Parental education and late-life dementia in the United States

Population attributable fractions of modifiable risk factors for dementia: a systematic review and meta-analysis

BACKGROUND

More than 57 million people have dementia worldwide. Evidence indicates a change in dementia prevalence and incidence in high-income countries, which is likely to be due to improved life-course population health. Identifying key modifiable risk factors for dementia is essential for informing risk reduction and prevention strategies. We therefore aimed to estimate the population attributable fraction (PAF) for dementia associated with modifiable risk factors.

METHODS

In this systematic review and meta-analysis, we searched Embase, MEDLINE, and PsycINFO, via Ovid, from database inception up to June 29, 2023, for population-derived or community-based studies and reviews reporting a PAF value for one or more modifiable risk factor for later-life dementia (prevalent or incident dementia in people aged ≥60 years), with no restrictions on dementia subtype, the sex or baseline age of participants, or the period of study. Articles were independently screened for inclusion by four authors, with disagreements resolved through consensus. Data including unweighted and weighted PAF values (weighted to account for communality or overlap in risk) were independently extracted into a predefined template by two authors and checked by two other authors. When five or more unique studies investigated a given risk factor or combination of the same factors, random-effects meta-analyses were used to calculate a pooled PAF percentage estimate for the factor or combination of factors. The review protocol was registered on PROSPERO, CRD42022323429.

FINDINGS

4024 articles were identified, and 74 were included in our narrative synthesis. Overall, PAFs were reported for 61 modifiable risk factors, with sufficient data available for meta-analysis of 12 factors (n=48 studies). In meta-analyses, the highest pooled unweighted PAF values were estimated for low education (17·2% [95% CI 14·4-20·0], p<0·0001), hypertension (15·8% [14·7-17·1], p<0·0001), hearing loss (15·6% [10·3-20·9], p<0·0001), physical inactivity (15·2% [12·8-17·7], p<0·0001), and obesity (9·4% [7·3-11·7], p<0·0001). According to weighted PAF values, low education (9·3% [6·9-11·7], p<0·0001), physical inactivity (7·3% [3·9-11·2], p=0·0021), hearing loss (7·2% [5·2-9·7], p<0·0001), hypertension (7·1% [5·4-8·8], p<0·0001), and obesity (5·3% [3·2-7·4], p=0·0001) had the highest pooled estimates. When low education, midlife hypertension, midlife obesity, smoking, physical inactivity, depression, and diabetes were combined (Barnes and Yaffe seven-factor model; n=9 studies), the pooled unweighted and weighted PAF values were 55·0% (46·5-63·5; p<0·0001) and 32·0% (26·6-37·5; p<0·0001), respectively. The pooled PAF values for most individual risk factors were higher in low-income and middle-income countries (LMICs) versus high-income countries.

INTERPRETATION

Governments need to invest in a life-course approach to dementia prevention, including policies that enable quality education, health-promoting environments, and improved health. This investment is particularly important in LMICs, where the potential for prevention is high, but resources, infrastructure, budgets, and research focused on ageing and dementia are limited.

FUNDING

UK Research and Innovation (Medical Research Council).

Disparate benefits of higher childhood socioeconomic status on cognition in young adulthood by intersectional social positions

OBJECTIVES

Emerging evidence supports the protective effects of higher childhood socioeconomic status (cSES) on cognition over the life course. However, less understood is if higher cSES confers benefits equally across intersecting social positions. Guided by a situational intersectionality perspective and the theory of Minority Diminished Returns (MDR), this study examined the extent to which associations between cSES and cognition in young adulthood are jointly moderated by racialized identity and region of childhood residence.

METHODS

Using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), we used multilevel modeling to test associations between cSES and delayed recall and working memory 14 years later when participants were ages 25-34. Further, we examined the influence of racialized identity and region of childhood residence on these associations.

RESULTS

Higher cSES was associated with higher delayed recall and working memory scores across social positions. However, the strength of the association between higher cSES and working memory differed across racialized subgroups and region of childhood residence. We found a statistically significant three-way interaction between cSES, race and region of childhood residence. Of particular important, a small yet statistically robust association was found in all groups, but was especially strong among White Southerners and especially weak among Black participants from the South.

CONCLUSIONS

This study contributes to a growing body of research indicating that the protective effects of higher cSES on cognition are not universal across subgroups of intersecting social positions, consistent with the theory of MDR. These findings provide evidence for the importance of considering the role of systemic racism across geographic contexts as part of initiatives to promote equity in life course cognitive aging and brain health.

Childhood engagement in cognitively stimulating activities moderates relationships between brain structure and cognitive function in adulthood

Greater engagement in cognitively stimulating activities (CSA) during adulthood has been shown to protect against neurocognitive decline, but no studies have investigated whether CSA during childhood protects against effects of brain changes on cognition later in life. The current study tested the moderating role of childhood CSA in the relationships between brain structure and cognitive performance during adulthood. At baseline (N=250) and 5-year follow-up (N=204) healthy adults aged 20-80 underwent MRI to assess four structural brain measures and completed neuropsychological tests to measure three cognitive domains. Participants were categorized into low and high childhood CSA based on self-report questionnaires. Results of multivariable linear regressions analyzing interactions between CSA, brain structure, and cognition showed that higher childhood CSA was associated with a weaker relationship between cortical thickness and memory at baseline, and attenuated the effects of change in cortical thickness and brain volume on decline in processing speed over time. These findings suggest higher CSA during childhood may mitigate the effects of brain structure changes on cognitive function later in life.

My Parent, Myself, or My Child: Whose Education Matters Most for Trajectories of Cognitive Aging in Middle Age?

