Neighborhood Environments and Cognitive Decline Among Middle-Aged and Older People in China

Household Environments and Functional Decline Among Middle-Aged and Older Adults in China: Variations by Gender, Age, and Residence

This study examined the associations between household social, economic, and physical environments and the trajectory of functional limitations over time among middle-aged and older adults in China, and how this relationship differs by gender, age, and residence. Linear growth curve models were applied to a sample of 13,564 respondents aged 45 years and older from four waves of the China Health and Retirement Longitudinal Study (CHARLS 2011-2018). Living alone, particularly for rural, female, and older respondents, was associated with a faster functional decline when compared to living with a spouse and without children. Improved housing quality was associated with a slower functional decline. Living with young descendants and without adult children for urban residents and a lower expenditure per capita for younger respondents were associated with a faster functional decline. These findings suggest that policies aimed at enhancing living conditions have the potential to improve physical functioning of older adults.

Neighbourhood environments and cognitive health in the longitudinal Personality and Total Health (PATH) through life study: A 12-year follow-up of older Australians

BACKGROUND

Urban neighbourhood environments may impact older adults' cognitive health. However, longitudinal studies examining key environmental correlates of cognitive health are lacking. We estimated cross-sectional and longitudinal associations of neighbourhood built and natural environments and ambient air pollution with multiple cognitive health outcomes in Australian urban dwellers aged 60+ years.

METHODS

The study included 1160 participants of the PATH Through Life study (60+ cohort) who were followed up for 12 years (four assessments; 2001/02 to 2013/15) and with data on socio-demographics, health, cognitive functions and diagnoses, and full residential address. Neighbourhood environmental features encompassed population and street-intersection densities, non-commercial land use mix, transit points, presence of blue space, percentages of commercial land, parkland and tree cover, and annual average PM2.5 and NO2 concentrations. All exposures except for tree cover were assessed at two time points. Generalised additive mixed models estimated associations of person-level average, and within-person changes in, exposures with cognitive functions. Multi-state hidden Markov models estimated the associations of neighbourhood attributes with transitions to/from mild cognitive impairment (MCI).

RESULTS

Dense, destination-rich neighbourhoods were associated with a lower likelihood of transition to MCI and reversal to no MCI. Positive cross-sectional and longitudinal associations of non-commercial land use mix, street intersection density and percentage of commercial land were observed especially with global cognition and processing speed. While access to parkland and blue spaces were associated with a lower risk of transition to MCI, the findings related to cognitive functions were mixed and supportive of an effect of parkland on verbal memory only. Higher levels of PM2.5 and NO2 were consistently associated with steeper declines and/or decreases in cognitive functions and worse cognitive states across time.

CONCLUSION

To support cognitive health in ageing populations, neighbourhoods need to provide an optimal mix of environmental complexity, destinations and access to the natural environment and, at the same time, minimise ambient air pollution.

Hukou Status and Cognitive Function Among Older Chinese Adults: Does Support from Friends Matter?

OBJECTIVES

This study examined whether older Chinese adults with different types of hukou status (government household registration system) exhibited different cognitive outcomes and whether receiving support from friends, an under-appreciated resource, helped mitigate the negative impacts of agricultural hukou status on cognitive health disparities.

METHODS

Using nationally representative data from the China Longitudinal Aging Social Survey, this study tested these relationships with well-validated measures.

RESULTS

Our results showed that older Chinese adults with agricultural hukou were more likely to have worse cognitive function than those with non-agricultural hukou. Further, friend support characteristics moderated the association between hukou status and cognitive function, whereby having better friend support was related to a weaker negative effect of agricultural hukou status on cognitive function.

DISCUSSION

The findings suggested that agricultural hukou status reflects the effects of accumulated disadvantage across the life course with negative consequences for late-life cognition. The cognitive health disparities between agricultural and non-agricultural residents may be reduced in the context of a higher level of friend support, supporting a stress buffering hypothesis.

Potential transition of depression of older adults affected by socioeconomic status show different styles: A longitudinal study of Chinese older adults

Socioeconomic status' (SES) impact on depressive symptoms has been extensively examined; however, previous studies have generally used variable-centered approaches and cross-sectional designs. Therefore, this study explored the subtypes of depression and examined the degree of association between SES and latent transition probabilities. We used latent profile and latent transition analyses with the 2015 and 2018 waves of data from the China Health and Retirement Longitudinal Study (N = 4904). Three subtypes of depression were identified based on symptoms: severe symptom (SS), low symptom (LS), and sub-health (MS). The SS subtype had the highest probability of staying within the original subtype. Individuals in the MS subtype were more likely to move to the SS subtype than those in the LS subtype. The heterogeneity analysis also showed that the effect of SES on latent transition probabilities is heterogeneous to the satisfaction with their relationship with their children, as well as the number of children. Additionally, decision tree analysis found SES and gender can predict transitioning. These findings add to literature on the effects of SES on the heterogeneity of depression and have implications for depression screening and identifying individuals in need of targeted interventions.

Household Environments and Cognitive Decline Among Middle-Aged and Older Adults in China: Exploring Gender, Age, and Residential Variations

This study examined the relationship between household environments and trajectories of cognitive function among middle-aged and older adults in China and its urban/rural, gender, and age variations. We estimated multi-level linear growth curve models using a representative sample of 16,111 respondents aged 45 years and over from the China Health and Retirement Longitudinal Study (2011-2018). Older people who lived with a spouse, but not with children, and those with higher living expenditures, better housing quality, and indoor clean fuels for cooking had a slower cognitive decline. Living arrangement more strongly predicted men's cognitive decline, while living expenditure, solid fuel use, and housing quality significantly predicted only women's cognitive decline. Only for older adults and rural residents, those living alone had significantly faster cognitive decline than those living with a spouse only. These findings underscore the importance of improving the living conditions of older adults to help alleviate their cognitive decline.

Perceived Neighborhood Conditions, Psychosocial Factors, and Sleep Problems Among Urban and Rural Older Adults in China

OBJECTIVES

To examine the associations between perceived neighborhood conditions and older Chinese adults' sleep problems, and whether these associations are mediated by psychosocial factors and moderated by urban-rural residence.

METHODS

Data were from the World Health Organization Study on global Ageing and Adult Health. We used OLS, binary, and multinomial logistic regression analyses. Karlson-Holm-Breen decomposition method was used to test mediation effects.

RESULTS

Positively perceived neighborhood social cohesion was associated with fewer insomnia symptoms and decreased odds of poor sleep quality, sleepiness, lethargy, and short sleep duration. Positively perceived neighborhood safety was related to decreased risks of poor sleep quality and sleepiness. Depression and perceived control partially mediated the effects of perceived neighborhood on sleep. Furthermore, the protective effects of neighborhood cohesion against sleep problems were more pronounced among older urban adults than their rural counterparts.

DISCUSSION

Interventions that make neighborhoods safer and more integrated will improve late-life sleep health.

Post-traumatic growth in later-life cognitive function? Evidence from the 1976 Great Tangshan Earthquake

OBJECTIVES

This study aimed to explore the long-term impacts of exposure to earthquake in adolescence on later-life cognitive function in China.

METHODS

Data were from the 2015 China Health and Retirement Longitudinal Study (CHARLS). Our analytical sample comprised 4394 participants aged 49 to 78 from two birth cohorts born between 1937 and 1966: exposed cohort during adolescence (born between 1952 and 1966), and non-exposed cohort during adolescence (born between 1937 and 1951). We defined earthquake exposure as the exposure severity of the 1976 Great Tangshan Earthquake (GTE). We selected community environmental characteristics as our key moderators. A difference-in-differences (DID) method was employed to estimate the long-term impact of the GTE on later-life cognitive function.

RESULTS

We found that exposure to the earthquake during adolescence resulted in higher scores of later-life cognitive function (for males: β = 2.18; 95% CI: 0.70-3.66; for females: β = 1.22; 95% CI: 0.11-2.33). For males, this impact was moderated by community environmental characteristics including the old-age allowance program (β = 3.07; 95% CI: 1.94-4.19) and the condition of basic community infrastructures (β = 1.52; 95% CI: 0.84-2.19).

CONCLUSIONS

Our study supports the post-traumatic growth theory. This finding suggest that individuals with early-life traumatic exposure need to be focused on. Additionally, improving the conditions of community infrastructures and establishing a community environment with comfort and security may be pretty important for promoting cognitive function and post-traumatic growth.

