Geographic distribution of dementia mortality: elevated mortality rates for black and white Americans by place of birth

Early learning difficulties, childhood stress, race, and risk of cognitive impairment among US adults over age 50: A cross-sectional analysis

Background and Aims

Most literature linking childhood factors to cognitive health outcomes has focused on educational attainment-defined as years of education attained. However, less has been studied about the other aspects of education, such as early learning problems, and stressful family environments. This study examined whether early learning problems and childhood stressors were associated with mid- and later life cognitive impairment among US adults, and if these associations varied by race.

Methods

We conducted a cross-sectional analysis using the Health and Retirement Study (HRS) along with respondents' early educational experiences from the 2015 to 2017 Life History Mail Survey (N = 9703). Early learning problems were defined as having any of the following: scholastic problems (reading, writing, mathematics), speaking/language issues, and sensorimotor issues- hearing, vision, speech, and motor-coordination. Cognitive status was classified as three levels (normal, cognitively impaired not demented [CIND], and demented) using the HRS Langa-Weir algorithm. Multinomial logistic regression models using generalized logits, estimated relative risk ratios (RRRs), and 95% confidence intervals (CI) with adjustment for sociodemographic factors.

Results

Having at least one early learning problem was associated with increased risk of later life cognitive impairment (RRR: 1.75, 95% CI: 1.34-2.29 for dementia, RRR: 1.42, 95% CI: 1.20-1.67 for CIND). Parental death before the age of 16 was associated with 17% higher risk of CIND in later life (RRR: 1.17, 95% CI: 1.01-1.34). However, learning problem-related differences in risk of cognitive impairment were dependent on race (learning problems × race, p = 0.0001). In the demented group, Blacks were 2.7 times more likely to be demented (RRR: 2.66, 95% CI: 1.69-4.17) amongst older adults that experienced childhood learning problems.

Conclusions

Early life exposures predicted risk of cognitive impairment. Policies and interventions that enhance diagnosis of early learning problems and improve childhood social contexts are needed to promote healthy cognitive aging amongst Americans, regardless of race.

Place of Birth and Cognition among Older Americans: Findings from the Harmonized Cognitive Assessment Protocol

Objectives

Growing evidence suggests that place of birth (PoB) and related circumstances may have long-lasting and multiplicative contributions to various later-life outcomes. However, the specific contributions to different domains of cognitive function in late life remain less understood. This study aimed to investigate the extent to which PoB contribute to a wide range of later-life cognitive outcomes.

Methods

A nationally representative sample of Americans aged 65 and older (N=3,216) from the Health and Retirement Study (HRS) Harmonized Cognitive Assessment Protocol (HCAP) was utilized. Cognitive outcomes were assessed in HCAP and linked to HRS state-level PoB data to explore the contribution of birthplace to later-life cognitive disparities. Regression-based Shapley decompositions were employed to quantify this contribution.

Results

PoB significantly contributed to all assessed cognitive outcomes including memory, executive function, language and fluency, visuospatial function, orientation, global cognitive performance, cognitive impairment and dementia. Geographic disparities in cognitive outcomes were evident, with individuals born in US southern states and foreign-born individuals performing worse than those born in other states. PoB overall accounted for 2.4-13.9% of the total variance in cognition after adjusting for age and sex. This contribution reduced by half when adjusting for a rich set of sociodemographic and health factors over the life course, but PoB still independently explained 2.0-7.1% of the total variance in cognition.

Discussion

PoB has lasting contributions to later-life cognitive health, with significant geographic disparities observed. Addressing these disparities requires promoting more equalized place-based policies, resources, and early-life environments to improve health equities over the life course.

Geographic Patterns of Dementia in the United States: Variation by Place of Residence, Place of Birth, and Subpopulation

OBJECTIVES

The prevalence of dementia varies geographically in the United States. However, the extent to which this variation reflects contemporary place-based experiences versus embodied exposures from earlier in the life course remains unclear, and little is known regarding the intersection of place and subpopulation. This study, therefore, evaluates whether and how risk for assessed dementia varies by place of residence and birth, overall and by race/ethnicity and education.

METHODS

We pool data from the 2000 to 2016 waves of the Health and Retirement Study, a nationally representative panel survey of older U.S. adults (n = 96,848 observations). We estimate the standardized prevalence of dementia by Census division of residence and birth. We then fit logistic regression models of dementia on region of residence and birth, adjusting for sociodemographic characteristics, and examine interactions between region and subpopulation.

RESULTS

The standardized prevalence of dementia ranges from 7.1% to 13.6% by division of residence and from 6.6% to 14.7% by division of birth, with rates highest throughout the South and lowest in the Northeast and Midwest. In models accounting for region of residence, region of birth, and sociodemographic covariates, Southern birth remains significantly associated with dementia. Adverse relationships between Southern residence or birth and dementia are generally largest for Black and less-educated older adults. As a result, sociodemographic disparities in predicted probabilities of dementia are largest for those residing or born in the South.

DISCUSSION

The sociospatial patterning of dementia suggests its development is a lifelong process involving cumulated and heterogeneous lived experiences embedded in place.

Rural versus Urban Residence in Adulthood and Incident Cognitive Impairment

INTRODUCTION

Rural versus urban living is a social determinant of cognitive health. We estimated the association of rural versus urban residence in the USA with incident cognitive impairment (ICI) and assessed effect heterogeneity by sociodemographic, behavioral, and clinical factors.

