Cognitive Disparities: The Impact of the Great Depression and Cumulative Inequality on Later-Life Cognitive Function

Mental disorders in elderly victims of man-made disasters: a scoping review

OBJECTIVE

To map studies on the presence of mental disorders in elderly individuals who have experienced man-made disasters.

METHODOLOGY

This is a scoping review based on the guidelines of the Joanna Briggs Institute. The strategy was applied to the databases Medline/PubMed, LILACS/BVS, PsycInfo, Embase, Web of Science, and CINAHL without temporal or linguistic restrictions. The study selection was performed blindly and in pairs, with conflicts resolved by a third reviewer.

RESULTS

A total of 36 studies were included in this review. Most of the studies were conducted in the US and were cross-sectional, focusing on terrorism and industrial accidents. The identified mental disorders included post-traumatic stress disorder, depressive disorder, anxiety disorder, panic disorder, and substance use or abuse.

CONCLUSION

The results indicate the presence of mental disorders in elderly victims of man-made disasters, despite greater resilience due to their life experiences.

Life Course Patterns of Work History and Cognitive Trajectories Among Community-Dwelling Older Adults

OBJECTIVES

Prior research indicated that diverse work experiences in early and middle life stages are associated with cognitive function in later life. However, whether life course patterns of work history are associated with later life cognitive function in China remains unknown.

METHODS

Data were derived from the China Health and Retirement Longitudinal Study, and 5,800 participants aged 60 years or older were included. We used sequence analysis to identify the work history patterns between ages 18 and 60. Growth curve modeling was performed to evaluate how the work-history patterns are associated with global and domain-specific (i.e., mental intactness and episodic memory) cognitive function.

RESULTS

We identified 8 work patterns, distinguished by duration, transitions, timing, and sequence of work history. Compared with individuals exposed to lifelong agricultural work, those engaged in lifelong nonagricultural employed work had better cognitive function in later life and experienced slower rates of cognitive decline in both global cognitive function and the mental intactness domain. In addition, individuals who shifted from agricultural to nonagricultural employed work early (around age 30) had better global cognitive function in later life, whereas the association was not significant for such a transition later (around age 50).

DISCUSSION

Our study highlights the importance of the duration, sequence, and timing of transitions in work history for cognitive health among older Chinese. Future interventions and policies aimed at improving cognitive function should fully consider the cumulative and dynamic nature of work from a life course perspective.

High School Curricular Rigor and Cognitive Function among White Older Adults

Most research on the strong relationship between education and cognitive aging has focused on years of schooling. Using data from the Wisconsin Longitudinal Study-a sample of White persons born in 1939-we explored whether greater curricular rigor in high school was also associated with better cognitive function in later life. We estimated multilevel structural equation models in data from 2,749 participants who attended 308 Wisconsin high schools, graduating in 1957. Independent of academic ability and performance and school-level financial and material resources, a more rigorous high school curriculum was associated with significantly better global cognitive functioning in 2020, when most participants were 81 years old. There was also a significant mediation via eventual degree attainment. The mediation was moderated such that men and participants from high socioeconomic status families benefited most from a rigorous curriculum. We discuss implications for modern educational policy.

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.

Associations of local area level new deal employment in childhood with late life cognition: evidence from the census-linked health and retirement study

BACKGROUND

Emergency employment programmes during the 1930s and 1940s invested income, infrastructure and social services into communities affected by the Great Depression. We estimate the long-term associations of growing up in an area exposed to New Deal emergency employment in 1940 with cognitive functioning in later life.

METHODS

Members of the Health and Retirement Study cohort (N=5095; mean age 66.3 at baseline) who were age 0-17 in 1940 were linked to their census record from that year, providing prospective information about childhood contextual and family circumstances. We estimated the association between subcounty-level emergency employment participation in 1940 and baseline cognition and rate of cognitive decline between 1998 and 2016.

