Rural/urban dwelling across the life-course and late-life cognitive ability in Mexico

Family Size Across the Life Course and Cognitive Decline in Older Mexican Adults

OBJECTIVES

A growing body of research has identified associations between family size and cognition in older adults. These studies largely focus on older adults' own fertility history instead of sibship size, defined as one's number of siblings. Sibship size may affect cognitive development during early childhood, creating differences that may persist into late life. Using a gendered life course framework, this study evaluates how family size across the life course (both sibship size and number of children) relates to cognitive aging among older Mexican adults.

METHODS

Data come from the 2012, 2015, 2018, and 2021 waves of the Mexican Health and Aging Study (n = 14,872 adults age 50+). We use latent growth curve models to evaluate how family size (sibship size and fertility history) relates with levels of latent general cognitive ability and 9-year cognitive decline and variation across gender.

RESULTS

Small sibship size related to higher levels of cognitive ability among men, but not women. This benefit was somewhat reduced when educational attainment was accounted for. Regarding fertility history, we observed an inverse U-shaped relationship with the level of cognitive ability, regardless of gender, that remained significant even after accounting for sibship size and other confounders. Neither family size measure predicted the rate of cognitive decline.

DISCUSSION

This research broadens our understanding of family size and cognition associations in the context of Mexico's changing demographics that challenge the reliance on family support in late life and highlights potential gender differences.

Investigating dynamic brain functional redundancy as a mechanism of cognitive reserve

Introduction

Individuals with higher cognitive reserve (CR) are thought to be more resilient to the effects of age-related brain changes on cognitive performance. A potential mechanism of CR is redundancy in brain network functional connectivity (BFR), which refers to the amount of time the brain spends in a redundant state, indicating the presence of multiple independent pathways between brain regions. These can serve as back-up information processing routes, providing resiliency in the presence of stress or disease. In this study we aimed to investigate whether BFR modulates the association between age-related brain changes and cognitive performance across a broad range of cognitive domains.

Methods

An open-access neuroimaging and behavioral dataset (n = 301 healthy participants, 18-89 years) was analyzed. Cortical gray matter (GM) volume, cortical thickness and brain age, extracted from structural T1 images, served as our measures of life-course related brain changes (BC). Cognitive scores were extracted from principal component analysis performed on 13 cognitive tests across multiple cognitive domains. Multivariate linear regression tested the modulating effect of BFR on the relationship between age-related brain changes and cognitive performance.

Results

PCA revealed three cognitive test components related to episodic, semantic and executive functioning. Increased BFR predicted reduced performance in episodic functioning when considering cortical thickness and GM volume as measures of BC. BFR significantly modulated the relationship between cortical thickness and episodic functioning. We found neither a predictive nor modulating effect of BFR on semantic or executive performance, nor a significant effect when defining BC via brain age.

Discussion

Our results suggest that BFR could serve as a metric of CR when considering certain cognitive domains, specifically episodic functioning, and defined dimensions of BC. These findings potentially indicate the presence of multiple underlying mechanisms of CR.

Late-life psychiatric factors and life satisfaction are associated with cognitive errors: evidence from an experimental module of a large-scale survey in India

Older adults are at risk of committing cognitive and decision-making errors due to the decline in cognitive functions. However, the understanding of the determining factors of cognitive errors among ageing adults is limited. In this study, we explored the role of various psychiatric factors, life satisfaction, and other socioeconomic, health and behavioural risk factors of committing cognitive errors among middle-aged and older adults in India. The study utilized the data from the experimental module of the Longitudinal Ageing Study in India (LASI) Wave-1 (2017-2018) with a sample of 12,754 adults aged 45 years and above. The cognitive error was measured using logical fallacies committed in the activity-based experiments. The study employed descriptive, bivariate statistics and multivariable logistic regression models to identify the factors associated with cognitive errors among the study participants. Depression (aOR = 1.28, 99%, CI: 1.16-1.41), life satisfaction (aOR = 0.99, 99%, CI: 0.98-1.00), and cognitive impairment (aOR = 1.13, 90% CI: 1.00-1.30) self-reported psychiatric) were significantly associated with higher odds of committing cognitive errors among the middle-aged and older adults. Also, ageing adults with low educational levels, functional limitations, sleep disturbances, smoking history, living in rural areas and belonging to scheduled tribes had a higher probability of committing cognitive errors. However, involvement in physical activity, reading habits and social interactions reduced the odds of cognitive errors among this sample. Mental health and well-being indicators, including depression, life satisfaction, cognitive impairment, and other health and behavioural health factors, determine cognitive errors among ageing adults. Programs and policies should be initiated to address these factors, reduce cognitive errors, and ensure active ageing.