The growing body of evidence linking intergenerational education and late-life cognitive decline is almost exclusively from high-income countries, despite rapid intergenerational changes in education in low- and middle-income countries (LMICs). We used data from the Mexican Health and Aging Study (n = 8,822), a cohort study of Mexican adults aged ≥50 years (2001-2018), to evaluate whether parental education (none vs. any formal schooling), one's own education (less than primary school vs. completion of primary school), or an adult child's education (less than high school vs. completion of high school) was associated with verbal memory z scores. We used linear mixed models with inverse probability of attrition weights. Educational attainment in all 3 generations was associated with baseline verbal memory scores, independent of the prior generation's education. Lower parental (β = -0.005, 95% confidence interval: -0.009, -0.002) and respondent (β = -0.013, 95% confidence interval: -0.017, -0.010) educational level were associated with faster decline in delayed (but not immediate) verbal memory z scores. Associations between adult child's education and respondent's verbal memory decline varied by exposure specification. The educational attainment of parents and adult children may influence the cognitive aging of middle-aged and older adults in LMICs. These results have important implications given recent structural shifts in educational attainment in many LMICs.

Early life adversity, race, and childhood socioeconomic status: intersecting drivers of later life cognition

OBJECTIVES

Research on associations between early life adversity (ELA) and later life cognition has yielded mixed results and generally have not considered how broader societal systems of stratification potentially influence associations. The current study addresses this gap by exploring if racialized identity and childhood socioeconomic status (cSES) moderate associations between ELA exposure and later life cognition.

METHODS

Using data from the Health and Retirement Study (Waves 2010-2018), we used growth curve modeling to examine if the confluence of ELA, cSES, and racialized identity is associated with cognition.

RESULTS

Among White participants, greater exposure to ELA was associated with poorer baseline cognitive functioning, and higher cSES buffered against this association. Among Black participants, exposure to ELA was not associated with baseline cognitive functioning, regardless of cSES. We did not find evidence of any associations between main predictors nor their interactions with change in cognition over time.

CONCLUSIONS

This study provides evidence that associations between ELA and later life cognition is contingent upon multiple social positions in the United States. These findings support the importance of integrating insights on intersecting social positions within life-course-oriented efforts to reduce racialized cognitive disparities.

Beneficial Effect of Societal Factors on APOE-ε2 and ε4 Carriers' Brain Health: A Systematic Review

BACKGROUND

Apolipoprotein-E (APOE) ε4 and ε2 are the most prevalent risk-increasing and risk-reducing genetic predictors of Alzheimer's disease, respectively. However, the extent to which societal factors can reduce the harmful impact of APOE-ε4 and enhance the beneficial impact of APOE-ε2 on brain health has not yet been examined systematically.

METHODS

To fill this gap, we conducted a systematic review searching for studies in MEDLINE, Embase, PsycINFO, and Scopus until June 2023, that included: (a) 1 of 5 social determinants of health (SDH) identified by Healthy People 2030, (b) APOE-ε2 or APOE-ε4 allele carriers, (c) cognitive or brain-biomarker outcomes, and (d) studies with an analysis of how APOE-ε2 and/ or APOE-ε4 carriers differ on outcomes when exposed to SDH.

RESULTS

From 14 076 articles retrieved, 124 met the inclusion criteria. In most of the studies, exposure to favorable SDH reduced APOE-ε4's detrimental effect and enhanced APOE-ε2's beneficial effect on cognitive and brain-biomarker outcomes (cognition: 70.5%, n: 74/105; brain-biomarkers: 71.4%, n: 20/28). A similar pattern of results emerged in each of the 5 Healthy People 2030 SDH categories, where finishing high school, having resources to satisfy basic needs, less air pollution, less negative external stimuli that can generate stress (eg, negative age stereotypes), and exposure to multiple favorable SDH were associated with better cognitive and brain health among APOE-ε4 and APOE-ε2 carriers.

CONCLUSIONS

Societal factors can reduce the harmful impact of APOE-ε4 and enhance the beneficial impact of APOE-ε2 on cognitive outcomes. This suggests that plans to reduce dementia should include community-level policies promoting favorable SDH.

Parental Education and Delirium Risk after Surgery in Older Adults

OBJECTIVES

Efforts to conceptualize risk factors for postoperative delirium in older adults have focused on the time proximate to the episode, but how early-life exposures influence delirium risk is poorly understood.

METHODS

An observational cohort of 547 patients aged 70+undergoing major non-cardiac surgery at two academic medical centers in Boston. Demographic characteristics, cognition, parental education, health, and participation in cognitively stimulating activities were assessed prior to surgery. Delirium incidence and severity were measured daily during hospitalization.

RESULTS

Higher paternal education was associated with significantly lower incidence of delirium (X2(1, N =547)=8.35, p <.001; odds ratio OR=.93, 95% CI, .87 to .98) and inversely associated with delirium severity (r(545)=-.13, p <.001). Higher maternal education was associated with lower delirium incidence but did not reach statistical significance. The effect of paternal education on delirium incidence was independent of the patient's education, estimated premorbid intelligence, medical comorbidities, neighborhood disadvantage, and participation in cognitively stimulating activities (X2(2, N =547)=31.22, p <.001).

CONCLUSIONS

Examining early-life exposures may yield unique insights into the risks and pathogenesis of delirium.

CLINICAL IMPLICATIONS

Evaluating long-term factors that increase vulnerability to delirium may improve our ability to calculate risk. It may guide clinical decision-making and inform pre- and post-operative recommendations.

The Role of Adverse Childhood Experiences in Multidimensional Nature of Subjective Age

OBJECTIVES

Age stereotypes and expectations about one's own aging commence in childhood, while most research focuses on predictive associations with midlife cognition and health outcomes in later life. This study instead aims to examine adverse childhood experiences (ACEs) contributing to multiple measures of subjective age (SA) among Chinese older adults and test whether these relationships differ by household registration (hukou).

METHODS

In a representative sample of Chinese older adults aged 60 and older from the 2018 China Longitudinal Aging and Social Survey (n = 7,815), ordinary least squares is used to examine the associations between ACEs and 3 facets of SA: felt age, look age, and self-defined aging standard.

