Ethnic differences in vascular stiffness and relations to hypertensive target organ damage

Characteristics of heart failure with a preserved ejection fraction in black South African patients

Background

Heart failure with a preserved ejection fraction (HFpEF) is common in the elderly (≥75 years) and associated with arterial stiffness. The mean age of HFpEF presentation is lower (40-55 years) in sub-Saharan Africa. No clinical study has been conducted on HFpEF in identifying and characterising this phenotype at a younger age, moreover in a South African black population where the risk of HFpEF is two times higher than in other ethnic groups. This study investigated the characteristics of HFpEF in a black South African population, the biochemical markers that predict HFpEF and cardiac structural changes in this HF phenotype.

Methods

Sixty-six participants with HFpEF and 213 controls were enrolled. All participants gave informed consent and completed a standardised questionnaire. Echocardiographic, anthropometric, central haemodynamic measurements, pulse wave velocity (PWV) and biomarker analysis were done.

Results

The mean age of HFpEF participants was 54.88 ± 13.51 years. Most of the participants (76 %) were between 20 and 64 years, while only 24 % were older. HFpEF participants were hypertensive, and more obese with increased incidence of alcohol consumption. PWV was increased in HFpEF (9.97 ± 2.78 m/s) when compared to participants without HFpEF (6.11 ± 2.18 m/s), p < 0.0001. There were no significant associations between central haemodynamic parameters, N-terminal pro B-type natriuretic peptide (NT-proBNP) (p = 0.9746), and galectin-3 (p = 0.2166). NT-proBNP, but not galectin-3, was associated with left ventricular hypertrophy (p = 0.0002) and left atrial diameter (p = 0.0005).

Conclusion

HFpEF in South Africa is predominant in obese young to middle-age individuals with arterial stiffness and who consume alcohol regularly. NT-proBNP could be used to diagnose HFpEF, however, should be interpreted with caution in populations with a high prevalence of obesity.

Examining Health-Seeking Behavior among Diverse Ethnic Subgroups within Black Populations in the United States and Canada: A Cross-Sectional Study

The Black populations, often treated as ethnically homogenous, face a constant challenge in accessing and utilizing healthcare services. This study examines the intra-group differences in health-seeking behavior among diverse ethnic subgroups within Black communities. A cross-sectional analysis included 239 adults ≥18 years of age who self-identified as Black in the United States and Canada. Multiple logistic regression assessed the relationship between health-seeking behaviors and ethnic origin, controlling for selected social and health-related factors. The mean age of the participants was 38.6 years, 31% were male, and 20% were unemployed. Sixty-one percent reported a very good or excellent health status, and 59.7% were not receiving treatment for chronic conditions. Advancing age (OR = 1.05, CI: 1.01-1.09), female gender (OR = 3.09, CI: 1.47-6.47), and unemployment (OR = 3.46, CI: 1.35-8.90) were associated with favorable health-seeking behaviors. Compared with the participants with graduate degrees, individuals with high school diplomas or less (OR = 3.80, CI: 1.07-13.4) and bachelor's degrees (OR = 3.57, CI: 1.3-9.23) were more inclined to have engaged in favorable health-seeking behavior compared to those with graduate degrees. Across the Black communities in our sample, irrespective of ethnic origins or country of birth, determinants of health-seeking behavior were age, gender, employment status, and educational attainment.

Perceptions of dietary intake amongst Black, Asian and other minority ethnic groups in high-income countries: a systematic review of qualitative literature

BACKGROUND

Minority ethnic groups are a fast-growing population in many high-income countries, partly due to the increasing population of immigrants and second-generation migrants. The dietary practices of some of these minority ethnic groups might make them to be disproportionately affected by obesity and increase their risks of developing non-communicable diseases. Population-specific interventions and strategies are vital to addressing poor nutritional practices among this population. Thus, this study systematically reviewed the perceptions of dietary intake amongst Black, Asian and other minority ethnic groups in high-income countries.

METHODS

This systematic review was conducted in line with the guidelines of the Joanna Briggs Institute (JBI) methodology for systematic reviews, using a meta-aggregative design. This systematic review identified and synthesised qualitative literature on the perceptions of dietary intake amongst BlackAsian and other minority  ethnic groups in high-income countries. An extensive and comprehensive database search was conducted between January 2000 - May 2022 and included twenty (20) studies that met the eligibility criteria from six countries. The included studies were assessed for quality using the JBI qualitative assessment and review instrument. The JBI data extraction tools were used to retrieve relevant data from included articles, and the data were thematically analysed.

RESULTS

We identified eight major themes across this database: (1) "Social and Cultural Factors," (2) "Availability and Accessibility," (3) "Family and Community Influences," (4) "Food Preferences", (5) "Home Country Food Versus Host Country Food" (6) "Dietary Acculturation" (7) "Health and Healthy Eating" (8) "Perception of Nutritional Information."

CONCLUSION

Overall, Black, Asian, and other minority ethnic groups individuals were found to be aware of the effects of unhealthy eating on their health, and some of them have nutritional knowledge, but social and cultural factors, including structural factors, were deterrents to their healthy eating behaviours. An important finding from this review is that some participants believed that nutritional information, based on bio-medical science, was intended for only White population groups and that it was antagonistic to their cultural and community well-being.

Are you as old as your arteries? Comparing arterial aging in Japanese and European patient groups using cardio-ankle vascular index

BACKGROUND

Most comparisons of arterial stiffness between ethnic groups focus on pulse wave velocity. This study used the cardio-ankle vascular index (CAVI) in European compared to Japanese individuals to investigate how cardiovascular risk factors affect arterial aging across geographic regions.

METHODS

Four hundred and ninety-four European and 1044 Japanese individuals underwent measurements of CAVI, blood pressure and information on cardiovascular risk factors. Both datasets included individuals with 0-5 cardiovascular risk factors.