The Association between Physical Frailty and Cognitive Performance in Older Adults Aged 60 to 96 Years: Data from the "Good Aging in Skåne" (GÅS) Swedish Population Study

BACKGROUND

The association between physical frailty and performance in different cognitive domains in the absence of cognitive disorders is poorly understood. Hence, we aimed to explore the associations between frailty levels based on the Fried Physical Frailty Phenotype and performance of different cognitive domains. We also aimed to examine the associations between cognitive function and each criterion in the Fried Frailty Scale using the same cognitive domains in a non-dementia population aged 60-96 years.

METHODS

This cross-sectional study included 4,329 participants aged 60-96 years, drawn from the "Good Aging in Skåne" population study. Frailty indices included handgrip strength, physical endurance, body mass index (BMI), physical activity, and walking speed. Cognitive function was assessed across eight domains: episodic memory, processing speed, semantic memory, verbal fluency, working memory, attention, executive function, and visual perception. We constructed adjusted multiple linear regression models for each cognitive domain, with the frailty levels as the independent variable. Likewise, we constructed linear regression models with each cognitive domain as the dependent variable and frailty criteria as independent variables.

RESULTS

Physical frailty was associated with poor performance in episodic memory, processing speed, semantic memory, verbal fluency, working memory, attention, and executive functions (p<0.001 for all associations). Weaker hand grip strength was independently associated with poorer performance in all cognitive domains (p < 0.015).

CONCLUSION

Higher levels of frailty were associated with poorer performance in all cognitive domains except visual perception. Describing frailty by considering cognitive functioning may provide a better understanding of frailty.

How does urbanization affect the cognitive function among older adults: A geospatial analysis in China

There has been a plethora of studies on urbanization and older adults, and more recent ones on how older adults adapt to this process with their cognitive competence. Yet it has been unclear about the relationship between them, like how the level and rate of urbanization affect the cognitive function among older adults. This study sourced, formed, and analyzed a set of geospatial big datasets from different sources, such as the Chinese Longitudinal Healthy Longevity Survey (CLHLS) data, and the NPP/VIIRS nighttime light (NTL) data. Results showed a generally negative linear association between the rate of urbanization and cognitive performance among older adults in China. The "U" shaped non-linear relationship between urbanization level and cognitive function, as well as the tipping point, were identified. At the same time, it should be noted that mediators such as education, physical activity, social activity, and community elderly service might be able to mitigate these negative associations. Furthermore, older adults living in eastern regions or urban areas appeared to have better cognitive function than those living in mid-western regions or rural areas in China. The findings also pointed to the importance of focusing on older adults with poor cognitive health status in rapidly urbanizing areas.

Rural and urban differences in lifetime occupation and its influence on mortality among Mexican adults

OBJECTIVE

To determine how primary lifetime occupation type is associated with mortality, and how the relationship varies by rural and urban dwelling.

MATERIALS AND METHODS

Data come from 2001-2018 Mexican Health and Aging Study (adults aged 50+, n=11 094). We created five occupation categories. Cox proportional hazard models predicted mortality using baseline covariates.

RESULTS

In both rural and urban settings, participants with manual jobs, such as agriculture and production/industrial jobs, had an increased risk of mortality compared to those with administrative/professional jobs. In urban settings, participants in the domestic/service and no main job categories had higher risk of mortality than those in the administrative/professional category. For men these differences remained, but not for women.

CONCLUSION

In a context of rural and urban demographic shifts, it is crucial to consider the implications that occupation as a socioeconomic factor can have on health and to identify the most vulnerable groups.

Mental health and cognitive function among medical students after the COVID-19 pandemic in China

Background

Chinese people experienced a nationwide coronavirus disease 2019 (COVID-19) pandemic after the adjustment of epidemic response policies from December 2022 to January 2023. This study aims to explore the prevalence of mental and cognitive symptoms and their associated factors among medical students after the COVID-19 pandemic.

Methods

A cross-sectional study was conducted between February 27th and March 8th, 2023. The symptoms of anxiety, depression, insomnia, post-traumatic stress disorder (PTSD), and cognitive function among medical students were examined using the Generalized Anxiety Disorder-7 (GAD-7), the Patient Health Questionnaire-9 (PHQ-9), the Athens Insomnia Scale (AIS), the Impact of Event Scale-6 (IES-6), and the Perceived Deficits Questionnaire-Depression-5 (PDQ-D-5). Data on demographic information was also collected. Statistical analyses were conducted to describe the prevalence and explore the associated factors of mental and cognitive symptoms.

Results

Among 947 participants, the proportion of students experiencing anxiety, depression, insomnia, and PTSD symptoms was 37.8, 39.3, 28.3, and 29.5%, respectively. The self-reported COVID-19 infection rate was 72.2%. Higher grades, childhood, and current rural residence were identified as potential risk factors for mental and cognitive symptoms. Gender, age, average monthly household income, and COVID-19 diagnosis were not associated with mental and cognitive symptoms among medical students.

