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

Familial Loss of a Loved One and Biological Aging: NIMHD Social Epigenomics Program

Importance

The link between familial loss of a loved one and long-term health decline is complex and not fully understood.

Objective

To test associations of losing a parent, sibling, child, or partner or spouse with accelerated biological aging.

Design, Setting, and Participants

Data from the National Longitudinal Study of Adolescent to Adult Health, a US population-based longitudinal cohort study, were analyzed. Participants were enrolled from 1994 to 1995 for wave 1, while in grades 7 to 12, and followed up through wave 5 in 2018. The study analyzed participant reports of loss collected at each wave from 1 to 5 over 24 years and used a banked wave 5 blood sample for subsequent DNA methylation testing and epigenetic clock calculation from 2018 to 2024. Data were analyzed from January 2022 to July 2024.

Exposure

Loss of biological parents or parental figures, partners or spouses, siblings, or children at waves 1 to 3 or during childhood, adolescence (aged <18 years), or adulthood at wave 4 to wave 5 (aged 18-43 years).

Main Outcomes and Measures

Biological aging assessed from blood DNA methylation using the Horvath, PhenoAge, GrimAge, and DunedinPACE epigenetic clocks at wave 5.

Results

Data from 3963 participants were analyzed, with a weighted mean (range) age of 38.36 (36.78-39.78) years at wave 5; 2370 (50.3%) were male, 720 (15.97%) were Black, 400 (8.18%) were Hispanic, and 2642 (72.53%) were White. Nearly 40% of participants experienced loss by wave 5 when they were aged 33 to 43 years, and participants who were Black (379 participants [56.67%]), Hispanic (152 participants [41.38%]), and American Indian (18 participants [56.08%]) experienced a greater proportion of losses compared with White participants (884 participants [34.09%]). Those who experienced 2 or more losses tended to have older biological ages for several of the clocks (PhenoAge β = 0.15; 95% CI, 0.02 to 0.28; GrimAge β = 0.27; 95% CI, 0.09 to 0.45; DunedinPACE β = 0.22; 95% CI, 0.10 to 0.34) compared with those with no losses. In contrast, there were no associations with 2 or more losses for the Horvath clock (β = -0.08; 95% CI, -0.23 to 0.06).

Conclusions and Relevance

This study reveals associations between various measures of loss experienced from childhood to adulthood and biological aging in a diverse sample of the US population. These findings underscore the potentially enduring impact of loss on biological aging even before middle age and may contribute to understanding racial and ethnic disparities in health and mortality.

The embodiment of parental death in early life through accelerated epigenetic aging: Implications for understanding how parental death before 18 shapes age-related health risk among older adults

Parental death in early life has been linked to various adverse health outcomes in older adulthood. This study extends prior research to evaluate how parental death in early life is tied to accelerated epigenetic aging, a potentially important biological mechanism from which social and environmental exposures impact age-related health. We used data from the 2016 Venous Blood Study (VBS), a component of the Health and Retirement Study (HRS), to examine the association between parental death in early life and accelerated epigenetic aging as measured by three widely used epigenetic clocks (PCPhenoAge, PCGrimAge, and DunedinPACE). We also assessed whether some of the association is explained by differences in educational attainment, depressive symptoms, and smoking behavior. Methods included a series of linear regression models and formal mediation analysis. Findings indicated that parental death in early life is associated with accelerated epigenetic aging for PCPhenoAge and DunedinPACE. The inclusion of educational attainment, depressive symptoms, and smoking behavior attenuated this association, with formal mediation analysis providing additional support for these observations. Parental death in early life may be one of the most difficult experiences an individual may face. The elevated biological risk associated with parental death in early life may operate through immediate changes but also through more downstream risk factors. This study highlights how early life adversity can set in motion biological changes that have lifelong consequences.

Mid-to-Late Life Healthy Lifestyle Modifies Genetic Risk for Longitudinal Cognitive Aging among Asymptomatic Individuals

IMPORTANCE

Genetic and lifestyle factors contribute to an individual's risk of developing Alzheimer's disease. However, it is unknown whether and how adherence to healthy lifestyles can mitigate the genetic risk of Alzheimer's.