METHODS

The Reasons for Geographic and Racial Differences in Stroke Study (REGARDS) is a population-based prospective observational cohort of 30,239 adults, 57% female, 36% Black, aged 45+ years, sampled from 48 contiguous states in the USA in 2003-2007. We analyzed 20,878 participants who at baseline were cognitively intact with no history of stroke and had ICI assessed on average 9.4 years later. We classified participants' home addresses at baseline as urban (population ≥50,000), large rural (10,000-49,999), or small rural (≤9,999) by Rural-Urban Commuting Area codes. We defined ICI as ≥1.5 SD below the mean on at least 2 of the following tests: word list learning, word list delayed recall, and animal naming.

RESULTS

Participants' home addresses were 79.8% urban, 11.7% large rural, and 8.5% small rural. ICI occurred in 1,658 participants (7.9%). Small rural residents had higher odds of ICI than urban residents, adjusted for age, sex, race, region, and education (OR = 1.34 [95% CI: 1.10, 1.64]), and after further adjustment for income, health behaviors, and clinical characteristics (OR = 1.24 [95% CI: 1.02, 1.53]). Former smoking versus never, nondrinking versus light alcohol drinking, no exercise versus ≥4 times/week, CES-D depressive symptom score of 2 versus 0, and fair versus excellent self-rated health had stronger associations with ICI in small rural areas than in urban areas. For example, in urban areas, lack of exercise was not associated with ICI (OR = 0.90 [95% CI: 0.77, 1.06]); however, lack of exercise combined with small rural residence was associated with 1.45 times the odds of ICI compared with ≥4 bouts of exercise/week in urban areas (95% CI: 1.03, 2.03). Overall, large rural residence was not associated with ICI; however, black race, hypertension, and depressive symptoms had somewhat weaker associations with ICI, and heavy alcohol drinking a stronger association with ICI, in large rural areas than in urban areas.

CONCLUSION

Small rural residence was associated with ICI among USA adults. Further research to better understand why rural residents are at higher risk for developing ICI and mechanisms to ameliorate that risk will support efforts to advance rural public health.

High-risk spatiotemporal patterns of cutaneous leishmaniasis: a nationwide study in Iran from 2011 to 2020

BACKGROUND

Cutaneous leishmaniasis (CL) is a wide-reaching infection of major public health concern. Iran is one of the six most endemic countries in the world. This study aims to provide a spatiotemporal visualization of CL cases in Iran at the county level from 2011 to 2020, detecting high-risk zones, while also noting the movement of high-risk clusters.

METHODS

On the basis of clinical observations and parasitological tests, data of 154,378 diagnosed patients were obtained from the Iran Ministry of Health and Medical Education. Utilizing spatial scan statistics, we investigated the disease's purely temporal, purely spatial, spatial variation in temporal trends and spatiotemporal patterns. At P = 0.05 level, the null hypothesis was rejected in every instance.

RESULTS

In general, the number of new CL cases decreased over the course of the 9-year research period. From 2011 to 2020, a regular seasonal pattern, with peaks in the fall and troughs in the spring, was found. The period of September-February of 2014-2015 was found to hold the highest risk in terms of CL incidence rate in the whole country [relative risk (RR) = 2.24, P < 0.001)]. In terms of location, six significant high-risk CL clusters covering 40.6% of the total area of the country were observed, with the RR ranging from 1.87 to 9.69. In addition, spatial variation in the temporal trend analysis found 11 clusters as potential high-risk areas that highlighted certain regions with an increasing tendency. Finally, five space-time clusters were found. The geographical displacement and spread of the disease followed a moving pattern over the 9-year study period affecting many regions of the country.

CONCLUSIONS

Our study has revealed significant regional, temporal, and spatiotemporal patterns of CL distribution in Iran. Over the years, there have been multiple shifts in spatiotemporal clusters, encompassing many different parts of the country from 2011 to 2020. The results reveal the formation of clusters across counties that cover certain parts of provinces, indicating the importance of conducting spatiotemporal analyses at the county level for studies that encompass entire countries. Such analyses, at a finer geographical scale, such as county level, might provide more precise results than analyses at the scale of the province.

Do prenatal factors shape the risk for dementia?: A systematic review of the epidemiological evidence for the prenatal origins of dementia

PURPOSE

Prenatal factors such as maternal stress, infection and nutrition affect fetal brain development and may also influence later risk for dementia. The purpose of this systematic review was to provide an overview of all studies which investigated the association between prenatal factors and later risk for dementia.

METHODS

We systematically searched MEDLINE and Embase for original human studies reporting on associations between prenatal factors and dementia from inception to 23 November 2022. Prenatal factors could be any factor assessed during pregnancy, at birth or postnatally, provided they were indicative of a prenatal exposure. Risk of bias was assessed using the Newcastle Ottawa Scale. We followed PRISMA guidelines for reporting.

RESULTS

A total of 68 studies met eligibility criteria (including millions of individuals), assessing maternal age (N = 30), paternal age (N = 22), birth order (N = 15), season of birth (N = 16), place of birth (N = 13), prenatal influenza pandemic (N = 1) or Chinese famine exposure (N = 1), birth characteristics (N = 3) and prenatal hormone exposure (N = 4). We observed consistent results for birth in a generally less optimal environment (e.g. high infant mortality area) being associated with higher dementia risk. Lower and higher birth weight and prenatal famine exposure were associated with higher dementia risk. The studies on season of birth, digit ratio, prenatal influenza pandemic exposure, parental age and birth order showed inconsistent results and were hampered by relatively high risk of bias.

CONCLUSION

Our findings suggest that some prenatal factors, especially those related to a suboptimal prenatal environment, are associated with an increased dementia risk. As these associations may be confounded by factors such as parental socioeconomic status, more research is needed to examine the potential causal role of the prenatal environment in dementia.