Systematic Review of Longitudinal Evidence and Methodologies for Research on Neighborhood Characteristics and Brain Health

Objective: Synthesize longitudinal research evaluating neighborhood environments and cognition to identify methodological approaches, findings, and gaps. Methods: Included studies evaluated associations between neighborhood and cognition longitudinally among adults >45 years (or mean age of 65 years) living in developed nations. We extracted data on sample characteristics, exposures, outcomes, methods, overall findings, and assessment of disparities. Results: Forty studies met our inclusion criteria. Most (65%) measured exposure only once and a majority focused on green space and/or blue space (water), neighborhood socioeconomic status, and recreation/physical activity facilities. Similarly, over half studied incident impairment, cognitive function or decline (70%), with one examining MRI (2.5%) or Alzheimer's disease (7.5%). While most studies used repeated measures analysis to evaluate changes in the brain health outcome (51%), many studies did not account for any type of correlation within neighborhoods (35%). Less than half evaluated effect modification by race/ethnicity, socioeconomic status, and/or sex/gender. Evidence was mixed and dependent on exposure or outcome assessed. Conclusion: Although longitudinal research evaluating neighborhood and cognitive decline has expanded, gaps remain in types of exposures, outcomes, analytic approaches, and sample diversity.

Spatial scale effects on associations between built environment and cognitive function: Multi-Ethnic Study of Atherosclerosis

Built environments have the potential to favorably support cognitive function. Despite growing work on this topic, most of the work has ignored variation in the spatial scale of the effect. The issue with spatial scale effects is that the size and shape of the areal unit within which built environment characteristics are measured naturally influence the built environment exposure metric and thus the estimated associations with health. We used spatial distributed lag modeling (DLM) to estimate how associations between built environment exposures (walkable destinations [WD], social destinations [SD]) and change in cognition varied across distance of these destinations from participants' residences. Cognition was assessed as maintained/improved processing speed (PS) and global cognition (GC). Person-level data from Exam 5 (2010-2012) and Exam 6 (2016-2018) of the Multi-Ethnic Study of Atherosclerosis was used (N = 1380, mean age 67). Built environment data were derived from the National Establishment Time Series. Higher availability of walkable and social destinations at closer distance from participants' residence was associated with maintained/improved PS. The adjusted associations between maintained/improved PS and destinations waned with increasing distance from the residence; associations were evident until approximately 1.9-km for WD and 1.5-km for SD. Associations were most apparent for participants living in areas with high population density. We found little evidence for associations between change in GC and built environment at any distance. These results highlight the importance of identifying appropriate spatial scale to understand the mechanisms for built environment-cognition associations.

Effects of neighborhood built environment on cognitive function in older adults: a systematic review

BACKGROUND

In the background of an aging population, the risk of cognitive impairment in the older population is prominent. Exposure to complex neighborhood built environments may be beneficial to the cognitive health of older adults, and the purpose of this study was to systematically review the scientific evidence on the effects of neighborhood built environments on cognitive function in older adults.

METHODS

Keywords and references were searched in Web of Science, Pubmed, PsycINFO, and MEDLINE. Studies examining the relationship between the built environment and cognitive function in older adults were included. The neighborhood built environment as an independent variable was classified according to seven aspects: density, design, diversity, destination accessibility, public transportation distance, blue/green space, and built environment quality. The cognitive function as the dependent variable was classified according to overall cognitive function, domain-specific cognitive function, and incidence of dementia. The quality of the included literature was assessed using the National Institutes of Health's Observational Cohort and Cross-Sectional Study Quality Assessment Tool.

RESULTS

A total of 56 studies were included that met the inclusion criteria, including 31 cross-sectional studies, 23 longitudinal studies, 1 cross-sectional study design combined with a case-control design, and 1 longitudinal study design combined with a case-control design. Most of the studies reviewed indicate that the built environment factors that were positively associated with cognitive function in older adults were population density, street connectivity, walkability, number of public transportation stops around the residence, land use mix, neighborhood resources, green space, and quality of the neighborhood built environment. Built environment factors that were negatively associated with cognitive function in older adults were street integration, distance from residence to main road. The relationship between residential density, destination accessibility, and blue space with cognitive function in older adults needs to be further explored.

CONCLUSION

Preliminary evidence suggests an association between the neighborhood built environment and cognitive function in older adults. The causal relationship between the built environment and cognitive function can be further explored in the future using standardized and combined subjective and objective assessment methods, and longitudinal or quasi-experimental study designs. For public health interventions on the cognitive health of older adults, it is recommended that relevant authorities include the neighborhood built environment in their intervention programs.

The effects of neighborhood socioeconomic status on ADL/IADL among Chinese older adults-neighborhood environments as mediators

Background

There have been few consistencies in the effects and pathways of neighborhood socioeconomic status (SES) on functional limitations. This study aimed to investigate whether neighborhood socioeconomic status influences ADL/IADL in older residents in China through the neighborhood built environment and social environment.

Methods

Activities of daily living/IADL were assessed in a sample of 5,887 Chinese individuals aged 60 or older, utilizing data obtained from the 2011 China Health and Retirement Longitudinal Study (CHARLS 2011). Neighborhood SES was measured by the neighborhood per-capita net income. Neighborhood built environment was measured by the security resources, motion resources, living resources, service resources for older adults, and medical resources of neighborhood. Neighborhood social environment was measured by the organizations, unemployment subsidies, minimum living allowance, subsidies to persons older than 65, and pensions to persons older than 80 of the neighborhood. The two-level logistical regression model and multilevel structural equation model (MSEM) were used.

Results

The rate of ADL/IADL loss among Chinese older adults aged 60 and above in 2011 were 32.17 and 36.87%, respectively. Neighborhood SES was significantly associated with ADL/IADL in older adults. Compared with the respondents living in communities with lower SES, those living in communities with higher SES possessed better ADL (β = -0.33, p < 0.05) and IADL (β = -0.36, p < 0.05) status. The path of neighborhood socioeconomic status on ADL was completely mediated by the neighborhood built environment (β = -0.110, p < 0.05) and neighborhood social environment (β = -0.091, p < 0.05). Additionally, the effect of neighborhood socioeconomic status on IADL was fully mediated by the neighborhood built environment (β = -0.082, p < 0.05) and neighborhood social environment (β = -0.077, p < 0.05).

Conclusion

Neighborhood SES was significantly correlated with ADL/IADL through the neighborhood environment. Improving the ADL/IADL status of older adults residing in low socioeconomic neighborhoods requires enhancing the built and social environment by provisioning additional neighborhood resources.

Monitoring and Evaluation of Dementia-Friendly Neighborhoods Using a Walkshed Approach: Protocol for a Scoping Review

BACKGROUND

The number of people in society living with dementia is growing. In Canada, most people who live with dementia live at home, often in a neighborhood setting. Neighborhood environments can be a source of independence, social engagement, and well-being. They can also contain barriers that limit physical activity, social engagement, and well-being. A dementia-friendly neighborhood includes assets that support persons living with dementia and their caregivers in multiple life domains, including those that support walking within the neighborhood environment.

OBJECTIVE

The objectives for this scoping review are twofold. First, focusing on walkshed analysis, we aim to extend scholarly understandings of methodological practices used in the monitoring and evaluation of dementia-friendly neighborhoods. Second, we aim to provide clear and practical guidance for those working in planning, design, and public health fields to assess the neighborhood context in support of evidence-based action to improve the lives of persons living with dementia.

METHODS

The study design follows Arksey and O'Malley's scoping review framework and PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) guidelines. We will conduct a search of peer-reviewed studies in 6 electronic databases to identify the use of Geographic Information System analysis to measure the walkshed of persons living with dementia in a community setting. As age is a primary risk factor associated with dementia, we will also include studies that focus more broadly on community-dwelling older adults aged 65 years and older. Data will be extracted, analyzed, and represented according to 3 domains. This includes study details, walkshed analysis methods, and criteria and indicators used to measure dementia-friendly neighborhoods.

RESULTS

The results of the study and the submission of a manuscript for peer review are expected in June 2024. The results of the review are expected to contribute to an understanding of methods for monitoring and evaluating dementia-friendly neighborhoods. Expected findings will include a detailed breakdown of current parameters and routines used to conduct walkshed analysis. Findings will also convey criteria that can be operationalized in a Geographic Information System as indicators to assess barriers and facilitators to walking in a neighborhood setting.

CONCLUSIONS

As far as we are aware, the proposed scoping review will be the first to provide comprehensive methodological or technical guidance for conducting walkshed analysis specific to persons living with dementia. Both the scalability and objective nature of walkshed analysis are likely to be of direct interest to public health practitioners, planners, and allied professionals. Clearly documenting methods used in walkshed analysis can spur increased collaboration across these disciplines to enable an evidence-informed approach to improving neighborhood environments for persons living with dementia.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/50548.

