The effects of ethnic discrimination and socioeconomic status on endothelin-1 among blacks and whites

Racial/Ethnic Discrimination and Cardiometabolic Diseases: A Systematic Review

INTRODUCTION

Racial discrimination has been identified as a risk factor for cardiometabolic diseases, the leading cause of morbidity and mortality among racial/ethnic minority groups; however, there is no synthesis of current knowledge on the association between discrimination and cardiometabolic diseases. The objective of this systematic review was to summarize evidence linking racial/ethnic discrimination and cardiometabolic diseases.

METHODS

The review was conducted based on studies identified via electronic searches of 5 databases (PubMed, Google Scholar, WorldWideScience.org, ResearchGate and Microsoft Academic) using terms related to discrimination and cardiometabolic disease.

RESULTS

Of the 123 eligible studies included in the review, 87 were cross-sectional, 25 longitudinal, 8 quasi-experimental, 2 randomized controlled trials and 1 case-control. Cardiometabolic disease outcomes discussed were hypertension (n = 46), cardiovascular disease (n = 40), obesity (n = 12), diabetes (n = 11), metabolic syndrome (n = 9), and chronic kidney disease (n = 5). Although a variety of discrimination measures was employed across the studies, the Everyday Discrimination Scale was used most often (32.5%). African Americans/Blacks were the most frequently studied racial/ethnic group (53.1%), and American Indians the least (0.02%). Significant associations between racial/ethnic discrimination and cardiometabolic disease were found in 73.2% of the studies.

DISCUSSION

Racial/ethnic discrimination is positively associated with increased risk of cardiometabolic disease and higher levels of cardiometabolic biomarkers. Identifying racial/ethnic discrimination as a potential key contributor to the health inequities associated with cardiometabolic diseases is important for addressing the significant burden borne by racial/ethnic minorities.

The association of perceived discrimination with dementia risk in Black older adults

INTRODUCTION

Non-Hispanic Black, compared to non-Hispanic White, older adults are at increased risk for dementia. This may be due partly to greater exposure to psychosocial stressors, such as discrimination; however, few studies have examined this association.

METHODS

We examined the association of perceived discrimination (e.g., everyday, lifetime, and discrimination burden) with dementia risk in 1583 Black adults co-enrolled in the Atherosclerosis Risk in Communities (ARIC) Study and the Jackson Heart Study (JHS). Perceived discrimination (defined continuously and using tertiles) was assessed at JHS Exam 1 (2000-2004; mean age ± SD:66.2 ± 5.5) and related to dementia risk through ARIC visit 6 (2017) using covariate-adjusted Cox proportional hazards models.

RESULTS

Associations of perceived everyday, lifetime, and burden of discrimination with dementia risk were not supported in age-adjusted models or demographic- and cardiovascular health-adjusted models. Results were similar across sex, income, and education.

DISCUSSION

In this sample, associations between perceived discrimination and dementia risk were not supported.

HIGHLIGHTS

In Black older adults perceived discrimination not associated with dementia risk. Younger age and greater education linked to greater perceived discrimination. Older age and less education among factors associated with dementia risk. Factors increasing exposure to discrimination (education) are also neuroprotective.

Exposure to socioenvironmental stress as a predictor of physical and mental health

The literature demonstrates links between socioenvironmental characteristics, dysregulation of the stress response system, and PTSD, though few studies integrate these factors in one model. In a secondary analysis of cross-sectional data collected by the Survey of the Health of Wisconsin (SHOW), structural equation modeling evaluated the relationships between socioenvironmental stress, cumulative biological risk (CBR), and PTSD symptom severity. The model hypothesized that exposure to socioenvironmental stress was associated with PTSD and that this relationship is mediated by increased CBR. Indices suggest the model provided a good fit to the data and supported socioenvironmental stress and CBR as valid latent constructs. Although the association between CBR and PTSD was not found to be statistically significant in this study, socioenvironmental stress was a significant predictor of PTSD and CBR. Given the role of socioenvironmental factors on CBR and PTSD symptoms, providers need to better assess and incorporate social stressors within evaluation and treatment.

Interplay of the Circadian Clock and Endothelin System

The peptide hormone endothelin-1 and its receptors are linked to several disease states. Pharmacological inhibition of this pathway has proven beneficial in pulmonary hypertension, yet its potential in other disease states remains to be realized. This review considers an often understudied aspect of endothelin biology, circadian rhythm regulation and how understanding the intersection between endothelin signaling and the circadian clock may be leveraged to realize the potential of endothelin-based therapeutics.

Dysregulation of Endothelin-1: Implications for Health Disparities in Alzheimer's Disease

Alzheimer's disease (AD) and related dementias disproportionately impact racial and ethnic minorities. The racial and ethnic disparities in AD could be explained by differences in cerebral vascular disease pathology. Endothelin-1 (ET-1) is a potent vasoconstrictive peptide that regulates smooth muscle, endothelial cell, and pericyte contractions that may result in cerebral vascular constriction, leading to cerebral hypoperfusion; over time, ET-1 may result in neuronal injury contributing to the pathology of AD. Upregulation of the ET-1 system has been observed in African Americans when compared with non-Hispanic Whites. The role of the ET-1 system as a driver of ethnic disparities in AD requires further investigation. Targeting of the ET-1 system as a therapeutic intervention that could impact AD progression also needs further study. Dysregulation of ET-1 in Hispanic/Latino populations largely have been unexplored. Genetics linking ET-1 dysregulation and racial disparities in AD also needs further investigation. In this review, I examine how AD effects underserved minority populations and how dysregulation of the ET-1 system specifically predisposes ethnic minorities to AD. In addition, I examine the molecular interactions of the ET-1 system and amyloid beta, the role the ET-1 system in neurodegeneration, potential therapeutics for ET-1 dysregulation, and the impact on AD progression.

