The aging mind: vascular health in normal cognitive aging

Non-employment over the working life: Implications for cognitive function and decline in later life

Objectives

Disuse theory predicts that cognitive function is vulnerable to transitions that remove factors that support cognitive skills. We sought to investigate whether non-employment over the working life was associated with cognitive function and decline in later life (≥60 years old), and possible gender differences in the association.

Study design

Longitudinal study.

Method

We used data from the MRC National Survey of Health and Development (NSHD). Cognitive function was measured by verbal memory and processing speed. Linear regression was used to test associations between non-employment duration and cognitive function at age 60-64, and conditional change models were used to examine associations between non-employment and cognitive decline from age 60-64 to 69. Gender specific models were adjusted for childhood factors and educational attainment, adult occupational features, and adult health and lifestyle indicators. Missing data was accounted for using multiple imputation by chained equations.

Results

In fully adjusted models >15 years non-employment was associated with lower cognitive function at age 60-64 in men (verbal memory: -0.72, 95%CI -1.18, -0.26; processing speed: -0.61, 95%CI -1.00, -0.28), but not women. Fully adjusted models also indicated that long-term and intermediate lengths of non-employment were associated with faster decline in verbal memory (-0.38, 95%CI -0.75, -0.02) and processing speed (-0.28, 95%CI -0.52, -0.03) in men. There was no association between non-employment and cognitive decline among women.

Conclusion

Long-term non-employment in men, but not women, is associated with accelerated cognitive ageing.

Atypical Hierarchical Connectivity Revealed by Stepwise Functional Connectivity in Aging

Hierarchical functional structure plays a crucial role in brain function. We aimed to investigate how aging affects hierarchical functional structure and to evaluate the relationship between such effects and molecular, microvascular, and cognitive features. We used resting-state functional magnetic resonance imaging (fMRI) data from 95 older adults (66.94 ± 7.23 years) and 44 younger adults (21.8 ± 2.53 years) and employed an innovative graph-theory-based analysis (stepwise functional connectivity (SFC)) to reveal the effects of aging on hierarchical functional structure in the brain. In the older group, an SFC pattern converged on the primary sensory-motor network (PSN) rather than the default mode network (DMN). Moreover, SFC decreased in the DMN and increased in the PSN at longer link-steps in aging, indicating a reconfiguration of brain hub systems during aging. Subsequent correlation analyses were performed between SFC values and molecular, microvascular features, and behavioral performance. Altered SFC patterns were associated with dopamine and serotonin, suggesting that altered hierarchical functional structure in aging is linked to the molecular fundament with dopamine and serotonin. Furthermore, increased SFC in the PSN, decreased SFC in the DMN, and accelerated convergence rate were all linked to poorer microvascular features and lower executive function. Finally, a mediation analysis among SFC features, microvascular features, and behavioral performance indicated that the microvascular state may influence executive function through SFC features, highlighting the interactive effects of SFC features and microvascular state on cognition.

Effects of a Brief Stair-Climbing Intervention on Cognitive Functioning and Mood States in Older Adults: A Randomized Controlled Trial

Despite an abundance of evidence that exercise benefits cognition and mood, physical activity levels among older adults remain low, with time and inaccessibility posing major barriers. Interval stair climbing is an accessible time-efficient form of physical activity demonstrated to benefit cognition and mood in young adults, but effectiveness in older adults remains unknown. To address this, 28 older adults (Mage = 69.78 years, 16 females) undertook cognitive and mood assessments twice, 1 week apart, once preceded by interval stair climbing. A fairly large, albeit only marginally significant, effect size (ηp2=.12) indicated improved cognition following the moderate- to high-intensity intervention; however, rather than improving mood, older adults reported feeling more tired (g = 0.51). These outcomes provide initial indications that this mode of exercise that can easily translate to naturalistic settings offers promise as an intervention strategy, but more research is needed to optimize the protocol to suit aged populations (ACTRN1261900169014).

Integrating Three Characteristics of Executive Function in Non-Demented Aging: Trajectories, Classification, and Biomarker Predictors

OBJECTIVE

With longitudinal executive function (EF) data from the Victoria Longitudinal Study, we investigated three research goals pertaining to key characteristics of EF in non-demented aging: (a) examining variability in EF longitudinal trajectories, (b) establishing trajectory classes, and (c) identifying biomarker predictors discriminating these classes.

METHOD

We used a trajectory analyses sample (n = 781; M age = 71.42) for the first and second goals and a prediction analyses sample (n = 570; M age = 70.10) for the third goal. Eight neuropsychological EF measures were used as indicators of three EF dimensions: inhibition, updating, and shifting. Data-driven classification analyses were applied to the full trajectory distribution. Machine learning prediction analyses tested 15 predictors from genetic, functional, lifestyle, mobility, and demographic risk domains.