Links between life-course SES and frailty trajectory moderated by community environment resources: Person-environment Fit perspective

INTRODUCTION

Drawing from the life course and person-environment fit perspectives, this study examined whether life-course SES disadvantages during childhood, adulthood and old- age influence frailty development in late- life and how community environment resources moderated the association between life-course SES disadvantages and frailty trajectories over a seven-year follow-up period.

METHODS

Data from 11,675 participants aged ≥ 50 years at baseline who participated in the four waves (2011-2018) of the China Health and Retirement Longitudinal Survey (CHARLS) were used. Life-course SES disadvantages were self-reported, and community environment resources (basic infrastructure and voluntary organizations) were ascertained from informed officials in the community. Frailty development was measured at each wave by the Frailty Index (FI) based on 39 potential deficits. Multilevel growth modeling was used to examine the interactive effect of life-course SES disadvantages and community environment resources on frailty development.

RESULTS

Life-course SES disadvantage exerted cumulatively negative effects on frailty trajectory, and individuals with SES disadvantages in two or three life stages reported higher initial levels of and faster increases in frailty scores. Community environmental resources (basic infrastructure and voluntary organizations) had a protective effect on frailty development and buffered the negative effects of SES vulnerability experiences accumulated over the life course. Community basic infrastructure resources played an important role in slowing the progression of frailty for individuals with cumulative SES disadvantage and downward mobility.

DISCUSSION

Our findings provided new evidence of person-environmental docility among older adults, documenting the role of community resources in buffering SES disparities in health during later-life.

Neighborhood Built Environments and Health in Later Life: A Literature Review

Objectives: This literature review aims to assess the current state of the field linking neighborhood environments to later-life health and wellbeing. Methods: We used electronic databases (e.g., PubMed, Google Scholar, and ProQuest) to search for studies published between 2010 and 2022 examining associations between neighborhood built environmental variables and later-life physical, cognitive, mental, and social health outcomes. Results: Among 168 studies reviewed, the majority were quantitative (n = 144) and cross-sectional (n = 122). Neighborhood environmental variables significantly associated with later-life health outcomes included population density/rurality, walkability/street connectivity, access to services and amenities, neighborhood quality and disorder, and parks/green/blue/open space. Neighborhoods operated through behavioral and biological pathways including hazardous exposures, affective states (e.g., stress and restoration), and lifestyle (e.g., exercise, socialization, and diet). Discussion: Neighborhoods and healthy aging research is a burgeoning interdisciplinary and international area of scholarship. Findings can inform upstream community interventions and strengthen clinical care.

Global rural health disparities in Alzheimer's disease and related dementias: State of the science

INTRODUCTION

Individuals living in rural communities are at heightened risk for Alzheimer's disease and related dementias (ADRD), which parallels other persistent place-based health disparities. Identifying multiple potentially modifiable risk factors specific to rural areas that contribute to ADRD is an essential first step in understanding the complex interplay between various barriers and facilitators.

METHODS

An interdisciplinary, international group of ADRD researchers convened to address the overarching question of: "What can be done to begin minimizing the rural health disparities that contribute uniquely to ADRD?" In this state of the science appraisal, we explore what is known about the biological, behavioral, sociocultural, and environmental influences on ADRD disparities in rural settings.

RESULTS

A range of individual, interpersonal, and community factors were identified, including strengths of rural residents in facilitating healthy aging lifestyle interventions.

DISCUSSION

A location dynamics model and ADRD-focused future directions are offered for guiding rural practitioners, researchers, and policymakers in mitigating rural disparities.

HIGHLIGHTS

Rural residents face heightened Alzheimer's disease and related dementia (ADRD) risks and burdens due to health disparities. Defining the unique rural barriers and facilitators to cognitive health yields insight. The strengths and resilience of rural residents can mitigate ADRD-related challenges. A novel "location dynamics" model guides assessment of rural-specific ADRD issues.

Association between chronic diseases and depression in the middle-aged and older adult Chinese population-a seven-year follow-up study based on CHARLS

Background

With the aging of the Chinese population, the prevalence of depression and chronic diseases is continually growing among middle-aged and older adult people. This study aimed to investigate the association between chronic diseases and depression in this population.

Methods

Data from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2018 longitudinal survey, a 7-years follow-up of 7,163 participants over 45 years old, with no depression at baseline (2011). The chronic disease status in our study was based on the self-report of the participants, and depression was defined by the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10). The relationship between baseline chronic disease and depression was assessed by the Kaplan-Meier method and Cox proportional hazards regression models.

Results

After 7-years follow-up, 41.2% (2,951/7163, 95% CI:40.1, 42.3%) of the participants reported depression. The analysis showed that participants with chronic diseases at baseline had a higher risk of depression and that such risk increased significantly with the number of chronic diseases suffered (1 chronic disease: HR = 1.197; 2 chronic diseases: HR = 1.310; 3 and more chronic diseases: HR = 1.397). Diabetes or high blood sugar (HR = 1.185), kidney disease (HR = 1.252), stomach or other digestive diseases (HR = 1.128), and arthritis or rheumatism (HR = 1.221) all significantly increased the risk of depression in middle-aged and older adult Chinese.

Conclusion

The present study found that suffering from different degrees of chronic diseases increased the risk of depression in middle-aged and older adult people, and these findings may benefit preventing depression and improving the quality of mental health in this group.

Monitoring and evaluation of dementia-friendly neighbourhoods using a walkshed approach: A scoping review protocol (Preprint).. [DOI: 10.2196/preprints.50548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

UNSTRUCTURED

The number of people in society living with Dementia is growing. In Canada, most people who live with dementia live at home, often in a neighbourhood setting. Neighbourhood environments can be source of independence, social engagement, and well-being, but can also contain barriers that limit physical activity, social engagement, and well-being. A dementia-friendly neighbourhood includes assets that support persons living with dementia and their caregivers in multiple life domains, including those that support walking within the neighbourhood environment. The study design follow’s Arksey and O’Malley’s scoping review framework and PRISMA-P guidelines. A search of peer-reviewed studies in six electronic databases will be conducted to identify the use of GIS analysis to measure the walkshed of persons living with dementia in a community setting. Data will be extracted, analyzed and represented according to three domains, including study details, walkshed analysis methods, and criteria and indicators used to measure dementia-friendly neighbourhoods. Results of the review are expected to contribute understanding of methods for monitoring and evaluation of dementia friendly neighbourhoods. Both the scalability and objective nature of walkshed analysis are likely to be of direct interest to public health practitioners and planning and allied professionals.

Rural-Urban Disparities in Multimorbidity Associated With Climate Change and Air Pollution: A Longitudinal Analysis Among Chinese Adults Aged 45

Background and Objectives

Chronic conditions and multimorbidity are increasing worldwide. Yet, understanding the relationship between climate change, air pollution, and longitudinal changes in multimorbidity is limited. Here, we examined the effects of sociodemographic and environmental risk factors in multimorbidity among adults aged 45+ and compared the rural-urban disparities in multimorbidity.

Research Design and Methods

Data on the number of chronic conditions (up to 14), sociodemographic, and environmental factors were collected in 4 waves of the China Health and Retirement Longitudinal Study (2011-2018), linked with the full-coverage particulate matter 2.5 (PM2.5) concentration data set (2000-2018) and temperature records (2000-2018). Air pollution was assessed by the moving average of PM2.5 concentrations in 1, 2, 3, 4, and 5 years; temperature was measured by 1-, 2-, 3-, 4-, and 5-year moving average and their corresponding coefficients of variation. We used the growth curve modeling approach to examine the relationship between climate change, air pollution, and multimorbidity, and conducted a set of stratified analyses to study the rural-urban disparities in multimorbidity related to temperature and PM2.5 exposure.

Results

We found the higher PM2.5 concentrations and rising temperature were associated with higher multimorbidity, especially in the longer period. Stratified analyses further show the rural-urban disparity in multimorbidity: Rural respondents have a higher prevalence of multimorbidity related to rising temperature, whereas PM2.5-related multimorbidity is more severe among urban ones. We also found temperature is more harmful to multimorbidity than PM2.5 exposure, but PM2.5 exposure or temperature is not associated with the rate of multimorbidity increase with age.

Discussion and Implications

Our findings indicate that there is a significant relationship between climate change, air pollution, and multimorbidity, but this relationship is not equally distributed in the rural-urban settings in China. The findings highlight the importance of planning interventions and policies to deal with rising temperature and air pollution, especially for rural individuals.