The role of feature-based discrimination in driving health disparities among Black Americans

Objective: A growing body of research finds that darker skin tone is often associated with poorer physical and mental health in Blacks. However, the psychosocial mechanisms underlying the skin tone-health link remain elusive. The present study seeks to address this knowledge gap by investigating the direct and indirect (through perceived discrimination, socioeconomic status, and self-esteem) effects of skin tone on self-reported physical and mental health.Design: An urban sample of 130 Blacks aged 35 and above completed a self-administered computerized survey as a part of larger cross-sectional study.Results: Self-esteem played a particularly important role in mediating the associations between skin tone and self-reported physical and mental health. This suggests that self-esteem could be a point of intervention to help Blacks with darker skin tone achieve better health.Conclusion: The present study highlights the important role feature-based discrimination plays in determining mental and physical health outcomes among Blacks.

Links between discrimination and cardiovascular health among socially stigmatized groups: A systematic review

BACKGROUND

There is a high prevalence of cardiovascular disease across diverse groups in the U.S. population, and increasing research has identified stigma as a potential barrier to cardiovascular disease prevention and treatment. This systematic review examines evidence linking discrimination and cardiovascular health among socially stigmatized groups.

STUDY DESIGN

Six databases were systematically reviewed from inception through February 2018 for studies with adult subjects, focusing on cardiovascular health indicators among social groups stigmatized because of their gender, race/ethnicity, age, body weight/obesity, or sexual orientation. The Newcastle-Ottawa Scale was used to evaluate the methodological quality and risk of bias for nonrandomized studies, and the Cochrane Collaboration 7-item domain for randomized controlled and experimental trials.

RESULTS

The search identified 84 eligible studies published between 1984 and 2017. Studies retrieved were categorized according to demonstrated links between stigma and cardiovascular disease risk factors including blood pressure (n = 45), heart rate variability (n = 6), blood/saliva cardiovascular biomarkers (n = 18), as well as other indicators of cardiovascular health (n = 15). Based on the findings from included studies, 86% concluded that there was a significant relationship among stigma or discrimination and cardiovascular health indicators among socially stigmatized groups. However, there were varying degrees of evidence supporting these relationships, depending on the type of discrimination and cardiovascular health indicator. The current evidence implies an association between perceived discrimination and cardiovascular health. However, a majority of these studies are cross-sectional (73%) and focus on racial discrimination (79%), while using a wide variety of measurements to assess social discrimination and cardiovascular health.

CONCLUSIONS

Future research should include longitudinal and randomized controlled trial designs, with larger and more diverse samples of individuals with stigmatized identities, using consistent measurement approaches to assess social discrimination and its relationship with cardiovascular health.

Endothelin neurotransmitter signalling controls zebrafish social behaviour

The formation of social groups is an adaptive behaviour that can provide protection from predators, improve foraging and facilitate social learning. However, the costs of proximity can include competition for resources, aggression and kleptoparasitism meaning that the decision whether to interact represents a trade-off. Here we show that zebrafish harbouring a mutation in endothelin receptor aa (ednraa) form less cohesive shoals than wild-types. ednraa^−/− mutants exhibit heightened aggression and decreased whole-body cortisol levels suggesting that they are dominant. These behavioural changes correlate with a reduction of parvocellular arginine vasopressin (AVP)-positive neurons in the preoptic area, an increase in the size of magnocellular AVP neurons and a higher concentration of 5-HT and dopamine in the brain. Manipulation of AVP or 5-HT signalling can rescue the shoaling phenotype of ednraa^−/− providing an insight into how the brain controls social interactions.

The Autonomic Nervous System and Hypertension: Ethnic Differences and Psychosocial Factors

PURPOSE OF THE REVIEW

In the present paper, we overview emerging research examining the autonomic nervous system (ANS), especially the parasympathetic nervous system as indexed by heart rate variability (HRV), and the impact of psychosocial factors on hypertension-related disease in African Americans.

RECENT FINDINGS

A growing corpus of studies has shown that (1) usual patterns of compensatory sympathetic-parasympathetic regulation differ between African Americans and European Americans; (2) despite their enhanced cardiovascular disease risk profile, African Americans tend to exhibit higher HRV relative to European Americans; and (3) racial discrimination and other forms of psychosocial stress are associated with diminished HRV among African Americans. Significant disparities in hypertension-related disease exist such that African Americans have greater risk. The underlying factors associated with this increased risk are, to date, not fully understood. The present review provides evidence for a unique pattern of ANS regulation in African Americans and shows that psychosocial factors such as racial discrimination may contribute to this paradoxical situation.