RESULTS

Average CAVI was higher in the Japanese than the European group in every age category, with significant differences up to 75 years for males and 85 for females. The correlation of CAVI with age, controlled for cardiovascular risk factors, was slightly higher in Japanese females (r = 0.594 vs. Europeans r = 0.542) but much higher in European males (r = 0.710 vs. Japanese r = 0.511). There was a significant correlation between CAVI and total cardiovascular risk factors in the Japanese (r = 0.141, P < 0.001) but not the European group. On linear regression, average CAVI was significantly dependent on age, sex, diabetes, BMI, SBP and geographic region. When divided into 'healthy' vs. 'high risk', the healthy group had a steeper correlation with age for Europeans (r = 0.644 vs. Japanese r = 0.472, Fisher's Z P < 0.001), whereas in the high-risk group, both geographic regions had similar correlations.

CONCLUSION

Japanese patient groups had higher arterial stiffness than Europeans, as measured by CAVI, controlling for cardiovascular risk factors. Europeans had greater increases in arterial stiffness with age in healthy individuals, particularly for males. However, cardiovascular risk factors had a greater impact on the Japanese group.

Prevalence of Chronic Kidney Disease as a Marker of Hypertension Target Organ Damage in Africa: A Systematic Review and Meta-Analysis

Introduction

Hypertension is a major global cause of cardiovascular disease and death with rising worldwide prevalence, particularly in low-income countries. With low awareness, poor treatment, and low control of hypertension in Africans, there is an increased number of patients with target organ damage (TOD), especially chronic kidney disease (CKD), as a consequence of hypertension. The aim of our study is to assess the prevalence of CKD from studies in Africa reporting TOD related to hypertension.

Methods

We performed a search of PubMed/MEDLINE, Web of Science, EBSCOhost, and African Journals Online (AJOL) for studies reporting on CKD as TOD in patients with hypertension. The pooled estimate of CKD was then presented by subregions, age group, eGFR equations, and urban or rural location.

Results

We identified 1,334 articles from which 12 studies were included for quantitative analysis. The studies included 5297 participants from 6 countries (Ghana, Nigeria, Uganda, Tanzania, Democratic Republic of Congo, and South Africa). The pooled prevalence of CKD was 17.8% (95% CI 13.0-23.3%), and CKD was significantly more prevalent in West Africa (21.3% (95% CI: 16.1-27.0); p < 0.0001) and in studies conducted in urban settings (p < 0.001). CKD prevalence was not significantly different by type of GFR equation or age.

Conclusion

This study reports a high prevalence of CKD related to hypertension with a higher prevalence in urban than rural areas. This emphasizes the role of hypertension in causing kidney damage, and the need for strategies to improve awareness, treatment, and control of hypertension in Africans. This study is registered with PROSPERO registration number CRD42018089263.

Arterial stiffness in black adults from Angola and Brazil

Ethnicity is an important determinant of blood pressure levels, being black individuals affected more than any other ethnic group. Arterial stiffening, an independent risk factor for hypertension, is also influenced by ethnicity. However, whether black individuals from different continents would have different patterns of arterial stiffening is still unknown. Thus, the authors aimed to compare pulse wave velocity (PWV) in black subjects living in Angola and Brazil. A total of 677 black individuals from two independent cross-sectional studies conducted in Brazil and Angola were included in this analysis. Carotid-to-femoral PWV was measured following the same protocols for both studies, as well as clinical and anthropometric variables. Adjusted PWV was higher in Brazilian blacks than in Angolans, regardless of sex (men from Brazil: 10.7 ± 1.8 vs men from Angola: 9.9 ± 1.8 m/s, P < .001; women from Brazil: 10.3 ± 1.5 vs women from Angola: 9.2 ± 1.3 m/s, P < .001). Although the cf-PWV was higher in Brazilian blacks, the age-related increase in cf-PWV was higher in Angolan men compared to Brazilians, but not in women. SBP showed the strongest association with cf-PWV, regardless of sex and country. However, age was associated with cf-PWV in all groups, except in Brazilian men. Our results clearly show a difference in PWV between two black populations, and highlight for sex differences in the hemodynamic parameters that might affect blood pressure levels in these populations.

The prospective relationship between prehypertension, race, and whole-brain white matter microstructure

Compared with whites, blacks develop hypertension earlier in life, progress from prehypertension to hypertension at an accelerated rate, and exhibit greater hypertension-mediated organ damage (e.g., kidney disease, stroke). In this paper, we tested whether the longitudinal associations between elevated systolic blood pressure and disruption of brain white matter structural integrity differ as a function of race. A community sample of 100 middle-aged adults with prehypertension underwent diffusion imaging to quantify indirect metrics of white matter structural integrity, including fractional anisotropy. Blood pressure and diffusion imaging measurements were collected at baseline and at a 2-year follow-up. Regression analyses showed that higher systolic blood pressure at baseline was associated with a decrease in fractional anisotropy over 2 years in blacks only (β = -0.51 [95% CI = -0.85, -0.16], t = -2.93, p = 0.004, ΔR2 = 0.09). These findings suggest that blacks are more susceptible to the impact of systolic prehypertension on white matter structural integrity.

Carotid and aortic stiffness in essential hypertension and their relation with target organ damage: the CATOD study

OBJECTIVE

The objective of the study is to investigate in the hypertensive population the possible differential association between increased aortic and/or carotid stiffness and organ damage in multiple districts, such as the kidney, the vessels, and the heart.

METHODS

In 314 essential hypertensive patients, carotid-femoral pulse wave velocity (cfPWV, by applanation tonometry) and carotid stiffness (from ultrasound images analysis), together with left ventricular hypertrophy, carotid intima-media thickness, urinary albumin-creatinin ratio, and glomerular filtration rate were measured. Increased cfPWV and carotid stiffness were defined according to either international reference values or the 90th percentile of a local control group (110 age and sex-matched healthy individuals).

RESULTS

When considering the 90th percentile of a local control group, increased cfPWV was associated with reduced glomerular filtration rate, either when carotid stiffness was increased [odds ratio (OR) 13.27 (confidence limits (CL) 95% 3.86-45.58)] or not [OR 7.39 (CL95% 2.25-24.28)], whereas increased carotid stiffness was associated with left ventricular hypertrophy, either when cfPWV was increased [OR 2.86 (CL95% 1.15-7.09)] or not [OR 2.81 (CL95% 1.13-6.97)]. No association between increased cfPWV or carotid stiffness and target organ damage was found when cutoffs obtained by international reference values were used. The concomitance of both increased cfPWV and carotid stiffness did not have an additive effect on organ damage.

