Cardiovascular Disease in Blacks: Can We Stop the Clock?

Association of Plasma Amyloid-β and Dementia Among Black and White Older Adults

Background

Plasma amyloid-β (Aβ) has emerged as an important tool to detect risks of Alzheimer's disease and related dementias, although research in diverse populations is lacking.

Objective

We compared plasma Aβ42/40 by race with dementia risk over 15 years among Black and White older adults.

Methods

In a prospective cohort of 997 dementia-free participants (mean age 74±2.9 years, 55% women, 54% Black), incident dementia was identified based on hospital records, medication, and neurocognitive test over 15 years. Plasma Aβ42/40 was measured at Year 2 and categorized into low, medium, and high tertile. We used linear regression to estimate mean Aβ42/40 by race and race-stratified Cox proportional hazards models to assess the association between Aβ42/40 tertile and dementia risk.

Results

Black participants had a lower age-adjusted mean Aβ 42/40 compared to White participants, primarily among APOE ɛ4 non-carriers (Black: 0.176, White: 0.185, p = 0.035). Among Black participants, lower Aβ 42/40 was associated with increased dementia risk: 33% in low (hazard ratios [HR] = 1.77, 95% confidence interval 1.09-2.88) and 27% in medium tertile (HR = 1.67, 1.01-2.78) compared with 18% in high Aβ 42/40 tertile; Increased risks were attenuated among White participants: 21% in low (HR = 1.43, 0.81-2.53) and 23% in medium tertile (HR = 1.27, 0.68-2.36) compared with 15% in high Aβ 42/40 tertile. The interaction by race was not statistically significant.

Conclusions

Among community-dwelling, non-demented older adults, especially APOE ɛ4 non-carriers, Black individuals had lower plasma Aβ 42/40 and demonstrated a higher dementia risk with low Aβ42/40 compared with White individuals.

Estrogen-mediated mechanisms in hypertension and other cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death globally for men and women. Premenopausal women have a lower incidence of hypertension and other cardiovascular events than men of the same age, but diminished sex differences after menopause implicates 17-beta-estradiol (E2) as a protective agent. The cardioprotective effects of E2 are mediated by nuclear estrogen receptors (ERα and ERβ) and a G protein-coupled estrogen receptor (GPER). This review summarizes both established as well as emerging estrogen-mediated mechanisms that underlie sex differences in the vasculature during hypertension and CVD. In addition, remaining knowledge gaps inherent in the association of sex differences and E2 are identified, which may guide future clinical trials and experimental studies in this field.

Relationships between neighborhood disadvantage and cardiovascular findings at autopsy in subjects with sudden death

BACKGROUND

Neighborhood disadvantage is associated with a higher risk of sudden cardiac death. However, autopsy findings have never been investigated in this context. Here, we sought to explore associations between neighborhood disadvantage and cardiovascular findings at autopsy in cases of sudden death in the State of Maryland.

METHODS

State of Maryland investigation reports from 2,278 subjects within the CVPath Sudden Death Registry were screened for street addresses and 9-digit zip codes. Area deprivation index (ADI), used as metric for neighborhood disadvantage, was available for 1,464 subjects; 650 of whom self-identified as Black and 814 as White. The primary study outcome measurements were causes of death and gross and histopathologic findings of the heart.

RESULTS

Subjects from most disadvantaged neighborhoods (i.e., ADI ≥ 8; n = 607) died at younger age compared with subjects from less disadvantaged neighborhoods (i.e., ADI ≤ 7; n = 857; 46.07 ± 14.10 vs 47.78 ± 13.86 years; P = 0.02) and were more likely Black or women. They were less likely to die from cardiac causes of death (61.8% vs 67.7%; P = 0.02) and had less severe atherosclerotic plaque features, including plaque burden, calcification, intraplaque hemorrhage, and thin-cap fibroatheromas. In addition, subjects from most disadvantaged neighborhoods had lower frequencies of plaque rupture (18.8% vs 25.1%, P = 0.004). However, these associations were omitted after adjustment for traditional risk factors and race.

CONCLUSION

Neighborhood disadvantage did not associate with cause of death or coronary histopathology after adjustment for cardiovascular risk factors and race, implying that social determinants of health other than neighborhood disadvantage play a more prominent role in sudden cardiac death.