Racial discrimination, educational attainment, and biological dysregulation among midlife African American women

OBJECTIVE

To examine the association between self-reported racial discrimination and allostatic load, and whether the association differs by socioeconomic position.

METHODS

We recruited a purposive cross-section of midlife (ages 30-50) African American women residing in four San Francisco Bay area counties (n = 208). Racial discrimination was measured using the Experience of Discrimination scale. Allostatic load was measured as a composite of 15 biomarkers assessing cardiometabolic, neuroendocrine, and inflammatory activity. We calculated four composite measures of allostatic load and three system-specific measures of biological dysregulation. Multivariable regression was used to examine associations, while adjusting for relevant confounders.

RESULTS

In the high education group, reporting low (b = -1.09, P = .02, 95% CI = -1.99, -0.18) and very high (b = -1.88, P = .003, 95% CI = -3.11, -0.65) discrimination was associated with lower allostatic load (reference=moderate). Among those with lower education, reporting low (b = 2.05, P = .008, 95% CI = 0.55,3.56) discrimination was associated with higher allostatic load. Similar but less consistent associations were found for poverty status. Associations were similar for cardiometabolic functioning, but not for neuroendocrine or inflammatory activity.

CONCLUSIONS

Racial discrimination may be an important predictor of cumulative physiologic dysregulation. Factors associated with educational attainment may mitigate this association for African American women and other groups experiencing chronic social stress.

Acute Pressor Response to Psychosocial Stress Is Dependent on Endothelium-Derived Endothelin-1

Background

Acute psychosocial stress provokes increases in circulating endothelin‐1 (ET‐1) levels in humans and animal models. However, key questions about the physiological function and cellular source of stress‐induced ET‐1 remain unanswered. We hypothesized that endothelium‐derived ET‐1 contributes to the acute pressor response to stress via activation of the endothelin A receptor.

Methods and Results

Adult male vascular endothelium‐specific ET‐1 knockout mice and control mice that were homozygous for the floxed allele were exposed to acute psychosocial stress in the form of cage switch stress (CSS), with blood pressure measured by telemetry. An acute pressor response was elicited by CSS in both genotypes; however, this response was significantly blunted in vascular endothelium‐specific ET‐1 knockout mice compared with control mice that were homozygous for the floxed allele. In mice pretreated for 3 days with the endothelin A antagonist, ABT‐627, or the dual endothelin A/B receptor antagonist, A‐182086, the pressor response to CSS was similar between genotypes. CSS significantly increased plasma ET‐1 levels in control mice that were homozygous for the floxed allele. CSS failed to elicit an increase in plasma ET‐1 in vascular endothelium‐specific ET‐1 knockout mice. Telemetry frequency domain analyses suggested similar autonomic responses to stress between genotypes, and isolated resistance arteries demonstrated similar sensitivity to α₁‐adrenergic receptor‐mediated vasoconstriction.

Conclusions

These findings specify that acute stress‐induced activation of endothelium‐derived ET‐1 and subsequent endothelin A receptor activation is a novel mediator of the blood pressure response to acute psychosocial stress.

Impact of Racial Discrimination and Hostility on Adrenergic Receptor Responsiveness in African American Adults

OBJECTIVE

Racial discrimination is increasingly recognized as a contributor to increased cardiovascular disease (CVD) risk among African Americans. Previous research has shown significant overlap between racial discrimination and hostility, an established predictor of CVD risk including alterations in adrenergic receptor functioning. The present study examined the associations of racial discrimination and hostility with adrenergic receptor responsiveness.

METHODS

In a sample (N = 57) of young to middle-aged African American adults (51% female) with normal and mildly elevated blood pressure, a standardized isoproterenol sensitivity test (CD25) was used to evaluate β-AR responsiveness, whereas the dose of phenylephrine required to increase mean arterial pressure by 25 mm Hg (PD25) was used to assess α1-AR responsiveness. Racial discrimination was measured using the Perceived Racism Scale and hostility was assessed using the Cook-Medley Hostility Scale.

RESULTS

In hierarchical regression models, greater racial discrimination, but not hostility, emerged as a significant predictor of decreased β-adrenergic receptor responsiveness (β = .38, p = .004). However, moderation analysis revealed that the association between racial discrimination and blunted β-adrenergic receptor responsiveness was strongest among those with higher hostility (β = .49, 95% confidence interval = .17-.82, p = .004). In addition, hostility, but not racial discrimination, significantly predicted α1-AR responsiveness.

CONCLUSIONS

These findings suggest racial discrimination was associated with blunted β-adrenergic receptor responsiveness, providing further evidence of the potential contribution of racial discrimination to increased CVD risk among African Americans. The adverse effects of discrimination on cardiovascular health may be enhanced in individuals with higher levels of hostility.

