Neighborhood psychosocial environment, apolipoprotein E genotype, and cognitive function in older adults

Midlife Residential Greenness and Late-Life Cognitive Decline among Nurses' Health Study Participants

BACKGROUND

Midlife residential exposure to greenspace may slow cognitive decline by increasing opportunities for physical activity and social connection, restoring attention, or reducing stress or adverse environmental exposures. However, prospective studies on the association between greenness and cognitive decline are sparse.

OBJECTIVE

We investigated the prospective association between greenness at midlife and cognitive decline later in life. We explored effect measure modification by apolipoprotein E (APOE)-ɛ4 carrier status, neighborhood socioeconomic status (NSES), and rural/urban regions.

METHODS

The Nurses' Health Study (N = 121,700 ) started in 1976 with married female nurses, 30-55 years of age, located across 11 US states. We examined 16,962 nurses who were enrolled in a substudy starting in 1995-2001 (mean age = 74 y ) through 2008. We assessed average summer residential greenness in a 270 -m buffer using Landsat Normalized Difference Vegetation Index data from 1986-1994. Starting in 1995-2001, participants underwent up to four repeated measures of five cognitive tests. A global composite score was calculated as the average of all z -scores for each task to evaluate overall cognition. We used linear mixed models to evaluate the association of average greenness exposure at midlife with cognitive decline in later life, adjusted for age, education, NSES, and depression.

RESULTS

In adjusted models, higher midlife greenness exposure [per interquartile range (IQR): 0.18] was associated with a 0.004-unit (95% CI: 0.001, 0.006) slower annual rate of cognitive decline. For comparison, we found that 1 year of age is related to a - 0.006 mean annual difference for global cognition in the full sample; thus, higher midlife greenness appeared equivalent to slowing cognitive decline by ∼ 8 months. In analysis exploring gene-environment interactions, we found that among APOE-ɛ4 carriers, an IQR increase in greenness was associated with a rate of decline that was slower by 0.01 units of global composite score (95% CI: 0.0004, 0.02). This association was attenuated among APOE-ɛ4 noncarriers. We did not observe associations between greenness and baseline or annual rate of cognitive decline of verbal memory.

DISCUSSION

Higher midlife greenness exposure is associated with slower cognitive decline later in life. Future research is necessary to confirm these findings. https://doi.org/10.1289/EHP13588.

Operationalizing Social Environments in Cognitive Aging and Dementia Research: A Scoping Review

BACKGROUND

Social environments are a contributing determinant of health and disparities. This scoping review details how social environments have been operationalized in observational studies of cognitive aging and dementia.

METHODS

A systematic search in PubMed and Web of Science identified studies of social environment exposures and late-life cognition/dementia outcomes. Data were extracted on (1) study design; (2) population; (3) social environment(s); (4) cognitive outcome(s); (5) analytic approach; and (6) theorized causal pathways. Studies were organized using a 3-tiered social ecological model at interpersonal, community, or policy levels.

RESULTS

Of 7802 non-duplicated articles, 123 studies met inclusion criteria. Eighty-four studies were longitudinal (range 1-28 years) and 16 examined time-varying social environments. When sorted into social ecological levels, 91 studies examined the interpersonal level; 37 examined the community/neighborhood level; 3 examined policy level social environments; and 7 studies examined more than one level.

CONCLUSIONS

Most studies of social environments and cognitive aging and dementia examined interpersonal factors measured at a single point in time. Few assessed time-varying social environmental factors or considered multiple social ecological levels. Future studies can help clarify opportunities for intervention by delineating if, when, and how social environments shape late-life cognitive aging and dementia outcomes.

Perceived Neighborhood Characteristics and Cognitive Functioning among Diverse Older Adults: An Intersectional Approach

Unfavorable neighborhood conditions are linked to health disparities. Yet, a dearth of literature examines how neighborhood characteristics contribute to cognitive health in diverse samples of older adults. The present study uses an intersectional approach to examine how race/ethnicity, gender, and education moderate the association between neighborhood perceptions and cognitive functioning in later life. We used data from adults ≥65 years old (n = 8023) in the 2010-2016 waves of the nationally representative Health and Retirement Study (HRS). We conducted race/ethnicity-stratified linear regression models where cognitive functioning, measured using the 35-point Telephone Interview Cognitive Screen (TICS), was regressed on three neighborhood characteristics-cleanliness, safety, and social cohesion. We examine whether there is heterogeneity within race/ethnicity by testing if and how the relationship between neighborhood characteristics and cognitive functioning differs by gender and education. Among White adults, worse neighborhood characteristics were associated with lower cognitive functioning among those with less education. However, for Black adults, poor perceived quality of one's neighborhood was associated with worse cognitive functioning among those with more years of education compared to those with fewer years of education. Among Mexicans, perceived neighborhood uncleanliness was associated with lower cognitive functioning among those with less education, but higher cognitive functioning for those with higher levels of education. Thus, this study contributes to the literature on racial/ethnic disparities in cognitive aging disparities by examining neighborhood contextual factors as determinants of cognitive functioning. In particular, we find that higher education in the context of less favorable neighborhood environments does not confer the same benefits to cognitive functioning among all older adults.

Social and behavioral science at the forefront of genomics: Discovery, translation, and health equity

This special issue highlights the unique role that social and behavioral science has to play at the forefront of genomics. Through the introduction of papers comprising this special issue, we outline priority research areas at the nexus of genomics and the social and behavioral sciences. These include: Discovery science; clinical and community translation, and equity, including engagement and inclusion of diverse populations in genomic science. We advocate for genomic discovery that considers social context, neural, cognitive, and behavioral endophenotypes, and that is grounded in social and behavioral science research and theory. Further, the social and behavioral sciences should play a leadership role in identifying best practices for effective clinical and community translation of genomic discoveries. Finally, inclusive research that engages diverse populations is necessary for genomic discovery and translation to benefit all. We also highlight ways that genomics can be a fruitful testbed for the development and refinement of social and behavioral science theory. Indeed, an expanded ecological lens that runs from genomes to society will be required to fully understand human behavior.

