (Wave 1) sample of 926 and a 2-year follow-up (Wave 2) sample of 751 subjects were retained for these analyses. Adiposity was measured using body mass index (BMI) and waist circumference (WC). Quality of life was measured using the Assessment of Quality of Life (6 dimensions) questionnaire (AQoL-6D) as well as the Satisfaction with Life Scale (SWLS). Linear regression and analysis of covariance (ANCOVA) were used to examine linear and non-linear relationships between BMI and WC and measures of health-related quality of life (HRQoL) and satisfaction with life, adjusting for age, sex, education, asthma, osteoporosis, depression, hearing and visual impairment, mild cognitive impairment, physical activity, and general health. Where a non-linear relationship was found, established BMI or WC categories were used in ANCOVA.

RESULTS

Greater adiposity was associated with lower HRQoL but not life satisfaction. Regression modelling in cross-sectional analyses showed that higher BMI and greater WC were associated with lower scores for independent living, relationships, and pain (i.e. worse pain) on the AQoL-6D. In planned contrasts within a series of univariate analyses, obese participants scored lower in independent living and relationships, compared to normal weight and overweight participants. Longitudinal analyses found that higher baseline BMI and WC were associated with lower independent living scores at Wave 2.

CONCLUSIONS

Obesity is associated with and predicts lower quality of life in elderly adults aged 70-90 years, and the areas most affected are independent living, social relationships, and the experience of pain.

Clinical outcomes in older surgical patients with mild cognitive impairment

INTRODUCTION

Older adults, including those with mild cognitive impairment (MCI), are increasingly undergoing surgery.

METHODS

Relative risks (RRs) of MCI alone or with delirium on adverse outcomes were estimated in an ongoing prospective, observational cohort study of 560 nondemented adults aged ≥70 years.

RESULTS

MCI (n = 61, 11%) was associated with increased RR of delirium (RR = 1.9, P < .001) and delirium severity (RR = 4.6, P < .001). Delirium alone (n = 107), but not MCI alone (n = 34), was associated with multiple adverse outcomes including more major postoperative complication(s) (RR = 2.5, P = .002) and longer length of stay (RR = 2.2, P < .001). Patients with concurrent MCI and delirium (n = 27) were more often discharged to a postacute facility (RR = 1.4, P < .001) and had synergistically increased risk for new impairments in cognitive functioning (RR = 3.6, P < .001).

DISCUSSION

MCI is associated with increased risk of delirium incidence and severity. Patients with delirium and MCI have synergistically elevated risk of developing new difficulties in cognitively demanding tasks.

Differentiation of Alzheimer's disease based on local and global parameters in personalized Virtual Brain models

Alzheimer's disease (AD) is marked by cognitive dysfunction emerging from neuropathological processes impacting brain function. AD affects brain dynamics at the local level, such as changes in the balance of inhibitory and excitatory neuronal populations, as well as long-range changes to the global network. Individual differences in these changes as they relate to behaviour are poorly understood. Here, we use a multi-scale neurophysiological model, “The Virtual Brain (TVB)”, based on empirical multi-modal neuroimaging data, to study how local and global dynamics correlate with individual differences in cognition. In particular, we modeled individual resting-state functional activity of 124 individuals across the behavioural spectrum from healthy aging, to amnesic Mild Cognitive Impairment (MCI), to AD. The model parameters required to accurately simulate empirical functional brain imaging data correlated significantly with cognition, and exceeded the predictive capacity of empirical connectomes.

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Modeled local and global dynamics correlate with individual cognition in Alzheimer's.

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Proof of concept of The Virtual Brain to characterize individual dynamics

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Brain-behaviour relations depend on the network modeled (whole brain or limbic).

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Model parameters predict cognition better than metrics of neuroimaging data.

Apathy and depressive symptoms in older people and incident myocardial infarction, stroke, and mortality: a systematic review and meta-analysis of individual participant data

Background

Previous findings suggest that apathy symptoms independently of depressive symptoms measured using the Geriatric Depression Scale (GDS) are associated with cardiovascular disease (CVD) in older individuals.