RESULTS

Compared with those living in the lowest emergency employment quintile in 1940, those who were exposed to moderate levels of emergency employment (third quintile) had better cognitive functioning in 1998 (b=0.092 SD, 95% CI 0.011 to 0.173), conditional on sociodemographic factors. This effect was modestly attenuated after adjusting for respondents' adult education, finances and health factors. There were no significant effects of area-level emergency employment on rate of cognitive decline.

CONCLUSIONS

Exposure to New Deal employment policies during childhood is associated with long-term cognitive health benefits. This is partially explained by increases in educational attainment among those with greater levels of emergency employment activity in the place where they were raised. Future research should investigate which types of New Deal investments may most be related to long-term cognitive health, or if the associations we observe are due to co-occurring programmes.

Income, wealth, and Black-White disparities in cognition

We investigated the contributions of income and wealth (beyond education) to Black-White disparities in cognition and evaluated whether the role of socioeconomic status (SES) varies by age. Based on data from a national survey of Americans (aged 23-94), we used regression models to quantify the overall racial disparities in episodic memory, executive function, and overall cognition, adjusted for sex and age. Potential mediators (i.e., measures of childhood environment, educational attainment, marital status, occupation, income, and wealth) were added in subsequent models. The age- and sex-adjusted Black-White differential in overall cognitive function was around one standard deviation (SD) between ages 25 and 50, but declined to 0.6 SD by age 80. Executive function followed a similar pattern, but the racial disparity in episodic memory declined more rapidly between ages 35 (0.7 SD) and 80 (0.2 SD). Childhood environment and the respondent's educational attainment accounted for 20-25% of the racial disparities in overall cognition. The incremental contribution of household income was small (1-5%). Although wealth had only a small effect at younger ages, the contribution grew with age. Wealth was much more important than income in explaining Black-White disparities in cognition at older ages. Childhood environment, marital status, and SES (including wealth) accounted for one-third of the racial disparity in overall cognition at ages 35-65, but an even greater share at age 80. Our study is the first to demonstrate that, with increasing age, wealth explains more of the Black-White disparity in cognition. A widening racial gap in wealth and the disproportionate financial impact of the Great Recession and the COVID-19 pandemic on minorities do not bode well for Black-White differentials in cognition. Working-age Americans suffered the brunt of the economic impact of those events; the impact on cognition may increase as those cohorts grow older.

The COVID-19 pandemic, well-being, and transitions to post-secondary education

This study examines the immediate and intermediate effects of the COVID-19 pandemic on the well-being of two high school graduation cohorts (2020 and 2021) and how changes in well-being affect students' educational plans and outcomes. Our unique panel data on 3697 students from 214 schools in 8 German federal states contain prospective survey information on three dimensions of well-being: mental health problems, self-rated health, and life satisfaction. Data is collected several months before (fall 2019), shortly before and soon after (spring 2020) as well as several months after (fall/winter 2020/21) the beginning of the COVID-19 pandemic. Applying difference-in-differences designs, random effect growth curve models, and linear regression models, we find that school closures had a positive immediate effect on students' well-being. Over the course of the pandemic, however, well-being strongly declined, mainly among the 2021 graduation cohort. We show that a strong decline in mental health is associated with changes in educational and career plans and transition outcomes. As adverse life experiences in adolescence are likely to accumulate over the life course, this study is the first to exhibit potential long-lasting negative effects of the COVID-19 pandemic on education and careers of young individuals.

Childhood Socioeconomic Disadvantage and Pathways to Memory Performance in Mid to Late Adulthood: What Matters Most?

OBJECTIVES

Childhood socioeconomic disadvantage is consistently associated with lower cognitive function in later life. This study aims to distinguish the contribution of specific aspects of childhood socioeconomic disadvantage for memory performance in mid-to-late adulthood, with consideration for direct and indirect effects through education and occupation.