Elevated Plasma Endothelin-1 Levels in Normal Tension Glaucoma and Primary Open-Angle Glaucoma: A Meta-Analysis

Purpose. The aim of this meta-analysis was to clarify the association between the plasma endothelin-1 level and the risks of normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG). Methods. Relevant publications were collected from three databases including PubMed, EMBASE, and the Web of Science through December 31, 2015. In this study, the terms "(endothelin OR ET) AND glaucoma" were searched. Review Manager 5.2 was used to process the data. Results. Seven studies (212 cases, 164 controls) were included for the NTG analysis. The mean plasma endothelin-1 level in the NTG subjects was 0.60 pg/mL (p = 0.02, 95% CI: 0.17-1.04) higher than that of the healthy controls. Six studies (160 cases, 174 controls) were included for the POAG analysis, and the endothelin-1 level was 0.63 pg/mL (p = 0.007, 95% CI: 0.12-1.15) higher in the POAG subjects than in the healthy controls. Additionally, two studies influenced the meta-analysis results regarding the association of plasma endothelin-1 with POAG by sensitivity analysis, and the probability of publication bias was low. Conclusions. The observation that NTG and POAG subjects showed significantly elevated endothelin-1 plasma concentrations suggests that a higher plasma level of endothelin-1 might increase the risk of NTG and POAG development.

Discrimination and Cumulative Disease Damage Among African American Women With Systemic Lupus Erythematosus

OBJECTIVES

We examined associations between unfair treatment, attributions of unfair treatment to racial discrimination, and cumulative disease damage among African American women with systemic lupus erythematosus (SLE).

METHODS

We used multivariable regression models to examine SLE damage among 578 African American women in metropolitan Atlanta, Georgia, recruited to the Georgians Organized Against Lupus cohort.

RESULTS

When we controlled for demographic, socioeconomic, and health-related covariates, reporting any unfair treatment was associated with greater SLE damage compared with reporting no unfair treatment (b = 0.55; 95% confidence interval = 0.14, 0.97). In general, unfair treatment attributed to nonracial factors was more strongly associated with SLE damage than was unfair treatment attributed to racial discrimination, although the difference was not statistically significant.

CONCLUSIONS

Unfair treatment may contribute to worse disease outcomes among African American women with SLE. Unfair treatment attributed to nonracial causes may have a more pronounced negative effect on SLE damage. Future research may further examine possible differences in the effect of unfair treatment by attribution.

Racism as a Determinant of Health: A Systematic Review and Meta-Analysis

Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants. Protocol PROSPERO registration number: CRD42013005464.

Perceived discrimination and markers of cardiovascular risk among low-income African American youth

OBJECTIVES

Our study examines the relationship between perceived discrimination and levels of C-reactive protein and blood pressure in low-income youth ages 10-15 years old.

METHODS

Data were collected from 10 to 15 year old focal children and their mothers. Face-to-face interviews were implemented to collect data on stressors including experiences of everyday discrimination from youth. High sensitivity CRP in dried blood spot samples and diastolic and systolic blood pressure were also collected at the time of the interview.

RESULTS

Perceived discrimination among youth was significantly associated with higher levels of CRP, systolic, and diastolic blood pressure. CRP, systolic, and diastolic blood pressure remained significant after controlling for age-adjusted BMI, waist circumference, and other factors.

CONCLUSIONS

Discrimination is a salient risk factor for inflammation and cardiovascular health. Early life course inflammation and cardiovascular reactivity are important candidate pathways through which the repeated exposure to discrimination for minority group members contributes to racial and economic health inequities in adulthood.

Discrimination, racial identity, and cytokine levels among African-American adolescents

PURPOSE

Low-grade inflammation, measured by circulating levels of cytokines, is a pathogenic mechanism for several chronic diseases of aging. Identifying factors related to inflammation among African-American youths may yield insights into mechanisms underlying racial disparities in health. The purpose of the study was to determine whether (1) reported racial discrimination from ages 17-19 years forecasts heightened cytokine levels at the age of 22 years and (2) this association is lower for youths with positive racial identities.

METHODS

A longitudinal research design was used with a community sample of 160 African-Americans who were aged 17 years at the beginning of the study. Discrimination and racial identity were measured with questionnaires, and blood was drawn to measure basal cytokine levels. Ordinary least squares regression analyses were used to examine the hypotheses.

RESULTS

After controlling for socioeconomic risk, life stress, depressive symptoms, and body mass index, racial discrimination (β = .307; p < .01), racial identity (β = -.179; p < .05), and their interaction (β = -.180; p < .05) forecast cytokine levels. Youths exposed to high levels of racial discrimination evinced elevated cytokine levels 3 years later. This association was not significant for young adults with positive racial identities.

CONCLUSIONS

High levels of interpersonal racial discrimination and the development of a positive racial identity operate jointly to determine low-grade inflammation levels that have been found to forecast chronic diseases of aging, such as coronary disease and stroke.