Aims

To study whether apathy and depressive symptoms in older people are associated with future CVD, stroke, and mortality using individual patient-data meta-analysis.

Methods

Medline, Embase, and PsycInfo databases up to September 3, 2013, were systematically searched without language restrictions. We sought prospective studies with older (mean age ≥65 years) community-dwelling populations in which the GDS was employed and subsequent stroke and/or CVD were recorded to provide individual participant data. Apathy symptoms were defined as the three apathy-related subitems of the GDS, with depressive symptoms the remaining items. We used myocardial infarction (MI), stroke, and all-cause mortality as main outcomes. Analyses were adjusted for age, sex, and MI/stroke history. An adaptation of the Newcastle–Ottawa scale was used to evaluate bias. Hazard ratios were calculated using one-stage random-effect Cox regression models.

Results

Of the 52 eligible studies, 21 (40.4%) were included, comprising 47,625 older people (mean age [standard deviation] 74 [7.4] years), over a median follow-up of 8.8 years. Participants with apathy symptoms had a 21% higher risk of MI (95% confidence interval [CI] 1.08–1.36), a 37% higher risk of stroke (95% CI 1.18–1.59), and a 47% higher risk of all-cause mortality (95% CI 1.38–1.56). Participants with depressive symptoms had a comparably higher risk of stroke (HR 1.36, 95% CI 1.18–1.56) and all-cause mortality (HR 1.44, 95% CI 1.35–1.53), but not of MI (HR 1.08, 95% CI 0.91–1.29). Associations for isolated apathy and isolated depressive symptoms were comparable. Sensitivity analyses according to risk of bias yielded similar results.

Conclusion

Our findings stress the clinical importance of recognizing apathy independently of depressive symptoms, and could help physicians identify persons at increased risk of vascular disease.

The association of regional white matter lesions with cognition in a community-based cohort of older individuals

Emerging evidence from lesion-symptom mapping (LSM) studies suggested that regional white matter lesions (WML) on strategic white matter (WM) fiber tracts are significantly associated with specific cognitive domains, independent of global WML burden. However, previous LSM investigations were mostly carried out in disease cohorts, with little evidence from community-based older individuals, making findings difficult to generalize. Moreover, most LSM studies applied a threshold to the probabilistic atlas, leading to the loss of information and threshold-dependent findings. Furthermore, it is still unclear whether associations between regional WML and cognition are independent of global grey matter (GM) and WM volumes, which have also been linked to cognition. In the current study, we undertook a region of interest (ROI) LSM study to examine the relationship between regional WML on strategic WM tracts and cognitive performance in a large community-based cohort of older individuals (N = 461; 70–90 years). WML were extracted using a publicly available pipeline, UBO Detector (https://cheba.unsw.edu.au/group/neuroimaging-pipeline). Mapping of WML to the Johns Hopkins University WM atlas was undertaken using an automated TOolbox for Probabilistic MApping of Lesions (TOPMAL), which we introduce here, and is implemented in UBO Detector. The results show that different patterns of brain structural volumes in the ageing brain were associated with different cognitive domains. Regional WML were associated with processing speed, executive function, and global cognition, independent of total GM, WM and WML volumes. Moreover, regional WML explained more variance in executive function, compared to total GM, WM and WML volumes. The current study highlights the importance of studying regional WML in age-related cognitive decline.

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We examined the associations of regional white matter lesions (WML) with cognition.

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Regional WML were associated with processing speed and executive function.

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Regional WML explained more variance in executive function than global measures.

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The toolbox for mapping WML to WM tracts has been implemented in our UBO Detector.