Apolipoprotein E Polymorphism and Frailty: Apolipoprotein ε4 Allele Is Associated with Fatigue but Not Frailty Syndrome in a Community-Dwelling Older Population Cohort

OBJECTIVE

Frailty is known to be influenced by genetics, however, little evidence on the association of Apolipoprotein E (ApoE) genotype and frailty exists which we aim to investigate.

DESIGN

This study is a cross-sectional analysis from a prospective longitudinal study cohort.

SETTING AND PARTICIPANTS

Community-dwelling individuals aged 55 years and older from Beijing region in China.

MEASUREMENTS

A total of 3,569 older adults with a mean age of 75.06(±6.79) years were included. We investigated the association between ApoE polymorphism and frailty syndrome using the frailty index (FI) and frailty phenotype (including association with individual components of the frailty phenotype). Logistic regressions were performed to investigate the relation between ApoE variants and frailty.

RESULTS

There was no significant association between ApoE variants and frailty as assessed by the FI. In the age and sex-adjusted model, compared to the ApoE e3/e3 carriers ApoE e4 carriers had almost 1.5 times higher odds of being frail as assessed by the frailty phenotype. However, the significance was lost on the model with adjustment for cognitive impairment. Compared to the ApoE e3/e3 carriers ApoE e4 carriers had almost two times higher odds of fatigue. ApoE e4 heterozygotes had higher odds of fatigue compared to ApoE e4 non-carriers. No significant association was found between ApoE variants and other components of frailty phenotype.

CONCLUSIONS

Our findings do not support an association between ApoE genotype and frailty irrespective of the frailty assessment tools. Fatigue in older adults is the only component of frailty phenotype influenced by ApoE genotype.

Influence of senior housing types on cognitive decline and nursing home admission among lower-income older adults

Objectives: Focusing on unique ageing populations in subsidized senior housing for lower-income older adults, this study contributes to literature on housing and aging; provides initial understanding of existing housing types; and explores the extent to which living in different housing types may influence changes in cognitive function and likelihood of nursing home admission.Method: Data came from seven waves (2002-2014) of the Health and Retirement Study. A latent-class clustering approach was used to identify senior-housing types among lower-income older people;Results: We identified four discernible housing types among lower-income older adults: (1) High physical & Low service, (2) Low physical & Low service, (3) High physical & High service, and (4) Medium physical & High service. Individuals in Medium physical & High service and High physical & Low service types were likely to have higher cognitive-function levels at baseline (B = 0.58, p < .001; 0.58, p < .001) and slower rates of decline over time (B = 0.42, p < .001; B = 0.32, p < .01). Older adults in High physical & High service are significantly less likely to be admitted to a nursing home (OR = 0.55, p < .00).Conclusion: The mismatch between health needs and lack of service and support suggests that current residents in each housing type relocate, based on knowledge of subsidized housing or availability. Future studies should examine possible mismatches between health needs and housing environment.

Individual and neighbourhood socioeconomic inequalities in cognitive impairment: cross-sectional findings from the French CONSTANCES cohort

OBJECTIVES

Despite the recent awareness of the environment impact on brain ageing, the influence of the neighbourhood socioeconomic status on cognitive impairment remains unclear. Here, we investigated the effects of individual and neighbourhood deprivation on cognitive impairment in middle-aged and young-old people.

DESIGN

Cross-sectional study.

SETTINGS

21 Health Screening Centres in the entire French metropolitan territory.

PARTICIPANTS

A total of 44 648 participants (age range: 45 to 69 years) from the French CONSTANCES cohort were included in the analyses.

MAIN OUTCOMES

Associations between the overall cognitive score (based on a standardised battery of cognitive tests administered by neuropsychologists) and individual deprivation (Evaluation of Deprivation and Inequalities in Health Screening Centres; EPICES score) and geographical deprivation (French Deprivation Index; FDep index).

RESULTS

Based on the EPICES score (validated cut-off ≥30.17), 12% of participants were considered to be deprived. After mutual adjustment, individual and geographical deprivation were associated with higher cognitive impairment in a multilevel logistic regression analysis that was also adjusted for sociodemographic, lifestyle and health factors. Specifically, individual deprivation was associated with an odds increase of 55% (OR=1.55, 95% CI: 1.45 to 1.66). The risk of global cognitive impairment progressively increased with the neighbourhood deprivation level, evaluated by the FDep index (reference Q1; Q2: OR=1.09, 95% CI: 0.98 to 1.20; Q3: OR=1.15, 95% CI: 1.04 to 1.27; Q4: OR=1.15, 95% CI: 1.04 to 1.28; Q5: OR=1.25, 95% CI: 1.13 to 1.39).

CONCLUSION

Our results suggest that the neighbourhood socioeconomic deprivation level is associated with cognitive impairment, independently of the individual deprivation level. A better understanding of this association could help to define new prevention strategies to target high-risk residents and high-risk geographical areas in order to reduce social health inequalities.

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.

Building the evidence for an ecological model of cognitive health

This is a commentary on Besser and colleagues' article "Associations between neighbourhood built environment and cognition vary by apolipoprotein E genotype: Multi-Ethnic Study on Atherosclerosis" published in Health & Place. Unlike previous studies, the authors found significant environment-cognition associations in apolipoprotein E (APOE) ε2 carriers and no significant associations in ε4 carriers. This commentary discusses the possible reasons for these findings and, in doing so, proposes an ecological model of cognitive health. The model highlights the importance of accounting for multiple environmental influences including the built and natural environment and air and noise pollution indicators. It also stresses the importance of studying the underlying biological mechanisms explaining differences in environment-cognition associations across APOE genotype categories.