CONCLUSION

Aortic and carotid stiffness are differentially associated with target organ damage in hypertensive patients. Regional arterial stiffness as assessed by cfPWV is associated with renal organ damage and local carotid stiffness with cardiac organ damage.

Ethnicity and arterial stiffness in children and adolescents from a Brazilian population

BACKGROUND

Increased stiffness of large arteries is an important determinant of cardiovascular disease risk. Higher values of arterial stiffness measured by carotid-femoral pulse wave velocity (cf-PWV) have been measured in adult African-Americans compared with whites. Studies assessing ethnic differences in cf-PWV among children and adolescents are scarce. This study sought to evaluate the association between ethnicity and cf-PWV in Brazilian children and adolescents.

METHODS

Seven hundred and seventy-one children and adolescents (211 blacks and 560 nonblacks, 11.3 ± 2.7 years) were included. Arterial stiffness was evaluated by cf-PWV. The ethnic classification was obtained by a single interviewer according to general phenotypes such as skin color, hair shape and facial traces.

RESULTS

Blood pressure was similar in blacks and nonblacks across all pubertal stages. Differently, cf-PWV was higher in blacks than nonblacks pubescent (5.9 ± 0.7 vs. 5.6 ± 0.8 m/s, P = 0.001) and postpubescent (6.1 ± 0.7 vs. 5.7 ± 0.7 m/s, P = 0.042), whereas no difference was detected between blacks and nonblacks prepubescent. These analyses were adjusted for sex, age, height, BMI, SBP and heart rate.

CONCLUSION

Our study showed that higher cf-PWV values in blacks appear in adolescence and are independent of blood pressure values. Therefore, our data suggest adolescence as the key phase for the appearance of the vascular profile found in adults black individuals.

Race-Related Differences in Left Ventricular Structural and Functional Remodeling in Response to Increased Afterload: The ARIC Study

OBJECTIVES

The aim of this study was to evaluate racial differences in arterial elastance (Ea), which reflects the arterial afterload faced by the left ventricle, and its associations with cardiac structure and function. The hypothesis under study was that the left ventricle in blacks displays heightened afterload sensitivity compared with whites.

BACKGROUND

Chronic increasing in arterial afterload may be an important trigger for left ventricular (LV) remodeling and dysfunction that lead to heart failure. Racial differences in the predisposition to heart failure are well described, but the underlying mechanisms remain unclear.

METHODS

In total, 5,727 community-based, older ARIC (Atherosclerosis Risk In Community) study participants (22% black) who underwent echocardiography between 2011 and 2013 were studied.

RESULTS

Blacks were younger (mean age 75 ± 5 years vs. 76 ± 5 years), were more frequently female (66% vs. 57%), and had higher prevalence rates of obesity (46% vs. 31%), hypertension (94% vs. 80%), and diabetes mellitus (47% vs. 34%) than whites. Adjusting for these baseline differences, Ea was higher among blacks (1.96 ± 0.01 mm Hg/ml vs. 1.80 ± 0.01 mm Hg/ml). In blacks, Ea was associated with greater LV remodeling (LV mass index, β = 3.21 ± 0.55 g/m2, p < 0.001) and higher LV filling pressures (E/e' ratio, β = 0.42 ± 0.11, p < 0.001). These relationships were not observed in whites (LV mass, β = 0.16 ± 0.32 g/m2, p = 0.61, p for interaction <0.001; E/e' ratio, β = -0.32 ± 0.06, p < 0.001, p for interaction <0.001).

CONCLUSIONS

These community-based data suggest that black Americans display heightened afterload sensitivity as a stimulus for LV structural and functional remodeling, which may contribute to their greater risk for heart failure compared with white Americans.

Racial Differences in Aortic Stiffness in Children

OBJECTIVE

To investigate racial differences in central blood pressure and vascular structure/function as subclinical markers of atherosclerotic cardiovascular disease in children.

STUDY DESIGN

This cross-sectional study recruited 54 African American children (18 female, 36 male; age 10.5 ± 0.9 years) and 54 white children (27 female, 26 male; age 10.8 ± 0.9 years) from the Syracuse City community as part of the Environmental Exposures and Child Health Outcomes study. Participants underwent blood lipid and vascular testing on 2 separate days. Carotid artery intima-media thickness and aortic stiffness were measured by ultrasonography and carotid-femoral pulse wave velocity, respectively. Blood pressure was assessed at the brachial artery and estimated in the carotid artery using applanation tonometry.

RESULTS

African American children had significantly higher pulse wave velocity (4.8 ± 0.8 m/s) compared with white children (4.2 ± 0.7 m/s; P < .05), which remained significant after adjustment for confounding variables including socioeconomic status. African American children had significantly higher intima-media thickness (African American 0.41 ± 0.06, white 0.39 ± 0.05 mm), and carotid systolic blood pressure (African American 106 ± 11, white 102 ± 8 mm Hg; P < .05) compared with white children, although these racial differences were no longer present after covariate adjustments for height.

CONCLUSIONS

Racial differences in aortic stiffness are present in childhood. Our findings suggest that racial differences in subclinical cardiovascular disease occur earlier than previously recognized.

Association of Family History With Cardiovascular Disease in Hypertensive Individuals in a Multiethnic Population

BACKGROUND

Hypertension alone is a poor predictor of the individual risk of cardiovascular disease. Hereditary factors of which hypertension is merely a marker may explain why some hypertensive individuals appear more susceptible to cardiovascular disease, and why some ethnicities have more often seemingly hypertension-related cardiovascular disease than others. We hypothesize that, in hypertensive individuals, a positive family history of cardiovascular disease identifies a high-risk subpopulation.

