Discrimination, social support, and telomere length: the Multi-Ethnic Study of Atherosclerosis (MESA)

Structural and social determinants of health: The multi-ethnic study of atherosclerosis

BACKGROUND

Researchers have increasingly recognized the importance of structural and social determinants of health (SSDOH) as key drivers of a multitude of diseases and health outcomes. The Multi-Ethnic Study of Atherosclerosis (MESA) is an ongoing, longitudinal cohort study of subclinical cardiovascular disease (CVD) that has followed geographically and racially/ethnically diverse participants starting in 2000. Since its inception, MESA has incorporated numerous SSDOH assessments and instruments to study in relation to CVD and aging outcomes. In this paper, we describe the SSDOH data available in MESA, systematically review published papers using MESA that were focused on SSDOH and provide a roadmap for future SSDOH-related studies.

METHODS AND FINDINGS

The study team reviewed all published papers using MESA data (n = 2,125) through January 23, 2023. Two individuals systematically reviewed titles, abstracts, and full text to determine the final number of papers (n = 431) that focused on at least one SSDOH variable as an exposure, outcome, or stratifying/effect modifier variable of main interest (discrepancies resolved by a third individual). Fifty-seven percent of the papers focused on racialized/ethnic groups or other macrosocial/structural factors (e.g., segregation), 16% focused on individual-level inequalities (e.g. income), 14% focused on the built environment (e.g., walking destinations), 10% focused on social context (e.g., neighborhood socioeconomic status), 34% focused on stressors (e.g., discrimination, air pollution), and 4% focused on social support/integration (e.g., social participation). Forty-seven (11%) of the papers combined MESA with other cohorts for cross-cohort comparisons and replication/validation (e.g., validating algorithms).

CONCLUSIONS

Overall, MESA has made significant contributions to the field and the published literature, with 20% of its published papers focused on SSDOH. Future SSDOH studies using MESA would benefit by using recently added instruments/data (e.g., early life educational quality), linking SSDOH to biomarkers to determine underlying causal mechanisms linking SSDOH to CVD and aging outcomes, and by focusing on intersectionality, understudied SSDOH (i.e., social support, social context), and understudied outcomes in relation to SSDOH (i.e., sleep, respiratory health, cognition/dementia).

Intersectionality and Social Drivers of Health in Cardiovascular Care

Social drivers of health (SDOH) are a significant contributor to persistent cardiovascular health disparities in the United States and globally. SDOH include psychosocial, environmental, socioeconomic, cultural, and governmental factors that impact health behaviors and outcomes. Multiple social drivers have been associated with trends in cardiovascular disease risk and health outcomes. These social drivers intersect in complex ways, and applying the concept of intersectionality is critical when considering ways to best address SDOH in cardiovascular care. Applying intersectionality, which considers the unique combination of social drivers associated with a community, allows for tailored interventions to address cardiovascular health disparities.

Absent Relations of Religious Coping to Telomere Length in African American and White Women and Men

OBJECTIVES

This study investigated whether race and sex moderated the relations of religious coping to telomere length (TL), a biomarker of cellular aging implicated in race-related health disparities.

METHODS

Participant data were drawn from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study, which included 252 socioeconomically diverse African American and White men and women aged (30-64 years old). Cross-sectional multivariable regression analyses examined interactive associations of religious coping, race, and sex to TL, adjusting for other sociodemographic characteristics.

RESULTS

Religious coping was unrelated to TL in this sample (p's > .05). There were no notable race or sex differences. Post hoc exploratory analyses similarly found that neither secular social support coping use nor substance use coping was associated with TL.

CONCLUSION

There was no evidence to support that religious coping use provided protective effects to TL in this sample of African American and White women and men. Nevertheless, future studies should use more comprehensive assessments of religious coping and intersectional identities to provide an in-depth examination of religiosity/spirituality as a potential culturally salient protective factor in cellular aging among African Americans in the context of specific chronic stressors such as discrimination.

Perceived Experiences of racism in Relation to Genome-Wide DNA Methylation and Epigenetic Aging in the Black Women's Health Study

BACKGROUND

African American women have a disproportionate burden of disease compared to US non-Hispanic white women. Exposure to psychosocial stressors may contribute to these health disparities. Racial discrimination, a major stressor for African American women, could affect health through epigenetic mechanisms.