Association between an Internet-Based Measure of Area Racism and Black Mortality

Racial disparities in health are well-documented and represent a significant public health concern in the US. Racism-related factors contribute to poorer health and higher mortality rates among Blacks compared to other racial groups. However, methods to measure racism and monitor its associations with health at the population-level have remained elusive. In this study, we investigated the utility of a previously developed Internet search-based proxy of area racism as a predictor of Black mortality rates. Area racism was the proportion of Google searches containing the "N-word" in 196 designated market areas (DMAs). Negative binomial regression models were specified taking into account individual age, sex, year of death, and Census region and adjusted to the 2000 US standard population to examine the association between area racism and Black mortality rates, which were derived from death certificates and mid-year population counts collated by the National Center for Health Statistics (2004-2009). DMAs characterized by a one standard deviation greater level of area racism were associated with an 8.2% increase in the all-cause Black mortality rate, equivalent to over 30,000 deaths annually. The magnitude of this effect was attenuated to 5.7% after adjustment for DMA-level demographic and Black socioeconomic covariates. A model controlling for the White mortality rate was used to further adjust for unmeasured confounders that influence mortality overall in a geographic area, and to examine Black-White disparities in the mortality rate. Area racism remained significantly associated with the all-cause Black mortality rate (mortality rate ratio = 1.036; 95% confidence interval = 1.015, 1.057; p = 0.001). Models further examining cause-specific Black mortality rates revealed significant associations with heart disease, cancer, and stroke. These findings are congruent with studies documenting the deleterious impact of racism on health among Blacks. Our study contributes to evidence that racism shapes patterns in mortality and generates racial disparities in health.

Do dimensions of ethnic identity mediate the association between perceived ethnic group discrimination and depressive symptoms?

Ethnic group discrimination represents a notable risk factor that may contribute to mental health problems among ethnic minority college students. However, cultural resources (e.g., ethnic identity) may promote psychological adjustment in the context of group-based discriminatory experiences. In the current study, we examined the associations between perceptions of ethnic group discrimination and depressive symptoms, and explored dimensions of ethnic identity (i.e., exploration, resolution, and affirmation) as mediators of this process among 2,315 ethnic minority college students (age 18 to 30 years; 37% Black, 63% Latino). Results indicated that perceived ethnic group discrimination was associated positively with depressive symptoms among students from both ethnic groups. The relationship between perceived ethnic group discrimination and depressive symptoms was mediated by ethnic identity affirmation for Latino students, but not for Black students. Ethnic identity resolution was negatively and indirectly associated with depressive symptoms through ethnic identity affirmation for both Black and Latino students. Implications for promoting ethnic minority college students' mental health and directions for future research are discussed.

The effect of ethnicity on the vascular responses to cold exposure of the extremities

PURPOSE

Cold injuries are more prevalent in individuals of African descent (AFD). Therefore, we investigated the effect of extremity cooling on skin blood flow (SkBF) and temperature (T sk) between ethnic groups.

METHODS

Thirty males [10 Caucasian (CAU), 10 Asian (ASN), 10 AFD] undertook three tests in 30 °C air whilst digit T sk and SkBF were measured: (i) vasomotor threshold (VT) test--arm immersed in 35 °C water progressively cooled to 10 °C and rewarmed to 35 °C to identify vasoconstriction and vasodilatation; (ii) cold-induced vasodilatation (CIVD) test--hand immersed in 8 °C water for 30 min followed by spontaneous warming; (iii) cold sensitivity (CS) test--foot immersed in 15 °C water for 2 min followed by spontaneous warming. Cold sensory thresholds of the forearm and finger were also assessed.

RESULTS

In the VT test, vasoconstriction and vasodilatation occurred at a warmer finger T sk in AFD during cooling [21.2 (4.4) vs. 17.0 (3.1) °C, P = 0.034] and warming [22.0 (7.9) vs. 12.1 (4.1) °C, P = 0.002] compared with CAU. In the CIVD test, average SkBF during immersion was greater in CAU [42 (24) %] than ASN [25 (8) %, P = 0.036] and AFD [24 (13) %, P = 0.023]. Following immersion, SkBF was higher and rewarming faster in CAU [3.2 (0.4) °C min(-1)] compared with AFD [2.5 (0.7) °C min(-1), P = 0.037], but neither group differed from ASN [3.0 (0.6) °C min(-1)]. Responses to the CS test and cold sensory thresholds were similar between groups.

CONCLUSION

AFD experienced a more intense protracted finger vasoconstriction than CAU during hand immersion, whilst ASN experienced an intermediate response. This greater sensitivity to cold may explain why AFD are more susceptible to cold injuries.

Perceived discrimination among African American adolescents and allostatic load: a longitudinal analysis with buffering effects

This study was designed to examine the prospective relations of perceived racial discrimination with allostatic load (AL), along with a possible buffer of the association. A sample of 331 African Americans in the rural South provided assessments of perceived discrimination from ages 16 to 18 years. When youth were 18 years, caregivers reported parental emotional support and youth assessed peer emotional support. AL and potential confounder variables were assessed when youth were 20. Latent growth mixture modeling identified two perceived discrimination classes: high and stable, and low and increasing. Adolescents in the high and stable class evinced heightened AL even with confounder variables controlled. The racial discrimination to AL link was not significant for young adults who received high emotional support.

Endothelin-1 and psychosocial risk factors for cardiovascular disease: a systematic review

OBJECTIVES

Psychosocial factors (i.e., social environment and emotional factors) contribute to an increased risk of cardiovascular disease (CVD). Perturbation in a potent vasoconstrictive peptide endothelin (ET)-1 could be one of the mechanisms linking psychosocial factors to CVD. Our aim was to evaluate the literature on the relationship between plasma ET-1 and psychosocial risk factors for CVD.

METHODS

MEDLINE and PsycINFO databases were searched for articles on human studies published in peer-reviewed English-language journals through September 2012.