RESULTS

Childhood starvation experience and limited health care access predict older felt age and look age, while parental death is associated with lower self-defined aging standard. Zooming in on hukou-specific associations shows that the dose-response relationship on older adults with rural hukou is particularly pronounced.

DISCUSSION

Findings provide empirical support for views of aging from a life-course perspective and highlight the enduring impact of ACEs for late-adulthood SA, as well as their differential influence on multiple indicators of SA. Interventions that focus on promoting health and development in childhood could potentially have effects beyond the childhood phase, and benefit for their positive aging attitude in later life.

Childhood socio-economic circumstances and dementia: prospective register-based cohort study of adulthood socio-economic and cardiovascular health mediators

Background

This study analysed the association between childhood socio-economic circumstances and the risk of dementia, and investigated the mediating role of potentially modifiable risk factors including adulthood socio-economic position and cardiovascular health.

Methods

We used a 10% sample of the 1950 Finnish population census linked with subsequent population and health registers (n = 95 381). Information of socio-economic characteristics, family structure and housing conditions at the age of 0–15 years was obtained from the 1950 census. We identified cohort members who developed dementia in 2000–2018 using national hospital, medication and death registers. Discrete time survival analysis using logistic regression and mediation analysis applying the Karlson–Holm–Breen (KHB) method were employed.

Results

An excess risk of dementia was observed for household crowding [odds ratio (OR) = 1.10; 95% CI 1.02–1.18 for 3 to &lt;4 persons per heated room; OR = 1.19; 95% CI 1.11–1.27 for ≥4 persons], single-father family (OR = 1.27; 95% CI 1.07–1.51) and eastern and northern region of residence (OR = 1.19; 95% CI 1.10–1.28). The effects of single-father family and region of residence were mostly direct with adulthood characteristics mediating 14% and 29% of the total effect, respectively. The largest indirect effect was observed for household crowding mediated through adulthood socio-economic position (47–65%).

Conclusions

The study shows that childhood socio-economic circumstances are associated with dementia, and that the underlying mechanisms only partly relate to adulthood socio-economic position and cardiovascular health. Socio-economic and health interventions targeted at families with children may carry long-term benefits by contributing to a lower dementia risk in later life.

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.

A framework of social determinants of health for delirium tailored to older adults

Delirium is a debilitating medical condition that disproportionately affects hospitalized older adults and is associated with adverse health outcomes, increased mortality, and high medical costs. Efforts to understand delirium risk in hospitalized older adults have focused on examining medical comorbidities, pre-existing cognitive deficits, and other clinical and demographic factors present in the period proximate to the hospitalization. The contribution of social determinants of health (SDOH), including social circumstances, environmental characteristics, and early-life exposures, referred as the social exposome, to delirium risk is poorly understood. Increased knowledge about the influence of SDOH will offer a more comprehensive understanding of factors that may increase vulnerability to delirium and poor outcomes. Clinically, these efforts can guide the development and implementation of holistic preventive strategies to improve clinical outcomes. We propose a SDOH framework for delirium adapted for older adults. We provide the definition, description, and rationale for the domains and variables in our proposed model.

Associations between childhood adversities and late-life cognitive function: Potential mechanisms

RATIONALE

Childhood adversity, which is related to negative cognitive consequences, is highly prevalent across the world. Nonetheless, there is still a scarcity of research on late-life cognitive function that accounted for multiple aspects of adverse events as well as the potential mediating mechanism of social context and individual's wellbeing in adulthood.

OBJECTIVE

This study aimed to investigate the relationship between childhood adversities and late-life cognitive function among the middle-aged and older Chinese population and to determine the mediating role of education attainment, marital status, financial status, and self-rated health in adulthood.

METHODS

We used three waves of data from China Health and Retirement Longitudinal Study from 2011 to 2015, which consisted of 23 807 participants aged 45 years and older. Generalized Estimating Equation and Structural Equation Model were applied to examine the association between childhood adversities and cognitive function (mental intactness and episodic memory) and the corresponding potential mechanisms.

RESULTS

Overall, 77.25%, 64.55%, 38.38%, and 15.03% of respondents experienced socioeconomic disadvantage, parental involved trauma, maladaptive parental trauma, and other trauma in childhood, respectively. Multivariate analyses suggest that all four types of childhood adversities were associated with a lower score of mental intactness and the first three were associated with episodic memory. A large proportion of the associations between childhood adversity and cognitive function was mainly mediated by education attainment, self-rated health and marital status in adulthood.

CONCLUSION

There are negative linkages between childhood adversities and cognitive function in the middle-aged and older Chinese population. Such associations were primarily functioning indirectly through adult social context and health conditions.

Dose-Response Meta-Analysis on Tooth Loss With the Risk of Cognitive Impairment and Dementia

OBJECTIVES

To quantify the dose-response associations between tooth loss and risk of cognitive impairment and dementia.

DESIGN

Longitudinal studies that examined the association between tooth loss and cognitive function were systematically searched on 6 databases through March 1, 2020. The study adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Risk estimates were pooled using random-effects models. The dose-response associations were assessed using generalized least squares spline models.

SETTING AND PARTICIPANTS

Adults from community, institution, outpatient or in-hospital were included in the meta-analysis.

MEASURES

Cognitive impairment and dementia were defined by neuropsychological tests, diagnostic criteria, or medical records. Tooth loss was self-reported or assessed by clinical examinations.

