Geographical segregation and IL-6: a marker of chronic inflammation in older adults

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.

Social determinants of health and metabolic syndrome in Colombian older adults

BACKGROUND AND AIMS

Social determinants of health (SDH) are critical in health outcomes. More insight is needed on the correlation between SDH and metabolic syndrome (MetS) in the aging population. This study assessed the association between SDH and MetS scores among older adults in Colombia.

METHODS AND RESULTS

This cross-sectional country-wide study includes a sample of 4085 adults aged ≥60 from the SABE Colombia Survey. MetS measurements were central obesity, hyperglycemia or diabetes, hypertriglyceridemia, arterial hypertension, and low HDL cholesterol (MetS score 0-5). SDH includes four levels: 1- general socioeconomic and environmental conditions; 2-social and community networks; 3- individual lifestyle; and 4-constitutional factors. In multivariate linear regression analysis, the SDH factors with greater effect sizes, calculated by Eta Squared, predicting higher MetS mean scores were women followed by low education, no alcohol intake, urban origin, and residing in unsafe neighborhoods. Two interactions: men, but not women, have lower MetS in safe neighborhoods compared to unsafe, and men, but not women, have lower MetS when having low education (0-5 years) compared to high (≥6).

CONCLUSION

Gender, education, alcohol intake, and origin have the greatest effect sizes on MetS. Education level and neighborhood safety modified the relationship between gender and MetS. Low-educated men or those residing in safe neighborhoods have lower MetS. Neighborhood environments and educational differences influencing MetS should be considered in future studies.

Interleukin-6, Diabetes, and Metabolic Syndrome in a Biracial Cohort: The Reasons for Geographic and Racial Differences in Stroke Cohort

OBJECTIVE

Black Americans have a greater risk of type 2 diabetes than White Americans. The proinflammatory cytokine interleukin-6 (IL-6) is implicated in diabetes pathogenesis, and IL-6 levels are higher in Black individuals. This study investigated associations of IL-6 with incident diabetes and metabolic syndrome in a biracial cohort.

RESEARCH DESIGN AND METHODS

The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled 30,239 Black and White adults age ≥45 years in 2003-2007, with a follow-up ∼9.5 years later. Baseline plasma IL-6 was measured in 3,399 participants at risk of incident diabetes and 1,871 at risk of metabolic syndrome. Relative risk (RR) by IL-6 was estimated with modified Poisson regression for both groups.

RESULTS

Incident diabetes occurred in 14% and metabolic syndrome in 20%; both rates rose across IL-6 quartiles. There was a three-way interaction of IL-6, race, and central adiposity for incident diabetes (P = 8 × 10-5). In Black participants with and without central adiposity, RRs were 2.02 (95% CI 1.00-4.07) and 1.66 (1.00-2.75) for the fourth compared with first IL-6 quartile, respectively. The corresponding RRs were 1.73 (0.92-3.26) and 2.34 (1.17-4.66) in White participants. The pattern was similar for IL-6 and metabolic syndrome.

CONCLUSIONS

Although IL-6 was higher in Black than in White participants and those with central adiposity, the association of IL-6 with diabetes risk was statistically significant only among White participants without central adiposity. The association with metabolic syndrome risk was similarly stronger in low-risk groups. The results support the concept of interventions to lower inflammation in diabetes prevention, but to reduce race disparities, better biomarkers are needed.

Looking Upstream to Understand Race/Ethnicity as a Moderator for Poststroke Neuroinflammation and a Social Determinant for Poststroke Aphasia Outcomes

INTRODUCTION

Over the past decade, the stroke literature has begun to acknowledge and explore explanations for longstanding racial/ethnic differences in stroke outcomes. Poststroke cognitive impairment (PSCI) and poststroke aphasia are two such negative poststroke outcomes where racial/ethnic differences exist. Physiological differences, such as stroke type and lesion size, have been used to partially explain the variation in PSCI and aphasia. However, there is some evidence, although limited, that suggests neuroinflammatory processes as part of allostatic load may be a key contributor to the observed disparities.

METHOD

In this tutorial, we explore the influence of race differences in inflammation on poststroke cognitive outcomes. We suggest lifetime stress and other external determinants of health such as neighborhood environment and discriminatory practices through "weathering" explain differences in inflammation. While using an allostatic load framework, we explore the literature focusing specifically on the role of neuroinflammation on poststroke outcomes.