Associations between neighborhood built environment and cognition vary by apolipoprotein E genotype: Multi-Ethnic Study of Atherosclerosis

We examined whether neighborhood built environment (BE) and cognition associations in older adults vary by apolipoprotein E (APOE) genotype, a genetic risk factor for Alzheimer's disease (AD). We conducted a cross-sectional analysis of 4091 participants. Neighborhood characteristics included social and walking destination density (SDD, WDD), intersection density, and proportion of land dedicated to retail. Individuals were categorized as APOE ε2 (lower AD risk), APOE ε4 (higher AD risk), or APOE ε3 carriers. Among APOE ε2 carriers, greater proportion of land dedicated to retail was associated with better global cognition, and greater SDD, WDD, intersection density, and proportion of land dedicated to retail was associated with better processing speed. These associations were not observed in APOE ε3 or ε4 carriers. APOE ε2 carriers may be more susceptible to the potentially beneficial effects of denser neighborhood BEs on cognition; however, longitudinal studies are needed.

Preventing Cognitive Decline in Black Individuals With Mild Cognitive Impairment: A Randomized Clinical Trial

Importance

Mild cognitive impairment (MCI) is a transition state between normal cognitive aging and dementia that increases the risk for progressive cognitive decline. Preventing cognitive decline is a public health priority.

Objective

To determine whether behavioral activation prevents cognitive and functional decline over 2 years in black individuals with MCI.

Design, Setting, and Participants

Single-center, single-masked, attention-controlled randomized clinical trial. Participants were enrolled from June 21, 2011, to October 3, 2014, and follow-up ended December 13, 2016. Community-based recruitment and treatment of black individuals older than 65 years with amnestic MCI. Volunteer sample of 1390 persons with memory complaints were screened. Overall, 536 individuals had baseline assessment, and 315 (58.8%) were ineligible, most often owing to normal cognition (205 of 315 [65%]) or dementia (59 of 315 [18.7%]); 221 fully eligible participants were randomized. Analyses were intention to treat.

Interventions

Participants were randomized to behavioral activation, which aimed to increase cognitive, physical, and social activity (111 [50.2%]), or supportive therapy, an attention control treatment (110 [49.8%]).

Main Outcomes and Measures

The prespecified primary outcome was a decline of 6 or more recalled words on the total recall score of the Hopkins Verbal Learning Test-Revised assessed at 6, 12, 18, and 24 months. The secondary outcome was functional decline.

Results

Of 221 randomized participants (mean [SD] age, 75.8 [7.0] years, 175 women [79%]), 77 behavioral activation participants (69.4%) and 87 supportive therapy participants (79.1%) had 2-year outcome assessments. After baseline, behavioral activation participants engaged in significantly more cognitive activities than supportive therapy participants. The 2-year incidence of memory decline was 1.2% (95% CI, 0.2-6.4) for behavioral activation vs 9.3% (95% CI, 5.30-16.4) for supportive therapy (relative risk, 0.12; 95% CI, 0.02-0.74; P = .02). Behavioral activation was associated with stable everyday function, whereas supportive therapy was associated with decline (difference in slopes, 2.71; 95% CI, 0.12-5.30; P = .04). Rates of serious adverse events for behavioral activation and supportive therapy, respectively, were: falls (14 [13%] vs 28 [25%]), emergency department visits (24 [22%] vs 24 [22%]), hospitalizations (36 [32%] vs 31 [28%]), and deaths (7 [5%] vs 3 [4%]).

Conclusions and Relevance

Behavioral activation prevented cognitive and functional decline, but this finding requires further investigation. Black individuals have almost twice the rate of dementia as white individuals; behavioral activation may reduce this health disparity.

Trial Registration

ClinicalTrials.gov Identifier: NCT01299766.

Person-Environment Fit Approach to Trajectories of Cognitive Function Among Older Adults Who Live Alone: Intersection of Life-Course SES Disadvantage and Senior Housing

OBJECTIVES

Drawing from life course and environmental perspectives, we examined the trajectory of cognitive function and how senior housing moderates the effects of life-course socioeconomic status (SES) disadvantage among older people living alone over time.

METHOD

Six waves of the Health and Retirement Study (HRS) were used with multilevel growth modeling to analyze developmental patterns of cognitive function over time and how various forms of life-course SES disadvantage affect cognitive function depending on senior housing residency status.

RESULTS

At baseline, we found a positive role of senior housing in four subgroups: SES disadvantage in childhood only, unstable mobility pattern (disadvantage in childhood and old age only), downward mobility (no disadvantage in childhood, but in later two life stages), and cumulative disadvantage (all three life stages). Over time, the positive role of senior housing for the unstable and the most vulnerable group persisted.

DISCUSSION

Our findings provide a much-needed practical and theoretical underpinning for environmental policy-making efforts regarding vulnerable elders who live alone.

The impact of rural-urban community settings on cognitive decline: results from a nationally-representative sample of seniors in China

BACKGROUND

Aging and rural-urban disparities are two major social problems in today's ever-developing China. Much of the existing literature has supported a negative association between adverse community setting with the cognitive functioning of seniors, but very few studies have empirically investigated the impact of rural-urban community settings on cognitive decline in the late life course of the population in developing countries.

METHODS

Data of seniors aged 65 or above (n = 1709) within CHARLS (The China Health and Retirement Longitudinal Study, a sister study of HRS), a nationally representative longitudinal cohort (2011-2015) in China, were analyzed using a multilevel modeling (MLM) of time within individuals, and individual within communities. Cognitive impairment was assessed with an adapted Chinese version of Mini-Mental State Examination.