Is cognitive reserve associated with the prevention of cognitive decline after stroke? A Systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analyses of the effect of socio-behavioral cognitive reserve (CR) proxies on cognitive decline after stroke.

METHOD

Three journal search and indexing databases (PubMed, Scopus and Web of Sciences) were crossed to examine the scientific evidence systematically. In addition, meta-analytic techniques, using mixed-effect methods, were carried out to estimate the impact (pooled effect size) of CR proxies on either dementia incidence or cognitive decline after stroke.

RESULTS

Twenty-two studies were included in the systematic revision, whereas nineteen of them were eligible for the meta-analysis. The findings showed that high education is associated with a decreased rate of post-stroke dementia. Moreover, other CR proxies (e.g., occupation, bilingualism or social interaction) demonstrate a protective effect against non-dementia cognitive decline after stroke, although some inconsistencies were found in the literature. Regarding the meta-analysis, occupational attainment and education) showed a protective effect against post-stroke cognitive impairment diagnosis in comparison with a mixed category of different CR proxies. Second, a main cognitive change effect was found, pointing to greater cognitive change after stroke in those with low vs. high CR.

CONCLUSIONS

Our findings emphasize that CR may prevent cognitive decline after stroke, but this effect can be modulated by different factors such the CR proxy and individual characteristics such as age or type of lesion. The methodological divergences of the studies (i.e., follow-up intervals, cognitive outcomes) need unification to diminish external sources of variability for predicting rates of cognitive decline after stroke.

Attitudes toward Alzheimer's disease and dementia caregiving and health outcomes: Racial and ethnic differences

This study aimed to explore racial/ethnic differences in the attitudes toward Alzheimer's Disease (AD) and dementia caregiving among midlife women who were family caregivers of persons living with AD (MWPLAD) in the U.S. and examine the associations of the attitudes to their health outcomes. This was a cross-sectional online survey study among 172 MWPLAD. The instruments included: the Attitude toward AD and Related Dementias Scale, the Questions on Attitudes toward AD Caregiving, the Social Readjustment Rating Scale, the EQ-5D-5L and the Midlife Women's Symptom Index. Multiple linear regression analyses were conducted. There were significant racial/ethnic differences in caregivers' attitudes toward dementia caregiving, health-related quality of life, and total severity scores of symptoms (p < .01). Controlling for covariates including race/ethnicity, caregivers' positive attitudes toward dementia caregiving were significantly associated with their health outcomes (p ≤ .05). Interventions for MWPLAD need to consider racial/ethnical differences in their attitudes toward dementia caregiving.

Race Inequity in School Attendance Across the Jim Crow South and Its Implications for Black-White Disparities in Trajectories of Cognitive Function Among Older Adults

OBJECTIVES

Although education is a key determinant of cognitive function, its role in determining Black-White disparities in cognitive function is unclear. This may be due, in part, to data limitations that have made it difficult to account for systemic educational inequities in the Jim Crow South experienced by older cohorts, including differences in the number of days Black students attended school compared to their White counterparts or Black peers in better-funded southern states. We determine if accounting for differential rates of school attendance across race, years, and states in the Jim Crow South better illuminates Black-White disparities in trajectories of cognitive function.

METHODS

We linked historical state-level data on school attendance from the 1919/1920 to 1953/1954 Biennial Surveys of Education to the Health and Retirement Study, a nationally representative, longitudinal study of U.S. adults older than age 50. We restricted our sample to Black and White older adults who attended school in the Jim Crow South and began primary school in/after 1919/1920 and completed primary/secondary school by 1953/1954 (n = 4,343). We used linear mixed models to estimate trajectories of total cognitive function, episodic memory, and working memory.

RESULTS

Self-reported years of schooling explained 28%-33% of the Black-White disparity in level of cognitive function, episodic memory, and working memory. Duration of school, a measure that accounted for differential rates of school attendance, explained 41%-55% of the Black-White disparity in these outcomes.

DISCUSSION

Our study highlights the importance of using a more refined measure of schooling for understanding the education-cognitive health relationship.

The role of geographic information system and global positioning system in dementia care and research: a scoping review

Background

Geographic Information System (GIS) and Global Positioning System (GPS), vital tools for supporting public health research, provide a framework to collect, analyze and visualize the interaction between different levels of the health care system. The extent to which GIS and GPS applications have been used in dementia care and research is not yet investigated. This scoping review aims to elaborate on the role and types of GIS and GPS applications in dementia care and research.

Methods

A scoping review was conducted based on Arksey and O’Malley’s framework. All published articles in peer-reviewed journals were searched in PubMed, Scopus, and Web of Science, subject to involving at least one GIS/GPS approach focused on dementia. Eligible studies were reviewed, grouped, and synthesized to identify GIS and GPS applications. The PRISMA standard was used to report the study.

Results

Ninety-two studies met our inclusion criteria, and their data were extracted. Six types of GIS/GPS applications had been reported in dementia literature including mapping and surveillance (n = 59), data preparation (n = 26), dementia care provision (n = 18), basic research (n = 18), contextual and risk factor analysis (n = 4), and planning (n = 1). Thematic mapping and GPS were most frequently used techniques in the dementia field.

Conclusions

Even though the applications of GIS/GPS methodologies in dementia care and research are growing, there is limited research on GIS/GPS utilization in dementia care, risk factor analysis, and dementia policy planning. GIS and GPS are space-based systems, so they have a strong capacity for developing innovative research based on spatial analysis in the area of dementia. The existing research has been summarized in this review which could help researchers to know the GIS/GPS capabilities in dementia research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12942-022-00308-1.