METHODS AND RESULTS

Healthy Life in Urban Settings (HELIUS) is a cohort study among participants of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish, and Moroccan origin aged 70 years and younger. In participants with hypertension (n=6467), we used logistic regression to assess the association of family history of cardiovascular disease with prevalent stroke and nonstroke cardiovascular disease, adjusting for sex, age, education, and smoking. To detect ethnic differences, we tested for interaction between family history and ethnicity and stratified the analysis by ethnicity. A positive family history was associated with a higher prevalence of nonstroke cardiovascular disease (odds ratio [OR], 2.05; 95% CI, 1.65-2.54) and stroke (OR, 1.62; 95% CI, 1.19-2.20). The strongest association of family history with nonstroke cardiovascular disease was found among the Dutch (OR, 2.47; 95% CI, 1.37-4.44) and with stroke among the African Surinamese (OR, 2.17; 95% CI, 1.32-3.57). The interaction between family history and African Surinamese origin for stroke was statistically significant.

CONCLUSIONS

In multiethnic populations of hypertensive patients, a positive family history of cardiovascular disease may be used clinically to identify individuals at high risk for nonstroke cardiovascular disease regardless of ethnic origin and African Surinamese individuals at high risk for stroke.

Carotid characteristics of black South Africans with five-year sustained hypertension

INTRODUCTION

An important feature of hypertension is a reduction in large artery distensibility, which may be due to structural and functional adaptations. Black populations are particularly prone to the development of hypertension. We therefore compared the carotid characteristics between five-year sustained hypertensive and normotensive black South Africans, and investigated how carotid characteristics relate to cardiometabolic risk factors, inflammation, endothelial activation and health behaviours.

METHODS

We included HIV-free black South Africans who were either consistently hypertensive (n = 351) or normotensive (n = 241) from 2005 to 2010. We assessed carotid characteristics, including intima-media thickness (IMT), distensibility and lumen diameter with B-mode ultrasound, and calculated Young's elastic modulus, cross-sectional wall area and beta-stiffness index. We measured the carotid dorsalis pedis pulse-wave velocity, brachial and central systolic blood pressure (cSBP) and determined metabolic, inflammatory and endothelial activation markers from blood samples. Health behaviours were reported in questionnaires.

RESULTS

The hypertensive group presented with higher brachial and central blood pressure, thicker IMT and stiffer carotid arteries (all p < 0.001). However, after adjustment for cSBP but not mean arterial pressure (MAP), all significant differences in carotid characteristics were lost. The carotid thickness measurements did not differ after adjustment for MAP. After adjustment, metabolic, inflammatory and endothelial activation markers did not differ between the two groups.

CONCLUSION

Our results suggest that besides structural changes, functional adaptations are also involved in deterioration of the carotid wall characteristics of hypertensive black South Africans. These results highlight the importance of proper hypertension control in Africa.

Do arterial stiffness and wave reflection underlie cardiovascular risk in ethnic minorities?

Increasing evidence indicates that remarkable differences in cardiovascular risk between ethnic groups cannot be fully explained by traditional risk factors such as hypertension, diabetes or dislipidemia measured in midlife. Therefore, the underlying pathophysiology leading to this “excess risk” in ethnic minority groups is still poorly understood, and one way to address this issue is to shift the focus from “risk” to examine target organs, particularly blood vessels and their arterial properties more directly. In fact, structural and functional changes of the vascular system may be identifiable at very early stages of life when traditional factors are not yet developed. Arterial stiffening, measured as aortic pulse wave velocity, and wave reflection parameters, especially augmentation index, seem to be an important pathophysiological mechanism for the development of cardiovascular disease and predict mortality independent of other risk factors. However, data regarding these arterial indices in ethnic minorities are relatively rare and the heterogeneity between populations, techniques and statistical methods make it difficult to fully understand their role.

Monocyte Chemoattractant Protein-1 and Large Artery Structure and Function in Young Individuals: The African-PREDICT Study

To better understand hypertension development, the authors determined whether monocyte chemoattractant protein-1 (MCP-1) is associated with arterial stiffness (pulse wave velocity [PWV]) and carotid intima-media wall thickness (cIMT) in a young apparently healthy black and white population (N=403, aged 20-30 years). Carotid-femoral PWV, central systolic blood pressure, and cIMT were measured, and MCP-1, reactive oxygen species, inflammatory markers (interleukin 6, tumor necrosis factor α), and endothelial activation (intercellular adhesion molecule, vascular cell adhesion molecule) were determined from blood samples. Although carotid-femoral PWV and cIMT were similar between blacks and whites, black men and women showed higher central systolic blood pressure, MCP-1, and reactive oxygen species than whites (all P<.05). In addition, black women had higher brachial blood pressure and interleukin 6 (all P<.001). A consistent positive association only in black women between cIMT and MCP-1 in multiple regression analyses was found (R²=0.151, β=0.248; P=.021). In this model, cIMT was also independently associated with vascular cell adhesion molecule (β=0.251; P=.022). The authors found elevated central systolic blood pressure and MCP-1 in young blacks, where cIMT was independently associated with MCP-1 in black women.

Sex Differences in Cardiovascular Disease Risk of Ghanaian- and Nigerian-Born West African Immigrants in the United States: The Afro-Cardiac Study

BACKGROUND

The number of African immigrants in the United States grew 40-fold between 1960 and 2007, from 35 355 to 1.4 million, with a large majority from West Africa. This study sought to examine the prevalence of cardiovascular disease (CVD) risk factors and global CVD risk and to identify independent predictors of increased CVD risk among West African immigrants in the United States.

METHODS AND RESULTS

This cross-sectional study assessed West African (Ghanaian and Nigerian) immigrants aged 35-74 years in the Baltimore-Washington metropolitan area. The mean age of participants was 49.5±9.2 years, and 58% were female. The majority (95%) had ≥1 of the 6 CVD risk factors. Smoking was least prevalent, and overweight or obesity was most prevalent, with 88% having a body mass index (in kg/m(2)) ≥25; 16% had a prior diagnosis of diabetes or had fasting blood glucose levels ≥126 mg/dL. In addition, 44% were physically inactive. Among women, employment and health insurance were associated with odds of 0.09 (95% CI 0.033-0.29) and 0.25 (95% CI 0.09-0.67), respectively, of having a Pooled Cohort Equations estimate ≥7.5% in the multivariable logistic regression analysis. Among men, higher social support was associated with 0.90 (95% CI 0.83-0.98) lower odds of having ≥3 CVD risk factors but not with having a Pooled Cohort Equations estimate ≥7.5%.