METHODS

Data were from adults aged 50-80 years who completed the life history module in the 2006/07 wave of the English Longitudinal Study of Ageing (n=4,553). The outcome, memory score, was based on word recall tests (range: 0-20 points). We used the g-formula to estimate direct and indirect effects of a composite variable for childhood socioeconomic disadvantage, and its four individual components: lower-skilled occupation of the primary breadwinner, having few books in the home, overcrowding in the home, and lack of water and heating facilities in the home.

RESULTS

Few books were the most consequential component of childhood socioeconomic disadvantage for later life memory (total effect: ⎼0.82 points for few books; 95% CI: ⎼1.04, ⎼0.60), with roughly half being a direct effect. The total effect of a breadwinner in lower-skilled occupations was smaller but not significantly different from few books (⎼0.67 points; 95% CI: ⎼0.88, ⎼0.46), while it was significantly smaller with overcrowding (⎼0.31 points; 95% CI: ⎼0.56, ⎼0.06). The latter two total effects were mostly mediated by education and occupation.

DISCUSSION

A literate environment in the childhood home may have lasting direct effects on memory function in mid-to-later life, while parental occupation and overcrowding appear to influence memory primarily through educational and occupational pathways.

Spousal bereavement and the cognitive health of older adults in the US: New insights on channels, single items, and subjective evidence

This study provides novel insights into older adults' cognitive functioning before and after widowhood onset and possible effect channels. It further examines gender heterogeneity in the adaptation to (anticipated or actual) spousal bereavement, comparing objective evidence with subjective evidence of cognitive abilities. We used longitudinal data of up to 26,584 participants of the Health and Retirement Study, aged over 50 at recruitment, assessed biennially between 1998 and 2016. Two-way fixed effects with dynamic treatment effects were estimated for various cognitive measures, including six aggregated indices and six single item scales. After adjusting for effect channels including depression, social vulnerability, and stress, there remained significant widowhood effects on older adults' cognitive health. Using single item scales, we established the adverse contemporaneous and adaptation effects on bereaved older females' short-term memory, semantic memory, and numeracy. For bereaved older males, working memory and focus-of-attention deteriorated after widowhood onset. Meanwhile, subjective memory rating remained intact, contrary to objective evidence. We conclude that cognitive transitions to and from widowhood can exhibit distinctive patterns across objective and subjective cognitive domains. With the effect channels in mind, cognitive intervention for widowed older adults should be tailored to the temporal distance to spousal loss, gender, and task.

Does postponing retirement affect cognitive function? A counterfactual experiment to disentangle life course risk factors

Evidence suggests that contemporaneous labor force participation affects cognitive function; however, it is unclear whether it is employment itself or endogenous factors related to individuals’ likelihood of employment that protects against cognitive decline. We exploit innovations in counterfactual causal inference to disentangle the effect of postponing retirement on later-life cognitive function from the effects of other life-course factors. With the U.S. Health and Retirement Study (1996–2014, n = 20,469), we use the parametric g-formula to estimate the effect of postponing retirement to age 67. We also study whether the benefit of postponing retirement is affected by gender, education, and/or occupation, and whether retirement affects cognitive function through depressive symptoms or comorbidities. We find that postponing retirement is protective against cognitive decline, accounting for other life-course factors (population: 0.34, 95% confidence interval (CI): 0.20,0.47; individual: 0.43, 95% CI: 0.26,0.60). The extent of the protective effect depends on subgroup, with the highest educated experiencing the greatest mitigation of cognitive decline (individual: 50%, 95% CI: 32%,71%). By using innovative models that better reflect the empirical reality of interconnected life-course processes, this work makes progress in understanding how retirement affects cognitive function.

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Research is inconclusive as to employments' protection against cognitive decline.

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Causal inference models can better reflect interconnected life-course processes.

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The parametric g-formula shows a substantial protective effect of ongoing employment.

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Protective effect holds for all subgroups, but is greatest for the highest educated.

Trends in the Risk of Cognitive Impairment in the United States, 1996-2014

Supplemental Digital Content is available in the text.