Are Brain and Cognitive Reserve Shaped by Early Life Circumstances?

When growing older, many people are faced with cognitive deterioration, which may even amount to a form of dementia at some point in time. Although neuropathological signs of dementia disorders can often be demonstrated in brains of patients, the degree to which clinical symptoms are present does mostly not accurately reflect the amount of neuropathology that is present. Sometimes existent pathology even goes without any obvious clinical presentation. An explanation for this phenomenon may be found in the concept of reserve capacity. Reserve capacity refers to the ability of the brain to effectively buffer changes that are associated with normal aging processes and to cope with pathological damage. A larger reserve capacity has been suggested to increase resilience against age-associated cognitive deterioration and dementia disorders. Traditionally, a division has been made between brain reserve, which is based on morphological characteristics of the brain, and cognitive reserve, which is based on functional characteristics of the brain. The present review discusses the premises that brain and cognitive reserve capacity are shaped by prenatal and early postnatal factors. Evidence is accumulating that circumstances during the first 1,000 days of life are of the utmost importance for the lifelong health of an individual. Cognitive deterioration and dementia disorders may also have their origin in early life and a potentially important pathway by which the early environment affects the risk for neurodegenerative diseases is by developmental programming of the reserve capacity of the brain. The basic idea behind developmental programming of brain and cognitive reserve is explained and an overview of studies that support this idea is presented. The review is concluded by a discussion of potential mechanisms, synthesis of the evidence and relevance and future directions in the field of developmental origins of reserve capacity.

Race, Childhood Socioeconomic Status, and Region of Childhood Residence as Intersectional Life Course Predictors of Cognitive Aging in the U.S

Background and Objectives

Race, childhood socioeconomic status (cSES), and region of childhood residence are each associated with later life cognition, but no studies have examined how the confluence of these factors influence later life cognitive performance. Guided by intersectionality theory, we examined individuals’ social positionality across these dimensions as a predictor of cognitive performance in later life among non-Hispanic White (NHW) and Black (NHB) older adults.

Research Design and Methods

We used data from the 2010-2016 waves of the Health and Retirement Study (HRS) with participants ages 65 and older in 2010. We employed growth curve modeling to estimate associations among race, cSES and region of childhood residence, as well as their interactions, and cognitive performance at baseline and over time.

Results

Identifying as NHB, residing in the South, and having lower cSES each were associated with poorer later life cognition at baseline. Childhood residence in the South was an especially strong risk factor for poorer cognition among NHBs. Among NHWs, higher cSES was associated with better baseline cognitive performance, especially among those from the South. NHBs from the South demonstrated a small advantage of higher cSES, but regardless of cSES, NHBs from the South had lower levels of baseline cognitive scores compared to all other subgroups. We found that Southern childhood residence predicted faster rates of change in over a 6-year period.

Discussion and Implications

Our findings suggest that intersectional social positions across race, cSES, and region of childhood residence primarily influence baseline cognition in later life. Results implicate the importance of attention to multiple social positions in the context of racism within social policies and other initiatives to promote equity in life course brain health.

Does a Cancer Diagnosis in Mid-to-Later Life Modify Racial Disparities in Memory Aging?

BACKGROUND

It is unknown whether an incident cancer diagnosis differentially impacts acute and long-term memory aging between older White and Black Americans.

METHODS

Incident cancer diagnoses and memory (immediate and delayed recall, combined with proxy-reported memory) were assessed at biennial study interviews in the US Health and Retirement Study (N=14,235, 1998-2016). We used multivariable segmented linear mixed-effects models to evaluate the rate of change in standardized memory score (SD/decade) in the years before, acutely at the time of, and in the years following an incident cancer diagnosis, compared to cancer-free adults, by race.

RESULTS

Black participants experienced faster memory decline than White participants (cancer-free group: -1.211 vs. -1.077; P<0.0001). An incident cancer diagnosis was associated with an acute memory drop in White, but not Black participants (-0.065 vs. 0.024; P<0.0001). However, White cancer survivors experienced slower memory decline than cancer-free White adults before and after diagnosis, but this memory advantage was not observed among Black cancer survivors.

CONCLUSIONS

Racial disparities in memory aging are not modified by an incident cancer diagnosis. The acute cancer-related memory decline and long-term memory advantage experienced by White, but not Black, cancer survivors relative to cancer-free older adults, requires further investigation.

Childhood Background Measures and Their Associations With Later-Life Physical, Mental, and Social Health in the National Social Life, Health, and Aging Project

OBJECTIVE

We describe each childhood background measure available in the National Social Life, Health, and Aging Project (NSHAP), report preliminary population estimates for each measure by age and gender, and validate the childhood measures by showing that the associations between the NSHAP childhood measures and later-life health outcomes are consistent with previous studies on this topic.

METHOD

Childhood background measures included family life happiness, family structure, parental educational attainment, perceived financial situation, experience of violence, witness of violence, childhood health, and place of birth. We measured self-rated health, depressive symptoms, and social support to assess later-life physical, mental, and social health. Logistic and linear regression models were used for the binary and continuous outcome variables, respectively.

RESULTS

Older age groups were more likely than those in younger age groups to report a poor financial situation in childhood, lower parental education, and intact family structure and were less likely to have experienced or witnessed a violent event as a child. Growing up in a happy and well-educated family was associated with better physical, mental, and social health in older ages.