RESULTS

Of the 20 studies that met the inclusion criteria, 14 were experimental studies of acute psychological/mental challenges and 6 were observational studies of psychological and social factors. The inferences drawn from this review were as follows: a) laboratory-induced acute psychological/mental stress may result in exaggerated plasma ET-1 release in those with CVD and those at risk for CVD (positive studies: 5/10); b) chronic/episodic psychosocial factors may have a positive relationship to plasma ET-1 (positive studies: 3/5); and c) race (African American), sex (male), and individual differences in autonomic and hemodynamic responses to stress (parasympathetic withdrawal and elevated blood pressure responsiveness) may moderate the relationship between psychosocial factors and plasma ET-1.

CONCLUSIONS

This review indicates that psychosocial risk factors for CVD are associated with elevated plasma ET-1; however, the relatively small number of studies, methodological differences, and variable assessment tools preclude definitive conclusions about the strength of the association. Specific suggestions regarding the selection of psychosocial factors, optimization of acute challenge protocols, and standardization of methods and timing of the ET-1 measures are provided.

Discrimination, racial bias, and telomere length in African-American men

BACKGROUND

Leukocyte telomere length (LTL) is an indicator of general systemic aging, with shorter LTL being associated with several chronic diseases of aging and earlier mortality. Identifying factors related to LTL among African Americans may yield insights into mechanisms underlying racial disparities in health.

PURPOSE

To test whether the combination of more frequent reports of racial discrimination and holding a greater implicit anti-black racial bias is associated with shorter LTL among African-American men.

METHODS

Cross-sectional study of a community sample of 92 African-American men aged between 30 and 50 years. Participants were recruited from February to May 2010. Ordinary least squares regressions were used to examine LTL in kilobase pairs in relation to racial discrimination and implicit racial bias. Data analysis was completed in July 2013.

RESULTS

After controlling for chronologic age and socioeconomic and health-related characteristics, the interaction between racial discrimination and implicit racial bias was significantly associated with LTL (b=-0.10, SE=0.04, p=0.02). Those demonstrating a stronger implicit anti-black bias and reporting higher levels of racial discrimination had the shortest LTL. Household income-to-poverty threshold ratio was also associated with LTL (b=0.05, SE=0.02, p<0.01).

CONCLUSIONS

Results suggest that multiple levels of racism, including interpersonal experiences of racial discrimination and the internalization of negative racial bias, operate jointly to accelerate biological aging among African-American men. Societal efforts to address racial discrimination in concert with efforts to promote positive in-group racial attitudes may protect against premature biological aging in this population.

Interactive influences of ethnicity, endothelin-1 gene, and everyday discrimination upon nocturnal ambulatory blood pressure

BACKGROUND

Everyday discrimination scale scores are associated with increased ambulatory blood pressure (BP) and reduced nocturnal dipping, and the endothelin-1 (ET-1)/Lys198Asn polymorphism is associated with increased resting BP and exaggerated BP reactivity among African Americans compared to European Americans. Combined influences of these factors on BP control are unknown.

PURPOSE

This study tested the hypothesis of a three-way interaction between ethnicity, ET-1 carrier status, and everyday discrimination upon ambulatory BP and nocturnal dipping.

METHODS

Baseline laboratory anthropometrics and the everyday discrimination scale were completed by 352 (175 African American) young adult normotensives, followed by 24-h ambulatory BP monitoring.

RESULTS

For nocturnal dipping, multiple regression models controlling for age, sex, ethnicity, and body mass index revealed significant three-way ET-1 × everyday discrimination × ethnicity interactions. Specifically, among African American ET-1 T-allele carriers, increases in everyday discrimination led to reduced nocturnal dipping.

CONCLUSIONS

African Americans that carry the ET-1/Lys198Asn T-allele and report higher everyday discrimination scores may be at particular risk for reduced nocturnal dipping.

The associations of multiple dimensions of discrimination and abdominal fat in African American adults: the Jackson Heart Study

BACKGROUND

Discrimination may be adversely associated with abdominal obesity, but few studies have examined associations with abdominal fat.

PURPOSE

The purpose of this study was to examine whether discrimination was independently associated with visceral (VAT) and subcutaneous (SAT) fat and whether these associations differed by sex and age.

METHODS

Participants self-reported experiences of everyday and lifetime discrimination. The main reason for and the coping response to these experiences were also reported. VAT and SAT were quantified by computed tomography.

RESULTS

In fully adjusted models, higher reports of everyday discrimination were associated with greater SAT, but not VAT, volumes in men only: SAT increased by 3.6 (standard error = 1.8) cm(3) for each unit increase in the everyday discrimination score. In women, higher reports of lifetime non-racial discrimination were associated with greater VAT (71.6 ± 32.0, P < 0.05) and SAT (212.6 ± 83.6, P < 0.05), but these relationships were attenuated after controlling for body mass index.

CONCLUSIONS

These cross-sectional findings do not fully support the independent hypothesis of discrimination and abdominal fat. Additional investigations involving longitudinal designs are warranted.