METHODS

We conducted an epigenome-wide association study (EWAS) to examine the association of interpersonal racism (in daily life and in institutional settings) with DNA methylation in blood in 384 participants of the Black Women's Health Study (BWHS). We also evaluated whether a greater number of perceived experiences of racism was associated with epigenetic aging as measured using different methylation clocks. Models were adjusted for chronological age, body mass index, years of education, neighborhood SES, geographic region of residence, alcohol drinking, smoking, and technical covariates.

RESULTS

Higher scores of racism in daily life were associated with higher methylation levels at the cg04494873 site in chromosome 5 (β = 0.64%; 95% CI = 0.41%, 0.87%; P = 6.35E-08). We also replicated one CpG site, cg03317714, which was inversely associated with racial discrimination in a previous EWAS among African American women. In the BWHS, higher scores of racism in daily life were associated with lower methylation levels at that CpG site (β = -0.94%; 95% CI = -1.37%, -0.51%; P = 2.2E-05). Higher racism scores were associated with accelerated epigenetic aging in more than one methylation clock.

CONCLUSIONS

Exposure to discriminatory events may affect the epigenome and accelerate biological aging, which may explain in part the earlier onset of disease in African American women.

The relationship between greenspace exposure and telomere length in the National Health and Nutrition Examination Survey

The exposome, reflecting the range of environmental exposures individuals encounter throughout their life, can influence a variety of health outcomes and can play a role in how the environment impacts our genes. Telomeres, genetic structures regulating cell growth and senescence, are one pathway through which the exposome may impact health. Greenspace exposure, representing the amount of green areas in one's neighborhood, is one component of the exposome and has been associated with multiple health benefits. To investigate the potential link between greenspace exposure and telomere length, we analyzed data from the 1999-2001 National Health and Nutrition Examination Survey (NHANES) sample. Our study examined individual, risk, and contextual factors. We found that greater greenspace exposure in one's neighborhood was associated with longer telomere lengths when considering individual and risk factors, suggesting a positive effect of living in greener neighborhoods. However, this relationship became non-significant when contextual factors, such as air pollution and deprivation, were included in the analysis. These findings highlight a complex relationship between greenspace and telomere length, warranting further research to explore contextual factors in detail.

Food Insecurity, telomere length and the potential modifying effects of social support in National Health and Nutrition Examination Survey

OBJECTIVE

Telomere length (TL) is a posited pathway through which chronic stress results in biological dysregulation and subsequent adverse health outcomes. Food insecurity is associated with shorter TL. Social support, which is defined by the size and function of an individual's social network, is associated with better health outcomes. The present study assesses whether social support modifies the relationship between food security and TL.

DESIGN

Cross-sectional study design. Linear regression was used to assess the association between food insecurity and TL, stratified by social support level. A multiplicative interacted model was used to formally test modification.

SETTING

Data come from the National Health and Nutrition Examination Survey 1999-2000 and 2001-2002 waves.

PARTICIPANTS

Adults aged 60 years and older who have measurements for TL.

RESULTS

Our sample comprised 2674 participants, and 63·5 % of the total sample had low social support, with 13·3 % being food insecure. In fully adjusted models, food insecurity was negatively though modestly associated (P = 0·13) with TL. Associations between food insecurity and TL were significantly modified by social support (interaction P = 0·026), whereby food insecurity had a stronger effect among individuals with high social support (coefficient = -0·099 (95 % CI: -0·161, -0·038)) compared to low social support (coefficient = -0·001, (95 % CI: -0·033, 0·032)).

CONCLUSION

Food insecurity is modestly associated with shorter TL. Contrary to our hypothesis, food insecurity had more deleterious effects on TL among participants with high social support than low social support. Results may indicate that the food insecure population is a higher needs population, and increased social support reflects these needs rather than providing protective effects.

The Water Surrounding the Iceberg: Cultural Racism and Health Inequities

Policy Points Cultural racism-or the widespread values that privilege and protect Whiteness and White social and economic power-permeates all levels of society, uplifts other dimensions of racism, and contributes to health inequities. Overt forms of racism, such as racial hate crimes, represent only the "tip of the iceberg," whereas structural and institutional racism represent its base. This paper advances cultural racism as the "water surrounding the iceberg," allowing it to float while obscuring its base. Considering the fundamental role of cultural racism is needed to advance health equity.

CONTEXT

Cultural racism is a pervasive social toxin that surrounds all other dimensions of racism to produce and maintain racial health inequities. Yet, cultural racism has received relatively little attention in the public health literature. The purpose of this paper is to 1) provide public health researchers and policymakers with a clearer understanding of what cultural racism is, 2) provide an understanding of how it operates in conjunction with the other dimensions of racism to produce health inequities, and 3) offer directions for future research and interventions on cultural racism.