DISCUSSION

NSHAP childhood data included a variety of measures assessing the family social environment during childhood, providing a valuable resource for the study of early-life determinants of health and well-being over the life course.

Stroke Belt birth state and late-life cognition in the Study of Healthy Aging in African Americans (STAR)

PURPOSE

We examined the association of Stroke Belt birth state with late-life cognition in The Study of Healthy Aging in African Americans (STAR).

METHODS

STAR enrolled 764 Black Americans ages 50+ who were long-term Kaiser Permanente Northern California members. Participants completed Multiphasic Health Check-ups (MHC; 1964-1985) where early-life overweight/obesity, hypertension, diabetes, and hyperlipidemia were measured. At STAR (2018), birth state, self-reported early-life socioeconomic status (SES), and executive function, verbal episodic memory, and semantic memory scores were collected. We used linear regression to examine the association between Stroke Belt birth and late-life cognition adjusting for birth year, gender, and parental education. We evaluated early-life SES and cardiovascular risk factors (CVRF) as potential mechanisms.

RESULTS

Twenty-seven percent of participants were born in the Stroke Belt with a mean age of 69 (standard deviation = 9) at STAR. Stroke Belt birth was associated with worse late-life executive function (β [95% confidence interval]: -0.18 [-0.33, -0.02]) and semantic memory (-0.37 [-0.53, -0.21]), but not verbal episodic memory (-0.04 [-0.20, 0.12]). Adjustment for SES and CVRF attenuated associations of Stroke Belt birth with cognition (executive function [-0.05 {-0.25, 0.14}]; semantic memory [-0.28 {-0.49, -0.07}]).

CONCLUSIONS

Black Americans born in the Stroke Belt had worse late-life cognition than those born elsewhere, underscoring the importance of early-life exposures on brain health.

Parental Death and Cognitive Impairment: An Examination by Gender and Race-ethnicity

OBJECTIVES

We provide the first nationally representative longitudinal study of cognitive impairment in relation to parental death from childhood through early adulthood, midlife, and later adulthood, with attention to heterogeneity in the experience of parental death.

METHOD

We analyzed data from the Health and Retirement Study (2000-2016). The sample included 13,392 respondents, contributing 72,860 person-periods. Cognitive impairment was assessed using the modified version of the Telephone Interview for Cognitive Status (TICS). Discrete-time hazard regression models were estimated to predict the odds of cognitive impairment.

RESULTS

Both exposure and timing of parental death were related to risk of cognitive impairment in late life and associations vary by gender. The detrimental effect of a father's death was comparable for daughters and sons although exposure to mother's death had stronger effects on daughter's than son's risk of cognitive impairment. Father's death at younger ages had the strongest effect on sons' late-life risk of cognitive impairment whereas mother's death in middle adulthood had the strongest effect on daughters' risk. We found no significant racial-ethnic variation in the association between parental death and cognitive impairment.

DISCUSSION

It is important to explore the gender-specific pathways through which parental death leads to increased risk of cognitive impairment so that effective interventions can be implemented to reduce risk.

Association and pathways of birth in the stroke belt on old age dementia and stroke Mortality

This paper uses data from the Diet and Health Study (DHS) to examine associations between being born in a "stroke belt" state and old age stroke and mortality outcomes. Adding to prior work that used administrative data, our paper explores educational and health mechanisms that are both stratified by geography and by mortality outcomes. Using logistic regression, we first replicate earlier findings of elevation in risk of dementia mortality (OR 1.13, CI [1.07, 1.20]) and stroke mortality (OR 1.17, CI [1.07, 1.29]) for white individuals born in a stroke belt state. These associations are largely unaffected by controls for educational attainment or by experiences with surviving a stroke and are somewhat attenuated by controls for self-rated health status in old age. The results suggest a need to consider additional life course mechanisms in order to understand the persistent effects of place of birth on old age mortality patterns.

Association of work-family experience with mid- and late-life memory decline in US women

OBJECTIVE

To test the hypothesis that life course patterns of employment, marriage, and childrearing influence later-life rate of memory decline among women, we examined the relationship of work-family experiences between ages 16 and 50 years and memory decline after age 55 years among US women.

METHODS

Participants were women ages ≥55 years in the Health and Retirement Study. Participants reported employment, marital, and parenthood statuses between ages 16 and 50 years. Sequence analysis was used to group women with similar work-family life histories; we identified 5 profiles characterized by similar timing and transitions of combined work, marital, and parenthood statuses. Memory performance was assessed biennially from 1995 to 2016. We estimated associations between work-family profiles and later-life memory decline with linear mixed-effects models adjusted for practice effects, baseline age, race/ethnicity, birth region, childhood socioeconomic status, and educational attainment.

RESULTS

There were 6,189 study participants (n = 488 working nonmothers, n = 4,326 working married mothers, n = 530 working single mothers, n = 319 nonworking single mothers, n = 526 nonworking married mothers). Mean baseline age was 57.2 years; average follow-up was 12.3 years. Between ages 55 and 60, memory scores were similar across work-family profiles. After age 60, average rate of memory decline was more than 50% greater among women whose work-family profiles did not include working for pay after childbearing, compared with those who were working mothers.

CONCLUSIONS

Women who worked for pay in early adulthood and midlife experienced slower rates of later-life memory decline, regardless of marital and parenthood status, suggesting participation in the paid labor force may protect against later-life memory decline.