Longitudinal association of edentulism with cognitive impairment, sarcopenia and all-cause mortality among older Chinese adults

BACKGROUND

Tooth loss may be a surrogate for systemic health and aging. However, no previous studies have systematically assessed multiple outcomes relevant to aging trajectory in this area, and many important confounders were not adjusted in most previous studies. This study aims to prospectively evaluate the associations of complete tooth loss (edentulism) with broad markers of sarcopenia, cognitive impairment and mortality.

METHODS

Data were derived from the China Health and Retirement Longitudinal Study, a nationally representative household study of the Chinese population aged 45 years and older. Multivariate Weibull proportional hazards regression was used to assess the association between edentulism with sarcopenia and all-cause mortality. Average changes in cognitive function by edentulism was estimated by mixed-effects linear regression models.

RESULTS

During the 5-year follow-up, the prevalence of edentulism among adults aged 45 and over was 15.4%. Participants with edentulism had a greater decline in cognitive function compared to those without (β=-0.70, 95%CI:-1.09, -0.31, P < 0.001). The association of edentulism and all-cause mortality for 45-64 age group (HR = 7.50, 95%CI: 1.99, 28.23, P = 0.003), but not statistically significant for the ≥ 65 age group (HR = 2.37, 95%CI: 0.97, 5.80, P = 0.057). Effects of edentulism on sarcopenia are statistically significant for all age groups (45-64 age group: HR = 2.15, 95%CI: 1.27, 3.66, P = 0.005; ≥65 age group: HR = 2.15, 95%CI: 1.27, 3.66, P = 0.002).

CONCLUSIONS

These findings could have important clinical and public health implications, as tooth loss is a quick and reproducible measurement that could be used in clinical practice for identifying persons at risk of accelerated aging and shortened longevity, and who may benefit most from intervention if causality is established.

Neighbourhood deprivation across eight decades and late-life cognitive function in the Lothian Birth Cohort 1936: a life-course study

INTRODUCTION

although neighbourhood may predict late-life cognitive function, studies mostly rely on measurements at a single time point, with few investigations applying a life-course approach. Furthermore, it is unclear whether the associations between neighbourhood and cognitive test scores relate to specific cognitive domains or general ability. This study explored how neighbourhood deprivation across eight decades contributed to late-life cognitive function.

METHODS

data were drawn from the Lothian Birth Cohort 1936 (n = 1,091) with cognitive function measured through 10 tests at ages 70, 73, 76, 79 and 82. Participants' residential history was gathered with 'lifegrid' questionnaires and linked to neighbourhood deprivation in childhood, young adulthood and mid-to-late adulthood. Associations were tested with latent growth curve models for levels and slopes of general (g) and domain-specific abilities (visuospatial ability, memory and processing speed), and life-course associations were explored with path analysis.

RESULTS

higher mid-to-late adulthood neighbourhood deprivation was associated with lower age 70 levels (β = -0.113, 95% confidence intervals [CI]: -0.205, -0.021) and faster decline of g over 12 years (β = -0.160, 95%CI: -0.290, -0.031). Initially apparent findings with domain-specific cognitive functions (e.g. processing speed) were due to their shared variance with g. Path analyses suggested that childhood neighbourhood disadvantage is indirectly linked to late-life cognitive function through lower education and selective residential mobility.

CONCLUSIONS

to our knowledge, we provide the most comprehensive assessment of the life-course neighbourhood deprivation and cognitive ageing relationship. Living in advantaged areas in mid-to-late adulthood may directly contribute to better cognitive function and slower decline, whereas an advantaged childhood neighbourhood likely affects functioning through cognitive reserves.

Socioeconomic and Contextual Differentials in Memory Decline: A Cross-Country Investigation Between England and China

OBJECTIVES

Although cognitive functioning is strongly associated with biological changes in the brain during the aging process, very little is known about the role of sociocultural differentials between the western and eastern parts of the world. We examined the associations between individual socioeconomic markers (e.g., education, household wealth) and contextual levels characteristics (e.g., urbanicity) with memory performance and memory decline over up to 8 years of follow-up in England and China.

METHODS

The analytical samples included participants aged 50+ from the English Longitudinal Study of Aging (n = 6,687) and the China Health and Retirement Longitudinal Study (n = 10,252). Mixed linear models were employed to examine the association between baseline individual socioeconomic markers (education, wealth) and contextual-level characteristics (urbanicity) on the change in memory over time.

RESULTS

Our analyses showed that higher education and wealth were associated with better baseline memory in both England and China. Still, the impact of contextual-level characteristics such as urbanicity differed between the 2 countries. For English individuals, living in a rural area showed an advantage in memory, while the opposite pattern was observed in China. Memory decline appeared to be socioeconomically patterned by higher education, wealth, and urbanicity in China but not in England.

DISCUSSION

Our findings highlight substantial socioeconomic and contextual inequity in memory performance in both England and China, as well as in the rate of memory decline primarily in China. Public health strategies for preventing memory decline should target the socioeconomic gaps at the individual and contextual levels to protect those particularly disadvantaged.

Education, neighborhood environment, and cognitive decline: Findings from two prospective cohort studies of older adults in China

INTRODUCTION

The impacts of education on cognitive decline across different neighborhood environments (NEs) have rarely been studied.

METHODS

We investigated and compared the associations between educational attainment and cognitive decline using data of 1286 participants from the Taizhou Imaging Study (TIS) and the Shanghai Aging Study (SAS).

RESULTS

Compared with low-educated participants, in TIS with disadvantaged NE, high-educated participants manifested a significantly slower decline in global cognition (.062 Z score per year, P < .001), memory (.054 Z score per year, P < .05), and attention (.065 Z score per year, P < .01), whereas in SAS with advanced NE, highly educated individuals exhibited a slower decline only in attention (.028 Z score per year, P < .05).

DISCUSSION

We observed the additive effect of educational attainment and NE on cognitive decline in older adults. Education is especially important for maintaining cognitive health in a disadvantaged environment.

Do neighbourhood traffic-related air pollution and socio-economic status moderate the associations of the neighbourhood physical environment with cognitive function? Findings from the AusDiab study

Characteristics of the neighbourhood environment, including the built and natural environment, area-level socio-economic status (SES) and air pollution, have been linked to cognitive health. However, most studies have focused on single neighbourhood characteristics and have not considered the extent to which the effects of environmental factors may interact. We examined the associations of measures of the neighbourhood built and natural environment, area-level SES and traffic-related air pollution (TRAP) with two cognitive function domains (memory and processing speed), and the extent to which area-level SES and TRAP moderated the associations. We used cross-sectional data from the AusDiab3 study, an Australian cohort study of adults (mean age: 61 years) in 2011-12 (N = 4141) for which geocoded residential addresses were available. Spatial data were used to create composite indices of built environment complexity (population density, intersection density, non-commercial land use mix, commercial land use) and natural environment (parkland and blue spaces). Area-level SES was obtained from national census indices and TRAP was based on estimates of annual average levels of nitrogen dioxide (NO2). Confounder-adjusted generalised additive mixed models were used to estimate the independent associations of the environmental measures with cognitive function and the moderating effects of area-level SES and TRAP. The positive associations between built environment complexity and memory were stronger in those living in areas with higher SES and lower NO2 concentrations. A positive association between the natural environment and memory was found only in those living in areas with lower NO2 concentrations and average or below-average SES. Built environment complexity and the natural environment were positively related to processing speed. Complex urban environments and access to nature may benefit cognitive health in ageing populations. For higher-order cognitive abilities, such as memory, these positive effects may be stronger in areas with lower levels of TRAP.

How Neighborhood Structural and Individual Characteristics Affect Frailty Progression: Evidence from the China Health and Retirement Longitudinal Study

OBJECTIVES

(1) To characterize the average trajectories of frailty over time in Chinese community-dwelling older adults; (2) To assess the effects of neighborhood structural and individual characteristics on frailty progression.

DESIGN

A nationally representative prospective cohort study.

SETTING

Communities in 28 provinces, China.

PARTICIPANTS

6238 respondents aged 60 and above in 447 communities from four waves of the China Health and Retirement Longitudinal Study.

MEASUREMENTS

Frailty was measured using the 61-item Frailty Index (FI).

RESULTS

The trajectory of FI was nonlinear, with an average growth rate of 0.025 that significantly slows down at the rate of 0.002 per year. Older, male, and uninsured respondents showed faster rates of growth in FI over time than younger, female, and insured counterparts. Respondents living in neighborhoods with a higher percentage of the older population and rural villages showed slower rates of growth in FI over time.