RESULTS

Fourteen studies were entered into the meta-analysis, including 34,074 participants and 4689 cases with diminished cognitive function. Participants with more tooth loss had a 1.48 times higher risk of developing cognitive impairment [95% confidence interval (CI) 1.18-1.87] and 1.28 times higher risk of being diagnosed with dementia (95% CI 1.09-1.49); however, the association was nonsignificant for participants using dentures (relative risk = 1.10, 95% CI 0.90-1.11). Eight studies were included in the dose-response analysis, and data supported the use of linear models. Each additional tooth loss was associated with a 0.014 increased relative risk of cognitive impairment and 0.011 elevated relative risks of dementia. Edentulous participants faced a 1.54 times higher risk of cognitive impairment and a 1.40 times higher risk of being diagnosed with dementia.

CONCLUSIONS AND IMPLICATIONS

Moderate-quality evidence suggested tooth loss was independently associated with cognitive impairment and dementia; risk of diminished cognitive function increased with incremental numbers of teeth lost. Furthermore, timely prosthodontic treatment with dentures may reduce the progression of cognitive decline related to tooth loss.

Pathways from early life SES to dementia risk in old age: The role of personality

OBJECTIVE

This study investigates the association between childhood socioeconomic status (cSES) and risk of cognitive impairment in older adulthood, and whether Five Factor Model personality traits mediated this association.

METHODS

A sample of 9,995 participants (mean age = 67.01 years) from the Health and Retirement Study were followed every two years from 2006 to 2018. cSES was tested as a predictor of risk of dementia and risk of cognitive impairment not dementia (CIND). Personality was tested as a mediator of these associations. Models were adjusted for age, gender, ethnicity, race, education, and baseline year.

RESULTS

Although effect sizes were modest, results indicated that lower cSES was associated with higher risk of dementia (HR=0.88, [0.775, 0.985]). Higher cSES was also associated with higher Conscientiousness and lower Neuroticism. Conscientiousness and Neuroticism each accounted for 7.9% of the total effect of cSES on dementia. Results were similar for CIND.

CONCLUSIONS

Early childhood socioeconomic factors may contribute to cognitive impairment in older adulthood, an association mediated, in part, through adult personality traits.

Childhood Socioeconomic Status Does Not Predict Late-Life Cognitive Decline in the 1936 Lothian Birth Cohort

This study examined childhood socioeconomic status (SES) as a predictor of later life cognitive decline. Data came from 519 participants in the Lothian Birth Cohort 1936 (LBC1936) study. SES measures at 11 years of age included parental educational attainment, father's occupational status, household characteristics and a composite measure of global childhood SES (i.e., a total of low SES childhood indicators). Cognitive abilities were assessed by the Mini-Mental State Exam at ages 69.8, 72.8 and 76.7 years. Most indicators of low childhood SES (i.e., father manual worker, less than secondary school father education, household overcrowding, exterior located toilet, and global childhood SES) did not predict cognitive decline between the ages of 69.8 and 76.7. Participants with less educated mothers showed an increase in cognitive decline (β = -0.132, p = 0.048, and CI = -0.80, -0.00). The relationship between maternal educational attainment and cognitive decline became non-significant when controlling for adult SES (i.e., participant educational attainment and occupation). Adult SES did not mediate the latter relationship. This study provides new evidence that childhood SES alone is not strongly associated with cognitive decline. New knowledge is critical to improving population health by identifying life span stages in which interventions might be effective in preventing cognitive decline.

Association of life course socioeconomic status and adult height with cognitive functioning of older adults in India and China

BACKGROUND

Cognitive functioning is an important measure of intrinsic capacity. In this study, we examine the association of life course socioeconomic status (SES) and height with cognitive functioning among older adults (50+) in India and China. The age pattern of cognitive functioning with measures of life course socioeconomic status has also been examined.

METHODS

Cross-sectional comparative analysis was conducted using the WHO's Study on global AGEing and adult health (SAGE) data for India and China. Multilevel mixed-effect linear regression analysis was used to examine the association of life course socioeconomic status and adult height with cognitive functioning.

RESULTS

In both India and China, parental education as a measure of childhood socioeconomic status was positively associated with cognitive functioning. The association between adult socioeconomic status and cognitive functioning was positive and significant. Height was significantly and positively associated with improved cognitive functioning of older adults in India and China. Furthermore, the age-related decline in cognitive functioning score was higher among older adults whose parents had no schooling, particularly in China. The cognitive functioning score with age was much lower among less-educated older adults than those with higher levels of education in China. Wealthier older adults in India had higher cognitive functioning in middle ages, however, wealth differences narrowed with age.

CONCLUSIONS

The results of this study suggest a significant association of lifetime socioeconomic status and cumulative net nutrition on later-life cognitive functioning in middle-income settings.

The Effect of Childhood Socioeconomic Position and Social Mobility on Cognitive Function and Change Among Older Adults: A Comparison Between the United States and England

OBJECTIVES

This study aims to examine the relationship between childhood socioeconomic position (SEP) and cognitive function in later life within nationally representative samples of older adults in the United States and England, investigate whether these effects are mediated by later-life SEP, and determine whether social mobility from childhood to adulthood affects cognitive function and decline.

METHOD

Using data from the Health and Retirement Study (HRS) and the English Longitudinal Survey of Ageing (ELSA), we examined the relationships between measures of SEP, cognitive performance and decline using individual growth curve models.

RESULTS

High childhood SEP was associated with higher cognitive performance at baseline in both cohorts and did not affect the rate of decline. This benefit dissipated after adjusting for education and adult wealth in the United States. Respondents with low childhood SEP, above median education, and high adult SEP had better cognitive performance at baseline than respondents with a similar childhood background and less upward mobility in both countries.

DISCUSSION

These findings emphasize the impact of childhood SEP on cognitive trajectories among older adults. Upward mobility may partially compensate for disadvantage early in life but does not protect against cognitive decline.

Quality of Education and Late-Life Cognitive Function in a Population-Based Sample From Puerto Rico

Background and Objectives

We examined quality of education, literacy, and years of education in relation to late-life cognitive function and decline in older Puerto Ricans.