OBJECTIVE

The aim of this study is to investigate whether adherence to healthy lifestyles can modify the impact of genetic predisposition to Alzheimer's disease on later-life cognitive decline.

DESIGN SETTING AND PARTICIPANTS

This prospective cohort study included 891 adults of European ancestry, aged 40 to 65, who were without dementia and had complete healthy-lifestyle and cognition data during the follow-up. Participants joined the Wisconsin Registry for Alzheimer's Prevention (WRAP) beginning in 2001. We conducted replication analyses using a subsample with similar baseline age range from the Health and Retirement Study (HRS).

EXPOSURES

We assessed participants' exposures using a continuous non-APOE polygenic risk score for Alzheimer's, a binary indicator for APOE-ε4 carrier status, and a weighted healthy-lifestyle score, including factors such as no current smoking, regular physical activity, healthy diet, light to moderate alcohol consumption, and frequent cognitive activities.

MAIN OUTCOMES AND MEASURES

We z-standardized cognitive scores for global (Preclinical Alzheimer's Cognitive Composite score 3 - PACC3) and domain-specific assessments (delayed recall and immediate learning).

RESULTS

We followed 891 individuals for up to 10 years (mean [SD] baseline age, 58 [6] years, 31% male, 38% APOE-ε4 carriers). After false discovery rate (FDR) correction, we found statistically significant PRS × lifestyle × age interactions on preclinical cognitive decline but the evidence is stronger among APOE-ε4 carriers. Among APOE-ε4 carriers, PRS-related differences in overall and memory-related domains between people scoring 0-1 and 4-5 regarding healthy lifestyles became evident around age 67 after FDR correction. These findings were robust across several sensitivity analyses and were replicated in the population-based HRS.

CONCLUSION

A favorable lifestyle can mitigate the genetic risk associated with current known non-APOE genetic variants for longitudinal cognitive decline, and these protective effects are particularly pronounced among APOE-ε4 carriers.

Types of bereavement and depressive symptoms among older adults: Does race/ethnicity matter?

AIM

To explore racial/ethnic differences in relation between types of bereavement and depressive symptoms among older adults in the USA.

METHODS

The sample limited to racially/ethnically diverse adults aged ≥55 (n = 879) was drawn from the third wave of the National Social Life, Health, and Aging Project (NSHAP). The NSHAP provides self-identified racial/ethnic categories (non-Hispanic Whites, Blacks, and Hispanics) of respondents who were categorized into three groups by experience of bereavement: non-loss, spousal loss, and parental loss. Using the weights, a two-way analysis of covariance with Bonferroni post-test was conducted to explore the main effect of types of loss and race/ethnicity and their interaction effects on depressive symptoms.

RESULTS

Spousal loss reported higher levels of depressive symptoms than non-loss or parental loss. Based on the interaction between types of loss and race/ethnicity; however, distinctive patterns were observed. Blacks and Hispanics who lose a parent reported significantly higher levels of depressive symptoms than non-Hispanic Whites did.

CONCLUSIONS

An increase in depressive symptoms after bereavement manifested distinctively based on racial/ethnic background and the relationship with the deceased. This implies that it is necessary to develop coping strategies concerning race/ethnicity and whom they lose. Geriatr Gerontol Int 2024; 24: 266-272.

Apolipoprotein E moderates the association between non-APOE polygenic risk score for Alzheimer's disease and aging on preclinical cognitive function

INTRODUCTION

Variation in preclinical cognitive decline suggests additional genetic factors related to Alzheimer's disease (eg, a non-APOE polygenic risk score [PRS]) may interact with the APOE ε4 allele to influence cognitive decline.

METHODS

We tested the PRS × APOE ε4 × age interaction on preclinical cognition using longitudinal data from the Wisconsin Registry for Alzheimer's Prevention. All analyses were fitted using a linear mixed-effects model and adjusted for within individual/family correlation among 1190 individuals.