CONCLUSIONS

The prevalence of CVD risk factors among West African immigrants was particularly high. Being employed and having health insurance were associated with lower CVD risk in women, but only higher social support was associated with lower CVD risk in men.

Panethnic Differences in Blood Pressure in Europe: A Systematic Review and Meta-Analysis

BACKGROUND

People of Sub Saharan Africa (SSA) and South Asians(SA) ethnic minorities living in Europe have higher risk of stroke than native Europeans(EU). Study objective is to provide an assessment of gender specific absolute differences in office systolic(SBP) and diastolic(DBP) blood pressure(BP) levels between SSA, SA, and EU.

METHODS AND FINDINGS

We performed a systematic review and meta-analysis of observational studies conducted in Europe that examined BP in non-selected adult SSA, SA and EU subjects. Medline, PubMed, Embase, Web of Science, and Scopus were searched from their inception through January 31st 2015, for relevant articles. Outcome measures were mean SBP and DBP differences between minorities and EU, using a random effects model and tested for heterogeneity. Twenty-one studies involving 9,070 SSA, 18,421 SA, and 130,380 EU were included. Compared with EU, SSA had higher values of both SBP (3.38 mmHg, 95% CI 1.28 to 5.48 mmHg; and 6.00 mmHg, 95% CI 2.22 to 9.78 in men and women respectively) and DBP (3.29 mmHg, 95% CI 1.80 to 4.78; 5.35 mmHg, 95% CI 3.04 to 7.66). SA had lower SBP than EU(-4.57 mmHg, 95% CI -6.20 to -2.93; -2.97 mmHg, 95% CI -5.45 to -0.49) but similar DBP values. Meta-analysis by subgroup showed that SA originating from countries where Islam is the main religion had lower SBP and DBP values than EU. In multivariate meta-regression analyses, SBP difference between minorities and EU populations, was influenced by panethnicity and diabetes prevalence.

CONCLUSIONS

1) The higher BP in SSA is maintained over decades, suggesting limited efficacy of prevention strategies in such group in Europe;2) The lower BP in Muslim populations suggests that yet untapped lifestyle and behavioral habits may reveal advantages towards the development of hypertension;3) The additive effect of diabetes, emphasizes the need of new strategies for the control of hypertension in groups at high prevalence of diabetes.

Systolic blood pressure response after high-intensity interval exercise is independently related to decreased small arterial elasticity in normotensive African American women

Aerobic exercise transiently lowers blood pressure. However, limited research has concurrently evaluated blood pressure and small arterial elasticity (SAE), an index of endothelial function, among African American (AA) and European American (EA) women the morning after (i.e., ≈22 h later) acute bouts of moderate-intensity continuous (MIC) and high-intensity interval (HII) exercise matched for total work. Because of greater gradients of shear stress, it was hypothesized that HII exercise would elicit a greater reduction in systolic blood pressure (SBP) compared to MIC exercise. After baseline, 22 AA and EA women initiated aerobic exercise training 3 times/week. Beginning at week 8, three follow-up assessments were conducted over the next 8 weeks at random to measure resting blood pressure and SAE. In total all participants completed 16 weeks of training. Follow-up evaluations were made: (i) in the trained state (TS; 8-16 weeks of aerobic training); (ii) ≈22 h after an acute bout of MIC exercise; and (iii) ≈22 h after an acute bout of HII exercise. Among AAs, the acute bout of HII exercise incited a significant increase in SBP (mm Hg) (TS, 121 ± 14 versus HII, 128 ± 14; p = 0.01) whereas responses (TS, 116 ± 12 versus HII, 113 ± 9; p = 0.34) did not differ in EAs. After adjusting for race, changes in SAE were associated (partial r = -0.533; p = 0.01) with changes in SBP following HII exercise. These data demonstrate an acute, unaccustomed bout of HII exercise produces physiological perturbations resulting in a significant increase in SBP that are independently associated with decreased SAE among AA women, but not EA women.

Disparities in hypertension among black Caribbean populations: a scoping review by the U.S. Caribbean Alliance for Health Disparities Research Group (USCAHDR)

Background

Despite the large body of research on racial/ethnic disparities in health, there are limited data on health disparities in Caribbean-origin populations. This scoping review aimed to analyze and synthesize published and unpublished literature on the disparities in hypertension and its complications among Afro-Caribbean populations.

Methods

A comprehensive protocol, including a thorough search strategy, was developed and used to identify potentially relevant studies. Identified studies were then screened for eligibility using pre-specified inclusion/exclusion criteria. An extraction form was developed to chart data and collate study characteristics including methods and main findings. Charted information was tagged by disparity indicators and thematic analysis performed. Disparity indicators evaluated include ethnicity, sex, socioeconomic status, disability, sexual orientation and geographic location. Gaps in the literature were identified and extrapolated into a gap map.

Results

A total of 455 hypertension related records, published between 1972 and 2012, were identified and screened. Twenty-one studies met inclusion criteria for detailed analysis. The majority of studies were conducted in the United Kingdom and utilized a cross-sectional study design. Overall, studies reported a higher prevalence of hypertension among Caribbean blacks compared to West African blacks and Caucasians. Hypertension and its related complications were highest in persons with low socioeconomic status. Gap analysis showed limited research data reporting hypertension incidence by sex and socioeconomic status. No literature was found on disability status or sexual orientation as it relates to hypertension. Prevalence and morbidity were the most frequently reported outcomes.

Conclusion

The literature on hypertension health disparities in Caribbean origin populations is limited. Future research should address these knowledge gaps and develop approaches to reduce them.

Electronic supplementary material

The online version of this article (doi:10.1186/s12939-015-0229-0) contains supplementary material, which is available to authorized users.

Subclinical Vascular Dysfunction Associated with Metabolic Syndrome in African Americans and Whites

CONTEXT

The diagnosis of metabolic syndrome (MetS) identifies individuals at risk for developing diabetes and cardiovascular disease. African Americans (AAs) have high rates of cardiovascular disease and subclinical vascular disease including arterial stiffness and microvascular dysfunction but have relatively low rates of MetS.