The hazardous effects of the environmental toxic gases on amyloid beta-peptide aggregation: A theoretical perspective

Alzheimer's disease (AD) is one of the leading causes of dementia in elderly people. It has been well documented that the exposure to environmental toxins such as CO, CO₂, SO₂ and NO₂ that are present in the air is considered as a hallmark for the progression of Alzheimer's disease. However, their actual mechanism by which environmental toxin triggers the aggregation of Aβ42 peptide at the molecular and atomic levels remain unknown. In this study, molecular dynamics simulation was carried out to study the aggregation mechanism of the Aβ₄₂ peptide due to its interaction of toxic gas (CO, CO₂, SO₂ and NO₂). During the 400 ns simulation, all the Aβ₄₂ interacted toxic gas (CO, CO₂, SO_2, and NO₂) complexes have smaller Root Mean Square Deviation values when compared to the Aβ₄₂ peptide, which shows that the interaction of toxic gases (CO, CO₂, SO_2, and NO₂) would increase the Aβ₄₂ peptide structural stability. The radius of gyration analysis also supports that Aβ₄₂ interacted CO₂ and SO₂ complexes have the minimum value in the range of 0.95 nm and 1.5 nm. It is accounted that the Aβ₄₂ interacted CO₂ and SO₂ complexes have a greater compact structure in comparison to Aβ₄₂ interacted CO and NO₂ complexes. Furthermore, all the Aβ₄₂ interacted toxic gas (CO, CO₂, SO_2, and NO₂) complexes exhibited an enhanced secondary structural probability for coil and turn regions with a reduced α-helix probability, which indicates that the interaction of toxic gases may enhance the toxicity and aggregation of Aβ₄₂.

Racial and ethnic differences in trends in dementia prevalence and risk factors in the United States

INTRODUCTION

Disparities in dementia prevalence across racial/ethnic groups in the United States may not be narrowing over time.

METHODS

Data from Health and Retirement Study (2000 to 2012) were analyzed. Dementia was ascertained based on cognitive, functional measures. Logistic regression was used to quantify association between dementia and risk factors, including chronic conditions, use of drug treatment for them, separately for whites, blacks, and Hispanics.

RESULTS

Disparities in dementia prevalence declined between blacks and whites and increased between Hispanics and whites. Adjusting for risk factors reduced but did not eliminate disparities. Compared to no hypertension, untreated hypertension was associated with increased risk of dementia for all racial/ethnic groups while treated hypertension was associated with reduced risk for whites. Diabetes treated with oral drugs was not associated with increased dementia risk.

DISCUSSION

Racial disparities in dementia may be reduced by prevention and management of disease and promoting educational attainment among blacks and Hispanics.

Differential Impact of Index Stroke on Dementia Risk in African-Americans Compared to Whites

OBJECTIVE

To compare whites and African-Americans in terms of dementia risk following index stroke.

METHODS

The data consisted of billing and International Classification of Diseases, Ninth Revision diagnosis codes from the South Carolina Revenue and Fiscal Affairs office on all hospital discharges within the state between 2000 and 2012. The sample consisted of 68,758 individuals with a diagnosis of ischemic stroke prior to 2010 (49,262 white [71.65%] and 19,496 African-Americans [28.35%]). We identified individuals in the dataset who were subsequently diagnosed with any of 5 categories of dementia and evaluated time to dementia diagnosis in Cox Proportional Hazards models. We plotted cumulative hazard curves to illustrate the effect of race on dementia risk after controlling for age, sex, and occurrence of intervening stroke.

RESULTS

Age at index stroke was significantly different between the 2 groups, with African-Americans being younger on average (70.0 [SD 12.5] in whites versus 64.5 [SD 14.1] in African-Americans, P < .0001). Adjusted hazard ratios revealed that African-American race increased risk for all 5 categories of dementia following incident stroke, ranging from 1.37 for AD to 1.95 for vascular dementia. Age, female sex, and intervening stroke likewise increased risk for dementia.

CONCLUSIONS

African-Americans are at higher risk for dementia than whites within 5 years of ischemic stroke, regardless of dementia subtype. Incident strokes may have a greater likelihood of precipitating dementia in African-Americans due to higher prevalence of nonstroke cerebrovascular disease or other metabolic or vascular factors that contribute to cognitive impairment.

The Role of Nutrition and Literacy on the Cognitive Functioning of Elderly Poor Individuals

Maintaining cognitive function is a prerequisite of living independently, which is a highly valued component in older individuals' well-being. In this article we assess the role of early-life and later-life nutritional status, education, and literacy on the cognitive functioning of older adults living in poverty in Peru. We exploit the baseline sample of the Peruvian noncontributory pension program Pension 65 and find that current nutritional status and literacy are strongly associated with cognitive functioning for poor older adults. In a context of rising popularity of noncontributory pension programs around the world, our study intends to contribute to the discussion of designing accompanying measures to the pension transfer, such as adult literacy programs and monitoring of adequate nutrition of older adults.

Ethnic Variations in Prognosis of Patients with Dementia: A Prospective Nationwide Registry Linkage Study in The Netherlands

BACKGROUND

Data on dementia prognosis among ethnic minority groups are limited in Europe.

OBJECTIVE

We assessed differences in short-term (1-year) and long-term (3-year) mortality and readmission risk after a first hospitalization or first ever referral to a day clinic for dementia between ethnic minority groups and the ethnic Dutch population in the NetherlandsMethods: Nationwide prospective cohorts of first hospitalized dementia patients (N = 55,827) from January 1, 2000 to December 31, 2010 were constructed. Differences in short-term and long-term mortality and readmission risk following hospitalization or referral to the day clinic between ethnic minority groups (Surinamese, Turkish, Antilleans, Indonesians) and the ethnic Dutch population were investigated using Cox proportional hazard regression models with adjustment for age, sex, and comorbidities.