RESULTS

We found statistically significant PRS × APOE ε4 × age interactions on immediate learning (P = 0.038), delayed recall (P < 0.001), and Preclinical Alzheimer's Cognitive Composite 3 score (P = 0.026). PRS-related differences in overall and memory-related cognitive domains between people with and without APOE ε4 emerge around age 70, with a much stronger adverse PRS effect among APOE ε4 carriers. The findings were replicated in a population-based cohort.

DISCUSSIONS

APOE ε4 can modify the association between PRS and cognition decline.

HIGHLIGHTS

APOE ε4 can modify the association between polygenic risk scores (PRSs) and longitudinal cognition decline, with the modifying effects more pronounced when the PRS is constructed using a conservative P threshold (eg, P < 5e-8 ). The adverse genetic effect caused by the combined effect of the currently known genetic variants is more detrimental among APOE ε4 carriers around age 70. Individuals who are APOE ε4 carriers with high PRSs are the most vulnerable to the harmful effects caused by genetic burden.

Parental Death Across the Life Course, Social Isolation, and Health in Later Life: Racial/Ethnic Disadvantage in the U.S

Bereavement is a risk factor for poor health, yet prior research has not considered how exposure to parental death across the life course may contribute to lasting social isolation and, in turn, poor health among older adults. Moreover, prior research often fails to consider the racial context of bereavement in the United States wherein Black and Hispanic Americans are much more likely than White Americans to experience parental death earlier in life. The present study uses longitudinal data from the Health and Retirement Study (HRS; 1998-2016) to consider linkages of parental death, social isolation, and health (self-rated health, functional limitations) for Black, Hispanic, and White older adults. Findings suggest that exposure to parental death is associated with higher levels of isolation, greater odds of fair/poor self-rated health, and greater odds of functional limitations in later life. Moreover, social isolation partially explains associations between parental bereavement and later-life health. These patterns persist net of psychological distress-an additional psychosocial response to bereavement. Racial inequities in bereavement are central to disadvantage: Black and Hispanic adults are more likely to experience a parent's death earlier in the life course, and this differential exposure to parental death in childhood or young adulthood has implications for racial and ethnic inequities in social isolation and health throughout life.

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.

Social Isolation: An Unequally Distributed Health Hazard

Social isolation is a potent predictor of poor health, mortality, and dementia risk. A great deal of research across national contexts provides causal evidence for these linkages and identifies key explanatory mechanisms through which isolation affects health. Research on social isolation recognizes that some people are more likely than others to be isolated, but over the past several decades, researchers have focused primarily on the consequences of isolation for health rather than a systematic assessment of the social conditions that foster isolation over the life course. In this article, we review the available evidence on inequities in social isolation and develop a conceptual framework to guide future research on structural systems that fuel social isolation over the life course. Future work in this area has the potential to identify root causes of inequality in social isolation, as well as targeted policy levers to reduce isolation in vulnerable populations.

"Outside the Skin": The Persistence of Black-White Disparities in U.S. Early-Life Mortality

Research on Black-White disparities in mortality emphasizes the cumulative pathways through which racism gets "under the skin" to affect health. Yet this framing is less applicable in early life, when death is primarily attributable to external causes rather than cumulative, biological processes. We use mortality data from the National Vital Statistics System Multiple Cause of Death files and population counts from the Surveillance, Epidemiology, and End Result Program to analyze 705,801 deaths among Black and White males and females, ages 15-24. We estimate age-standardized death rates and single-decrement life tables to show how all-cause and cause-specific mortality changed from 1990 to 2016 by race and sex. Despite overall declines in early-life mortality, Black-White disparities remain unchanged across several causes-especially homicide, for which mortality is nearly 20 times as high among Black as among White males. Suicide and drug-related deaths are higher among White youth during this period, yet their impact on life expectancy at birth is less than half that of homicide among Black youth. Critically, early-life disparities are driven by preventable causes of death whose impact occurs "outside the skin," reflecting racial differences in social exposures and experiences that prove harmful for both Black and White adolescents and young adults.