RESULTS

Urban community setting showed a significant protective effect (β = - 1.978, p < .000) on cognitive impairment in simple linear regression, and the MLM results showed it also had a significant lower cognitive impairment baseline (β = - 2.278, p < .000). However, the curvature rate of cognitive decline was faster in urban community setting indicated by a positive interaction between the quadratic time term and urban community setting on cognitive impairment (β = 0.320, p < .05). A full model adjusting other individual SES factors was built after model fitness comparison, and the education factor accounted for most of the within and between community setting variance.

CONCLUSIONS

The findings suggest that urban community setting in one's late-life course has a better initial cognitive status but a potentially faster decline rate in China, and this particular pattern of senior cognitive decline emphasize the importance of more specific preventive measures. Meanwhile, a more holistic perspective should be adopted while construct a risk factor model of community environment on cognitive function, and the influence at society level needs to be further explored in future research.

Cognition in Context: The Role of Objective and Subjective Measures of Neighborhood and Household in Cognitive Functioning in Later Life

BACKGROUND AND OBJECTIVES

Although the role of place on health is not new, less is known about how place matters for cognition. By investigating both neighborhood and home as the sociospatial realms of older adults, we explore associations between health and place across multiple contexts. We also distinguish objective and subjective measures of place and disentangle their differential associations with cognition.

RESEARCH DESIGN AND METHODS

We analyzed place effects on cognition from the National Social Life, Health, and Aging Project (N = 2,260) linked to neighborhood characteristics and crime data. We measured place in four ways: (a) objective indicators of neighborhood such as police-reported crime rates and interviewer-reported on presence of disordered conditions on the streets; (b) perceptions of neighborhood by respondents (perceived danger and social cohesion); (c) objective conditions of home (interviewer's report on presence of clutters, odor, and messiness); (4) perceived social support, strain, and threat by household members. The MoCA-SA was used to assess cognitive functioning.

RESULTS

Subjective interpretations appeared to have more direct effects on cognition than did objective indicators of neighborhood or home. When examining these living environments together, we found the association between neighborhood and cognition is partially explained by characteristics of home environment, especially perceived social support. We found a buffering effect of social support on cognition for women, not for men.

DISCUSSION AND IMPLICATIONS

Late life living environments are important contexts for aging. Aging-in-Place interventions should address subjective interpretations of place to reduce future risks of cognitive decline.

Sex-specific association between neighborhood characteristics and dementia: The Three-City cohort

INTRODUCTION

The living environment affects general health and may influence cognitive aging; however, the relationships between neighborhood characteristics and dementia are still poorly understood.

METHODS

We used data from a French population-based prospective study (the Three-City cohort) that included 7016 participants aged 65 years and older with a 12-year follow-up. We used principal components analysis of neighborhood composition indicators to construct the Three-City deprivation score. To study its impact on dementia incidence, we performed survival analyses using a marginal Cox model to take into account intraneighborhood correlations. As interaction with sex was significant, analyses were stratified by sex.

RESULTS

Even after controlling on individual factors, women living in deprived neighborhoods were at higher risk of dementia (hazard ratio = 1.29, 95% confidence interval 1.00-1.67) and Alzheimer's disease (hazard ratio = 1.42, 95% confidence interval 1.09-1.84). No association was found for men.

DISCUSSION

Living in a deprived neighborhood is associated with higher risk of dementia in women.

Neighborhood Environment and Cognition in Older Adults: A Systematic Review

CONTEXT

Some evidence suggests that treating vascular risk factors and performing mentally stimulating activities may delay cognitive impairment onset in older adults. Exposure to a complex neighborhood environment may be one mechanism to help delay cognitive decline.

EVIDENCE ACQUISITION

PubMed, Web of Science, and ProQuest Dissertation and Theses Global database were systematically reviewed, identifying 25 studies published from February 1, 1989 to March 5, 2016 (data synthesized, May 3, 2015 to October 7, 2016). The review was restricted to quantitative studies focused on: (1) neighborhood social and built environment and cognition; and (2) community-dwelling adults aged ≥45 years.

EVIDENCE SYNTHESIS

The majority of studies were cross-sectional, U.S.-based, and found at least one significant association. The diversity of measures and neighborhood definitions limited the synthesis of findings in many instances. Evidence was moderately strong for an association between neighborhood SES and cognition, and modest for associations between neighborhood demographics, design, and destination accessibility and cognition. Most studies examining effect modification found significant associations, with some evidence for effect modification of the neighborhood SES-cognition association by individual-level SES. No studies had low risk of bias and many tested multiple associations that increased the chance of a statistically significant finding. Considering the studies to date, the evidence for an association between neighborhood characteristics and cognition is modest.

CONCLUSIONS

Future studies should include longitudinal measures of neighborhood characteristics and cognition; examine potential effect modifiers, such as sex and disability; and study mediators that may help elucidate the biological mechanisms linking neighborhood environment and cognition.

Cognitive functioning among Dutch older adults: Do neighborhood socioeconomic status and urbanity matter?