RESULTS

First, we observed: (a) significant variability in EF trajectories over a 40-year band of aging and (b) significantly variable patterns of EF decline. Second, a four-class EF trajectory model was observed, characterized with classes differentiated by an algorithm of level and slope information. Third, the highest group class was discriminated from lowest by several prediction factors: more education, more novel cognitive activity, lower pulse pressure, younger age, faster gait, lower body mass index, and better balance.

CONCLUSION

First, with longitudinal variability in EF aging, the data-driven approach showed that long-term trajectories can be differentiated into separable classes. Second, prediction analyses discriminated class membership by a combination of multiple biomarkers from demographic, lifestyle, functional, and mobility domains of risk for brain and cognitive aging decline.

Coagulation factor VIII, white matter hyperintensities and cognitive function: Results from the Cardiovascular Health Study

OBJECTIVE

To investigate the relationship between high FVIII clotting activity (FVIII:C), MRI-defined white matter hyperintensities (WMH) and cognitive function over time.

METHODS

Data from the population-based Cardiovascular Health Study (n = 5,888, aged ≥65) were used. FVIII:C was measured in blood samples taken at baseline. WMH burden was assessed on two cranial MRI scans taken roughly 5 years apart. Cognitive function was assessed annually using the Modified Mini-Mental State Examination (3MSE) and Digit Symbol Substitution Test (DSST). We used ordinal logistic regression models adjusted for demographic and cardiovascular factors in cross-sectional and longitudinal WMH analyses, and adjusted linear regression and linear mixed models in the analyses of cognitive function.

RESULTS

After adjustment for confounding, higher levels of FVIII:C were not strongly associated with the burden of WMH on the initial MRI scan (OR>p75 = 1.20, 95% CI 0.99-1.45; N = 2,735) nor with WMH burden worsening over time (OR>p75 = 1.18, 95% CI 0.87-1.59; N = 1,527). High FVIII:C showed no strong association with cognitive scores cross-sectionally (3MSE>p75 β = -0.06, 95%CI -0.45 to 0.32, N = 4,005; DSST>p75 β = -0.69, 95%CI -1.52 to 0.13, N = 3,954) or over time (3MSE>p75 β = -0.07,95% CI -0.58 to 0.44, N = 2,764; DSST>p75 β = -0.22, 95% CI -0.97 to 0.53, N = 2,306) after confounding adjustment.

INTERPRETATION

The results from this cohort study of older adult participants indicate no strong relationships between higher FVIII:C levels and WMH burden or cognitive function in cross-sectional and longitudinal analyses.

Glycated Peptide Levels Are Associated With Cognitive Decline Among Nondiabetic Older Women

BACKGROUND

The association between diabetes and dementia may be explained in part by elevated levels of glycated peptides; we sought to determine whether serum-glycated peptides predicted cognitive decline in nondiabetic older adults.

METHODS

We prospectively studied 525 community-dwelling nondiabetic women, mean age of 82 years, and analyzed baseline glycated peptides (serum level of fructosamine and glycated albumin). Cognitive outcomes included 5-year decline on the short Mini-Mental State Examination (sMMSE), Trails B, and performance on a battery of five other cognitive tests at the follow-up visit. Generalized linear models were adjusted for education, age, race, physical activity, body mass index, and vascular disease.

RESULTS

Women with higher level of fructosamine (upper two tertiles) had greater 5-year decline in Trails B performance compared with women in the lowest tertile (adjusted mean change = 67 vs 50 seconds, p = .046), but change in sMMSE was not different between groups. Higher fructosamine was also associated with worse cognitive function 5 years later: adjusted mean score for the California Verbal Learning Test-II Short Form was 22.7 versus 23.9 (p = .010) and for Category Fluency was 10.1 versus 11.1 (p = .003). Higher glycated albumin was also associated with worse performance on Category Fluency (10.1 vs 11.1, p = .003) but not on any other test.

CONCLUSIONS

Among older nondiabetic women, higher concentrations of glycated peptides may be associated with greater cognitive decline, especially in measures of executive function. These associations may present new opportunities for targeted prevention and therapeutic strategies in cognitive aging.