METHODS

We conducted a nonsystematic, multidisciplinary review of theory and empirical evidence that conceptualizes, measures, and documents the consequences of cultural racism for social and health inequities.

FINDINGS

Cultural racism can be defined as a culture of White supremacy, which values, protects, and normalizes Whiteness and White social and economic power. This ideological system operates at the level of our shared social consciousness and is expressed in the language, symbols, and media representations of dominant society. Cultural racism surrounds and bolsters structural, institutional, personally mediated, and internalized racism, undermining health through material, cognitive/affective, biologic, and behavioral mechanisms across the life course.

CONCLUSIONS

More time, research, and funding is needed to advance measurement, elucidate mechanisms, and develop evidence-based policy interventions to reduce cultural racism and promote health equity.

Social support and telomere length: a meta-analysis

Previous studies have shown that lower social support is associated with higher all-cause mortality (Holt-Lunstad et al. in PLoS ONE Medicine 7:e1000316, 2010). While social support has been associated with system-specific biological measures (e.g., cardiovascular), there is the need to elucidate more general biological mechanisms linking social support to health risk across a number of diseases. In this meta-analytic review, the link between social support and telomere length (Cawthon et al. in Lancet 361:393-395, 2003) was conducted based on the updated PRISMA guidelines (Page et al., 2021). Across 17 studies, higher social support was not significantly related to longer telomere length (Zr = 0.010, 95% CI [- 0.028, 0.047], p > 0.05). The confidence interval indicated that the bulk of plausible values were small to null associations. Little evidence for bias was found as shown by funnel plots and Kendall's Tau. Moderator analyses focusing on the measure of support, health of sample, age, type of assay specimen, and gender were not significant. In conclusion, this review showed no significant relationship between social support and telomere length and highlights important future directions.

By what molecular mechanisms do social determinants impact cardiometabolic risk?

While it is well known from numerous epidemiologic investigations that social determinants (socioeconomic, environmental, and psychosocial factors exposed to over the life-course) can dramatically impact cardiovascular health, the molecular mechanisms by which social determinants lead to poor cardiometabolic outcomes are not well understood. This review comprehensively summarizes a variety of current topics surrounding the biological effects of adverse social determinants (i.e., the biology of adversity), linking translational and laboratory studies with epidemiologic findings. With a strong focus on the biological effects of chronic stress, we highlight an array of studies on molecular and immunological signaling in the context of social determinants of health (SDoH). The main topics covered include biomarkers of sympathetic nervous system and hypothalamic-pituitary-adrenal axis activation, and the role of inflammation in the biology of adversity focusing on glucocorticoid resistance and key inflammatory cytokines linked to psychosocial and environmental stressors (PSES). We then further discuss the effect of SDoH on immune cell distribution and characterization by subset, receptor expression, and function. Lastly, we describe epigenetic regulation of the chronic stress response and effects of SDoH on telomere length and aging. Ultimately, we highlight critical knowledge gaps for future research as we strive to develop more targeted interventions that account for SDoH to improve cardiometabolic health for at-risk, vulnerable populations.

There is urgent need to treat atherosclerotic cardiovascular disease risk earlier, more intensively, and with greater precision: A review of current practice and recommendations for improved effectiveness

Atherosclerotic cardiovascular disease (ASCVD) is epidemic throughout the world and is etiologic for such acute cardiovascular events as myocardial infarction, ischemic stroke, unstable angina, and death. ASCVD also impacts risk for dementia, chronic kidney disease peripheral arterial disease and mobility, impaired sexual response, and a host of other visceral impairments that adversely impact the quality and rate of progression of aging. The relationship between low-density lipoprotein cholesterol (LDL-C) and risk for ASCVD is one of the most highly established and investigated issues in the entirety of modern medicine. Elevated LDL-C is a necessary condition for atherogenesis induction. Basic scientific investigation, prospective longitudinal cohorts, and randomized clinical trials have all validated this association. Yet despite the enormous number of clinical trials which support the need for reducing the burden of atherogenic lipoprotein in blood, the percentage of high and very high-risk patients who achieve risk stratified LDL-C target reductions is low and has remained low for the last thirty years. Atherosclerosis is a preventable disease. As clinicians, the time has come for us to take primordial and primary prevention more serously. Despite a plethora of therapeutic approaches, the large majority of patients at risk for ASCVD are poorly or inadequately treated, leaving them vulnerable to disease progression, acute cardiovascular events, and poor aging due to loss of function in multiple visceral organs. Herein we discuss the need to greatly intensify efforts to reduce risk, decrease disease burden, and provide more comprehensive and earlier risk assessment to optimally prevent ASCVD and its complications. Evidence is presented to support that treatment should aim for far lower goals in cholesterol management, should take into account many more factors than commonly employed today and should begin significantly earlier in life.