Positive associations of neighborhood socioeconomic characteristics and older adults' cognitive functioning have been demonstrated in previous studies, but overall results have been mixed and evidence from European countries and particularly the Netherlands is scarce. We investigated the effects of socioeconomic status (SES) and urbanity of neighborhoods on four domains of cognitive functioning in a sample of 985 Dutch older adults aged 65-88 years from the Longitudinal Aging Study Amsterdam. Besides cross-sectional level differences in general cognitive functioning, processing speed, problem solving and memory, we examined cognitive decline over a period of six years. Growth models in a multilevel framework were used to simultaneously assess levels and decline of cognitive functioning. In models not adjusting for individual SES, we found some evidence of higher levels of cognitive functioning in neighborhoods with a higher SES. In the same models, urbanity generally showed positive or inversely U-shaped associations with levels of cognitive functioning. Overall, effects of neighborhood urbanity remained significant when adjusting for individual SES. In contrast, level differences by neighborhood SES were largely explained by the respondents' individual SES. This suggests that neighborhood SES does not influence levels of cognitive functioning beyond the fact that individuals with a similar SES tend to self-select into neighborhoods with a corresponding SES. No evidence of systematically faster decline in neighborhoods with lower SES or lower degrees of urbanity was found. The findings suggest that neighborhood SES has no independent effect on older adults cognitive functioning in the Netherlands. Furthermore, the study reveals that neighborhood urbanity should be considered a determinant of cognitive functioning. This finding is in line with theoretical approaches that assume beneficial effects of exposure to complex environments on cognitive functioning. We encourage further investigations into the effect of urbanity in other contexts before drawing firm conclusions.

Does Apolipoprotein e4 Status Moderate the Association of Family Environment with Long-Term Child Functioning following Early Moderate to Severe Traumatic Brain Injury? A Preliminary Study

OBJECTIVES

To examine whether apolipoprotein e4 (APOE) status moderates the association of family environment with child functioning following early traumatic brain injury (TBI).

METHODS

Sixty-five children with moderate to severe TBI and 70 children with orthopedic injury (OI) completed assessments 6, 12, 18 months, and 3.5 and 6.8 years post injury. DNA was extracted from saliva samples and genotyped for APOE e4 status. Linear mixed models examined moderating effects of APOE e4 status on associations between two family environment factors (parenting style, home environment) and three child outcomes (executive functioning, behavioral adjustment, adaptive functioning).

RESULTS

Children with TBI who were carriers of the e4 allele showed poorer adaptive functioning relative to non-carriers with TBI and children with OI in the context of low authoritarianism. At high levels of authoritarianism, non-carriers with TBI showed the poorest adaptive functioning among groups. There were no main effects or interactions involving APOE and executive functioning or behavioral adjustment.

CONCLUSIONS

The APOE e4 allele was detrimental for long-term adaptive functioning in the context of positive parenting, whereas in less optimal parenting contexts, being a non-carrier was detrimental. We provide preliminary evidence for an interaction of APOE e4 status and parenting style in predicting long-term outcomes following early TBI. (JINS, 2016, 22, 859-864).

Associations of neighborhood environment with brain imaging outcomes in the Australian Imaging, Biomarkers and Lifestyle cohort

INTRODUCTION

"Walkable" neighborhoods offer older adults opportunities for activities that may benefit cognition-related biological mechanisms. These have not previously been examined in this context.

METHODS

We objectively assessed neighborhood walkability for participants (n = 146) from the Australian Imaging, Biomarkers and Lifestyle study with apolipoprotein E (APOE) genotype and two 18-month-apart brain volumetric and/or amyloid β burden assessments. Linear mixed models estimated associations of neighborhood walkability with levels and changes in brain imaging outcomes, the moderating effect of APOE ε4 status, and the extent to which associations were explained by physical activity.

RESULTS

Cross-sectionally, neighborhood walkability was predictive of better neuroimaging outcomes except for left hippocampal volume. These associations were to a small extent explained by physical activity. APOE ε4 carriers showed slower worsening of outcomes if living in walkable neighborhoods.

DISCUSSION

These findings indicate associations between neighborhood walkability and brain imaging measures (especially in APOE ε4 carriers) minimally attributable to physical activity.

Social support and cognition in a community-based cohort: the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

social support has demonstrated cross-sectional associations with greater cognitive function and a protective effect against cognitive decline in older adults, but exploration of its temporal role in cognitive ageing from mid-life to older adulthood has been limited. We aimed to quantify the associations of social support, assessed at mid-life, with cognitive function in mid-life and with cognitive decline into late life among African Americans and Caucasians.

METHODS

data from the community-based, prospective Atherosclerosis Risk in Communities (ARIC) cohort of 15,792 biracial participants were examined for baseline and longitudinal associations of mid-life social support with global cognition at mid-life and with 20-year change in global cognition, respectively, stratified by race. Interactions with sociodemographic and cardiometabolic covariates were additionally explored within each race group. Social support was ascertained using two metrics: interpersonal support and social network.

RESULTS

interpersonal support was directly associated with greater global cognition at baseline in both race groups. Social network was directly associated with greater global cognition at baseline among Caucasians and African American females, but it was not significantly associated with global cognition in African American males. Neither mid-life social support measure was associated with 20-year change in global cognition.

CONCLUSIONS

higher levels of social support were moderately associated with greater multi-dimensional cognitive function at mid-life, but mid-life social support was not associated with temporal change in global cognitive function over 20 years into late life. Prospective studies with time-dependent measures of social support and cognition are needed to better understand the role of social engagement in ageing-related cognitive functioning.

A randomized trial to measure the impact of a community-based cognitive training intervention on balance and gait in cognitively intact Black older adults

INTRODUCTION

Fall prevention is important for maintaining mobility and independence into old age. Approaches for reducing falls include exercise, tai chi, and home modifications; however, causes of falling are multifactorial and include not just physical but cognitive factors. Cognitive decline occurs with age, but older adults with the greatest declines in executive function experience more falls. The purpose of this study was twofold: to demonstrate the feasibility of a community-based cognitive training program for cognitively intact Black older adults and to analyze its impact on gait and balance in this population.