Neuropsychology of aging

All people want to age "successfully," maintaining functional capacity and quality of life as they reach advanced age. Achieving this goal depends on preserving optimal cognitive and brain functioning. Yet, significant individual differences exist in this regard. Some older adults continue to retain most cognitive abilities throughout their lifetime. Others experience declines in cognitive and functional capacity that range from mild decrements in certain cognitive functions over time to severe dementia among those with neurodegenerative diseases. Even among relatively healthy "successful agers," certain cognitive functions are reduced from earlier levels. This is particularly true for cognitive functions that are dependent on cognitive processing speed and efficiency. Working memory and executive and attentional functions tend to be most vulnerable. Learning and memory functions are also usually reduced, although in the absence of neurodegenerative disease learning and retrieval efficiency rather than memory storage are affected. Other functions, such as visual perception, language, semantics, and knowledge, are often well preserved. Structural, functional, and physiologic/metabolic brain changes correspond with age-associated cognitive decline. Physiologic and metabolic mechanisms, such as oxidative stress and neuroinflammation, may contribute to these changes, along with the contribution of comorbidities that secondarily affect the brain of older adults. Cognitive frailty often corresponds with physical frailty, both affected by multiple exogenous and endogenous factors. Neuropsychologic assessment provides a way of measuring the cognitive and functional status of older adults, which is useful for monitoring changes that may be occurring. Neuroimaging is also useful for characterizing age-associated structural, functional, physiologic, and metabolic brain changes, including alterations in cerebral blood flow and metabolite concentrations. Some interventions that may enhance cognitive function, such as cognitive training, neuromodulation, and pharmacologic approaches, exist or are being developed. Yet, preventing, slowing, and reversing the adverse effects of cognitive aging remains a challenge.

Frailty Screening and Case-Finding for Complex Chronic Conditions in Older Adults in Primary Care

With the aging population, escalating demand for seniors' care and limited specialist resources, new care delivery models are needed to improve capacity for primary health care for older adults. This paper describes the "C5-75" (Case-finding for Complex Chronic Conditions in Seniors 75+) program, an innovative care model aimed at identifying frailty and commonly associated geriatric conditions among older adults within a Canadian family practice setting and targeting interventions for identified conditions using a feasible, systematic, evidence-informed multi-disciplinary approach. We screen annually for frailty using gait speed and handgrip strength, screen for previously undiagnosed comorbid conditions, and offer frail older adults multi-faceted interventions that identify and address unrecognized medical and psychosocial needs. To date, we have assessed 965 older adults through this program; 14% were identified as frail based on gait speed alone, and 5% identified as frail based on gait speed with grip strength. The C5-75 program aims to re-conceptualize care from reactive interventions post-diagnosis for single disease states to a more proactive approach aimed at identifying older adults who are at highest risk of poor health outcomes, case-finding for unrecognized co-existing conditions, and targeting interventions to maintain health and well-being and potentially reduce vulnerability and health destabilization.

Insulin Resistance and Future Cognitive Performance and Cognitive Decline in Elderly Patients with Cardiovascular Disease

BACKGROUND

The role of insulin resistance (IR) in the pathogenesis of cognitive performance is not yet clear.

OBJECTIVE

To examine the associations between IR and cognitive performance and change in cognitive functions two decades later in individuals with cardiovascular disease with and without diabetes.

METHODS

A subset of 489 surviving patients (mean age at baseline 57.7±6.5 y) with coronary heart disease who previously participated in the secondary prevention Bezafibrate Infarction Prevention (BIP trial; 1990-1997), were included in the current neurocognitive study. Biochemical parameters including IR (using the homeostasis model of assessment; HOMA-IR) were measured at baseline. During 2004-2008, computerized cognitive assessment and atherosclerosis parameters were measured (T1; n = 558; mean age 72.6±6.4 years). A second cognitive assessment was performed during 2011-2013 (T2; n = 351; mean age 77.2±6.4 years). Cognitive function, overall and in specific domains, was assessed. We used linear regression models and linear mixed models to evaluate the differences in cognitive performance and decline, respectively.

RESULTS

Controlling for potential confounders, IR (top HOMA-IR quartile versus others) was associated with subsequent poorer cognitive performance overall (β= -4.45±Standard Error (SE) 1.54; p = 0.004) and on tests of memory and executive function among non-diabetic patients (β= -7.16±2.38; p = 0.003 and β= -3.33±1.84; p = 0.073, respectively). Moreover, among non-diabetic patients, IR was related to a greater decline overall (β= -0.17±0.06; p = 0.008), and in memory (β= -0.22±0.10; p = 0.024) and executive function (β= -0.19±0.08; p = 0.012). The observed associations did not differ after excluding subjects with prevalent stroke or dementia.

CONCLUSION

IR is related to subsequent poorer cognitive performance and greater cognitive decline among patients with cardiovascular disease with and without diabetes.