Sex-, Race- and Ethnicity-Based Differences in Thromboembolic Events Among Adults Hospitalized With COVID-19

Background

Patients hospitalized with COVID‐19 have an increased risk of thromboembolic events. Whether sex, race or ethnicity impacts these events is unknown. We studied the association between sex, race, and ethnicity and venous and arterial thromboembolic events among adults hospitalized with COVID‐19.

Methods and Results

We used the American Heart Association Cardiovascular Disease COVID‐19 registry. Primary exposures were sex and race and ethnicity, as defined by the registry. Primary outcomes were venous thromboembolic events and arterial thromboembolic events. We used logistic regression for risk adjustment. We studied 21 528 adults hospitalized with COVID‐19 across 107 centers (54.1% men; 38.1% non‐Hispanic White, 25.4% Hispanic, 25.7% non‐Hispanic Black, 0.5% Native American, 4.0% Asian, 0.4% Pacific Islander, and 5.9% other race and ethnicity). The rate of venous thromboembolic events was 3.7% and was more common in men (4.2%) than women (3.2%; P<0.001), and in non‐Hispanic Black patients (4.9%) than other races and ethnicities (range, 1.3%–3.8%; P<0.001). The rate of arterial thromboembolic events was 3.9% and was more common in men (4.3%) than women (3.5%; P=0.002), and in non‐Hispanic Black patients (5.0%) than other races and ethnicities (range, 2.3%–4.7%; P<0.001). Compared with men, women were less likely to experience venous thromboembolic events (adjusted odds ratio [OR], 0.71; 95% CI, 0.61–0.83) and arterial thromboembolic events (adjusted OR, 0.76; 95% CI, 0.66–0.89). Compared with non‐Hispanic White patients, non‐Hispanic Black patients had the highest likelihood of venous thromboembolic events (adjusted OR, 1.27; 95% CI, 1.04–1.54) and arterial thromboembolic events (adjusted OR, 1.35; 95% CI, 1.11–1.65).

Conclusions

Men and non‐Hispanic Black adults hospitalized with COVID‐19 are more likely to have venous and arterial thromboembolic events. These subgroups may represent at‐risk patients more susceptible to thromboembolic COVID‐19 complications.

Ocular blood flow as it relates to race and disease on glaucoma

Glaucoma is a multifactorial progressive and degenerative optic neuropathy representing one of the world's leading cause of irreversible blindness. Currently, reduction of intraocular pressure remains the only universally approved therapy, yet a wealth of studies has identified significant vascular contributions to the disease process in certain individuals. Population-based studies have identified important racial disparities and differential risk factors in glaucoma prevalence, incidence, and progression. A more significant vascular component has been identified in persons of African descent. Elucidating risk modifiers, including genetic and racial influence, is important when considering individually tailored clinical management of glaucoma. The application of artificial intelligence and mathematical modeling inclusive of demographic considerations, vascular health, and clinical biomarkers may help reduce disease disparities, advance personalized medicine, and provide a comprehensive model of glaucoma.

Ocular blood flow as a clinical observation: Value, limitations and data analysis

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.

Ethnic and racial disparities in hypertension management among women

Hypertension is a major independent risk factor for cardiovascular disease for all ethnic and racial groups. Compared with other lifestyle and metabolic risk factors, hypertension is the leading cause of death in women. Women with preeclampsia are three times more likely to develop chronic hypertension and have an elevated risk of future cardiovascular disease. The objective of this article is to provide a review of the factors related to racial and ethnic disparities in blood pressure control. This is followed by a summary of contemporary clinical practice guidelines for the prevention, through lifestyle behavioral modification, and treatment of hypertension with pharmacotherapy.

Differences in ocular blood flow in glaucoma between patients of African and European descent

PURPOSE

To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG).

PATIENTS AND METHODS

A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values <0.05 considered statistically significant.

RESULTS

OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P<0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters.

CONCLUSIONS

Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.

Vascular considerations in glaucoma patients of African and European descent

Glaucoma is the leading cause of blindness in individuals of African descent (AD). While open-angle glaucoma (OAG) disproportionately affects individuals of AD compared with persons of European descent (ED), the physiological mechanisms behind this disparity are largely unknown. The more rapid progression and greater severity of the disease in persons of AD further raise the concern for identifying these underlying differences in disease pathophysiology between AD and ED glaucoma patients. Ocular structural differences between AD and ED patients, including larger optic disc area, cup:disc ratio and thinner corneas, have been found. AD individuals are also disproportionately affected by systemic vascular diseases, including hypertension, cardiovascular disease, stroke and diabetes mellitus. Abnormal ocular blood flow has been implicated as a risk factor for glaucoma, and pilot research is beginning to identify localized ocular vascular differences between AD and ED OAG patients. Given the known systemic vascular deficits and the relationship between glaucoma and ocular blood flow, exploring these concepts in terms of glaucoma risk factors may have a significant impact in elucidating the mechanisms behind the disease disparity in the AD population.