METHOD

This pilot study used a pretest/posttest randomized trial design with assignment to an intervention or control group. Participants assigned to the intervention completed a computer-based cognitive training class that met 2 days a week for 60 min over 10 weeks. Classes were held at senior/community centers. Primary outcomes included balance as measured by the Berg Balance Scale (BBS), 10-meter gait speed, and 10-meter gait speed under visuospatial dual-task condition. All measures were assessed at baseline and immediately post-intervention.

RESULTS

Participants were community-dwelling Black adults with a mean age of 72.5 and history of falls (N = 45). Compared to controls, intervention participants experienced statistically significant improvements in BBS and gait speed. Mean performance on distracted gait speed also improved more for intervention participants compared to controls.

CONCLUSION

Findings from this pilot randomized trial demonstrate the feasibility of a community-based cognitive training intervention. They provide initial evidence that cognitive training may be an efficacious approach toward improving balance and gait in older adults known to have a history of falls.

Genetic polymorphisms and traumatic brain injury: the contribution of individual differences to recovery

Recovery after Traumatic Brain Injury (TBI) is variable, even for patients with similar severity of brain injury. Recent research has highlighted the contribution that genetic predisposition plays in determining TBI outcome. This review considers the potential for genetic polymorphisms to influence recovery of cognitive and social processes following TBI. Limitations and considerations that researchers should make when assessing the potential impact of polymorphisms on TBI outcome are also discussed. Understanding the genetic factors that support neuroplasticity will contribute to an understanding of the variation in outcome following injury and help to identify potential targets for rehabilitation.

EFFECT OF THE APOE ε4 ALLELE AND COMBAT EXPOSURE ON PTSD AMONG IRAQ/AFGHANISTAN-ERA VETERANS

BACKGROUND

The apolipoprotein E (APOE) ε4 allele has been implicated in a range of neuropsychiatric conditions. The present research examined if the ε4 allele of the APOE gene moderated the effect of combat exposure on posttraumatic stress disorder (PTSD) among Iraq/Afghanistan-era veterans.

METHOD

Participants included 765 non-Hispanic White (NHW) and 859 non-Hispanic Black (NHB) Iraq/Afghanistan-era veterans. A structured interview established psychiatric diagnoses. Combat exposure and PTSD symptom severity were assessed via self-report.

RESULTS

The most common lifetime diagnoses were depression (39.2%), PTSD (38.4%), and alcohol dependence (24.38%). After correcting for multiple comparisons, no significant effects were observed on any of the outcomes among the NHW sample; however, within the NHB sample, significant gene × environment (G × E) interactions were observed for lifetime PTSD (P = .0029) and PTSD symptom severity (P = .0009). In each case, the APOE ε4 allele had no effect on the outcomes when combat exposure was low; however, when combat exposure was high, an additive effect was observed such that ε4 homozygotes exposed to high levels of combat reported the highest rates of PTSD (92%) and the worst symptom severity scores on the Davidson Trauma Scale (M = 79.5).

CONCLUSIONS

Although preliminary, these findings suggest that the APOE ε4 allele, in conjunction with exposure to high levels of combat exposure, may increase veterans' risk for developing PTSD.

The association between community environment and cognitive function: a systematic review

PURPOSES

The aim of this study is to review the published evidence on the association between community environment and cognitive function in older people, focusing on the findings and a critique of the existing studies.

METHODS

A literature search was conducted to identify studies linking the community environment and cognitive function in older people. The results and methodological factors, including the definition of community, individual level characteristics and the measurements of cognitive function and community environment were extracted from each study. The measurements of community environment were mainly categorized into two types: compositional, generated by aggregating individual and household data (community-level socioeconomic status, deprivation index) and contextual, targeting at the features of built or social environment in local areas (green space, street conditions, crime rate).

RESULTS

Fourteen of the fifteen studies used compositional measurements such as community-level socioeconomic status and deprivation index and significant associations were found in eleven studies. Some individual level factors (ethnicity, genotype and socioeconomic status) were found to modify the association between community environment and cognitive function. Few contextual measurements were included in the existing studies. A conceptual framework for the pathway from community environment to cognitive function of older people is provided in this review.

CONCLUSIONS

To disentangle the additional effect of place from individual risk factors and investigate the casual direction of community environment and cognition in later life, longitudinal studies with measurements targeting built and social environments of community and change of cognitive functions over time need to be included in future studies.

Interactions between the apolipoprotein E ε4 allele status and adverse childhood experiences on depressive symptoms in older adults

BACKGROUND

The influence of childhood adversity on depression is modulated by genetic vulnerability. The apolipoprotein E ε4 (APOE-ε4) allele is a strong genetic risk factor for Alzheimer's disease (AD). Because late-life depressive symptoms could be a part of the preclinical course of AD, the APOE-ε4 allele may contribute to depression in old age.

OBJECTIVE

The aim of this study was to evaluate whether an APOE-ε4 carrier status was associated with depressive symptoms in older adults and to detect the gene-environment interaction between APOE-ε4 status and childhood adversity in relation to depressive symptoms in old age.

METHOD

The participants consisted of 137 older adults (age range 50-70) without any psychiatric history or clinically significant cognitive impairment. APOE genotypes and measures of childhood adversity and depressive symptoms were obtained.

RESULTS

There was a significant positive association between adverse childhood experiences (ACE) scores and depressive symptoms (B=0.60; 95% CI=0.26, 0.93 for a 1 score increase in ACE scores; p=0.001). Although APOE-ε4 status per se was not associated with depressive symptoms, there was a significant interaction of the ACE scores with the APOE genotype in relation to depressive symptoms (B=0.78; 95% CI=0.02, 1.55; p=0.044). There was a significantly higher effect of childhood adversity on depressive symptoms in APOE-ε4 carriers than non-carriers (t=2.13, p=0.035).