Background:

Accumulating evidence suggests risk of cognitive impairment is declining in high-income countries. Much of this research uses longitudinal surveys in which learning over repeated tests may bias results. We analyze trends in cognitive impairment in the United States, accounting for prior test experience and selective mortality.

Methods:

We use the Health and Retirement Study, a population-based, nationally representative panel dataset and include individuals ages 50 years and older in 1996–2014 (n = 32,784). We measure cognitive impairment and dementia using standard cutpoints of the modified Telephone Interview for Cognitive Status. We estimate logistic regression models for any impairment and dementia over time, adjusting for age, sex, and race/ethnicity, comparing models with and without adjustment for practice effects and education. We examine heterogeneity in trends by age, sex, race/ethnicity, and education.

Results:

Models not controlling for test experience suggest that risk of cognitive impairment and dementia decreased over the study period. Controlling for test experience reverses the trend. In our primary models, prevalence of any cognitive impairment increased for women from 18.7% to 21.2% (annual change 0.7%, 95% confidence interval [CI], 0.1%, 1.3%) and for men from 17.6% to 21.0% (annual change 1.0%, CI, 0.5%, 1.4%). For dementia, women’s annual increase was 1.7% (CI, 0.8%, 2.6%) and men’s 2.0% (CI, 1.0%, 2.9%). If not for education, the increase would have been stronger. Increased risk was particularly rapid for Latinas, the least educated, and older ages.

Conclusions:

Risk of cognitive impairment increased from 1996 to 2014. Uncovering determinants of increasing cognitive impairment risk should become a research priority. See video abstract: http://links.lww.com/EDE/B702.

Are Positive Childhood Experiences Linked to Better Cognitive Functioning in Later Life?: Examining the Role of Life Course Pathways

Objectives: We examine whether childhood family well-being is associated with cognitive functioning and to what extent the association between the family context and cognitive functioning is explained by adulthood resources. Methods: Data are drawn from the National Social Life, Health, and Aging Project Wave 3 (2015/2016; N = 3361). We measured cognitive functioning using the Montreal Cognitive Assessment. Childhood family factors included family-life happiness, family structure, and family socioeconomic status. Education, social connectedness, self-mastery, and self-rated health were assessed as adulthood resources. Results: Respondents who grew up in a happy family had significantly higher levels of cognitive functioning. The formal mediation test suggests that a happy family life during childhood has a positive association with later cognition, in part, by enhancing self-mastery in adulthood. Discussion: Our findings provide evidence that positive childhood experiences are linked to later life cognition. The sense of control people have over their life circumstances is one potential pathway explaining this association.

The Relationship of Race, Psychosocial Stress and Resiliency Indicators to Neurocognitive Impairment among Older Americans Enrolled in the Health and Retirement Survey: A Cross-Sectional Study

BACKGROUND

Race/ethnicity, toxic stress (TS), resilience-promoting factors (RPFs), and their interactions were investigated in relationship to neurocognitive impairment (NI) in a nationally representative sample of adult Americans ≥50 years enrolled in the Health and Retirement Study (HRS) between 2012 and 2014.

METHODS

NI was defined as physician diagnosis of Alzheimer's disease/dementia or HRS total cognition score ≤ 10. Race/ethnicity (i.e., African American, White, or Other), TS (i.e., everyday discrimination and chronic stressors), and mastery (as indicator of RPF) were self-reported. Multivariable logistic regression models estimated race-, TS-, RPF-associated odds ratios (ORs), and 95% confidence intervals (CI) for NI adjusting for socio-demographic confounders.

RESULTS

6317 respondents interviewed between the years 2012 and 2014, age range 55-104 years old, 83% White, 13% Black and 4% Other race were included in the study. Chronic stress (OR = 1.88, 95% CI: 1.42-2.48), discrimination (OR = 3.31, 95% CI: 2.12-5.19) and low mastery (OR = 1.85, 95% CI: 1.38-2.48) were each associated with higher NI risk while low mastery was associated with higher NI risk in discrimination and race/ethnicity dependent manner. Specifically, low mastery-associated risk for NI was evident among adults that denied experiencing discrimination (OR = 2.01, 95% CI: 1.51-2.68), but absent among those that experienced discrimination (OR = 0.72, 95% CI: 0.32-1.62). Further, AA race was associated with NI risk but only among adults with high mastery (OR = 2.00, 95% CI: 1.20-3.35).