Conclusion

Our findings revealed a high prevalence of mental and cognitive symptoms among Chinese medical students after the COVID-19 pandemic. Special attention should be paid to the mental health of higher-grade students and those residing in rural areas.

Life course rural/urban place of residence, depressive symptoms and cognitive impairment among older adults: findings from the Longitudinal Aging Study in India

BACKGROUND

Given the unique socioeconomic structures, and the rural/urban differentials in the prevalence of mental illnesses in the country, this study aimed to explore the associations of childhood, adulthood and late-life rural/urban place of residence with mental health outcomes, namely depressive symptoms and cognitive impairment, among older adults in India. The study also examined the relationship between older individuals' life-course rural/urban place of residence and late-life mental and cognitive health.

METHODS

Utilizing data from the Longitudinal Aging Study in India (n = 28,027 older adults age 60 years and above), the study employed multivariable logistic and linear regression models to examine the association between urban/rural residential status, life-course residence, depressive symptoms and cognitive impairment among older adults.

RESULTS

Childhood and adulthood place of residence was not associated with depressive symptoms in older men and women. Current rural place of residence was positively associated with depressive symptoms in older women [adjusted odds ratio (aOR): 1.37, confidence interval (CI): 1.05-1.80] but not men. Childhood [aOR: 1.88, CI: 1.16-3.04], adulthood [aOR: 2.00, CI: 1.26-3.16] and current rural residence [aOR: 1.93, CI: 1.27-2.91] was positively associated with cognitive impairment in men. Only current rural residence [aOR: 1.71, CI: 1.29-2.27] was associated with cognitive impairment in women. There was no significant association between life-course place of residence and depressive symptoms except in case of lifetime rural residence Respondents with urban-urban-urban (childhood-adulthood-current) place of residence were less likely to have depressive symptoms [adjusted coefficient (aCoef.): -0.14, CI: -0.21- -0.07] compared to those with rural-rural-rural place of residence. There were significant associations between life-course residence and cognitive impairment except among rural-urban-rural and urban-rural-rural migrants, showing an urban advantage in cognitive function among older adults.

CONCLUSIONS

This study showed significant associations between life-course residence and depressive symptoms among permanent rural/urban residents. The study also showed significant associations between life-course residence and cognitive impairment except among rural-urban-rural and urban-rural-rural migrants. Considering the rural disadvantage in mental and cognitive health among older adults, the government should continue to support policies that can improve access to education and healthcare among people residing in rural areas and women, in particular. The findings also urge social scientists and gerontologists in particular, to consider the importance of lifetime historical context while evaluating mental and cognitive health of older persons.

Rural residence across the life course and late-life cognitive decline in KHANDLE: A causal inference study

Background

Modifiable risks for dementia are more prevalent in rural populations, yet there is a dearth of research examining life course rural residence on late-life cognitive decline.

Methods

The association of rural residence and socioeconomic status (SES) in childhood and adulthood with late-life cognitive domains (verbal episodic memory, executive function, and semantic memory) and cognitive decline in the Kaiser Healthy Aging and Diverse Life Experiences cohort was estimated using marginal structural models with stabilized inverse probability weights.

Results

After adjusting for time-varying SES, the estimated marginal effect of rural residence in childhood was harmful for both executive function (β = -0.19, 95% confidence interval [CI] = -0.32, -0.06) and verbal episodic memory (β = -0.22, 95% CI = -0.35, -0.08). Effects of adult rural residence were imprecisely estimated with beneficial point estimates for both executive function (β = 0.19; 95% CI = -0.07, 0.44) and verbal episodic memory (β = 0.24, 95% CI = -0.07, 0.55).

Conclusions

Childhood rurality is associated with poorer late-life cognition independent of SES.

Food Insecurity across the Life-Course and Cognitive Function among Older Mexican Adults

BACKGROUND

Food insecurity remains a global public health problem. Experiencing food insecurity is related to poorer cognitive function among older adults. However, few studies have examined how food insecurity, experienced over the life-course, relates to cognitive function among older adults in Mexico.

METHODS

Data came from the 2015 Mexican Health and Aging Study (n = 11,507 adults aged 50 and over). Early- and late-life food insecurity were ascertained by self-report. We evaluated how both measures of food insecurity related to the performance of multiple cognitive tasks (Verbal Learning, Verbal Recall, Visual Scanning, and Verbal Fluency), while controlling for key health and sociodemographic confounders using linear regression.

RESULTS

In descriptive analyses, respondents who experienced food insecurity in either early or late life performed significantly worse on all cognitive tasks when compared to the food secure. In models adjusted for health and sociodemographic confounders, early-life food insecurity predicted worse Verbal Learning performance and late-life food insecurity was associated with poorer Visual Scanning performance.

CONCLUSIONS

Food insecurity was related to poorer cognitive function in a nationally representative sample of older adults in Mexico. However, results suggested that the significance of effects depended on cognitive task and when in the life-course food insecurity was experienced.