Research Design and Methods

Our sample consisted of 3,385 community-dwelling adults aged 60 years and older from the Puerto Rican Elderly: Health Conditions study. Quality of education was based on principal component analysis of variables gathered from Department of Education and Census reports. Literacy (yes/no) and years of education were self-reported. Cognitive function was assessed in participants’ homes at baseline and 4 years later using a previously validated Spanish-language 20-point global screening measure for dementia, the minimental Cabán. Regression models were adjusted for sociodemographic and life course covariates.

Results

Quality of education was positively correlated with both educational attainment and cognitive performance. Independent of years of education, literacy, childhood economic hardship, and adult economic hardship, compared to participants in the lowest quartile of education quality, those in the highest quartile had significantly better baseline cognitive performance (β = 0.09, p < .001). Quality of education did not consistently show an association with change in cognitive function over 4 years. Literacy and greater educational attainment were each independently associated with better cognitive function at baseline and less cognitive decline.

Discussion and Implications

Quality of education, literacy, and years of education, while interrelated, also show independent associations with cognitive functioning in older Puerto Ricans. The downstream factors of literacy and years of education were more closely related to age-related cognitive decline than quality of education.

Cognitive processing speed in pediatric-onset multiple sclerosis: Baseline characteristics of impairment and prediction of decline

BACKGROUND

Cognitive impairment occurs in approximately one-third of pediatric-onset multiple sclerosis (POMS) patients. The Symbol Digit Modalities Test (SDMT), a widely used cognitive screen in adults, has yet to be incorporated early into the standard care of POMS.

OBJECTIVE

To screen for cognitive impairment early in the course of POMS and analyze predictive factors.

METHODS

Of the 955 POMS or clinically isolated syndrome (CIS) patients prospectively assessed from March 2014 to July 2018, 500 POMS and 116 CIS patients met inclusion criteria (disease onset before the age of 18, one or more SDMTs, and 8 years or older at the time of testing). Those with relapse were analyzed separately from those who were relapse-free.

RESULTS

At initial assessment, the mean (interquartile range (IQR)) age at symptom onset was 13.5 years (12.0, 15.9) and the mean (±SD) disease duration was 3.0 ± 2.9 years. Impaired processing speed occurred in 23.4% of POMS and in 16.4% of CIS. On serial testing (n = 383, mean follow-up: 1.8 years), 14.1% had clinically meaningful decline predicted by older age of multiple sclerosis (MS) onset and male gender. Disease relapse or steroid use led to transient worsening on the SDMT.

CONCLUSION

Early in the disease, some POMS and CIS patients are at risk for cognitive impairment and subsequent decline.

Childhood Socioeconomic Status and Later Life Cognition: Evidence From the Wisconsin Longitudinal Study

Objectives:This study examined childhood socioeconomic status (SES) as a predictor of later life cognition and the extent to which midlife SES accounts for associations. Methods: Data came from 5,074 participants in the Wisconsin Longitudinal Study. Measures from adolescence included parents' educational attainment, father's occupational status, and household income. Memory and language/executive function were assessed at ages 65 and 72 years. Results: Global childhood SES was a stronger predictor of baseline levels of language/executive function than baseline memory. Associations involving parents' education were reduced in size and by statistical significance when accounting for participants' midlife SES, whereas associations involving parental income and occupational status became statistically nonsignificant. We found no associations between childhood SES and change in cognition. Discussion: Findings contribute to growing evidence that socioeconomic differences in childhood have potential consequences for later life cognition, particularly in terms of the disparate levels of cognition with which people enter later life.

Mother's education and late-life disparities in memory and dementia risk among US military veterans and non-veterans

BACKGROUND

Adverse childhood socioeconomic status (cSES) predicts higher late-life risk of memory loss and dementia. Veterans of U.S. wars are eligible for educational and economic benefits that may offset cSES disadvantage. We test whether cSES disparities in late-life memory and dementia are smaller among veterans than non-veterans.

METHODS

Data came from US-born men in the 1995-2014 biennial surveys of the Health and Retirement Study (n=7916 born 1928-1956, contributing n=38 381 cognitive assessments). Childhood SES was represented by maternal education. Memory and dementia risk were assessed with brief neuropsychological assessments and proxy reports. Military service (veteran/non-veteran) was evaluated as a modifier of the effect of maternal education on memory and dementia risk. We employed linear or logistic regression models to test whether military service modified the effect of maternal education on memory or dementia risk, adjusted for age, race, birthplace and childhood health.

RESULTS

Low maternal education was associated with worse memory than high maternal education (β = -0.07 SD, 95% CI -0.08 to -0.05), while veterans had better memory than non-veterans (β = 0.03 SD, 95% CI 0.02 to 0.04). In interaction analyses, maternal education disparities in memory were smaller among veterans than non-veterans (difference in disparities = 0.04 SD, 95% CI 0.01 to 0.08, p = 0.006). Patterns were similar for dementia risk.

CONCLUSIONS

Disparities in memory by maternal education were smaller among veterans than non-veterans, suggesting military service and benefits partially offset the deleterious effects of low maternal education on late-life cognitive outcomes.

Childhood socioeconomic status and genetic risk for poorer cognition in later life

The ε4 allele of the APOE gene is associated with poorer cognition in later life. This study aimed to advance understanding of how environments potentially moderate this genetic risk by focusing on childhood socioeconomic status (SES). Previous research across diverse national contexts has found that older adults from higher-SES families in childhood demonstrate better cognitive functioning than their lower-SES counterparts. Nevertheless, few studies have examined whether higher childhood SES might also promote later life cognition by mitigating the effects of ε4 carrier status. To address this gap, we used data from 3017 participants in the Wisconsin Longitudinal Study, which has followed a random sample of people who graduated from Wisconsin high schools in 1957. Childhood SES included parents' educational attainment, father's occupational status, and household income in adolescence. We constructed measures of memory and of language/executive functioning using scores from neurocognitive tests administered when participants were approximately ages 65 and 72. APOE ε4 status was measured through saliva samples. Results from cross-controlled multilevel models indicated that APOE ε4 status-and not childhood SES-independently predicted memory, whereas childhood SES-and not APOE ε4 status-independently predicted language/executive functioning. Moreover, a statistical interaction between APOE ε4 status and childhood SES for memory indicated that at baseline, higher childhood SES protected against the risk of APOE ε4 status, whereas lower childhood SES exacerbated the risk of APOE ε4 status. However, by follow-up, these moderating effects dissipated, and APOE ε4 status alone was associated with memory. We interpret these results in light of theorizing on differential susceptibility for poorer cognition across the life course.