A Meta-Analysis of Genome-Wide Association Studies of Growth Differentiation Factor-15 Concentration in Blood

Blood levels of growth differentiation factor-15 (GDF-15), also known as macrophage inhibitory cytokine-1 (MIC-1), have been associated with various pathological processes and diseases, including cardiovascular disease and cancer. Prior studies suggest genetic factors play a role in regulating blood MIC-1/GDF-15 concentration. In the current study, we conducted the largest genome-wide association study (GWAS) to date using a sample of ∼5,400 community-based Caucasian participants, to determine the genetic variants associated with MIC-1/GDF-15 blood concentration. Conditional and joint (COJO), gene-based association, and gene-set enrichment analyses were also carried out to identify novel loci, genes, and pathways. Consistent with prior results, a locus on chromosome 19, which includes nine single nucleotide polymorphisms (SNPs) (top SNP, rs888663, p = 1.690 × 10^-35), was significantly associated with blood MIC-1/GDF-15 concentration, and explained 21.47% of its variance. COJO analysis showed evidence for two independent signals within this locus. Gene-based analysis confirmed the chromosome 19 locus association and in addition, a putative locus on chromosome 1. Gene-set enrichment analyses showed that the“COPI-mediated anterograde transport” gene-set was associated with MIC-1/GDF15 blood concentration with marginal significance after FDR correction (p = 0.067). In conclusion, a locus on chromosome 19 was associated with MIC-1/GDF-15 blood concentration with genome-wide significance, with evidence for a new locus (chromosome 1). Future studies using independent cohorts are needed to confirm the observed associations especially for the chromosomes 1 locus, and to further investigate and identify the causal SNPs that contribute to MIC-1/GDF-15 levels.

The relationship between voxel-based metrics of resting state functional connectivity and cognitive performance in cognitively healthy elderly adults

In previous studies, resting-state functional connectivity (FC) metrics of specific brain regions or networks based on prior hypotheses have been correlated with cognitive performance. Without constraining our analyses to specific regions or networks, we employed whole-brain voxel-based weighted degree (WD), a measure of local FC strength, to be correlated with three commonly used neuropsychological assessments of language, executive function and memory retrieval in both positive and negative directions in 67 cognitively healthy elderly adults. We also divided voxel-based WD into short-ranged and long-ranged WDs to evaluate the influence of FC distance on the WD-cognition relationship, and performed three validation tests. Our results showed that for language and executive function tests, positive WD correlates were located in the frontal and temporal cortices, and negative WD correlates in the precuneus and occipital cortices; for memory retrieval, positive WD correlates were located in the inferior temporal cortices, and negative WD correlates in the anterior cingulate cortices and supplementary motor areas. An FC-distance-dependent effect was also observed, with the short-ranged WD correlates of language and executive function tests located in the medial brain regions and the long-ranged WD correlates in the lateral regions. Our findings suggest that inter-individual differences in FC at rest are predictive of cognitive ability in the elderly adults. Moreover, the distinct patterns of positive and negative WD correlates of cognitive performance recapitulate the dichotomy between task-activated and task-deactivated neural systems, implying that a competition between distinct neural systems on functional network topology may have cognitive relevance.

The independent influences of age and education on functional brain networks and cognition in healthy older adults

Healthy aging is accompanied by a constellation of changes in cognitive processes and alterations in functional brain networks. The relationships between brain networks and cognition during aging in later life are moderated by demographic and environmental factors, such as prior education, in a poorly understood manner. Using multivariate analyses, we identified three latent patterns (or modes) linking resting-state functional connectivity to demographic and cognitive measures in 101 cognitively normal elders. The first mode (P = 0.00043) captures an opposing association between age and core cognitive processes such as attention and processing speed on functional connectivity patterns. The functional subnetwork expressed by this mode links bilateral sensorimotor and visual regions through key areas such as the parietal operculum. A strong, independent association between years of education and functional connectivity loads onto a second mode (P = 0.012), characterized by the involvement of key hub regions. A third mode (P = 0.041) captures weak, residual brain-behavior relations. Our findings suggest that circuits supporting lower level cognitive processes are most sensitive to the influence of age in healthy older adults. Education, and to a lesser extent, executive functions, load independently onto functional networks-suggesting that the moderating effect of education acts upon networks distinct from those vulnerable with aging. This has important implications in understanding the contribution of education to cognitive reserve during healthy aging. Hum Brain Mapp 38:5094-5114, 2017. © 2017 Wiley Periodicals, Inc.