Physical Therapy for Neurological Conditions in Geriatric Populations

With more of the world’s population surviving longer, individuals often face age-related neurology disorders and decline of function that can affect lifestyle and well-being. Despite neurophysiological changes affecting the brain function and structure, the aged brain, in some degree, can learn and relearn due to neuroplasticity. Recent advances in rehabilitation techniques have produced better functional outcomes in age-related neurological conditions. Physical therapy (PT) of the elderly individual focuses in particular on sensory–motor impairments, postural control coordination, and prevention of sarcopenia. Geriatric PT has a significant influence on quality of life, independent living, and life expectancy. However, in many developed and developing countries, the profession of PT is underfunded and understaffed. This article provides a brief overview on (a) age-related disease of central nervous system and (b) the principles, approaches, and doctrines of motor skill learning and point out the most common treatment models that PTs use for neurological patients.

Incident risk and progression of cerebral microbleeds in healthy adults: a multi-occasion longitudinal study

Decline in cerebrovascular health complicates brain aging, and development of cerebral microbleeds (CMBs) is one of its prominent indicators. In a large sample of healthy adults (N = 251, age 18-78 years at baseline, 70% women), the contributions of chronological age and vascular health indicators to the risk of developing a CMB, as well as the change in CMB size and iron content, were examined in a prospective 8-year longitudinal study using susceptibility weighted imaging. Twenty-six persons (10.4%), most of whom were 40 years of age or older, had at least 1 CMB during the study. Older age was associated with greater risk for developing a CMB (odds ratio 1.03). Elevation of combined metabolic syndrome indicators (b = 0.15, p = 0.001) conferred additional risk (odds ratio 1.02). High body mass index exacerbated the risk associated with poor vascular health (b = 0.75, p < 0.001) and frequent exercise mitigated it (b = -0.46, p = 0.03). CMBs persisted over time, yet their volume decreased (mean change = -0.32, p < 0.05), whereas their relative iron content remained stable (mean change = -0.14, p = 0.05). We conclude that although developing a CMB is unlikely during normal aging, risk increases with declining vascular health, which is modifiable via behavioral and pharmaceutical intervention.

Association of early left ventricular dysfunction with advanced magnetic resonance white matter and gray matter brain measures: The CARDIA study

INTRODUCTION

Relations between heart failure and clinically manifested stroke are well known, but the associations between heart and brain early abnormalities are not totally clear.

AIMS

We explore relations of subclinical brain abnormalities with early cardiac dysfunction in a large healthy middle-aged biracial cohort.

METHODS

The CARDIA study enrolled 5115 young adults aged 18-30 years at baseline (1985-1986). We assessed 719 Caucasian and African American participants of the CARDIA study, with echocardiograms and brain MRI at follow-up year 25 (2010-2011). Echocardiography assessed aortic root diameter; LVEF; circumferential, longitudinal, and radial deformation. Cerebral MRI DTI, and, on a subset, ASL perfusion sequences were used to assess white matter fractional anisotropy and gray matter cerebral blood flow (CBF). Linear regression explored relations between cardiac parameters and cerebral measures, adjusting for anthropometrics, risk factors, and brain constitutional variation.

RESULTS

Mean age 50 ± 4 years, SBP 118 ± 15 mm Hg; 60% white, and 48% men. Mean CBF was 46 ± 9 mL/100 g/min, and white matter fractional anisotropy was 0.31 ± 0.02. Worse circumferential deformation and larger aortic root were related to worse white matter fractional anisotropy. Worse radial systolic deformation was related to worse CBF in multivariable models. LVEF did not relate to early brain abnormalities.

CONCLUSIONS

In spite of no apparent effect of LV ejection fraction, early subclinical cardiac dysfunction and brain abnormalities are present and associated in middle-aged generally healthy individuals.