CONCLUSIONS

Examination of the immune response poststroke provides a foundation for understanding the mechanisms of PSCI and poststroke aphasia and the potential contributions of neuroinflammatory processes on poststroke cognitive outcomes. Furthermore, understanding of racial differences in those processes may contribute to a better understanding of racial disparities in general stroke outcomes as well as poststroke aphasia.

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.

Neighbourhood Socioeconomic Processes and Dynamics and Healthy Ageing: A Scoping Review

Elderly citizens are concentrated in urban areas and are particularly affected by the immediate residential environment. Cities are unequal and segregated places, where there is an intensification of urban change processes such as gentrification and displacement. We aimed to understand how neighbourhood socioeconomic processes and dynamics influence older people’s health. Three bibliographic databases—PubMed, Web of Science, and Scopus—were used to identify evidence of the influence of neighbourhood socioeconomic deprivation, socio-spatial segregation, urban renewal, and gentrification on healthy ageing. We followed the method of Arksey and O’Malley, Levac and colleagues, the Joanna Briggs Institute, and the PRISMA-ScR. The included studies (n = 122) were published between 2001 and 2021. Most evaluated neighbourhood deprivation (n = 114), followed by gentrification (n = 5), segregation (n = 2), and urban renewal (n = 1). Overall, older people living in deprived neighbourhoods had worse healthy ageing outcomes than their counterparts living in more advantaged neighbourhoods. Older adults pointed out more negative comments than positive ones for gentrification and urban renewal. As to segregation, the direction of the association was not entirely clear. In conclusion, the literature has not extensively analysed the effects of segregation, gentrification, and urban renewal on healthy ageing, and more quantitative and longitudinal studies should be conducted to draw better inferences.

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.

Structural racism and its pathways to asthma and atopic dermatitis

Black, Latinx, and Indigenous people in the United States experience a disproportionate burden of asthma and atopic dermatitis. The study of these disease disparities has focused on proximal socioenvironmental exposures and on the biomechanistic (including genetic) differences between racial and ethnic groups. Although biomedical research in allergy and immunology stands to benefit from the inclusion of diverse study populations, the narrow focus on biologic mechanisms disregards the complexity of interactions across biologic and structural factors, including the effects of structural racism. Structural racism is the totality of ways in which society fosters discrimination by creating and reinforcing inequitable systems through intentional policies and practices sanctioned by government and institutions. It is embedded across multiple levels, including the economic, educational, health care, and judicial systems, which are manifested in inequity in the physical and social environment. In this review, we present a conceptual framework and pull from the literature to demonstrate how structural racism is a root cause of atopic disease disparities by way of residential segregation, socioeconomic position, and mass incarceration, which may lead to aberrations in the innate and adaptive immune response and the augmentation of physiologic stress responses, contributing to a disproportionate disease burden for racial and ethnic populations.

All-cause mortality and three aspects of social relationships: an eight-year follow-up of older adults from one entire Korean village

Various aspects of social relationships have been examined as risk factors for mortality. In particular, most research has focused on either loneliness or social disengagement. We aimed to extend the current research by adding a group-level segregation measure utilizing the whole social network of one entire village in South Korea. The analyses were based on the Korean Social Life, Health and Aging Project data collected over eight years across five waves. Of the 679 old adults who participated throughout the entire project (to wave 5), 63 were confirmed as deceased. All three aspects of social relationships examined, loneliness, social disengagement, and group-level segregation, were associated with mortality in the traditional Cox proportional hazard model without considering health-related time-varying covariates. However, a Cox marginal structural model, a counterfactual statistical measure that is designed to control for censoring bias due to sample attrition over the eight years and time-varying confounding variables, revealed that only group-level segregation was associated with mortality. Our results strongly suggest that more attention is needed on group-level segregation for mortality studies, as well as on well-known individual-level risk factors, including social disengagement and loneliness. All methods were carried out in accordance with relevant guidelines and regulations.

Health Disparities in COVID-19: Addressing the Role of Social Determinants of Health in Immune System Dysfunction to Turn the Tide

It is evident that health disparities exist during the COVID-19 pandemic, a pandemic caused by the novel coronavirus SARS-CoV-2. Underlying reasons for COVID-19 health disparities are multi-factorial. However, social determinants, including those regarding socioeconomic status, social inequalities, health behaviors, and stress, may have implications on these disparities. Exposure to one or more of these social determinants is associated with heightened inflammatory responses, particularly increases in the cytokine interleukin-6 (IL-6), as well as immune system dysfunction. Thus, an amplified effect during COVID-19 could occur, potentially resulting in vulnerable patients experiencing an intensified cytokine storm due to a hyperactive and dysfunctional immune response. Further understanding how social determinants play a mechanistic role in COVID-19 disparities could potentially help reduce health disparities overall and in future pandemics.