RESULTS

Age-sex-adjusted short-term and long-term risks of death following a first hospitalization with dementia were comparable between the ethnic minority groups and the ethnic Dutch. Age- and sex-adjusted risk of admission was higher only in Turkish compared with ethnic Dutch (HR 1.57, 95% CI,1.08-2.29). The difference between Turkish and the Dutch attenuated and was no longer statistically significant after further adjustment for comorbidities. There were no ethnic differences in short-term and long-term risk of death, and risk of readmission among day clinic patients.

CONCLUSION

Compared with Dutch patients with a comparable comorbidity rate, ethnic minority patients with dementia did not have a worse prognosis. Given the poor prognosis of dementia, timely and targeted advance care planning is essential, particularly in ethnic minority groups who are mired by cultural barriers and where uptake of advance care planning is known to be low.

Association Between Birth in a High Stroke Mortality State, Race, and Risk of Dementia

Importance

Birth in a group of predominantly southern US states is robustly linked to increased stroke risk. Given the role of cerebrovascular disease in dementia risk, geographic patterning may also occur for dementia incidence.

Objective

To determine whether birth in 9 high stroke mortality states (HSMSs) is associated with dementia in a diverse cohort of individuals living in Northern California.

Design, Setting, and Participants

An observational cohort study included 7423 members of Kaiser Permanente Northern California (KPNC), an integrated health care delivery system, with health survey and clinical examination data available. Data were collected between 1964 and 1973 when the individuals were middle-aged and 1996 and 2015 when participants were in later life.

Exposures

Self-reported state of birth in an HSMS (top quintile of states for stroke mortality).

Main Outcomes and Measures

Dementia diagnoses obtained from electronic health records from January 1, 1996, to October 15, 2015. Place of birth, race, educational level, and midlife vascular risk factors data were collected between 1964 and 1973.

Results

Of the 7423 persons included in the analysis, 4049 (54.5%) were women; 1354 (18.2%) were black. The mean (SD) age of study participants at their first visit between 1963 and 1974 was 42.94 (1.73) years and mean (SD) age at the beginning of follow-up for dementia in 1996 was 71.14 (2.72) years. Dementia was diagnosed in 2254 (30.4%) of the participants and was more common among those born in an HSMS than those born outside of one (455 [39.0%] vs 1799 [28.8%]). Birth in an HSMS was 9.6 times more common for black participants (795 [58.7%]) than nonblack participants (371 [6.1%]). Overall, birth in an HSMS was associated with a 28% higher risk of dementia (adjusted hazard ratio [aHR], 1.28; 95% CI, 1.13-1.46) adjusted for age, sex, and race. Compared with nonblack persons born outside of an HSMS, black individuals born in an HSMS had the highest dementia risk (aHR, 1.67; 95% CI, 1.48-1.88), followed by black individuals not born in an HSMS (aHR, 1.48; 95% CI, 1.28-1.72), and nonblack persons born in an HSMS had a 46% increased risk (aHR, 1.46; 95% CI, 1.23-1.74). Cumulative 20-year dementia risks at age 65 years were 30.13% (95% CI, 26.87%-32.93%) and 21.80% (95% CI, 20.51%-22.91%) for individuals born in and outside an HSMS, respectively.

Conclusions and Relevance

To our knowledge, this is the first study to date of place of birth and incident dementia and shows increased risk for individuals born in an HSMS, even though all participants subsequently resided in California. Birth in an HSMS was common among black participants. Place of birth has enduring consequences for dementia risk and may be a major contributor to racial disparities in dementia.

Predicting later life health status and mortality using state-level socioeconomic characteristics in early life

Studies extending across multiple life stages promote an understanding of factors influencing health across the life span. Existing work has largely focused on individual-level rather than area-level early life determinants of health. In this study, we linked multiple data sets to examine whether early life state-level characteristics were predictive of health and mortality decades later. The sample included 143,755 U.S. employees, for whom work life claims and administrative data were linked with early life state-of-residence and mortality. We first created a "state health risk score" (SHRS) and "state mortality risk score" (SMRS) by modeling state-level contextual characteristics with health status and mortality in a randomly selected 30% of the sample (the "training set"). We then examined the association of these scores with objective health status and mortality in later life in the remaining 70% of the sample (the "test set") using multivariate linear and Cox regressions, respectively. The association between the SHRS and adult health status was β=0.14 (95%CI: 0.084, 0.20), while the hazard ratio for the SMRS was 0.96 (95%CI: 0.93, 1.00). The association between the SHRS and health was not statistically significant in older age groups at a p-level of 0.05, and there was a statistically significantly different association for health status among movers compared to stayers. This study uses a life course perspective and supports the idea of "sensitive periods" in early life that have enduring impacts on health. It adds to the literature examining populations in the U.S. where large linked data sets are infrequently available.

Inequalities in dementia incidence between six racial and ethnic groups over 14 years

INTRODUCTION

Reducing racial/ethnic disparities is a primary objective of the National Alzheimer's Plan (NAPA), yet direct comparisons within large samples representing diversity of the United States are lacking.

METHODS

Dementia incidence from January 1, 2000 to December 31, 2013 and a 25-year cumulative risk in 274,283 health care members aged 64+ (n = 18,778 African-American, n = 4543 American Indian/Alaska Native [AIAN], n = 21,000 Latino, n = 440 Pacific Islander, n = 206,490 white, n = 23,032 Asian-Americans). Cox proportional hazard models were adjusted for age, sex, medical utilization, and comorbidities.