Aerobic fitness, hippocampal viscoelasticity, and relational memory performance

The positive relationship between hippocampal structure, aerobic fitness, and memory performance is often observed among children and older adults; but evidence of this relationship among young adults, for whom the hippocampus is neither developing nor atrophying, is less consistent. Studies have typically relied on hippocampal volumetry (a gross proxy of tissue composition) to assess individual differences in hippocampal structure. While volume is not specific to microstructural tissue characteristics, microstructural differences in hippocampal integrity may exist even among healthy young adults when volumetric differences are not diagnostic of tissue health or cognitive function. Magnetic resonance elastography (MRE) is an emerging noninvasive imaging technique for measuring viscoelastic tissue properties and provides quantitative measures of tissue integrity. We have previously demonstrated that individual differences in hippocampal viscoelasticity are related to performance on a relational memory task; however, little is known about health correlates to this novel measure. In the current study, we investigated the relationship between hippocampal viscoelasticity and cardiovascular health, and their mutual effect on relational memory in a group of healthy young adults (N=51). We replicated our previous finding that hippocampal viscoelasticity correlates with relational memory performance. We extend this work by demonstrating that better aerobic fitness, as measured by VO2max, was associated with hippocampal viscoelasticity that mediated the benefits of fitness on memory function. Hippocampal volume, however, did not account for individual differences in memory. Therefore, these data suggest that hippocampal viscoelasticity may provide a more sensitive measure to microstructural tissue organization and its consequences to cognition among healthy young adults.

Dispositional Optimism and Incidence of Cognitive Impairment in Older Adults

OBJECTIVE

Higher levels of optimism have been linked with positive health behaviors, biological processes, and health conditions that are potentially protective against cognitive impairment in older adults. However, the association between optimism and cognitive impairment has not been directly investigated. We examined whether optimism is associated with incident cognitive impairment in older adults.

METHODS

Data are from the Health and Retirement Study. Optimism was measured by using the Life Orientation Test-R and cognitive impairment with a modified version of the Telephone Interview for Cognitive Status derived from the Mini-Mental State Examination. Using multiple logistic regression models, we prospectively assessed whether optimism was associated with incident cognitive impairment in 4624 adults 65 years and older during a 4-year period.

RESULTS

Among participants, 312 women and 190 men developed cognitive impairment during the 4-year follow-up. Higher optimism was associated with decreased risk of incident cognitive impairment. When adjusted for sociodemographic factors, each standard deviation increase in optimism was associated with reduced odds (odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.61-0.81) of becoming cognitively impaired. A dose-response relationship was observed. Compared with those with the lowest levels of optimism, people with moderate levels had somewhat reduced odds of cognitive impairment (OR = 0.78, 95% CI = 0.59-1.03), whereas people with the highest levels had the lowest odds of cognitive impairment (OR = 0.52, 95% CI = 0.36-0.74). These associations remained after adjusting for health behaviors, biological factors, and psychological covariates that could either confound the association of interest or serve on the pathway.

CONCLUSIONS

Optimism was prospectively associated with a reduced likelihood of becoming cognitively impaired. If these results are replicated, the data suggest that potentially modifiable aspects of positive psychological functioning such as optimism play an important role in maintaining cognitive functioning.

Cognitive Difficulty Intensifies Age-related Changes in Anterior Frontal Hemodynamics: Novel Evidence from Near-infrared Spectroscopy

Alongside age-related brain deterioration, cognitive functioning declines, particularly for more demanding tasks. Past research indicates that, to offset this decline, older adults exhibit hemodynamic changes consistent with recruitment of more anterior brain regions. However, the nature of the hemodynamic changes remains unclear. To address this knowledge gap, we used near-infrared spectroscopy in 36 young adults (aged 18-30 years) and 36 older adults (aged 60-72 years) to assess anterior frontal hemodynamic responses to engagement in three cognitive tasks of increasing difficulty. Behavioral results for all three tasks confirmed aging deficits (evidenced by slower reaction times and reduced accuracy rates) that progressively increased with task difficulty. Hemodynamic results showed opposing effects in young versus older adults, with oxygenated and total hemoglobin decreasing in young but increasing in older adults, particularly during the harder tasks. Also, tissue oxygenation increased only in older adults during the harder tasks. Among the older adults only, anterior frontal hemodynamic changes correlated with better cognitive performance, indicating that they were compensatory in nature. These findings provide novel evidence of age-related anterior frontal hemodynamic changes that intensify with cognitive demands and compensate for performance deficits.

Climacteric symptoms in middle-aged women with chronic somatic diseases

OBJECTIVES

Chronic diseases may aggravate or simulate climacteric symptoms. Although acknowledged in clinical practice, there is a lack of research systematically analysing the association between chronic diseases and climacteric symptoms.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Our study was a cross-sectional population-based study, which included 3421 women, aged 41-54 years. Climacteric symptoms were evaluated using the Women's Health Questionnaire (WHQ), of which we included seven symptom domains (vasomotor, sleep, depressive, anxiety/fears, cognitive, sexual, and menstrual) and a question concerning whether the women were worried about growing old. The occurrence of various diseases (cardiovascular, neurological, sensory organ, bronchopulmonary, musculoskeletal, gastrointestinal, urological, dermatological, and thyroid disease, diabetes, and cancer) was recorded. The associations between the diseases and symptoms were defined with multivariable analyses, adjusting for various confounding factors.