Classifying MCI Subtypes in Community-Dwelling Elderly Using Cross-Sectional and Longitudinal MRI-Based Biomarkers

Amnestic MCI (aMCI) and non-amnestic MCI (naMCI) are considered to differ in etiology and outcome. Accurately classifying MCI into meaningful subtypes would enable early intervention with targeted treatment. In this study, we employed structural magnetic resonance imaging (MRI) for MCI subtype classification. This was carried out in a sample of 184 community-dwelling individuals (aged 73-85 years). Cortical surface based measurements were computed from longitudinal and cross-sectional scans. By introducing a feature selection algorithm, we identified a set of discriminative features, and further investigated the temporal patterns of these features. A voting classifier was trained and evaluated via 10 iterations of cross-validation. The best classification accuracies achieved were: 77% (naMCI vs. aMCI), 81% (aMCI vs. cognitively normal (CN)) and 70% (naMCI vs. CN). The best results for differentiating aMCI from naMCI were achieved with baseline features. Hippocampus, amygdala and frontal pole were found to be most discriminative for classifying MCI subtypes. Additionally, we observed the dynamics of classification of several MRI biomarkers. Learning the dynamics of atrophy may aid in the development of better biomarkers, as it may track the progression of cognitive impairment.

Intraindividual Stepping Reaction Time Variability Predicts Falls in Older Adults With Mild Cognitive Impairment

Background

Reaction time measures have considerable potential to aid neuropsychological assessment in a variety of health care settings. One such measure, the intraindividual reaction time variability (IIV), is of particular interest as it is thought to reflect neurobiological disturbance. IIV is associated with a variety of age-related neurological disorders, as well as gait impairment and future falls in older adults. However, although persons diagnosed with Mild Cognitive Impairment (MCI) are at high risk of falling, the association between IIV and prospective falls is unknown.

Methods

We conducted a longitudinal cohort study in cognitively intact (n = 271) and MCI (n = 154) community-dwelling adults aged 70-90 years. IIV was assessed through a variety of measures including simple and choice hand reaction time and choice stepping reaction time tasks (CSRT), the latter administered as a single task and also with a secondary working memory task.

Results

Logistic regression did not show an association between IIV on the hand-held tasks and falls. Greater IIV in both CSRT tasks, however, did significantly increase the risk of future falls. This effect was specific to the MCI group, with a stronger effect in persons exhibiting gait, posture, or physiological impairment.

Conclusions

The findings suggest that increased stepping IIV may indicate compromised neural circuitry involved in executive function, gait, and posture in persons with MCI increasing their risk of falling. IIV measures have potential to assess neurobiological disturbance underlying physical and cognitive dysfunction in old age, and aid fall risk assessment and routine care in community and health care settings.

Is intraindividual reaction time variability an independent cognitive predictor of mortality in old age? Findings from the Sydney Memory and Ageing Study

Intraindividual variability of reaction time (IIV_RT), a proposed cognitive marker of neurobiological disturbance, increases in old age, and has been associated with dementia and mortality. The extent to which IIV_RT is an independent predictor of mortality, however, is unclear. This study investigated the association of IIV_RT and all-cause mortality while accounting for cognitive level, incident dementia and biomedical risk factors in 861 participants aged 70–90 from the Sydney Memory and Ageing Study. Participants completed two computerised reaction time (RT) tasks (76 trials in total) at baseline, and comprehensive medical and neuropsychological assessments every 2 years. Composite RT measures were derived from the two tasks—the mean RT and the IIV_RT measure computed from the intraindividual standard deviation of the RTs (with age and time-on-task effects partialled out). Consensus dementia diagnoses were made by an expert panel of clinicians using clinical criteria, and mortality data were obtained from a state registry. Cox proportional hazards models estimated the association of IIV_RT and mean RT with survival time over 8 years during which 191 (22.2%) participants died. Greater IIV_RT but not mean RT significantly predicted survival time after adjusting for age, sex, global cognition score, cardiovascular risk index and apolipoprotein ɛ4 status. After excluding incident dementia cases, the association of IIV_RT with mortality changed very little. Our findings suggest that greater IIV_RT uniquely predicts shorter time to death and that lower global cognition and prodromal dementia in older individuals do not explain this relationship.