CONCLUSION

Expanding health insurance coverage and keeping a high clustering of the elderly in neighborhoods may be the potential strategies for population-level frailty prevention and interventions.

Associations of PM2.5 intensity and duration with cognitive impairment: A longitudinal analysis of middle-aged and older adults in China

Long-term exposure to air pollution is associated with a higher risk of cognitive impairment; however, the understanding of this association is incomplete. We aimed to explore the relationship between fine particulate matter (PM_2.5) exposure and cognitive function using a prospective cohort of ageing adults, including 19,389 respondents in four waves of the China Health and Retirement Longitudinal Study (CHARLS, 2011-2018) linked with the historical PM_2.5 concentrations (2000-2018) in China. By extending the measurement of PM_2.5 exposure from exposure intensity (averaged PM_2.5 concentrations) to exposure duration (the number of months with higher PM_2.5 concentrations), we employed two linear models, the fixed-effect and mixed-effect linear models, to estimate the associations between PM_2.5 exposure and cognitive impairment, with adjustments for individual and regional covariates. Our findings show that the higher PM_2.5 intensity was associated with worse cognitive function, but the associations were only statistically significant in a longer exposure period (more than one year), especially in the 10-year exposure (Coefficient: -0.13; 95% Confidence Interval: -0.22, -0.04). Similar patterns were seen for fully adjusted models of PM_2.5 duration: a longer duration in PM_2.5 exposure was associated with lower cognitive scores, and the duration with higher cut-off points had stronger effects on cognitive function except for the duration at 75 μg/m³, suggesting a possible coincidence of increasing air pollution and economic development. The stronger exposure to PM_2.5 was associated with poorer cognitive function among Chinese adults, while more work is necessary to explore the causal effect of air pollution, independent of individual and contextual background characteristics.

How does neighbourhood environment influence loneliness in later life in Urban China? The role of financial status

This study aimed to examine whether older adults' financial status moderated the association between neighbourhood environment (i.e. physical and social environment) and loneliness among older adults in urban China. A cross-sectional survey was collected from urban communities of Shanghai in mid-2020. The final analytic sample was 459 older adults (age range = 60-91 years; proportion of women: 55.8%). Multiple group analysis was applied to test the hypothesised model. A measurement model of community social capital (i.e. cognitive and structural dimensions of social capital), a crucial indicator of neighbourhood social environment, was first established in both high-income and low-income groups. Factor loading invariance was established in these two groups. The results show that structural social capital (i.e. organisation memberships, volunteering, social participation and citizenship activities) was negatively associated with loneliness among older respondents from the high-income group only, whereas better community security was significantly associated with lower levels of loneliness among low-income older respondents only. The findings imply that both structural social capital and household income should be considered as important indicators in needs assessment among lonely older adults. Future social policies and interventions should pay attention to enhancing the role of both social and physical neighbourhood environment among older adults.

Healthy aging index and its link with relative education between individual and neighborhood: a population-based, cohort study

OBJECTIVES

There is increasing recognition of the importance of neighborhood socioeconomic status (SES) for establishing an age-friendly society. Despite the benefits of improved neighborhood SES, little is known about the link of relative education between individuals and neighborhoods with healthy aging. This study aims to construct a healthy aging index (HAI) accounting for indicators' interlinkages and to test the association of the HAI with relative education between neighborhoods and individuals.

METHODS

The study used data from the China Health and Retirement Longitudinal Study from 2011 to 2018, including middle-aged and older adults (≥ 45 years). The final sample comprised 11633 participants residing in 443 neighborhoods with 34123 observations. Based on 13 health indicators, a hybrid method integrating network analysis with TOPSIS was applied to construct a HAI accounting for health interlinkages. Weighted multilevel linear and ordered logistic models were used to estimate the effects of neighborhood education.

RESULTS

Among the 11633 participants (mean [SD] age, 58.20 [8.91] years; 6415 women [52.82%]), the mean (SD) HAI was 48.94 (7.55) at baseline, showing a downward trend with age. Approximately 10% of participants had a HAI trajectory characterized by a low starting point and fast decline. A one-year increase in neighborhood education was independently associated with a 0.37-point increase (95% CI, 0.23-0.52) in HAI. Regardless of individual education, each participant tended to gain benefits from a neighborhood with higher education. However, the effects of increased neighborhood education were weaker for individuals whose education was lower than the neighborhood average.

CONCLUSIONS

The HAI is an interaction system. Improving neighborhood education was beneficial to healthy aging, but individuals with lower education relative to the neighborhood average may experience poor person-environment fit and obtain fewer benefits from improved neighborhood education. Thus, in the process of improving neighborhood SES, individual-based interventions should be conducted for individuals whose education level is lower than the neighborhood average to achieve person-environment fit.

Cognability: An Ecological Theory of neighborhoods and cognitive aging

While a growing body of evidence points to potentially modifiable individual risk factors for dementia, the built and social environments in which people develop and navigate cognitive decline are largely overlooked. This paper proposes a new theoretical concept, Cognability, to conceptualize how supportive an area is to cognitive health among aging residents. Cognability incorporates a constellation of both positive and negative neighborhood features related to physical activity, social interaction and cognitive stimulation in later life. We analyzed data from the REasons for Geographic And Racial Differences in Stroke Study, a national sample of older Black and white adults in the United States (n = 21,151; mean age at assessment = 67; data collected 2006-2017). Generalized additive multilevel models examined how cognitive function varied by neighborhood features. Access to civic and social organizations, recreation centers, fast-food and coffee establishments, arts centers, museums, and highways were significantly associated with cognitive function. Race-, gender-, and education-specific models did not yield substantial improvements to the full-model. Our results suggest that the unequal distribution of amenities and hazards across neighborhoods may help account for considerable inequities observed in cognitive health among older adults. Cognability advances ecological theories of aging through an innovative "whole neighborhood" approach. It aims to identify which specific neighborhood features are most protective of cognitive health among aging adults to inform upstream public health initiatives, community interventions, and policy.

The complex relationship of air pollution and neighborhood socioeconomic status and their association with cognitive decline

BACKGROUND

Air pollution and neighborhood socioeconomic status (nSES) have been shown to affect cognitive decline in older adults. In previous studies, nSES acts as both a confounder and an effect modifier between air pollution and cognitive decline.

OBJECTIVES

This study aims to examine the individual and joint effects of air pollution and nSES on cognitive decline on adults 50 years and older in Metro Atlanta, USA.

METHODS

Perceived memory and cognitive decline was assessed in 11,897 participants aged 50+ years from the Emory Healthy Aging Study (EHAS) using the cognitive function instrument (CFI). Three-year average air pollution concentrations for 12 pollutants and 16 nSES characteristics were matched to participants using census tracts. Individual exposure linear regression and LASSO models explore individual exposure effects. Environmental mixture modeling methods including, self-organizing maps (SOM), Bayesian kernel machine regression (BKMR), and quantile-based G-computation explore joint effects, and effect modification between air pollutants and nSES characteristics on cognitive decline.

RESULTS

Participants living in areas with higher air pollution concentrations and lower nSES experienced higher CFI scores (beta: 0.121; 95 % CI: 0.076, 0.167) compared to participants living in areas with low air pollution and high nSES. Additionally, the BKMR model showed a significant overall mixture effect on cognitive decline, suggesting synergy between air pollution and nSES. These joint effects explain protective effects observed in single-pollutant linear regression models, even after adjustment for confounding by nSES (e.g., an IQR increase in CO was associated with a 0.038-point lower (95 % CI: -0.06, -0.01) CFI score).

DISCUSSION

Observed protective effects of single air pollutants on cognitive decline can be explained by joint effects and effect modification of air pollutants and nSES. Researchers must consider nSES as an effect modifier if not a co-exposure to better understand the complex relationships between air pollution and nSES in urban settings.

A longitudinal analysis of PM2.5 exposure and multimorbidity clusters and accumulation among adults aged 45-85 in China

While previous studies have emphasised the role of individual factors in understanding multimorbidity disparities, few have investigated contextual factors such as air pollution (AP). We first use cross-sectional latent class analysis (LCA) to assess the associations between PM2.5 exposure and multimorbidity disease clusters, and then estimate the associations between PM2.5 exposure and the development of multimorbidity longitudinally using growth curve modelling (GCM) among adults aged 45-85 in China. The results of LCA modelling suggest four latent classes representing three multimorbidity patterns (respiratory, musculoskeletal, cardio-metabolic) and one healthy pattern. The analysis shows that a 1 μg/m3 increase in cumulative exposure to PM2.5 is associated with a higher likelihood of belonging to respiratory, musculoskeletal or cardio-metabolic clusters: 2.4% (95% CI: 1.02, 1.03), 1.5% (95% CI: 1.01, 1.02) and 3.3% (95% CI: 1.03, 1.04), respectively. The GCM models show that there is a u-shaped association between PM2.5 exposure and multimorbidity, indicating that both lower and higher PM2.5 exposure is associated with increased multimorbidity levels. Higher multimorbidity in areas of low AP is explained by clustering of musculoskeletal diseases, whereas higher AP is associated with cardio-metabolic disease clusters. The study shows how multimorbidity clusters vary contextually and that PM2.5 exposure is more detrimental to health among older adults.