CONCLUSIONS

Our results suggest that the APOE-ε4 may modulate the association between childhood adversity and depressive symptoms in older adults. However, more research in a larger sample is needed to gain a better understanding of the relationship between the APOE-ε4, childhood adversity, and depression.

The influence of neighborhood characteristics on police officers' encounters with persons suspected to have a serious mental illness

OBJECTIVE

Police officers' decisions and behaviors are impacted by the neighborhood context in which police encounters occur. For example, officers may use greater force and be more likely to make arrests in disadvantaged neighborhoods. We examined whether neighborhood characteristics influence police encounters with individuals suspected to have a serious mental illness, addictive disorder, or developmental disability.

METHOD

We obtained data on 916 encounters from 166 officers in six jurisdictions in Georgia, USA and abstracted geographical data pertaining to the location of these encounters from United States Decennial Census data. Encounters were nested within 163 census tracts. Officer-reported data covered general encounter characteristics, the officer's perception of the subject's condition, subject demographics, use of force, and disposition of the encounter (e.g., arrest v. referral or transport to treatment services). Geographical data included 17 variables representing population and housing characteristics of the census tracts, from which three indices pertaining to neighborhood income, stability, and immigration status were derived using factor-analytic techniques. We then examined associations of these indices with various encounter-related variables using multi-level analysis.

RESULTS

Encounters taking place in higher-income and higher-stability census tracts were more likely to be dispatch-initiated and take place in a private home compared to those in lower-income and lower-stability neighborhoods. In higher-income neighborhoods, encounters were more likely to involve a subject suspected to have a mental illness (as opposed to an addictive disorder or developmental disability) and less likely to involve a subject suspected to have alcohol problems. The officer's level of force used was not associated with neighborhood factors. Regarding disposition, although the likelihood of arrest was unrelated to neighborhood characteristics, encounters taking place in higher-immigrant neighborhoods were more likely to result in referral or transport to services than those in lower-immigrant neighborhoods.

CONCLUSION

Neighborhood characteristics are important to consider in research on police interactions with individuals with serious mental illnesses, addictive disorders, or developmental disabilities. Such research could inform departmental training policies and procedures based on the needs of the jurisdictions served.

Stress, race, and APOE: understanding the interplay of risk factors for changes in cognitive functioning

OBJECTIVES

Biological and environmental factors are thought to contribute to the development of cognitive decline (CD). The Apolipoprotein E (APOE) ϵ4 allele is the greatest known genetic risk factor. The current study focused on the extent to which environmental factors, specifically stress, influence the relationship between the APOE allele and cognitive functioning and whether this relationship is stronger for African-Americans compared to Caucasians.

METHODS

Participants consisted of community-dwelling older adults from the Duke Established Populations for Epidemiologic Studies of the Elderly (N = 4,162). Data were drawn from two waves, which were three years apart. Cognitive functioning was assessed at both waves using the Short Portable Mental Status (SPMSQ).

RESULTS

Whereas there was no main effect of stress, there was a significant interaction between APOE status and stressful life events, such that increased stress in individuals with an ϵ4 allele lead to more errors on the SPMSQ than individuals with no allele. Inconsistent with predictions, there was a significant interaction between stress and race such that increased stressful events predicted CD in Caucasians but not African-Americans.

CONCLUSIONS

Recent stressful late-life events have a greater impact on the cognitive status of individuals with an ϵ4 allele. While Caucasians appear to be less vulnerable to cognitive losses at lower levels of stress, as the number of stressful life events increases that advantage disappears for Caucasians.

Interaction of APOE genotype and testosterone on episodic memory in middle-aged men

Age-related changes in testosterone are believed to be a key component of the processes that contribute to cognitive aging in men. The APOE-ε4 allele may interact with testosterone and moderate the hormone's association with cognition. The goals of the present study were to examine the degree to which free testosterone is associated with episodic memory in a community-based sample of middle-aged men, and examine the potential interaction between free testosterone and the APOE-ε4 allele. Data were used from 717 participants in the Vietnam Era Twin Study of Aging. Average age was 55.4 years (standard deviation = 2.5). Significant positive associations were observed between free testosterone level and verbal episodic memory, as well as a significant interaction between free testosterone and APOE-ε4 status. In ε4 carriers free testosterone was positively associated with verbal episodic memory performance (story recall), whereas no association was observed in ε4 noncarriers. Results support the hypothesis that APOE-ε4 status increases susceptibility to other risk factors, such as low testosterone, which may ultimately contribute to cognitive decline or dementia.

Cultural diversity and views on Alzheimer disease in older African Americans

Cultural constructs prevalent in older African Americans may influence their risk perceptions and knowledge of Alzheimer disease (AD). To examine this issue, we administered 3 sociocultural scales, the AD Knowledge Scale, and a Risk Perception questionnaire to 271 older African Americans who were recruited from a large community senior center and local churches. Higher Present Time Orientation was significantly related to perceptions of having little control over risks to health (P=0.004), God's Will in determining AD (P=0.001), and lower AD knowledge (P<0.0001) and marginally related to having little control over developing AD (P=0.052). Religiosity was marginally related to having little control over risks to health (P=0.055) and getting AD (P=0.057). Post hoc intergroup comparisons found significant differences in the highest versus lowest scoring Religiosity groups. There were no significant differences by Future Time Orientation. Most subjects (57.6%) were unaware that African Americans were at higher risk for AD than whites. These data indicate that cultural diversity within older African Americans may shape health perceptions and knowledge of AD. This diversity may contribute to disparities in the detection and treatment of AD in this high-risk population.