OBJECTIVE

The objective of the study was to evaluate the relationship between MetS and vascular function in a biracial cohort with the hypothesis that the diagnosis of MetS underestimates subclinical vascular disease in AAs.

DESIGN

We measured components of MetS in a community-based cohort of 951 AAs and white subjects (aged 48.8 ± 11 y, 47% AA, 55% female).

MAIN OUTCOME MEASURES

Using digital pulse amplitude tonometry, we estimated the reactive hyperemia index (RHI), a measure of microvascular endothelial function. Using applanation tonometry (Sphygmocor), central augmentation index (CAIx) and pulse wave velocity (PWV) were measured as indices of wave reflections and arterial stiffness, respectively.

RESULTS

MetS was present in 24.0% of subjects and was associated with increased PWV (P < .001) and CAIx (P < .001) and a trend to lower RHI (P = .068) in both races. However, in subjects without MetS, AAs had lower RHI (P < .001) and higher PWV (P = .003) and CAIx (P = .002) compared with white subjects. Addition of an extra MetS criterion point for AAs with hypertension eliminated the racial differences in PWV and CAIx but not RHI.

CONCLUSION

Although MetS is associated with microvascular dysfunction and increased arterial stiffness in both racial groups, AAs without MetS have greater vascular dysfunction compared with whites. Additional weighting for hypertension in AAs attenuated the racial differences in subclinical disease associated with MetS.

Ethnic differences in arterial stiffness the Helius study

OBJECTIVE

Well-known ethnic differences in cardiovascular risk exist, which may be explained by ethnic differences in arterial stiffness. Our aim was to assess ethnic differences in arterial stiffness, to explore whether these differences are accounted for by conventional cardiovascular risk factors, and study whether they differ across age.

METHODS

Cross-sectional data of 1797 Dutch, 1846 South-Asian Surinamese, 1840 African Surinamese, and 1673 Ghanaian participants of the observational HELIUS study (aged 18-70 years) were used. Arterial stiffness was assessed by duplicate pulse wave velocity (PWV) measurements using the Arteriograph system.

RESULTS

Linear regression showed that South-Asian Surinamese had higher PWVs as compared with Dutch (age-adjusted mean difference (95% CI) was 0.55 (0.39-0.70) m/s in men and 0.82 (0.63-1.01) m/s in women). These differences were largely, but not completely, explained by conventional risk factors (particularly age and MAP). These ethnic differences were not found at young age (<35 years). African Surinamese and Ghanaians had higher PWVs as compared with Dutch across the entire age range (ranging from 0.22 (0.06-0.39) m/s in African Surinamese men to 1.07 (0.89-1.26) m/s in Ghanaian women), but these differences disappeared or reversed after adjustment for risk factors.

CONCLUSIONS

PWV levels paralleled the well-known ethnic differences in cardiovascular risk. After adjustment for cardiovascular risk factors, however, these ethnic differences in PWV largely disappear. Together with the absence of ethnic differences in PWV at young age, our results support the hypothesis that higher PWV in South-Asian and African ethnic groups develops due to higher exposure to cardiovascular risk factors.

Exercise interventions and peripheral arterial function: implications for cardio-metabolic disease

Physical inactivity is a major risk factor for the development of obesity and other cardiovascular (CV) disease (CVD). Vascular endothelial dysfunction is a key event in the development of CVD and is associated with a sedentary lifestyle in otherwise healthy adults. In addition, vascular endothelial dysfunction may be exacerbated in sedentary individuals who are obese and insulin resistant, since excess body fat is associated with elevated levels of pro-atherogenic inflammatory adipokines and cytokines that reduce the nitric oxide (NO) and other upstream paracrine signaling substances which reduces vascular health. Since blood flow-related shear stress is a major stimulus to NO release from the endothelium, disturbed flow or low shear stress is the likely mechanism by which vascular endothelial function is altered with inactivity. Evidence shows that regular physical exercise has beneficial effects on CVD and the risk factors that promote peripheral arterial function and health. Both aerobic and resistance exercise training are generally believed to improve endothelial function and are commonly recommended for CV health, including the management of obesity, hypertension, and insulin resistance. However, many factors including age, disease status, and race appear to influence these outcomes. Although evidence supporting the health benefits of exercise is compelling, the optimum prescription (volume and intensity) and the exact mechanism underlying the effects of exercise training on arterial function and cardiometabolic risk has yet to be identified. The focus of this review will be on the evidence supporting exercise interventions for peripheral arterial function.

Sex and race (black-white) differences in the relationship of childhood risk factors to adulthood arterial stiffness: the Bogalusa Heart Study

BACKGROUND

Cardiovascular risk factors in childhood are predictive of adulthood arterial stiffness. However, it is unknown whether this relationship varies by race or sex.

METHODS

Six hundred and eighty adults aged 24 to 43 had been followed for an average of 26.3 years, from the Bogalusa Heart Study. Brachial to ankle pulse wave velocity (baPWV) measured by an automatic oscillometric technique was used as the outcome variable for arterial stiffness during adulthood. Body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, and systolic blood pressure (SBP), all measured in childhood, were used as predictors. The average values of childhood measurements at multiple time points were used, standardized to age, race, and sex-specific z-scores.

RESULTS

In the total sample, childhood SBP was the only significant predictor (P < 0.001) for adult baPWV. Significant interactions between sex and BMI (P = 0.001), between sex and LDL-C (P = 0.035), and between race and HDL-C (P = 0.002) on adult baPWV were identified. Childhood predictors of adult baPWV were BMI (30.9 cm/s reduction in baPWV per standard deviation increase, 95% confidence interval [CI]: -55.0, -6.9 cm/s), LDL-C (30.8 cm/s increase, 95% CI: 2.9, 59.5 cm/s), and HDL-C (46.8 cm/s reduction, 95% CI: -76.2, -17.4 cm/s) in white males; SBP (38.2 cm/s increase, 95% CI: 11.0, 65.4 cm/s) in white females; BMI (71.3 cm/s reduction, 95% CI: -119.9, -22.7 cm/s) in black males; and none in black females.