Contribution of Socioeconomic Status at 3 Life-Course Periods to Late-Life Memory Function and Decline: Early and Late Predictors of Dementia Risk

Both early life and adult socioeconomic status (SES) predict late-life level of memory; however, evidence is mixed on the relationship between SES and rate of memory decline. Further, the relative importance of different life-course periods for rate of late-life memory decline has not been evaluated. We examined associations between life-course SES and late-life memory function and decline. Health and Retirement Study participants (n = 10,781) were interviewed biennially from 1998-2012 (United States). SES measurements for childhood (composite score including parents' educational attainment), early adulthood (high-school or college completion), and older adulthood (income, mean age 66 years) were all dichotomized. Word-list memory was modeled via inverse-probability weighted longitudinal models accounting for differential attrition, survival, and time-varying confounding, with nonrespondents retained via proxy assessments. Compared to low SES at all 3 points (referent), stable, high SES predicted the best memory function and slowest decline. High-school completion had the largest estimated effect on memory (β = 0.19; 95% confidence interval: 0.15, 0.22), but high late-life income had the largest estimated benefit for slowing declines (for 10-year memory change, β = 0.35; 95% confidence interval: 0.24, 0.46). Both early and late-life interventions are potentially relevant for reducing dementia risk by improving memory function or slowing decline.

Association of Playing High School Football With Cognition and Mental Health Later in Life

Importance

American football is the largest participation sport in US high schools and is a leading cause of concussion among adolescents. Little is known about the long-term cognitive and mental health consequences of exposure to football-related head trauma at the high school level.

Objective

To estimate the association of playing high school football with cognitive impairment and depression at 65 years of age.

Design, Setting, and Participants

A representative sample of male high school students who graduated from high school in Wisconsin in 1957 was studied. In this cohort study using data from the Wisconsin Longitudinal Study, football players were matched between March 1 and July 1, 2017, with controls along several baseline covariates such as adolescent IQ, family background, and educational level. For robustness, 3 versions of the control condition were considered: all controls, those who played a noncollision sport, and those who did not play any sport.

Exposures

Athletic participation in high school football.

Main Outcomes and Measures

A composite cognition measure of verbal fluency and memory and attention constructed from results of cognitive assessments administered at 65 years of age. A modified Center for Epidemiological Studies' Depression Scale score was used to measure depression. Secondary outcomes include results of individual cognitive tests, anger, anxiety, hostility, and heavy use of alcohol.

Results

Among the 3904 men (mean [SD] age, 64.4 [0.8] years at time of primary outcome measurement) in the study, after matching and model-based covariate adjustment, compared with each control condition, there was no statistically significant harmful association of playing football with a reduced composite cognition score (-0.04 reduction in cognition vs all controls; 97.5% CI, -0.14 to 0.05) or an increased modified Center for Epidemiological Studies' Depression Scale depression score (-1.75 reduction vs all controls; 97.5% CI, -3.24 to -0.26). After adjustment for multiple testing, playing football did not have a significant adverse association with any of the secondary outcomes, such as the likelihood of heavy alcohol use at 65 years of age (odds ratio, 0.68; 95% CI, 0.32-1.43).

Conclusions and Relevance

Cognitive and depression outcomes later in life were found to be similar for high school football players and their nonplaying counterparts from mid-1950s in Wisconsin. The risks of playing football today might be different than in the 1950s, but for current athletes, this study provides information on the risk of playing sports today that have a similar risk of head trauma as high school football played in the 1950s.

The Long Arm of Childhood in China: Early-Life Conditions and Cognitive Function Among Middle-Aged and Older Adults

Objective: This study examined the association between childhood conditions and cognitive function among middle-aged and older adults in China. Method: We analyzed data from the 2011 China Health and Retirement Longitudinal Study ( N = 11,868). Cognitive function was measured by word recall, a test of episodic memory. We examined the association between childhood conditions and cognitive function among the middle-aged (45-59 years) and the older (60 years and older) adults separately, using multilevel linear regressions. Results: Indicators of childhood socioeconomic status (SES) and nutrition were significantly associated with memory performance among the middle-aged and the older adults in China. Adulthood SES, education in particular, accounted for some but not all the associations. The protective effect of childhood urban residence was stronger for middle-aged women than for middle-aged men. Discussion: Childhood conditions are significantly associated with mid- to late-life cognitive function in China. The strengths of the associations may vary by gender and cohort.

Life-Course Socioeconomic Position and Hippocampal Atrophy in a Prospective Cohort of Older Adults

OBJECTIVE

Low socioeconomic position (SEP) has been linked to an increased risk of dementia and cognitive decline. However, little is known about the association between SEP and morphologic brain changes in older age. This study examines the relationships between indicators of life-course SEP with both hippocampal volume (HcV) and HcV loss in a population-based cohort of 1328 older adults aged 65 to 80 years.

METHODS

Multivariable linear regression models were used to estimate the associations of SEP with baseline HcV and the annual rate of HcV atrophy according to three life-course conceptual models: the sensitive/critical periods model (which explored SEP in specific periods: in childhood [using parental education], early adulthood [based on participants' education], and midlife [based on participants' socioprofessional group]); the accumulation-of-risk model (life-course cumulative SEP), and the social mobility model (life-course SEP trajectories).