RESULTS

Dementia incidence (n = 59,555) was highest for African-Americans (26.6/1000 person-years) and AIANs (22.2/1000 person-years); intermediate for Latinos (19.6/1000 person-years), Pacific Islanders (19.6/1000 person-years), and whites (19.3/1000 person-years) and lowest among Asian-Americans (15.2/1000 person-years). Risk was 65% greater for African-Americans (hazard ratio = 1.65; 95% confidence interval = 1.58-1.72) versus Asian-Americans. Cumulative 25-year risk at age 65 was as follows: 38% African-Americans, 35% AIANs, 32% Latino, 25% Pacific Islanders, 30% white, and 28% Asian-Americans.

DISCUSSION

Dementia rates varied over 60% between groups, providing a comprehensive benchmark for the NAPA goal of reducing disparities.

Correlation of Alzheimer's disease death rates with historical per capita personal income in the USA

Alzheimer’s disease (AD) is a progressive degenerating disease of complex etiology. A variety of risk factors contribute to the chance of developing AD. Lifestyle factors, such as physical, mental and social activity, education, and diet all affect the susceptibility to developing AD. These factors are in turn related to the level of personal income. Lower income usually coincides with lower level of education, lesser mental, leisure—social and physical activity, and poorer diet. In the present paper, we have analyzed the correlation of historical (1929–2011) per capita personal income (PCPI) for all states of the USA with corresponding age-adjusted AD death rates (AADR) for years 2000, 2005 and 2008. We found negative correlations in all cases, the highest one (R ≈ -0.65) for the PCPIs in the year 1970 correlated against the AADRs in 2005. From 1929 to 2005 the R value varies in an oscillatory manner, with the strongest correlations in 1929, 1970, 1990 and the weakest in 1950, 1980, 1998. Further analysis indicated that this oscillatory behavior of R is not artificially related to the economic factors but rather to delayed biological consequences associated with personal income. We conclude that the influence of the income level on the AD mortality in 2005 was the highest in the early years of life of the AD victims. Overall, the income had a significant, lifelong, albeit constantly decreasing, influence on the risk of developing AD. We postulate that the susceptibility of a population to late-onset AD (LOAD) is determined to a large extent by the history of income-related modifiable lifestyle risk factors. Among these risk factors, inappropriate diet has a significant contribution.

Spatial distribution and secular trends in the epidemiology of Alzheimer's disease

There are well-established differences in dementia incidence between communities and within communities over time. In part, these differences may be attributable to local improvements in dementia diagnosis and classification. Nevertheless, there are grounds for cautious optimism that there have been slight, but significant, recent reductions in dementia incidence. Possible causes include public health measures to reduce mortality attributable to stroke and heart disease, improved nutrition, and greater personal wealth. A life-course approach to dementia pathophysiology may help to elucidate the nature and timing of interventions that might delay dementia onset.

Prostate cancer mortality and birth or adult residence in the southern United States

PURPOSE

Although there are few confirmed risk factors for prostate cancer (PCa), mortality rates are known to vary geographically across the United States. PCa mortality is higher among black and younger white men in a band of states spanning from Washington DC to Louisiana (the "PCa belt"). This study assessed the associations of birth and adult residence in the PCa belt with PCa mortality among black and white men and trends in these associations over time.

METHODS

PCa-specific mortality rates in 1980, 1990, and 2000 for black and white men born in the continental US, aged 40-89, were calculated by linking national mortality records with population data based on birth state, state of residence at the census, race, and age. PCa belt (Washington DC, Virginia, North Carolina, South Carolina, Georgia, Mississippi, Alabama, and Louisiana) birth was cross-classified against PCa belt adult residence.

RESULTS

Black men born in the PCa belt had elevated PCa mortality in 1980, 1990, and 2000. Associations were independent of adult residence in the PCa belt. For example, in 2000, black men aged 65-89 who were born in the PCa belt but no longer lived there in adulthood had an odds ratio of 1.19 (1.14-1.24) for PCa mortality compared to black men born and residing outside the PCa belt. The PCa belt was not associated with PCa mortality among whites.

CONCLUSIONS

Geographically patterned childhood exposures, for example, differences in social or environmental conditions, or behavioral norms, may influence PCa mortality.

Differences in mortality associated with dementia in U.S. blacks and whites

OBJECTIVES

To test the hypothesis that the geographic pattern of mortality with dementia coded on the death certificate varies according to race and that racial differences vary according to geography in the United States.

DESIGN

Analysis of the U.S. multiple-cause-of-death files for 1999 to 2004.

SETTING

United States.

PARTICIPANTS

Decedents with dementia coded as underlying or contributing cause of death on the death certificate.

MEASUREMENTS

Age-adjusted death rates for U.S. Census geographic divisions for blacks and whites aged 65 and older.

RESULTS

From 1999 to 2004, the U.S. age-adjusted annual death rate per 100,000 for dementia was 628 in blacks and 647 in whites. The difference between rates in blacks and whites ranged from -130 deaths per 100,000 (-36%) in the Middle Atlantic region to +55 (+8%) in the South Atlantic division. Blacks had higher rates in three divisions and whites in five. In the Middle Atlantic and in the United States as a whole, blacks were relatively more likely to receive a diagnosis of unspecified dementia or senility (66%) than Alzheimer's disease (30%) than whites (58% and 41%, respectively).

CONCLUSION

Although overall rates were similar, geographic variation in racial differences in rates of death with dementia occurred between U.S. regions. Further research is needed to assess geographic and racial variation in artifacts of certification versus biological variation as possible causes of variation to enhance utility of mortality data for disease monitoring and health-disparities research.