Association of Social Support Network with Telomere Length: A Cross-Sectional Study with Community-Dwelling Older Adults

Considering that telomere length can be determined not only by issues related to cell biology but also by aspects related to social factors and environmental exposures, studies on the relationship between social aspects and telomere length can help to better understand the still scarcely known aspects of the human aging process. Thus, this research seeks to verify whether social support networks are associated with telomere length in older adults. This is a cross-sectional study conducted with 448 individuals aged at least 60 years living in the urban area of an inland Brazilian municipality. Relative quantification of telomere length was obtained through real-time qPCR. Social support was assessed through the Medical Outcomes Study Social Support Scale. Descriptive statistics and multiple logistic regression were used in data analysis. The evaluated social support networks for older adults consist in a mean of 16.4 people, and the percentage of older adults who reported up to five members in their network was 27.75%. Shorter telomere length was identified in 25% of the participants, and the older adults who reported having up to five members in their support network were more likely to have a shorter telomere length than those who reported more numerous networks (odds ratio: 1.89, p = 0.011) regardless of gender, age, household arrangement, cognitive decline, and dependence for basic and instrumental activities of daily living, which suggests that measures that stimulate the creation and maintenance of social support networks should be implemented to improve older adults' health.

Lifetime discrimination in low to middle income mothers and cellular aging: A prospective analysis

BACKGROUND

Experiences of discrimination on the basis of race, ethnicity, and other characteristics are associated with adverse health outcomes, including elevated rates of morbidity in later life and earlier mortality. Acceleration of biological aging is a plausible pathway linking discrimination to disease risk. The objective of this study was to examine the relationship of self-reported lifetime and everyday discrimination to women's telomere length several years after birth of a child in a longitudinal cohort study.

METHODS

The Community Child Health Network (CCHN) conducted a community-based participatory research project focused on racial, ethnic, and socioeconomic disparities in maternal and child health. Data for the current substudy are from a longitudinal cohort study in 3 of the 5 project sites. This multi-site community-based longitudinal study was conducted in Lake County, IL north of Chicago, Washington, D.C., and rural North Carolina. Participants were low to middle-income mothers (N = 103) with a primary identity of Hispanic/Latina, Black, or non-Hispanic White who rated their experience of everyday and lifetime discrimination during an at-home interview one-month postpartum. Buccal samples were collected to assay buccal cell telomere length several years later when a consecutive child was 3-5 years of age. Telomere length derived from buccal cells was used as a biomarker indicating cellular aging and a risk factor for age-related disease.

RESULTS

Mothers (18-39 years old) who reported higher lifetime discrimination had shorter telomere length an average of 5.6 years later (B = -0.22 [SE = 0.04], p < 0.001). Mother's reports of everyday discrimination were not significantly related to telomere length (0.01[0.01], p = 0.15).

CONCLUSIONS

These findings suggest that lifetime exposure to discrimination, but not necessarily current reports of everyday discrimination, may increase biological aging as indicated by shorter buccal cell telomere length, providing evidence of a plausible route through which discrimination contributes to increased risk for earlier onset aging and age-related disease in women.

Association between Childhood Exposure to Family Violence and Telomere Length: A Meta-Analysis

The aims of this meta-analysis were to examine the association between childhood exposure to family violence and telomere length and the moderating variables that influence this association. Relevant works published on or before 1st September 2022 were identified through a search in five major databases in English and 19 articles (N = 18,977) finally met the inclusion criteria. A meta-analysis was conducted to compute the pooled effect size (correlation; r), and moderator analyses were performed using a random effects meta-analytic model. The studies yielded a significant inverse association between childhood exposure to family violence and telomere length, with a small effect size (r = -0.038, 95% CI [-0.070, -0.005], p = 0.025). Furthermore, the strength of this association was stronger in studies examining the co-occurrence of multiple types of violence than in those examining just one type (Q = 8.143, p = 0.004). These findings suggested that victims' telomere length may be negatively influenced by childhood exposure to family violence and that such impairment appears to be stronger for those who are exposed to multiple types of violence. Future studies are necessary to examine the moderating and mediating factors underlying the association between childhood exposure to family violence and telomere length.