RESULTS

The women with the diseases had more symptoms. Vasomotor symptoms and sleep problems were associated only with gastrointestinal diseases, and lower sexual functioning only with diabetes. The remaining symptoms were associated with several diseases, except being worried about growing old, which was not associated with any.

CONCLUSIONS

Many symptoms connected to the climacteric may manifest also due to chronic diseases. Thus, health-care professionals should consider the origin of the symptoms when treating middle-aged women with chronic diseases.

Associations between anxiety and depression symptoms and cognitive testing and neuroimaging in type 2 diabetes

AIMS

Anxiety, depression, accelerated cognitive decline, and increased risk of dementia are observed in individuals with type 2 diabetes. Anxiety and depression may contribute to lower performance on cognitive tests and differences in neuroimaging observed in individuals with type 2 diabetes.

METHODS

These relationships were assessed in 655 European Americans with type 2 diabetes from 504 Diabetes Heart Study families. Participants completed cognitive testing, brain magnetic resonance imaging, the Brief Symptom Inventory Anxiety subscale, and the Center for Epidemiologic Studies Depression-10.

RESULTS

In analyses adjusted for age, sex, educational attainment, and use of psychotropic medications, individuals with comorbid anxiety and depression symptoms had lower performance on all cognitive testing measures assessed (p≤0.005). Those with both anxiety and depression also had increased white matter lesion volume (p=0.015), decreased gray matter cerebral blood flow (p=4.43×10(-6)), decreased gray matter volume (p=0.002), increased white and gray matter mean diffusivity (p≤0.001), and decreased white matter fractional anisotropy (p=7.79×10(-4)). These associations were somewhat attenuated upon further adjustment for health status related covariates.

CONCLUSIONS

Comorbid anxiety and depression symptoms were associated with cognitive performance and brain structure in a European American cohort with type 2 diabetes.

Cognitive Aging in Parents of Children with Disabilities

OBJECTIVE

This study examines the cognitive functioning of parents of children with disabilities, specifically, whether there is an evidence of accelerated cognitive aging among these parents. In addition, the study investigates the moderating influences of two variables: parents' gender and stress from negative parenting experience.

METHOD

The analyses utilize data from the National Survey of Midlife in the United States (2005). The analytic sample consisted of two groups of parents, who completed the cognitive battery, the interview, and the mail-back survey: 128 parents who had children with childhood-onset disabilities and 512 matched comparison parents who had only nondisabled children.

RESULTS

Age differences in episodic memory were more pronounced among mothers of children with disabilities than among mothers with nondisabled children, especially among mothers with higher levels of negative parenting experience. In contrast, there were no interaction effects of parenting status, age, and negative parenting experience among fathers.

DISCUSSION

The results show that parenting children with disabilities over a prolonged period of time jeopardizes cognitive function (especially memory) among older mothers, possibly via the mechanism of heightened parenting stress due to higher levels of negative parenting experience.

Heritability and genetic association analysis of cognition in the Diabetes Heart Study

Cognitive performance is an important component of healthy aging. Type 2 diabetes (T2D) is associated with negative outcomes for the brain and cognition, although causal mechanisms have not been definitely determined. Genetic risk factors warrant further consideration in this context. This study examined the heritability of cognitive function as assessed by (1) the Digit Symbol Substitution Task; (2) the Modified Mini-Mental State Examination; (3) the Stroop Task; (4) the Rey Auditory-Verbal Learning Task; and (5) the Controlled Oral Word Association Task for Phonemic and Semantic Fluency, in the family-based, T2D-enriched, Diabetes Heart Study sample (n = 550 participants from 257 families). The genetic basis of these cognitive measures was further evaluated by association analysis with candidate single-nucleotide polymorphisms (SNPs) and genome-wide SNP data. Measures of cognitive function were significantly heritable (hˆ(2) = 0.28-0.62) following adjustment for age, gender, and education. A total of 31 SNPs (from 26 genes/regions) selected to form an a priori set of candidate SNPs showed limited evidence of association with cognitive function when applying conservative metrics of significance. Genome-wide assessment of both noncoding and coding variants revealed suggestive evidence of association for several coding variants including rs139509083 in CNST (p = 4.9 × 10(-9)), rs199968569 in PLAA (p = 4.9 × 10(-9)) and rs138487371 in PCDH8 (p = 3.7 × 10(-8)). The identification of a heritable component to cognitive performance in T2D suggests a role for genetic contributors to cognitive performance even in the presence of metabolic disease and other associated comorbidities and is supported by the identification of genetic association signals in functionally plausible candidates.