Implicit racial bias as a moderator of the association between racial discrimination and hypertension: a study of Midlife African American men

OBJECTIVES

Empirical findings on racial discrimination and hypertension risk have been inconsistent. Some studies have found no association between self-reported experiences of discrimination and cardiovascular health outcomes, whereas others have found moderated or curvilinear relationships. The current cross-sectional study examined whether the association between racial discrimination and hypertension is moderated by implicit racial bias among African American midlife men.

METHODS

This study examined the data on 91 African American men between 30 and 50 years of age. Primary variables were self-reported experiences of racial discrimination and unconscious racial bias as measured by the Black-White Implicit Association Test. Modified Poisson regression models were specified, examining hypertension, defined as a mean resting systolic level of at least 140 mm Hg or diastolic level of at least 90 mm Hg, or self-reported history of cardiovascular medication use with a physician diagnosis of hypertension.

RESULTS

No main effects for discrimination or implicit racial bias were found, but the interaction of the two variables was significantly related to hypertension (χ(2)(1) = 4.89, p < .05). Among participants with an implicit antiblack bias, more frequent reports of discrimination were associated with a higher probability of hypertension, whereas among those with an implicit problack bias, it was associated with lower risk.

CONCLUSIONS

The combination of experiencing racial discrimination and holding an antiblack bias may have particularly detrimental consequences on hypertension among African American midlife men, whereas holding an implicit problack bias may buffer the effects of racial discrimination. Efforts to address both internalized racial bias and racial discrimination may lower cardiovascular risk in this population.

Racial/ethnic and gender differences in the association between self-reported experiences of racial/ethnic discrimination and inflammation in the CARDIA cohort of 4 US communities

Inflammation is etiologically implicated in cardiometabolic diseases for which there are known racial/ethnic disparities. Prior studies suggest there may be an association between self-reported experiences of racial/ethnic discrimination and inflammation, particularly C-reactive protein (CRP). It is not known whether that association is influenced by race/ethnicity and gender. In separate hierarchical linear models with time-varying covariates, we examined that association among 901 Black women, 614 Black men, 958 White women, and 863 White men in the Coronary Artery Risk Development in Young Adults (CARDIA) study in four US communities. Self-reported experiences of racial/ethnic discrimination were ascertained in 1992-93 and 2000-01. Inflammation was measured as log-transformed CRP in those years and 2005-06. All analyses were adjusted for blood pressure, plasma total cholesterol, triglycerides, homeostatic model assessment for insulin resistance (HOMA-IR), age, education, and community. Our findings extend prior research by suggesting that, broadly speaking, self-reported experiences of racial/ethnic discrimination are associated with inflammation; however, this association is complex and varies for Black and White women and men. Black women reporting 1 or 2 experiences of discrimination had higher levels of CRP compared to Black women reporting no experiences of discrimination (β = 0.141, SE = 0.062, P < 0.05). This association was not statistically significant among Black women reporting 3 or more experiences of discrimination and not independent of modifiable risks (smoking and obesity) in the final model. White women reporting 3 or more experiences of discrimination had significantly higher levels of CRP compared to White women reporting no experiences of discrimination independent of modifiable risks in the final model (β = 0.300, SE = 0.113, P < 0.01). The association between self-reported experiences of racial/ethnic discrimination and CRP was not statistically significant among Black and White men reporting 1 or 2 experiences of discrimination. Further research in other populations is needed.

Exaggerated vasopressor response to exercise and cerebral blood flow velocity

We studied 10 young adults, normotensive at rest, comprising a control group (n = 5) with normal blood pressure responsiveness to exercise and an experimental group exhibiting greater percentage of body fat and body mass index (BMI) than the controls, with exaggerated blood pressure (vasopressor) responsiveness to exercise (EEBPR) (n = 5). Lower absolute and varying oxygen consumption/body weight normalized units of middle cerebral arterial blood flow velocity (MCAV) were found during exercise in the experimental group (P < .01). These findings support the hypothesis that the combination of EEBPR and high BMI is associated with low MCAV that may put such individuals at risk for cerebral hypoperfusion and cognitive deficits.

Differential Impact of Stress Reduction Programs upon Ambulatory Blood Pressure among African American Adolescents: Influences of Endothelin-1 Gene and Chronic Stress Exposure

Stress-activated gene × environment interactions may contribute to individual variability in blood pressure reductions from behavioral interventions. We investigated effects of endothelin-1 (ET-1) LYS198ASN SNP and discriminatory stress exposure upon impact of 12-week behavioral interventions upon ambulatory BP (ABP) among 162 prehypertensive African American adolescents. Following genotyping, completion of questionnaire battery, and 24-hour ABP monitoring, participants were randomized to health education control (HEC), life skills training (LST), or breathing awareness meditation (BAM). Postintervention ABP was obtained. Significant three-way interactions on ABP changes indicated that among ET-1 SNP carriers, the only group to show reductions was BAM from low chronic stress environments. Among ET-1 SNP noncarriers, under low chronic stress exposure, all approaches worked, especially BAM. Among high stress exposure noncarriers, only BAM resulted in reductions. If these preliminary findings are replicated via ancillary analyses of archival databases and then via efficacy trials, selection of behavioral prescriptions for prehypertensives will be edging closer to being guided by individual's underlying genetic and environmental factors incorporating the healthcare model of personalized preventive medicine.