Prescribing patterns in the treatment of hypertension among underserved African American elderly

INTRODUCTION

Hypertension among African Americans is higher compared to Whites and has an early onset, greater severity, and is associated with more organ damage. We examined whether pharmaceutical treatment of hypertension among underserved African American elderly is consistent with the current treatment guidelines and whether treatment variations occur due to existing co-morbidities among the hypertensive.

METHODS

Our study surveyed 400 African Americans, aged ≥ 65 years, recruited from 16 predominantly African American churches located in South Los Angeles. The study used face-to-face interviews which documented type, frequency, and dosage of all medications used by participants. Label information of each drug was recorded.

RESULTS

Our data indicate: 1) 29% were on one anti-hypertensive medication; 60% were taking 2-3 medications; and 9% were on four classes of anti-hypertensive medication; 2) among the elderly taking a combination of two or more drugs, ACE or ARB was used 76% in combination of agents, diuretics 60%, calcium channel blockers 63%, and beta-blocker 61%; and 3) 26% of the elderly were taking ≥ 3 medications including a diuretic.

CONCLUSIONS

Treatment of hypertension appears to be inconsistent with the prevailing treatment guidelines for nearly one-third of the aged African Americans. Further investigation is needed to determine why a significant number of individuals from this under-served population are not receiving care based on established clinical guidelines.

Mathematical modeling approaches in the study of glaucoma disparities among people of African and European descents

Open angle glaucoma (OAG) is a severe ocular disease characterized by progressive and irreversible vision loss. While elevated intraocular pressure (IOP) is a well-established risk factor for OAG, the progression of OAG in many cases, despite IOP treatment, suggests that other risk factors must play significant roles in the development of the disease. For example, various structural properties of the eye, ocular blood flow properties, and systemic conditions have been identified as risk factors for OAG. Ethnicity has also been indicated as a relevant factor that affects the incidence and prevalence of OAG; in fact, OAG is the leading cause of blindness among people of African descent. Numerous clinical studies have been designed to examine the possible correlation and causation between OAG and these factors; however, these studies are met with the challenge of isolating the individual role of multiple interconnected factors. Over the last decade, various mathematical modeling approaches have been implemented in combination with clinical studies in order to provide a mechanical and hemodynamical description of the eye in relation to the entire human body and to assess the contribution of single risk factors to the development of OAG. This review provides a summary of the clinical evidence of ocular structural differences, ocular vascular differences and systemic vascular differences among people of African and European descent, describes the mathematical approaches that have been proposed to study ocular mechanics and hemodynamics while discussing how they could be used to investigate the relevance to OAG of racial disparities, and outlines possible new directions of research.

Low-level arsenic exposure, AS3MT gene polymorphism and cardiovascular diseases in rural Texas counties

Most Americans living in rural areas use groundwater for drinking. Exposure to low-level (around the current U.S. standard 10 μg/L) arsenic in drinking water is associated with increased mortality of cardiovascular diseases. The current study was to determine if coronary heart disease, hypertension, and hyperlipidemia were associated with low-level arsenic exposure and AS3MT gene single nucleotide polymorphism (SNP) A35991G (rs10748835) in rural Texas. Subjects (156 men, 343 women, 40-96 years of age with a mean of 61) were residents from rural counties Cochran, Palmer, and Bailey, Texas. Groundwater arsenic concentration at each subject's home was estimated with ArcGIS inverse distance weighted interpolation based on the residential location's distances to surrounding wells with known water arsenic concentrations. The estimated groundwater arsenic concentration ranged from 2.2 to 15.3 (mean 6.2) μg/L in this cohort. Logistic regression analysis showed that coronary heart disease was associated with higher arsenic exposure (p<0.05) and with AS3MT genotype GG vs. AA (p<0.05) after adjustments for age, ethnicity, gender, education, smoking status, alcoholism, and anti-hyperlipidemia medication. Hypertension was associated with higher arsenic exposure, while hyperlipidemia was associated with genotype AG vs. AA of the AS3MT gene (p<0.05). Thus, coronary heart disease and its main risk factors were associated with low-level arsenic exposure, AS3MT polymorphism or both.

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.