RESULTS

Participants with lower midlife SEP had smaller HcV (-0.08 cm; 95% confidence interval, -0.15 to -0.01) and 0.17% (95% confidence interval, 0.04%-0.30%) faster hippocampal atrophy than participants with higher midlife SEP. Childhood and early adulthood SEPs were not related to hippocampal measures. The accumulation-of-risk and the social mobility models revealed that the accumulation of socioeconomic disadvantage and declining socioeconomic trajectories were related to faster hippocampal atrophy.

CONCLUSIONS

In this cohort of older adults, lower socioprofessional attainment in midlife and disadvantageous life-course socioeconomic position were associated with faster hippocampal atrophy, a cerebral change linked to cognitive disorders. Results support the hypothesized links between socioenvironmental exposures related to stress and/or cognitive enrichment and brain/cognitive reserve capacities.

Alzheimer's disease prevention: A way forward

This review proposes a more optimistic view of Alzheimer's disease (AD), in contrast to that contributed by the ageing of the population and the failure of potentially curative therapies (vaccines and others). Treatment failure is likely due to the fact that AD gestates in the brain for decades but manifests in old age. This review updates the concept of AD and presents the results of recent studies that show that primary prevention can reduce the incidence and delay the onset of the disease. Half of all cases of AD are potentially preventable through education, the control of cardiovascular risk factors, the promotion of healthy lifestyles and specific drug treatments. These approaches could substantially reduce the future incidence rate of this disease.

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.

Maternal education, anthropometric markers of malnutrition and cognitive function (ELSA-Brasil)

Background

The early exposure to poor social and nutritional conditions may influence cognitive function during adult age. However, the relative impact of these factors has not yet been established and they can vary during the course of life.

Methods

Analysis of data from 12,997 participants (35-64 years) of the baseline exams (2008-2010) of the Longitudinal Study of Adult Health (ELSA-Brasil), a cohort of Brazilian civil servants. Four cognitive tests were applied: learning, recall and word recognition; semantic and phonemic verbal fluency; trail-making test version B. The markers of early nutritional and social conditions were maternal educational level, birth weight, and length of trunk and leg. The presence of independent association between every early marker and the poor performance in each cognitive test was investigated by multiple logistic regression, after mutual adjustment and considering the effects of gender, age and participant’s schooling level. The cut off for poor performance was the worst age-specific percentile of the final score distribution for each test.

Results

After full adjustments, lower maternal education increased the chances of poor performance in all cognitive tests, with a dose-response gradient; low birth-weight was related to poor performance in the trail-making test B (OR = 1.63, 95% IC = 1.29-2.06); and greater trunk length decreased the chances of poor performance in the semantic and phonemic verbal fluency (OR = 0.96, 95% IC = 0.94-0.97) and in the trail-making test B (OR = 0.94, 95% IC = 0.92-0.95). Leg length was not associated with any of the tests examined. The associations found were not modified by the educational attainment of the participants.

Conclusions

Early exposure to adverse social and nutritional conditions appear detrimental to semantic memory, learning, concentration, executive control and language among adults, independent of adulthood educational achievement.

Early life development in a multiethnic sample and the relation to late life cognition

OBJECTIVES

Poor quality of early life conditions has been associated with poorer late life cognition and increased risk of dementia. Early life physical development can be captured using adult measures of height and head circumference. Availability of resources may be reflected by socioeconomic indicators, such as parental education and family size. We sought to determine the association between early life development and experience and late life semantic memory, episodic memory, and executive functioning abilities, as well as rate of cognitive decline.

METHOD

This study was conducted using the UC Davis Aging Diversity cohort, an ethnically diverse sample of Caucasian, African American, and Hispanic individuals from northern California. We used latent variable modeling to measure growth and childhood socioeconomic environment (SES) and examine their associations with longitudinal cognitive outcomes using mixed effects modeling.

RESULTS

Growth was positively related to higher childhood SES. Higher childhood SES was associated with better semantic memory. Both low growth and low SES were associated with increased rate of cognitive decline.

DISCUSSION

These findings demonstrate that early life experiences influence the trajectory of cognitive aging. Early life development and experience appears to provide a distal basis upon which additional risk and protective factors interact in the development of dementia.

Is cognitive aging predicted by one's own or one's parents' educational level? results from the three-city study

The authors examined the associations of participants' and their parents' educational levels with cognitive decline while addressing methodological limitations that might explain inconsistent results in prior work. Residents of Dijon, France (n = 4,480) 65 years of age or older who were enrolled between 1999 and 2001 were assessed using the Isaacs' verbal fluency test, Benton Visual Retention Test, Trail Making Test B, and Mini-Mental State Examination up to 5 times over 9 years. The authors used random-intercepts mixed models with inverse probability weighting to account for differential survival (conditional on past performance) and quantile regressions to assess bias from measurement floors or ceilings. Higher parental educational levels predicted better average baseline performances for all tests but a faster average decline in score on the Isaacs' test. Higher participant educational attainment predicted better baseline performances on all tests and slower average declines in Benton Visual Retention Test, Trail Making Test B, and Mini-Mental State Examination scores. Slope differences were generally small, and most were not robust to alternative model specifications. Quantile regressions suggested that ceiling effects might have modestly biased effect estimates, although the direction of this bias might depend on the test instrument. These findings suggest that the possible impacts of educational experiences on cognitive change are small, domain-specific, and potentially incorrectly estimated in conventional analyses because of measurement ceilings.