A systematic review and meta-analysis of the Everyday Discrimination Scale and biomarker outcomes

Discrimination has consistently been associated with multiple adverse health outcomes. Like other psychosocial stressors, discrimination is thought to impact health through stress-related physiologic pathways including hypothalamic-pituitary-adrenal (HPA) axis activation, dysregulation of inflammation responses, and accelerated cellular aging. Given growing attention to research examining the biological pathways through which discrimination becomes embodied, this systematic review and meta-analysis synthesizes empirical evidence examining relationships between self-reported discrimination and four biomarker outcomes (i.e., cortisol, C-reactive protein (CRP), interleukin-6 (IL-6), and telomere length) among studies that have used the Everyday Discrimination Scale. We conducted a systematic review of studies discussing self-reported, everyday, or chronic discrimination in the context of health by searching Medline / PubMed (National Library of Medicine, NCBI), PsycInfo (APA, Ebsco) and Web of Science Core Collection (Clarivate). Twenty-five articles met the criteria for meta-analysis, with several reporting on multiple outcomes. Discrimination was associated with elevated CRP levels (r = 0.11; 95% CI: 0.01, 0.20, k = 10), though not cortisol (r = 0.05; 95% CI: -0.06, 0.16, k = 9), IL-6 (r = 0.05; 95% CI: -0.32, 0.42, k = 5), or telomere length (r = 0.03; 95% CI: -0.01, 0.07, k = 6). We identify several points of consideration for future research including addressing heterogeneity in assessment of biomarker outcomes and the need for longitudinal assessments of relationships between discrimination and biomarker outcomes.

Social Determinants of Cardiovascular Disease

Social determinants of health (SDoH), which encompass the economic, social, environmental, and psychosocial factors that influence health, play a significant role in the development of cardiovascular disease (CVD) risk factors as well as CVD morbidity and mortality. The COVID-19 pandemic and the current social justice movement sparked by the death of George Floyd have laid bare long-existing health inequities in our society driven by SDoH. Despite a recent focus on these structural drivers of health disparities, the impact of SDoH on cardiovascular health and CVD outcomes remains understudied and incompletely understood. To further investigate the mechanisms connecting SDoH and CVD, and ultimately design targeted and effective interventions, it is important to foster interdisciplinary efforts that incorporate translational, epidemiological, and clinical research in examining SDoH-CVD relationships. This review aims to facilitate research coordination and intervention development by providing an evidence-based framework for SDoH rooted in the lived experiences of marginalized populations. Our framework highlights critical structural/socioeconomic, environmental, and psychosocial factors most strongly associated with CVD and explores several of the underlying biologic mechanisms connecting SDoH to CVD pathogenesis, including excess stress hormones, inflammation, immune cell function, and cellular aging. We present landmark studies and recent findings about SDoH in our framework, with careful consideration of the constructs and measures utilized. Finally, we provide a roadmap for future SDoH research focused on individual, clinical, and policy approaches directed towards developing multilevel community-engaged interventions to promote cardiovascular health.

Longitudinal Associations between Discrimination, Neighborhood Social Cohesion, and Telomere Length: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

We aimed to examine if neighborhood social cohesion moderated longitudinal associations between baseline reports of discrimination and 10-year changes in Leukocyte Telomere Length (LTL).

METHODS

Data are from the Multi-Ethnic Study of Atherosclerosis (MESA; N=1,064; age range 45-84 years). Baseline discrimination was measured using the Major Experiences of Discrimination Scale (MDS; none, 1 domain, ≥2 domains) and the Experiences of Discrimination Scale (EDS; none, moderate, high). Neighborhood social cohesion at baseline was assessed via a community survey within census tract defined neighborhoods. 10-year change in LTL was defined as Regression to the Mean corrected 10-year difference in the ratio of telomeric DNA to a single copy gene (T/S).

RESULTS

In linear mixed effects models, we found that neighborhood social cohesion modified the effect of baseline reports of MDS on 10-year changes in LTL, independent of sociodemographic characteristics, health behaviors, and health conditions (p(χ 2)=0.01). Among those residing in neighborhoods with low social cohesion, experiencing major discrimination in ≥2 domains was associated with faster LTL attrition over 10-years, compared to reporting no discrimination (β=-0.03; 95% CI: -0.06, -0.003). We found no main associations for either discrimination measure and no interaction between EDS and neighborhood social cohesion.

CONCLUSIONS

Results indicate that neighborhood social cohesion is an important dimension of the neighborhood context that may moderate the impact of major experiences of discrimination on telomere length attrition. These findings help advance our understanding of the integral role that neighborhood environments play in attenuating the effect of discrimination on accelerated cell aging.