Racial/ethnic residential segregation and self-reported hypertension among US- and foreign-born blacks in New York City

BACKGROUND

Research examining the association of residence in racially segregated neighborhoods with physical and mental health outcomes among blacks is mixed. Research elucidating the relationship between segregation and hypertension has been limited. This study examines the association between segregation and hypertension among US- and foreign-born blacks in New York City (NYC).

METHODS

Individual-level data from the NYC Community Health Survey (n = 4,499) were linked to neighborhood-level data from the US Census and Infoshare Online. Prevalence ratios (PRs) for the association between segregation and self-reported hypertension among US- and foreign-born blacks were estimated.

RESULTS

After adjusting for individual- and neighborhood-level covariates, segregation was not associated with hypertension among US-born blacks or foreign-born blacks under 65 years of age. Older foreign-born blacks in highly segregated areas had a 46% lower probability (PR = 0.54; 95% confidence interval, 0.40-0.72) of reporting hypertension than older foreign-born blacks residing in low segregation areas.

CONCLUSIONS

In this NYC-based sample, no association between segregation and hypertension was observed among US-born or younger foreign-born blacks; however, our results suggest possible benefits of segregation for older foreign-born blacks. Further studies should determine whether this association is observed in other cities and identify factors that may mitigate against the adverse effects of segregation.

The contribution of hypertension to black-white differences in likelihood of coronary artery disease detected during elective angiography

BACKGROUND

Black patients in the United States undergoing angiography for suspected coronary artery disease (CAD) have consistently been found to have less disease than whites. As the effects of hypertension are greater in blacks than whites, and hypertensive heart disease may mimic CAD and lead to catheterization, we examined the association between race and hypertension as an explanation for the disparities in angiographic CAD.

METHODS

Using an academic hospital's institutional database, we studied patients undergoing first-time elective angiography from 2001 to 2008. Using multivariable logistic regression with data on patient demographics, CAD risk factors, and coronary stenoses, we compared rates of angiographic disease for blacks and whites, creating models separately for patients with and without hypertension. We then tested the significance of an interaction term between race and hypertension on angiographic findings.

RESULTS

We identified 1,203 black and 2,538 white patients who underwent initial elective angiography. Black patients were less likely to have a significant stenotic lesion (≥50% stenosis in the left main artery or ≥70% stenosis elsewhere) than whites (adjusted risk ratio 0.65; 95% confidence interval (CI) 0.55-0.75). Among patients with hypertension this difference was exaggerated (adjusted risk ratio 0.60; 95% CI 0.51-0.71). However, among patients without hypertension, the risk of having a significant lesion was similar in blacks and whites (adjusted risk ratio 0.97; 95% CI 0.67-1.37). The interaction term for race and hypertension was confirmed as statistically significant.

CONCLUSIONS

Among patients electively referred for angiography, hypertension, and its effects may contribute to the lower rate of CAD found in blacks compared to whites.

Endothelial function: the impact of objective and subjective socioeconomic status on flow-mediated dilation

BACKGROUND

Although objective and subjective indicators of socioeconomic status (SES) are linked to cardiovascular disease (CVD), little is known about their relationship to endothelial dysfunction, which often precedes CVD.

PURPOSE

This study examined how objective and subjective SES relate to brachial artery flow-mediated dilation (FMD).

METHODS

FMD was assessed in 72 healthy adults (mean age 36 years). The MacArthur Scale of Subjective Social Status assessed perceived social standing in the USA (SSS-USA) and local community (SSS-Community). Objective SES measures included income and the Hollingshead Two-Factor Index of Social Position (education, occupation).

RESULTS

Adjusted regressions revealed that SSS-Community positively correlated with FMD (p < 0.05) and explained 8% of the variance. No other SES measures were significant for FMD. The association between FMD and SSS-Community remained significant (p < 0.01) after adjustment for objective SES and other covariates.

CONCLUSIONS

Lower subjective social status in one's community may be linked to CVD via impaired vasodilation.

High level of plasma endothelin-1 predicts development of hypertension in normotensive subjects

BACKGROUND

Endothelin-1 (ET-1) is a potent vasoconstrictor derived from the endothelium. However, most large scale cross-sectional studies in humans have indicated no relationship between plasma ET-1 levels and hypertension. The present study was designed to determine whether high plasma ET-1 levels predict the development of hypertension.

METHODS

A total of 1,492 subjects received a health examination in the Japanese cohort of Seven Countries Study in 1999, when, we examined blood pressure (BP), body mass index (BMI), and blood chemistries. Data on fasting ET-1 were obtained from 1,451 individuals. Seven years later, 1,261 subjects (494 males and 767 females) were re-examined (follow-up rate = 87%).

RESULTS

Of 814 normotensives (BP <140/90 mm Hg without antihypertensive medications) at baseline, 222 subjects developed hypertension. We divided the baseline plasma ET-1 levels into quartiles. The odds ratio for the development of hypertension after 7 years was 1.79 (95% confidence interval (CI): 1.08-2.96) in the highest quartile vs. the lowest quartile of ET-1 level after adjustment for confounding factors.

CONCLUSION

A high level of plasma ET-1 predicted the development of hypertension in normotensive subjects.