CONCLUSIONS

The associations of childhood cardiovascular risk factors with adult arterial stiffness varied by race and sex.

The burden and correlates of hypertension in rural Ghana: a cross-sectional study

AIM

Cardiovascular diseases (CVDs), of which hypertension is a major risk factor, are predicted to account for four times as many deaths as from communicable diseases by the year 2020. Hypertension, once rare, is rapidly becoming a major public health burden in sub-Saharan Africa (SSA). However, data on its prevalence, awareness, treatment and control are paltry, especially for rural communities. This study was done to determine the burden and correlates of adult hypertension in the rural Barekese sub-district of Ghana.

METHODS

A cross-sectional survey was conducted on 425 adults aged ≥ 35 in the Barekese sub district (estimated population 18,510). Socio-demographic characteristics, modifiable and non-modifiable risk factors, blood pressure (BP) and anthropometric measurements were collected using standardized protocols.

RESULTS

Overall, the proportion of hypertension and isolated systolic hypertension is 44.7% and 32.7% respectively in the study population. However, 64.9% of these were on treatment, with only 8.9% having controlled blood pressure (<140/90 mmHg). The mean systolic and diastolic BP were 134.38 mmHg (standard deviation, SD: 21.46) and 84.32 mmHg (SD: 12.44). Obesity (Body Mass Index, BMI>30 kg/m²) was found in 37 (10.4% of the population), out of whom 7 (15.9%) were extremely obese (BMI> 40 kg/m²). Increasing age and level of education were positively correlated with increasing blood pressure.

CONCLUSION

The high burden of hypertension in this population along with the considerable less detection, treatment and control is of great concern. There is the need to promote health education measures that will foster prevention and early detection of hypertension.

Conduit vessel stiffness in British south Asians of Indian descent relates to 25-hydroxyvitamin D status

BACKGROUND

South Asians migrating to Northern latitudes are more susceptible to premature cardiovascular disease (CVD) than expected for given levels of blood pressure. Vitamin D deficiency is common in this group and may play an important role mediating vascular wall senescence in response to central pressure effects.

METHODS

A cross-sectional association study. South Asian and White European participants were randomly recruited from a population-based diabetes-screening programme. Carotid-femoral pulse wave velocity (cfPWV), biochemistry (25-hydroxyvitamin D, fasting glucose), anthropometrics, resting blood pressure and a physical activity measure (International Physical Activity Questionnaire) were measured under controlled conditions.

PARTICIPANTS

One hundred and thirty-two and 125 age-matched South Asians and White Europeans not taking vitamin D supplementation with a risk factor for diabetes but no overt CVD.

RESULTS

Age (mean south Asian: 55.7 vs. White European: 56.0 years), mean arterial pressure (MAP) and calculated CVD risk were similar in both groups. Unadjusted (cf)PWV (m/s) was higher (9.32 vs. 8.68 P = 0.001) and 25-hydroxyvitamin D (nmol/l) lower in (21.29 vs. 52.5 P < 0.001) south Asians. 25-Hydroxyvitamin D independently associated with cfPWV in multivariate modelling adjusted for age, MAP, sex, glucose, heart rate, vasoactive medication and south Asian ethnicity (R = 0.73, P = 0.004). 25-Hydroxyvitamin D but not physical activity was negatively correlated with cfPWV independent of south Asian ethnicity.

CONCLUSION

Aortic stiffness is increased in British Indo-Asians without vascular disease despite conventional risk profiles, which are comparable to age-matched white Europeans. This effect may be mediated by a greater pressure-dependent increase in stiffness in individuals with vitamin D insufficiency.

Aging and atherosclerosis: mechanisms, functional consequences, and potential therapeutics for cellular senescence

Atherosclerosis is classed as a disease of aging, such that increasing age is an independent risk factor for the development of atherosclerosis. Atherosclerosis is also associated with premature biological aging, as atherosclerotic plaques show evidence of cellular senescence characterized by reduced cell proliferation, irreversible growth arrest and apoptosis, elevated DNA damage, epigenetic modifications, and telomere shortening and dysfunction. Not only is cellular senescence associated with atherosclerosis, there is growing evidence that cellular senescence promotes atherosclerosis. This review examines the pathology of normal vascular aging, the evidence for cellular senescence in atherosclerosis, the mechanisms underlying cellular senescence including reactive oxygen species, replication exhaustion and DNA damage, the functional consequences of vascular cell senescence, and the possibility that preventing accelerated cellular senescence is a therapeutic target in atherosclerosis.

Redefining the ECG in urban South Africans: electrocardiographic findings in heart disease-free Africans

BACKGROUND

The 12-lead electrocardiogram (ECG) represents an important diagnostic tool for detecting heart disease, but the "normal" ECG in those of African descent has yet to be definitively described.

METHODS

We systematically analysed 12-lead ECGs from 387 urban South Africans determined to be heart disease free (using the Minnesota code) following advanced cardiologic assessment, including echocardiography, at the Baragwanath Hospital in Soweto, South Africa.

RESULTS

123 males (32%, 41.2 ± 14.5 years) and 264 females (37.4 ± 14.2 years) were studied. Most were in sinus rhythm (87%) and had normal axis (89%). Mean interval data were: PR interval (156 ± 28 ms; 95% CI: 153-159 ms), QRS duration (82 ± 16 ms; 95% CI: 80-84 ms), QT interval (379 ± 48 ms; 95% CI: 374-384 ms) and QTc interval (426 ± 32 ms; 95% CI: 423-429 ms). Overall, 199 (51%; 95% CI: 46.0% to 56.0%) subjects had an ECG "abnormality" or normal variant and 67 ECGs (17%; 95% CI: 13.3% to 20.7%) had major and minor abnormalities. ECG changes normally ascribed to myocardial ischaemia were: i) ST elevation (9.3%; 95% CI: 6.2 to 11.9%), ii) Q waves (7.4%; 95% CI: 4.4 to 9.5%) and iii) ST depression (2.3%; 95% CI: 0.8 to 3.8%). Sokolow-Lyon Index voltage exceeding 38 mm indicative of left ventricular hypertrophy was more prominent in males than females (23.6% vs. 6.4%; OR=4.5; 95% CI: 2.3-8.5).