Should general anaesthesia be avoided in the elderly?

Surgery and anaesthesia exert comparatively greater adverse effects on the elderly than on the younger brain, manifest by the higher prevalence of postoperative delirium and cognitive dysfunction. Postoperative delirium and cognitive dysfunction delay rehabilitation, and are associated with increases in morbidity and mortality among elderly surgical patients. We review the aetiology of postoperative delirium and cognitive dysfunction in the elderly with a particular focus on anaesthesia and sedation, discuss methods of diagnosing and monitoring postoperative cognitive decline, and describe the treatment strategies by which such decline may be prevented.

Trajectories of the Framingham general cardiovascular risk profile in midlife and poor motor function later in life: the Whitehall II study

BACKGROUND

Vascular risk factors are associated with increased risk of cognitive impairment and dementia, but their association with motor function, another key feature of aging, has received little research attention. We examined the association between trajectories of the Framingham general cardiovascular disease risk score (FRS) over midlife and motor function later in life.

METHODS

A total of 5376 participants of the Whitehall II cohort study (29% women) who had up to four repeat measures of FRS between 1991-1993 (mean age=48.6 years) and 2007-2009 (mean age=65.4 years) and without history of stroke or coronary heart disease in 2007-2009 were included. Motor function was assessed in 2007-2009 through objective tests (walking speed, chair rises, balance, finger tapping, grip strength). We used age- and sex-adjusted linear mixed models.

RESULTS

Participants with poorer performances for walking speed, chair rises, and balance in 2007-2009 had higher FRS concurrently and also in 1991-1993, on average 16 years earlier. These associations were robust to adjustment for cognition, socio-economic status, height, and BMI, and not explained by incident mobility limitation prior to motor assessment. No association was found with finger tapping and grip strength.

CONCLUSIONS

Cardiovascular risk early in midlife is associated with poor motor performances later in life. Vascular risk factors play an important and under-recognized role in motor function, independently of their impact on cognition, and suggest that better control of vascular risk factors in midlife may prevent physical impairment and disability in the elderly.

The influence of subclinical cardiovascular disease and related risk factors on cognition in type 2 diabetes mellitus: The DHS-Mind study

We hypothesized that measures of coronary artery calcified plaque (CAC) collected at baseline from the Diabetes Heart Study (DHS) would explain associations between cognition and diabetes collected at follow-up approximately 7 years later. The DHS is a sibling study of cardiovascular disease (CVD) in a cohort with a high prevalence of type 2 diabetes (~80%). Associations between baseline CAC and cognitive performance were tested using generalized estimating equations and mixed effects models to adjust for familial relationships. Diabetes status was associated (p<0.05) with poorer performance on tests of verbal memory, processing speed, and semantic fluency adjusting for age, sex, education, and hypertension status. As hypothesized, including CAC in the statistical model attenuated this association. Additionally, CAC and fasting glucose predicted performance in tasks not associated with diabetes status in this study (Stroop Task, Phonemic Fluency). These results confirm work attributing the heterogeneity of cognitive outcomes in type 2 diabetes to subclinical risk factors that combine to affect different aspects of brain function. Importantly, these results imply that risk factor intervention should begin before comorbidities, particularly CVD, become clinically apparent.

Memory aging and brain maintenance

Episodic memory and working memory decline with advancing age. Nevertheless, large-scale population-based studies document well-preserved memory functioning in some older individuals. The influential ‘reserve’ notion holds that individual differences in brain characteristics or in the manner people process tasks allow some individuals to cope better than others with brain pathology and hence show preserved memory performance. Here, we discuss a complementary concept, that of brain maintenance (or relative lack of brain pathology), and argue that it constitutes the primary determinant of successful memory aging. We discuss evidence for brain maintenance at different levels: cellular, neurochemical, gray- and white-matter integrity, and systems-level activation patterns. Various genetic and lifestyle factors support brain maintenance in aging and interventions may be designed to promote maintenance of brain structure and function in late life.