CONCLUSIONS

Discrimination, chronic stress, and low mastery were associated with worse cognition. Persisting cognitive disadvantage for AA vs. White/Other race only among high mastery adults suggests that adverse social experiences may counteract mastery-associated cognitive benefits among AA population. TS reduction through policies that promote equal treatment by race/ethnicity in social life, health, justice, and economic systems may promote successful cognitive aging.

Gender Differences in the Impact of Depression on Cognitive Decline Among Korean Older Adults

This study aimed to investigate whether (1) depression is associated with cognitive decline in Korean older adults and (2) the relationship between depression and cognitive function varies by gender. Using Korean Longitudinal Study of Aging data of 2006 to 2014, we studied 1787 adults aged 65 years or older who had normal cognitive function at baseline. This study examined the effects of depression on cognitive decline by using an interaction term of baseline depression and time, and compared relationships by gender. Among male participants, K-MMSE (Korean-Mini-Mental Status Examination) scores decreased with age, at an annual rate of approximately 0.465 points. Baseline depression was found to accelerate the decline in cognitive function, by approximately 0.184 points per year. Among female participants, K-MMSE scores decreased with age, at an annual rate of approximately 0.585 points. Baseline depression was not related to the decline in cognitive function. These results suggest the need for community-based programs to increase awareness of mental health problems need to be developed to encourage the use of health services to prevent or delay cognitive decline in older Korean males.

College Selectivity and Later-Life Memory Function: Evidence From the Wisconsin Longitudinal Study

Research has shown a consistent association between college completion and laterlife cognition. We extend this work by examining whether college selectivity—the achievement level required to gain admission to a college—is associated with memory functioning more than 50 years later. We analyze data from 10,317 participants in the 1957–2011 Wisconsin Longitudinal Study to examine the relationship between college selectivity and later-life memory. Models control for childhood, midlife socioeconomic status, and later-life health and adjust for selection bias. Selective college attendance was associated with small benefits in memory at age of 72 even after accounting for socioeconomic status in both childhood and midlife and later-life health. The results of this study suggest that college selectivity may be an important component of the education–cognitive functioning relationship that has modest implications for intracohort differences in later-life cognition.

Life Course Pathways From Childhood Socioeconomic Status to Later-Life Cognition: Evidence From the Wisconsin Longitudinal Study

OBJECTIVES

A growing body of research indicates that older adults are at greater risk for poorer cognition if they experienced low socioeconomic status (SES) as children. Guided by life course epidemiology, this study aimed to advance understanding of processes through which childhood SES influences cognition decades later, with attention to the role of scholastic performance in adolescence and SES in midlife.

METHOD

We used data from the Wisconsin Longitudinal Study (WLS), which has followed a cohort of high school graduates since they were 18 years old in 1957. Childhood SES was measured prospectively in adolescence, and measures of memory and language/executive functioning were based on neurocognitive assessments at age 72. We used participants' scores on a statewide standardized test in high school as an indicator of scholastic performance in adolescence. The measure of SES in midlife included years of postsecondary education, income, and occupation status at age 53.

RESULTS

Findings from structural equation models indicated that scholastic performance in adolescence and midlife status attainment together fully mediated associations between childhood SES and both memory and language/executive functioning at age 72. Adolescent scholastic performance was directly associated with later-life cognition, as well as indirectly through midlife status attainment.

DISCUSSION

Findings provide support for both latency and social pathway processes when considering how SES in childhood influences later-life cognition. Results contribute to growing calls for social policies and programs to support optimal brain health at multiple phases throughout the life course, especially among individuals with lower SES as children.