Gene-environment interaction of ApoE genotype and combat exposure on PTSD

Factors determining who develops PTSD following trauma are not well understood. The €4 allele of the apolipoprotein E (apoE) gene is associated with dementia and unfavorable outcome following brain insult. PTSD is also associated with dementia. Given evidence that psychological trauma adversely affects the brain, we hypothesized that the apoE genotype moderates effects of psychological trauma on PTSD pathogenesis. To investigate the moderation of the relationship between PTSD symptoms and combat exposure, we used 172 participants with combat trauma sustained during the Vietnam War. PTSD symptoms were the dependent variable and number of combat experiences, apoE genotype, and the combat experiences × apoE genotype interaction were predictors. We also examined the outcome of a diagnosis of PTSD (n = 39) versus no PTSD diagnosis (n = 131). The combat × apoE genotype interaction was significant for both PTSD symptoms (P = .014) and PTSD diagnosis (P = .009). ApoE genotype moderates the relationship between combat exposure and PTSD symptoms. Although the pathophysiology of PTSD is not well understood, the €4 allele is related to reduced resilience of the brain to insult. Our results are consistent with the €4 allele influencing the effects of psychological trauma on the brain, thereby affecting the risk of PTSD.

Evidence that the wider social environment moderates the association between familial liability and psychosis spectrum outcome

BACKGROUND

Familial liability to both severe and common mental disorder predicts psychotic disorder and psychotic symptoms, and may be used as a proxy in models examining interaction between genetic risk and the environment at individual and contextual levels.

METHOD

In a representative general population sample (n=4011) in Izmir, Turkey, the full spectrum of expression of psychosis representing (0) no symptoms, (1) subclinical psychotic experiences, (2) low-impact psychotic symptoms, (3) high-impact psychotic symptoms and (4) full-blown clinical psychotic disorder was assessed in relation to mental health problems in the family (proxy for familial liability) and the wider social environment. Quality of the wider social environment was assessed in an independent sample using contextual measures of informal social control, social disorganization, unemployment and low income, aggregated to the neighbourhood level.

RESULTS

The association between familial liability to severe mental illness and expression of psychosis spectrum was stronger in more deprived neighbourhoods [e.g. this association increased from β=0.33 (p=0.01) in low-unemployment neighbourhoods to β=0.92 (p<0.001) in high-unemployment neighbourhoods] and in neighbourhoods high in social control, while neighbourhood variables did not modify the association between familial liability to common mental disorder and the psychosis outcome. Neighbourhood variables mediated urbanicity effects.

CONCLUSIONS

Contextual effects may be important in moderating the expression of psychosis liability in populations, representing a specific pathway independent of the link between common mental disorder and psychosis.

Gene by neuroticism interaction and cognitive function among older adults

OBJECTIVES

Both apolipoprotein E (ApoE) ε-4 allele(s) and elevated trait neuroticism, the tendency to experience distress, are associated with cognitive function among older adults. We predicted that neuroticism moderates the association between ApoE and cognitive function and also explored whether other personality dimensions (openness to experience, agreeableness, extraversion, and conscientiousness) affect the association between ApoE status and cognitive function.

METHOD

Five-hundred and ninety-seven older adults (mean age of 78 years) enrolled in the Ginkgo Evaluation of Memory study completed the NEO five-factor inventory of personality. Cognitive function was assessed via the cognitive portion of the Alzheimer's Disease Assessment Scale, and a blood sample for ApoE genotyping was drawn.

RESULTS

As hypothesized, regression analysis indicated that neuroticism moderated the relationship between the presence of ApoE ε-4 and cognitive function. Individuals with high neuroticism scores had significantly lower scores on the cognitive portion of the Alzheimer's Disease Assessment Scale compared with individuals with low neuroticism scores, but this was true only among carriers of ApoE ε-4 (interaction effect β = 0.124, p = 0.028). There was scant evidence that other personality dimensions moderate the association between ApoE ε-4 and cognitive function.

CONCLUSIONS

Cognitive function may be affected by ApoE and neuroticism acting in tandem. Research on the underlying physiological mechanisms by which neuroticism amplifies the effect of ApoE ε-4 is warranted. The study of genotype by phenotype interactions provides an important and useful direction for the study of cognitive function among older adults and for the development of novel prevention programs.

Neighborhood Influences on Late Life Cognition in the ACTIVE Study

Low neighborhood-level socioeconomic status has been associated with poorer health, reduced physical activity, increased psychological stress, and less neighborhood-based social support. These outcomes are correlates of late life cognition, but few studies have specifically investigated the neighborhood as a unique source of explanatory variance in cognitive aging. This study supplemented baseline cognitive data from the ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly) study with neighborhood-level data to investigate (1) whether neighborhood socioeconomic position (SEP) predicts cognitive level, and if so, whether it differentially predicts performance in general and specific domains of cognition and (2) whether neighborhood SEP predicts differences in response to short-term cognitive intervention for memory, reasoning, or processing speed. Neighborhood SEP positively predicted vocabulary, but did not predict other general or specific measures of cognitive level, and did not predict individual differences in response to cognitive intervention.

Social disorder, APOE-E4 genotype, and change in cognitive function among older adults living in Chicago

The goal of this paper is to describe the simultaneous influence of social and genetic risk factors on declines in cognitive functioning among older American adults. We use detailed information about the social characteristics of older adults' neighborhoods from the Chicago Health and Aging Project (n = 1655; ages 65+) in conjunction with information about respondent's APOE genotype to predict changes in cognitive function over time. Results indicate that the presence of the ε4 allele is associated with a significantly lower cognitive function score at baseline and greater declines in cognitive function compared to those without this risk allele. Importantly, we also show significant variation in the effect of the ε4 allele across neighborhoods and our results indicate that this genotype is more strongly associated with cognitive function for residents of neighborhoods with the lowest levels of social disorder. Our findings support the non-causal social push gene-environment interaction model.