A genome-wide scan for common variants affecting the rate of age-related cognitive decline

Age-related cognitive decline is likely promoted by accumulated brain injury due to chronic conditions of aging, including neurodegenerative and vascular disease. Because common neuronal mechanisms may mediate the adaptation to diverse cerebral insults, we hypothesized that susceptibility for age-related cognitive decline may be due in part to a shared genetic network. We have therefore performed a genome-wide association study using a quantitative measure of global cognitive decline slope, based on repeated measures of 17 cognitive tests in 749 subjects from the Religious Orders Study. Top results were evaluated in 3 independent replication cohorts, consisting of 2279 additional subjects with repeated cognitive testing. As expected, we find that the Alzheimer's disease (AD) susceptibility locus, APOE, is strongly associated with rate of cognitive decline (P(DISC) = 5.6 × 10(-9); P(JOINT)= 3.7 × 10(-27)). We additionally discover a variant, rs10808746, which shows consistent effects in the replication cohorts and modestly improved evidence of association in the joint analysis (P(DISC) = 6.7 × 10(-5); P(REP) = 9.4 × 10(-3); P(JOINT) = 2.3 × 10(-5)). This variant influences the expression of 2 adjacent genes, PDE7A and MTFR1, which are potential regulators of inflammation and oxidative injury, respectively. Using aggregate measures of genetic risk, we find that known susceptibility loci for cardiovascular disease, type 2 diabetes, and inflammatory diseases are not significantly associated with cognitive decline in our cohort. Our results suggest that intermediate phenotypes, when coupled with larger sample sizes, may be a useful tool to dissect susceptibility loci for age-related cognitive decline and uncover shared molecular pathways with a role in neuronal injury.

Advanced glycation end product level, diabetes, and accelerated cognitive aging

OBJECTIVE

Several studies report that diabetes increases risk of cognitive impairment; some have hypothesized that advanced glycation end products (AGEs) underlie this association. AGEs are cross-linked products that result from reactions between glucose and proteins. Little is known about the association between peripheral AGE concentration and cognitive aging.

METHODS

We prospectively studied 920 elders without dementia, 495 with diabetes and 425 with normal glucose (mean age 74.0 years). Using mixed models, we examined baseline AGE concentration, measured with urine pentosidine and analyzed as tertile, and performance on the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and repeatedly over 9 years. Incident cognitive impairment (a decline of >1.0 SD on each test) was analyzed with logistic regression.

RESULTS

Older adults with high pentosidine level had worse baseline DSST score (p=0.05) but not different 3MS score (p=0.32). On both tests, there was a more pronounced 9-year decline in those with high and mid pentosidine level compared to those in the lowest tertile (3MS 7.0, 5.4, and 2.5 point decline, p overall <0.001; DSST 5.9, 7.4, and 4.5 point decline, p=0.03). Incident cognitive impairment was higher in those with high or mid pentosidine level than those in the lowest tertile (3MS: 24% vs 17%, odds ratio=1.55; 95% confidence interval 1.07-2.26; DSST: 31% vs 22%, odds ratio=1.62; 95% confidence interval 1.13-2.33). There was no interaction between pentosidine level, diabetes status, and cognitive decline. Multivariate adjustment for age, sex, race, education, hypertension, cardiovascular disease, estimated glomerular filtration rate, and diabetes diminished results somewhat but overall patterns remained similar.

CONCLUSION

High peripheral AGE level is associated with greater cognitive decline in older adults with and without diabetes.

Age-related changes in the thickness of cortical zones in humans

Structural neuroimaging studies have demonstrated that all regions of the cortex are not affected equally by aging, with frontal regions appearing especially susceptible to atrophy. The "last in, first out" hypothesis posits that aging is, in a sense, the inverse of development: late-maturing regions of the brain are preferentially vulnerable to age-related loss of structural integrity. We tested this hypothesis by analyzing age-related changes in regional cortical thickness via three methods: (1) an exploratory linear regression of cortical thickness and age across the entire cortical mantle (2) an analysis of age-related differences in the thickness of zones of cortex defined by functional/cytoarchitectural affiliation (including primary sensory/motor, unimodal association, heteromodal association, and paralimbic zones), and (3) an analysis of age-related differences in the thickness of regions of cortex defined by surface area expansion in the period between birth and early adulthood. Subjects were grouped as young (aged 18-29, n = 138), middle-aged (aged 30-59, n = 80), young-old (aged 60-79, n = 60), and old-old (aged 80+, n = 38). Thinning of the cortex between young and middle-aged adults was greatest in heteromodal association cortex and regions of high postnatal surface area expansion. In contrast, thinning in old-old age was greatest in primary sensory/motor cortices and regions of low postnatal surface area expansion. In sum, these results lead us to propose a sequential "developmental-sensory" model of aging, in which developmental factors influence cortical vulnerability relatively early in the aging process, whereas later-in more advanced stages of aging-factors specific to primary sensory and motor cortices confer vulnerability. This model offers explicitly testable hypotheses and suggests the possibility that normal aging may potentially allow for multiple opportunities for intervention to promote the structural integrity of the cerebral cortex.