Neighborhood SES is particularly important to the cardiovascular health of low SES individuals

RATIONALE

Health disparities defined by neighborhood socioeconomic status (SES) are well established; it is less well understood whether neighborhood SES is differentially associated with health depending on one's own SES.

OBJECTIVE

The double jeopardy hypothesis, collective resources model, fundamental cause theory, and relative deprivation hypothesis support differential patterns of association between neighborhood and individual SES with health. The first three models suggest that higher neighborhood SES predicts health more strongly among lower, as compared to higher, SES individuals. The relative deprivation hypothesis suggests that higher SES neighborhoods bring no extra health benefit to low SES individuals and could even bring a health deficit. This study examined competing hypotheses with prospective associations between cardiovascular (CV) health and individual SES, neighborhood SES, and their interaction.

METHOD

Data were from two waves of the Midlife in the United States (MIDUS) Study (N = 1012), a national survey of adults ages 25 and older at baseline. Neighborhood SES was a composite of five census tract-level SES indicators from the 1990 census. Individual SES was a composite of educational attainment and household income at wave one (1995-1996). CV health at wave two (2004-2008), was computed as a composite based on smoking status, body mass index, physical activity, diet, total cholesterol, blood pressure, and glucose.

RESULTS

Individual and neighborhood SES were each associated with CV health net of baseline health status and other covariates. Interactions between individual and neighborhood SES showed that higher neighborhood SES was associated with better CV health for those of lower, not higher, individual SES.

CONCLUSION

Results are consistent with the double jeopardy hypothesis, the collective resources model, and the fundamental cause theory, but not with a relative deprivation hypothesis. Results suggest that additional attention to the neighborhood socioeconomic context of lower SES individuals may reduce SES disparities in cardiovascular health.

A novel approach for measuring residential socioeconomic factors associated with cardiovascular and metabolic health

Individual-level characteristics, including socioeconomic status, have been associated with poor metabolic and cardiovascular health; however, residential area-level characteristics may also independently contribute to health status. In the current study, we used hierarchical clustering to aggregate 444 US Census block groups in Durham, Orange, and Wake Counties, NC, USA into six homogeneous clusters of similar characteristics based on 12 demographic factors. We assigned 2254 cardiac catheterization patients to these clusters based on residence at first catheterization. After controlling for individual age, sex, smoking status, and race, there were elevated odds of patients being obese (odds ratio (OR)=1.92, 95% confidence intervals (CI)=1.39, 2.67), and having diabetes (OR=2.19, 95% CI=1.57, 3.04), congestive heart failure (OR=1.99, 95% CI=1.39, 2.83), and hypertension (OR=2.05, 95% CI=1.38, 3.11) in a cluster that was urban, impoverished, and unemployed, compared with a cluster that was urban with a low percentage of people that were impoverished or unemployed. Our findings demonstrate the feasibility of applying hierarchical clustering to an assessment of area-level characteristics and that living in impoverished, urban residential clusters may have an adverse impact on health.

Neighborhood walkable urban form and C-reactive protein

BACKGROUND

Walkable urban form predicts physical activity and lower body mass index, which lower C-reactive protein (CRP). However, urban form is also related to pollution, noise, social and health behavior, crowding, and other stressors, which may complement or contravene walkability effects.

PURPOSE

This paper assesses within-neighborhood correlation of CRP, and whether three features of walkable urban form (residential density, street connectivity, and land use mix) are associated with CRP levels.

METHODS

CRP measures (n=610) and sociodemographic data come from the 2001-3 Chicago Community Adult Health Study, linked with objective built environment data.

RESULTS

Within-neighborhood correlations of CRP are greater than those of related health measures. A one standard deviation increase in residential density predicts significantly higher log CRP (e.g. β=0.11, p<.01) in Chicago, while a one standard deviation increase in land use mix predicts significantly lower CRP (e.g. β=-0. 19, p<0.01). Street connectivity is unrelated to CRP in this highly walkable city.

DISCUSSION

Results suggest that residential density may be a risk factor for inflammation, while greater walkability of mixed land use areas may be protective. It may be that negative aspects of density overcome the inflammatory benefits of walking.