Depressive symptoms in the context of Chinese grandparents caring for grandchildren

OBJECTIVES

This study examined the longitudinal association of depressive symptoms with grandchild care intensity and whether the association varies by household structure, residential area, and gender for Chinese grandparents.

METHODS

Using data from three waves of the China Health and Retirement Longitudinal Study (CHARLS, 2011-2015), we applied multilevel mixed effects models to examine changes in depressive symptoms and the associations with caregiving intensity and to test the moderation effects of residence, living arrangement, and gender.

RESULTS

After controlling for sociodemographic and health covariates, we found that providing a medium level of grandchild care was associated with fewer baseline depressive symptoms compared with non-caregivers. Providing low-level care among those living with spouse/partner and among those living with child(ren)/others was associated with fewer depressive symptoms relative to non-caregivers with similar living arrangements.

CONCLUSION

Findings indicate that a medium level of involvement in childcare was associated with better mental wellness and low levels of caregiving may benefit nonresidential caregivers. More prospective longitudinal studies are needed to improve the operationalization of grandparent caregiving, validate the associated health outcomes, and apply a contextual approach to examine socioeconomic, cultural, and policy-related contexts of caregiving in the changing world of China.

Green Space, Air Pollution, Weather, and Cognitive Function in Middle and Old Age in China

Prior research has shown that environmental hazards, such as limited green space, air pollution, and harmful weather, have the strong adverse impact on older adults' cognitive function; however, most of the studies were conducted in developed countries and limited to cross-sectional analyses. China has the largest aging population in the world so the research evidence from it can offer an insight to the study in other developing countries facing similar issues and inform future public health policy and disease control. This study examined the long-term impact of environmental factors, namely, green space coverage, air pollution, and weather conditions on cognitive function using a nationally representative sample consisting of adults aged 45 years and older selected from the China Health and Retirement Longitudinal Study (CHARLS 2011–2018), the China City Statistical Yearbook, and other sources. Multilevel growth curve models were utilized for analysis and the mediator effects of physical activity and social engagement on the relationship between environmental factors and cognitive function were examined. Findings of this study showed that after controlling for sociodemographic characteristics, annual precipitation of 80 cm or more, living in areas with July temperature of 28°C or higher, urban community, and green space coverage were positively associated with cognition score at the baseline and lower precipitation, urban community, and greater green space coverage were associated with slower cognitive decline over a 7-year period. The impact of gross domestic product (GDP) seemed to take into effect more and more over time. These effects did not substantially change after weekly total hours of physical activities and levels of social engagement were added. More research on the mechanisms of the effect of environmental factors on cognition is needed such as the subgroup analyses and/or with more aspects of environmental measures.

The association between community-level socioeconomic status and depressive symptoms among middle-aged and older adults in China

BACKGROUND

There was little evidence concerning the association of community socioeconomic status (SES) and the cross-level interaction between community- and individual-level SES with depressive symptoms in China. This study aimed to investigate the association of community-level SES with depressive symptoms among Chinese middle-aged and older people and to examine whether individual-level SES moderates this relationship.

METHODS

Using data from the China Health and Retirement Longitudinal 2011-2018 Study, the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10) short form was used to measure depressive symptoms in 35,546 Chinese individuals aged 45 years and older. Community SES was calculated as a sum of z scores of the average years of schooling and household income per capita, which were derived by aggregating the individual measures to the community level. Two-level hierarchical linear regression was used.

RESULTS

Community SES was negatively related to CES-D-10 scores (coef=-0.438). A 1-SD increase in individual SES was associated with lower CES-D-10 scores (coef=-0.490). The cross-level interaction on individual- and community-level SES was significantly associated with depressive symptoms, indicating that with the increase of individual-level SES, the effect of community-level SES on depression decreases. Stratified analyses observed robust associations of community SES with CES-D scores between urban and rural residents.

CONCLUSIONS

This study showed that individuals who live in lower-SES communities had more severe depressive symptoms, particularly individuals with low SES. Additional attention should be given to the community socioeconomic context of middle-aged and older adults with lower SES, which may be helpful to reduce SES inequalities in depressive symptoms in China.

The Impact of Early Neighborhood Cohesion, and Its Mechanism, on Cognitive Function in Later Life

Objectives

This study aimed to explore the impact of early neighborhood cohesion, and its mechanism, on cognitive function in later life.

Methods

In total, 10,727 Chinese elderly, aged 60-90, forming two datasets (2014 and 2018) from the China Health and Retirement Longitudinal Study (CHARLS) were used as a sample. Childhood neighborhood cohesion was measured by the extent of how much neighbors were willing to help and how close-knit neighbors were. Mini-Mental State Examination (MMSE) and Center for Epidemiologic Studies Depression Scale (CESD-10) were used to assess the cognitive functions and depression of the elderly. We used a structural equation model to examine the relationship between early neighborhood cohesion and late-life cognitive function and conducted bootstrapping analyses to assess the mechanism.

Results

Cognitive function was positively predicted by childhood neighborhood cohesion (β = 0.06, p < 0.001), and cognitive function of the elderly were also positively predicted through the mediating effects of childhood friendships, which included depression and social activity participation as two chain paths.

Conclusion

The findings suggest that childhood neighborhood cohesion positively predicts cognitive function among elderly people through the mediating roles of childhood friendship, depression, and social activity engagement. Childhood neighborhood cohesion is correlated with better childhood friendships, then to fewer depression symptoms and greater elderly social activity participation, and finally to better cognitive functions in the elderly.

Coexistent physical and cognitive decline and the development of fear of falling among Korean older adults

OBJECTIVES

Although hand grip strength and cognitive function are associated with fear of falling (FOF), little is known about whether coexisting physical and cognitive decline is jointly related to FOF. This study examines whether grip strength and cognitive function interact to shape FOF and FOF-related activity restriction (FAR) among Korean older adults.

METHODS/DESIGN

This study used seven waves of the Korean Longitudinal Study of Ageing (N = 3373 older adults aged 65 or over). Grip strength was assessed by a handgrip dynamometer, and cognitive function by Korean Mini-mental State Examination (K-MMSE). Fixed effects models were estimated to account for time-invariant confounders such as genetic predispositions, innate ability, and health endowments. This study estimated a joint model that included interaction effects between grip strength and cognitive function.

RESULTS

Declines in grip strength and cognitive function were independently associated with FOF. Fixed effects estimates suggested that, despite some attenuation, controlling for individual heterogeneity does not confound the associations. The interaction model showed that coexistence of low grip strength and cognitive decline leads to a greater risk of FOF and FAR than having a single condition. Similar patterns were found for FAR.

CONCLUSIONS

This study provides evidence that coexistent cognitive and physical decline are a significant risk factor for FOF and FAR. Given the well-established adverse effects of FOF on older adults' health and well-being, results of this study lend support to interventions to target old adults with coexistent cognitive and physical decline to remove excessive concerns about FOF.

Individual and environmental factors associated with cognitive function in older people: a longitudinal multilevel analysis

BACKGROUND

Individual and environmental factors have been found to be related to cognitive function. However, few studies have examined the longitudinal effects of both individual and environmental factors over time. The purpose of this study was to examine the effects of individual and environmental factors over time on older people's cognitive function.

METHODS

Nationally representative panel data from the Taiwan Longitudinal Survey on Aging 1999-2015 (n = 6349 persons, observations = 12,042) were used. City-level indicator data were sourced from the government. A multilevel mixed linear model analysis was conducted.

RESULTS

Better cognitive function was significantly related to individuals' work, ethnicity, younger age, higher education level, better self-rated health, higher level of emotional support received, being more religious, higher economic satisfaction, and living in the cities with higher population densities. Education and social connectedness were protective factors over time.

CONCLUSION

Socioeconomics and social connectedness are related to cognitive function. A more social integrated lifestyle and financially secure living is suggested in the policy.