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

We hypothesized that patterns of elevated stroke mortality among those born in the United States Stroke Belt (SB) states also prevailed for mortality related to all-cause dementia or Alzheimer Disease. Cause-specific mortality (contributing cause of death, including underlying cause cases) rates in 2000 for United States-born African Americans and whites aged 65 to 89 years were calculated by linking national mortality records with population data based on race, sex, age, and birth state or state of residence in 2000. Birth in a SB state (NC, SC, GA, TN, AR, MS, or AL) was cross-classified against SB residence at the 2000 Census. Compared with those who were not born in the SB, odds of all-cause dementia mortality were significantly elevated by 29% for African Americans and 19% for whites born in the SB. These patterns prevailed among individuals who no longer lived in the SB at death. Patterns were similar for Alzheimer Disease-related mortality. Some non-SB states were also associated with significant elevations in dementia-related mortality. Dementia mortality rates follow geographic patterns similar to stroke mortality, with elevated rates among those born in the SB. This suggests important roles for geographically patterned childhood exposures in establishing cognitive reserve.

Explaining differences in episodic memory performance among older African Americans and Whites: the roles of factors related to cognitive reserve and test bias

Older African Americans tend to perform poorly in comparison with older Whites on episodic memory tests. Observed group differences may reflect some combination of biological differences, measurement bias, and other confounding factors that differ across groups. Cognitive reserve refers to the hypothesis that factors, such as years of education, cognitive activity, and socioeconomic status, promote brain resilience in the face of pathological threats to brain integrity in late life. Educational quality, measured by reading test performance, has been postulated as an important aspect of cognitive reserve. Previous studies have not concurrently evaluated test bias and other explanations for observed differences between older African Americans and Whites. We combined data from two studies to address this question. We analyzed data from 273 African American and 720 White older adults. We assessed DIF using an item response theory/ordinal logistic regression approach. DIF and factors associated with cognitive reserve did not explain the relationship between race, and age- and sex-adjusted episodic memory test performance. However, reading level did explain this relationship. The results reinforce the importance of considering education quality, as measured by reading level, when assessing cognition among diverse older adults.

Reducing case ascertainment costs in U.S. population studies of Alzheimer's disease, dementia, and cognitive impairment-Part 1

Establishing methods for ascertainment of dementia and cognitive impairment that are accurate and also cost-effective is a challenging enterprise. Large population-based studies often using administrative data sets offer relatively inexpensive and reliable estimates of severe conditions including moderate to advanced dementia that are useful for public health planning, but they can miss less severe cognitive impairment which may be the most effective point for intervention. Clinical and epidemiological cohorts, intensively assessed, provide more sensitive detection of less severe cognitive impairment but are often costly. In this article, several approaches to ascertainment are evaluated for validity, reliability, and cost. In particular, the methods of ascertainment from the Health and Retirement Study are described briefly, along with those of the Aging, Demographics, and Memory Study (ADAMS). ADAMS, a resource-intense sub-study of the Health and Retirement Study, was designed to provide diagnostic accuracy among persons with more advanced dementia. A proposal to streamline future ADAMS assessments is offered. Also considered are algorithmic and Web-based approaches to diagnosis that can reduce the expense of clinical expertise and, in some contexts, can reduce the extent of data collection. These approaches are intended for intensively assessed epidemiological cohorts where goal is valid and reliable case detection with efficient and cost-effective tools.

Implications of Lifecourse Epidemiology for Research on Determinants of Adult Disease

Many diseases commonly associated with aging are now thought to have social and physiologic antecedents in early life. Understanding how the timing of exposure to early life risk factors influences later-life health may illuminate mechanisms driving adult health inequalities and identify possible points for effective interventions. Recognizing chronic diseases as developing across the lifecourse also has implications for the conduct of research on adult risk factors for disease. We review alternative conceptual models that describe how the timing of risk factor exposure relates to the development of disease. We propose some expansions of lifecourse models to improve their relevance for research on adult chronic disease, using the relationship between education and adult cognitive decline and dementia as an example. We discuss the important implications each of the lifecourse conceptual models has on study design, analysis, and interpretation of research on aging and chronic diseases. We summarize several research considerations implied by the lifecourse framework, including: advantages of analyzing change in function rather than onset of impairment; the pervasive challenge of survivor bias; the importance of controlling for possible confounding by early life conditions; and the likely heterogeneity in responses of adults to treatment.

Secular changes in cognitive predictors of dementia and mortality in 70-year-olds

BACKGROUND

Successive elderly birth cohorts improved in cognitive performance during the 20th century. It is not clear whether this influences cognitive predictors of dementia and mortality.

OBJECTIVE

In 2 longitudinal population studies, representing 2 cohorts of 70-year-olds examined 30 years apart, we investigated the relation between baseline cognitive function and 5-year occurrence of dementia and mortality.

METHODS

Two representative cohorts of 70-year-olds initially free from dementia born in 1901-1902 (cohort 1901-1902: n = 381) and 1930 (cohort 1930: n = 551) from Gothenburg, Sweden, were examined in 1971-1972 and 2000-2001 and after 5 years for the outcome of dementia and death. Recent memory was evaluated during psychiatric examinations, and nonmemory domains using psychometric tests.

RESULTS

At age 70, cohort 1930 performed better on psychometric tests, and had fewer recent memory problems compared to cohort 1901-1902. During 5-year follow-up, 5.0% in cohort 1901-1902 and 4.4% in cohort 1930 (p = 0.742) developed dementia, and 15.7% in cohort 1901-1902 and 4.4% in cohort 1930 died (p < 0.001). Recent memory was associated with incident dementia in both cohorts. Low scores in nonmemory tests were associated with incident dementia in cohort 1901-1902, but not in cohort 1930. Recent memory problems and lower scores in nonmemory tests were associated with 5-year mortality in cohort 1901-1902, but not in cohort 1930.

CONCLUSIONS

Secular changes in cognitive performance may influence cognitive predictors of dementia and mortality, despite similar incidence of dementia. The findings should be taken cautiously due to differences between cohorts in refusal rates, quality of education, and dementia recognition in medical records.