The association between community-level socioeconomic status and cognitive function among Chinese middle-aged and older adults: a study based on the China Health and Retirement Longitudinal Study (CHARLS)

Background

Although numerous studies focused on the relationship between area socioeconomic status (SES) and health, only a few of them investigated how community-level SES was linked to late-life cognitive function as well as the potential pathways underlying this association, and very few of them focused on the context of China. This study examined how community-level SES was linked to cognitive function and the potential pathways underlying this association among middle-aged and older adults in China.

Methods

Data was drawn from the waves 1–4 of China Health and Retirement Longitudinal Study. We measured cognitive function with the components of the Telephone Interview of Cognitive Status battery. Community-level SES was derived from a sum of z scores of the percentage of the illiterate and the per-capita net income status within communities. We adopted two-level hierarchical linear regression models to explore the associations between community-level SES and cognitive function. A multilevel mediation analysis with structural equation modeling was undertaken to disaggregate the direct and indirect pathways of the associations.

Results

Higher community-level SES was associated with better cognitive function (β = 0.562, 95% CI = 0.390, 0.734), and this significant association was only present in rural participants, not in urban participants. Furthermore, we discovered the mediating effects of outdoor exercise facilities within communities (β = 0.023, 95% CI = 0.000, 0.056) and individual-level SES (β = 0.108, 95% CI = 0.057, 0.156) to explain the relationship between community SES and cognitive function.

Conclusions

These findings highlight the importance of community environmental interventions in maintaining individuals’ cognitive health in China, especially for older adults. Our results provided solid empirical evidence for reducing mental health inequalities in China, and suggested that developing an aging-friendly environment and properly distributing community resources are important to improve cognitive function of older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02946-3.

Association between community environment and depressive symptoms among Chinese middle-aged and older adults: evidence from national longitudinal surveys from 2011 to 2018

BACKGROUND

Despite the growing evidence on the relationship between community environment and depressive symptoms, little is known about the longitudinal relationship in older adults. This study aimed to examine the longitudinal association between community environment and depressive symptoms based on a nationally representative survey among Chinese middle-aged and older adults.

METHODS

A total of 6872 participants from the latest four waves (2011, 2013, 2015 and 2018) of China Health and Retirement Longitudinal Study were included. The Centre for Epidemiologic Studies Depression scale was used to measure depressive symptoms, and Cox proportional hazards regression models were conducted to investigate the longitudinal association between community environment and depressive symptoms after adjusting included covariates.

RESULTS

Both community infrastructure and organisations were significantly associated with depression, and infrastructure was associated with higher risk reduction in depression (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.66-0.89). Furthermore, we estimated the heterogeneous effects of community infrastructure and organisations for vulnerable populations. Additionally, family-based elder-care centre (HR, 0.63; 95% CI, 0.46-0.86) and outdoor exercise facilities (HR, 0.76; 95% CI, 0.68-0.84) were found as significant correlates associated with lower depressive symptom risk.

CONCLUSIONS

Our findings indicated that targeted and specific measures should be taken to improve the construction of community infrastructure and strengthen the role of community organisations. Specifically, providing a family-based elder-care centre and establishing outdoor exercise facilities might be effective methods to reduce the risk of depression and relieve related public health burdens among Chinese middle-aged and older adults.

Cognitive reserve over life course and 7-year trajectories of cognitive decline: results from China health and retirement longitudinal study

Background

Cognitive reserve (CR) could partly explain the individual heterogeneity in cognitive decline. No study measured CR from a life course perspective and investigated the association between CR and trajectories of cognitive decline in older Chinese adults.

Methods

Data of 6795 Chinese adults aged 60+ from China Health and Retirement Longitudinal Study were used. Global cognition score (0–32) was assessed in all four waves. A life-course CR score was constructed using markers of childhood circumstance, education, highest occupational class, and leisure activities in later life. Latent growth curve modelling (LGCM) was applied to assess the association between CR and trajectories of cognitive decline.

Results

For the life-course CR, factor loadings of markers in adulthood and later life were larger than that of markers in childhood. The life-course CR score (ranged between − 2.727 and 6.537, SD: 1.74) was higher in urban Chinese adults (0.75, SD: 1.90) than in rural Chinese adults (− 0.50, SD: 1.43). The unconditional LGCM results showed that urban older Chinese adults had better global cognition at baseline (intercept: 15.010, 95% CI: 14.783, 15.237) and a slower rate of cognitive decline per year (linear slope: -0.394, 95% CI: − 0.508, − 0.281) than their rural counterparts (intercept: 12.144, 95% CI: 11.960, 12.329; linear slope: -0.498, 95% CI: − 0.588, − 0.408). After controlling for all covariates, one-unit higher CR score was associated with 1.615 (95% CI: 1.521, 1.709) and 1.768 (95% CI: 1.659, 1.876) unit higher global cognition at baseline for urban and rural older Chinese adults, respectively. The slower rate of cognitive decline associated with higher CR was more evident in rural residents (slope: 0.083, 95% CI: 0.057, 0.108) than in their urban counterparts (0.054, 95% CI: 0.031, 0.077).

Conclusions

CR was associated with better baseline cognition and slower cognitive decline in Chinese older adults. Although rural residents were disadvantaged in both CR and cognition, the protective effect of CR against cognitive decline was stronger for them than in those who live in urban area.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12671-6.

The effect of the 2018 Japan Floods on cognitive decline among long-term care insurance users in Japan: a retrospective cohort study

BACKGROUND

The July 2018 Japan Floods caused enormous damage to western Japan. Such disasters can especially impact elderly persons. Research has shown that natural disasters exacerbated a decline in cognitive function, but to date, there have been no studies examining the effects of this disaster on the elderly. The object of this study was to reveal the effect of this disaster in terms of cognitive decline among the elderly.

METHODS

Study participants were certified users of the long-term care insurance (LTCI) system in Hiroshima, Okayama, and Ehime prefectures from May 2018 to June 2018. The observation period was from July 2018 to December 2018. Our primary outcome was cognitive decline after the disaster using a dementia symptomatology assessment. In addition to a crude model, a multivariate Cox proportional hazards model was used to assess the cognitive decline of victims, adjusting for age classification, gender, the level of dementia scale before the disaster occurred, residential environment, whether a participant used facilities shut down after the disaster, and population density. After we confirmed that the interaction term between victims and residential environment was statistically significant, we stratified them for the analysis.

RESULTS

The total number of participants was 264,614. Victims accounted for 1.10% of the total participants (n = 2,908). For the Cox proportional hazards model, the hazard ratio of the victims was 1.18 (95% confidential interval (CI): 1.05-1.32) in the crude model and 1.12 (95% CI: 1.00-1.26) in the adjusted model. After being stratified by residential environment, the hazard ratio of home victims was 1.20 (95% CI: 1.06-1.36) and the hazard ratio of facility victims was 0.89 (95% CI: 0.67-1.17).

CONCLUSIONS

This study showed that elderly living at home during the 2018 Japan Floods were at risk for cognitive decline. Medical providers, care providers, and local governments should establish a system to check on the cognitive function of elderly victims and provide necessary care support.

Neighborhood built environment associated with cognition and dementia risk among older adults: A systematic literature review

Cognitive impairment associated with aging is a serious and growing public health problem. This systematic literature review contributes to better understanding the current state of knowledge on the roles of neighborhood environments in supporting cognitive health in later life. Literature search was carried out in 2020 using the seven databases most relevant to the topic. This review was restricted to peer-reviewed observational and quantitative studies that focused on 1) community-dwelling older adults as target populations; 2) neighborhood built environments as independent variables; and 3) cognition or dementia as outcome variables. Thirty-seven studies published between 1989 and 2020 met the inclusion criteria. The neighborhood built environment domains covered in these included urbanity/rurality, land use, neighborhood physical disorder, transportation infrastructure, urban design, and urban nature. Neighborhood resources and green space exposure were most frequently studied and linked to cognition-related outcomes. Neighborhood built environment was shown to be more pertinent to older adults' global cognition, memory, and dementia. Physical activity showed a mediating role between neighborhood built environment and cognition. The effect of neighborhood built environment on cognitive function was stronger among older women and those with disabilities or lower socioeconomic status. Evidence on the relationship between neighborhood built environment and cognition/dementia among older adults is moderate. Our findings highlight the need for more standardized and longitudinal measures of neighborhood built environment and high-sensitivity cognitive tests that capture the specific and relevant domains of cognition, to facilitate further exploration of the mediating and moderating effects of neighborhood built environment with cognition/dementia in older adults. This review offers insights for future research and policy efforts toward creating communities to support cognitive health and aging in place.

Vision impairment, vision correction, and cognitive decline among middle-aged and older Chinese: results from the China health and retirement longitudinal study

OBJECTIVES

To investigate the associations between vision impairment (VI), vision correction (VC), and cognitive function.

METHOD

We included 20,677 participants aged ≥45 years from the China Health and Retirement Longitudinal Study (2011-2015). Participants were grouped into no VI, distance VI (DVI) only, near VI (NVI) only, or both distance and near VI (DNVI), and VI(+)/VC(-), VI(+)/VC(+), VI(-)/VC(-), or VI(-)/VC(+) further at baseline. Cognitive function at baseline and subsequently every two years was applied as a dependent variable in a generalized estimating equation model.

RESULTS

DVI only, NVI only, and DNVI had significantly worse cognitive function over time than no VI (all p < .05). DNVI had significantly worse cognitive function over time than DVI only and NVI only (all p < .001). VI(+)/VC(+), VI(-)/VC(-), and VI(-)/VC(+) had significantly better cognitive function over time than VI(+)/VC(-) (all p < .05). VI(-)/VC(+) had significantly better cognitive function over time than VI(+)/VC(+) and VI(-)/VC(-) (all p < .05).

CONCLUSION

Cognitive function was worse in middle-aged and older Chinese with VI, especially in those with DNVI. VC was associated with better cognitive function over time regardless of the status of vision.

Housing Poverty and Healthy Aging in China: Evidence from the China Health and Retirement Longitudinal Study

BACKGROUND

Although prior research on the housing-health linkage suggested that those with poor housing conditions are more likely to report poor health, it is dominated by Western studies and offers little evidence on the housing-health relation in China. Scarce is empirical evidence on the potentially detrimental impact of either qualitative or quantitative housing poverty on health outcomes, especially for seniors in China. This paper aims to fill this void by using data from the 2011-2015 China Health and Retirement Longitudinal Study (CHARLS) to provide a comprehensive analysis of the demographic, socioeconomic, and behavioral factors that contribute to changes in healthy aging among Chinese adults aged 60 and over.

METHODS

Data collected from 8839 adults aged 60 and over in the 2011 and 2015 CHARLS (3732 in 2011 and 5107 in 2015) were used. We first used six blood-based biomarkers to construct a composite measure of the Chinese Healthy Aging Index (CHAI, ranging from 0 (healthiest) to 12 (unhealthiest)) and then assessed the psychometric properties of the CHAI score, including acceptability, internal consistency, convergent validity, discriminative validity and precision. In addition, we employed both mean-based Blinder-Oaxaca and unconditional quantile regression decomposition to decompose the change in healthy aging within the 2011-2015 period.

RESULTS

We overall identified a decrease in CHAI score from 5.69 in 2011 to 5.20 in 2015, which implies an improvement in healthy aging during this period. Our linear decomposition revealed that dependent on the type of measure used (whether quality, quantity, or combined quality-quantity), housing poverty explained 4-8% of the differences in CHAI score. Our distributional decompositions also highlighted an important role for housing poverty in the change in healthy aging, accounting for approximately 7-23% of the explained portion. Within this latter, the relative contribution of housing quantity and quality poverty was more pronounced at the median and upper end of the CHAI distribution. We also found household expenditure to be significantly associated with healthy aging among older Chinese adults and made the largest contribution to the improvement in healthy aging over time.

CONCLUSIONS

The association between housing poverty and CHAI is independent of household expenditure. Regardless of type, housing poverty is positively associated with a decrease in healthy aging. Thus, improved housing conditions boost healthy aging, and housing amelioration initiatives may offer the most effective solution for augmenting healthy aging in China. Improvement of flush toilets and the access to potable water and a separate kitchen require particular attention. Since high-density congested housing has a negative impact on healthy aging, more attention can also be paid to improvements in the available space for older people. Especially at an institutional level, the government may extend the housing policy from a homeownership scheme to a housing upgrading scheme by improving housing conditions.

Unhealthy lifestyles, environment, well-being and health capability in rural neighbourhoods: a community-based cross-sectional study

BACKGROUND

Non-communicable diseases are a leading cause of health loss worldwide, in part due to unhealthy lifestyles. Metabolic-based diseases are rising with an unhealthy body-mass index (BMI) in rural areas as the main risk factor in adults, which may be amplified by wider determinants of health. Changes in rural environments reflect the need of better understanding the factors affecting the self-ability for making balanced decisions. We assessed whether unhealthy lifestyles and environment in rural neighbourhoods are reflected into metabolic risks and health capability.

METHODS

We conducted a community-based cross-sectional study in 15 Portuguese rural neighbourhoods to describe individuals' health functioning condition and to characterize the community environment. We followed a qualitatively driven mixed-method design to gather information about evidence-based data, lifestyles and neighbourhood satisfaction (incorporated in eVida technology), within a random sample of 270 individuals, and in-depth interviews to 107 individuals, to uncover whether environment influence the ability for improving or pursuing heath and well-being.

RESULTS

Men showed to have a 75% higher probability of being overweight than women (p-value = 0.0954); and the reporting of health loss risks was higher in women (RR: 1.48; p-value = 0.122), individuals with larger waist circumference (RR: 2.21; IC: 1.19; 4.27), overweight and obesity (RR: 1.38; p-value = 0.293) and aged over 75 years (RR: 1.78; p-value = 0.235; when compared with participants under 40 years old). Metabolic risks were more associated to BMI and physical activity than diet (or sleeping habits). Overall, metabolic risk linked to BMI was higher in small villages than in municipalities. Seven dimensions, economic development, built (and natural) environment, social network, health care, demography, active lifestyles, and mobility, reflected the self-perceptions in place affecting the individual ability to make healthy choices. Qualitative data exposed asymmetries in surrounding environments among neighbourhoods and uncovered the natural environment and natural resources specifies as the main value of rural well-being.

CONCLUSIONS

Metabolic risk factors reflect unhealthy lifestyles and can be associated with environment contextual-dependent circumstances. People-centred approaches highlight wider socioeconomic and (natural) environmental determinants reflecting health needs, health expectations and health capability. Our community-based program and cross-disciplinary research provides insights that may improve health-promoting changes in rural neighbourhoods.

The Influences of Community-Enriched Environment on the Cognitive Trajectories of Elderly People

To examine the influences of community-enriched environment on the cognitive trajectories of the elderly in China, using panel data of 10,057, 3994, 2387, and 1749 older persons aged 65–104 years of the 2005, 2008, 2011, and 2014 waves from the Chinese Longitudinal Health Longevity Survey (CLHLS) and a growth curve model, the authors analyzed the changing trend of elderly people’s cognitive abilities with age. The influences of community-enriched environments on cognitive abilities were also investigated. Results show that when all the factors are out of consideration except age, for an older person aged 82.5 years, as he/she grows one year older, his/her cognitive abilities will be reduced by 0.139 points, while for one aged 92.5 years, they will be reduced by 0.199 points, which means cognitive abilities decline rapidly as the individuals grow older. The elderly people from communities with enriched environments have higher cognitive levels and slower declining speeds of cognitive abilities than the other elderly people, proving the long-term ability of such environments to facilitate cognitive abilities. An increase in the stimulation of the enriched environment is needed to prevent or slow down the degeneration of cognitive abilities.

Environmental Factors Affecting Cognitive Function among Community-Dwelling Older Adults: A Longitudinal Study

Although neighborhood environmental factors have been found to be associated with cognitive decline, few longitudinal studies have focused on their effect on older adults living in rural areas. This longitudinal study aimed to investigate the role of neighborhood environmental factors in cognitive decline among rural older adults. The data of 485 older adults aged ≥60 years who were living in Unnan City in Japan and had participated in two surveys conducted between 2014 and 2018 were analyzed. Cognitive function was assessed using the Cognitive Assessment for Dementia, iPad version 2. Elevation, hilliness, residential density, and proximity to a community center were determined using geographic information system. We applied a generalized estimating equation with odds ratios (OR) and 95% confidence intervals (CIs) of cognitive decline in the quartiles of neighborhood environmental factors. A total of 56 (11.6%) participants demonstrated a decrease in cognitive function at follow up. Elevation (adjusted OR 2.58, 95% CI (1.39, 4.77) for Q4 vs. Q1) and hilliness (adjusted OR 1.93, 95% CI (1.03, 3.63) for Q4 vs. Q1) were associated with a higher likelihood of cognitive decline. The second quartiles of residential density showed significantly lower likelihoods of cognitive decline compared with the first quartiles (adjusted OR 0.36, 95% CI (0.19, 0.71) for Q2 vs. Q1). Thus, an elevated hilly environment and residential density predicted cognitive decline among rural older adults.