CONCLUSIONS

These data provide a contemporary reference to the 12-lead ECG in urban South Africans found to be heart disease free, with both major and minor abnormalities detected.

Hypertension in sub-Saharan Africa: cross-sectional surveys in four rural and urban communities

Background

Cardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania.

Methods and Findings

We performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009–2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study.

The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3–21.3) in rural Nigeria, 21.4% (19.8–23.0) in rural Kenya, 23.7% (21.3–26.2) in urban Tanzania, and 38.0% (35.9–40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥160/100 mmHg) or grade 3 hypertension (≥180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania).

Conclusion

Hypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed.

Associations of dietary phosphorus intake, urinary phosphate excretion, and fibroblast growth factor 23 with vascular stiffness in chronic kidney disease

OBJECTIVE

Elevated serum phosphate concentrations are established risk factors for cardiovascular disease and mortality in chronic kidney disease (CKD). Independent associations of other indices of phosphorus metabolism, such as phosphorus intake, urinary phosphate excretion, or hormones that regulate these systems, like fibroblast growth factor 23 (FGF23), with markers of cardiovascular disease in CKD, have been studied in less detail.

DESIGN

Cross-sectional study.

PARTICIPANTS

Seventy-four adult CKD patients with mean creatinine clearance of 51 ± 19 mL/minute.

OUTCOME

Augmentation index (AI)--a surrogate marker of arterial stiffness.

RESULTS

Although serum phosphate varied little across quartiles of creatinine clearance, average daily phosphorus intake and 24-hour urinary phosphate excretion decreased from highest to lowest quartile (by 31% and 60%, respectively, P for trend <.05). FGF23 was associated with serum phosphate (r = 0.24, P = .03) and creatinine clearance (r = -0.4, P = .001), but not with dietary phosphorus or 24-hour urinary phosphate excretion (P > .05 for both). Older age, higher systolic blood pressure, female gender, and black race were independently associated with increased AI. In contrast, there were no associations of serum phosphate, dietary phosphorus intake, urinary phosphate excretion, or FGF23 with AI in multivariate-adjusted models.

CONCLUSIONS

In this sample of patients with CKD, established risk factors for arterial stiffness, but not mediators of phosphorus metabolism, were associated with increased AI. In addition, there were no significant associations between FGF23 and dietary phosphorus or urinary phosphate excretion. Future studies are needed to determine the main factors associated with elevations in FGF23 in CKD and to further assess the association of disordered phosphorus metabolism with subclinical markers of vascular disease.

Current and projected prevalence of arterial hypertension in sub-Saharan Africa by sex, age and habitat: an estimate from population studies

INTRODUCTION

In sub-Saharan Africa (SSA), data on hypertension prevalence in terms of urban or rural and sex difference are lacking, heterogeneous or contradictory. In addition, there are no accurate estimates of hypertension burden.

OBJECTIVE

To estimate the age-specific and sex-specific prevalence of arterial hypertension in SSA in urban and rural adult populations.

METHODS

We searched for population studies, conducted from 1998 through 2008 in SSA. We extracted data from selected studies on available prevalences and used a logistic regression model to estimate all age/sex/habitat (urban/rural)/country-specific prevalences for SSA up to 2008 and 2025. On the basis of the United Nations Population Fund data for 2008 and predictions for 2025, we estimated the number of hypertensives in both years.

RESULTS

Seventeen studies pertaining to 11 countries were analysed. The overall prevalence rate of hypertension in SSA for 2008 was estimated at 16.2% [95% confidence interval (CI) 14.1-20.3], ranging from 10.6% in Ethiopia to 26.9% in Ghana. The estimated prevalence was 13.7% in rural areas, 20.7% in urban areas, 16.8% in males, and 15.7% in women. The total number of hypertensives in SSA was estimated at 75 million (95% CI 65-93 million) in 2008 and at 125.5 million (95% CI 111.0-162.9 million) by 2025.

CONCLUSION

The estimated number of hypertensives in 2008 is nearly four times higher than the last (2005) estimate of the World Health Organization Regional Office for Africa. Prevalences were significantly higher in urban than in rural populations. Population data are lacking in many countries underlining the need for national surveys.

Arterial stiffness profiles: investigating various sections of the arterial tree of African and Caucasian people

In Africans, arterial stiffness progression seems more pronounced compared to Caucasians. We compared the arterial stiffness profiles of different age groups and focused on muscular arteries and two more central arterial segments in African and Caucasian people from South Africa. In African (N = 374) and Caucasian (N = 376) participants (20-70 years), we measured carotid-radial (C-R) and carotid-dorsalis pedis (C-DP) pulse wave velocity (PWV) and aortic characteristic impedance (Zao). Major findings were that normotensive and high-normal/hypertensive (HT) Caucasians indicated increased trends of C-R PWV with aging (P = .029 and P = .067), not seen in the African groups (P = .122 and P = .526). Both ethnic groups showed significant increases of C-DP PWV and Zao with aging. High-normal/hypertensive Africans had significantly stiffer arteries than hypertensive Caucasians for almost all age groups, and for all stiffness measures. African C-R PWV correlated significantly with blood pressure (BP), but not with age. Opposite results were observed for Caucasians. In conclusion, the stiffness of muscular arteries is already elevated in young Africans, in both those with normal or elevated BP. This is possibly due to an earlier deterioration during childhood, or perhaps already present from birth. Also, in Caucasians stiffness seems more age-related, while in Africans it seems to be more pressure-related.

Ethnic differences in aortic pulse wave velocity occur in the descending aorta and may be related to vitamin D

We studied aortic pulse wave velocity (aPWV), a predictor of cardiovascular events independent of blood pressure, in a multiethnic sample of British men, to investigate the roles for blood levels of vitamin D and aldosterone in total and regional aortic stiffness. Total aPWV was estimated noninvasively by the Arteriograph device (aPWV(AG)) in 198 men, with its length measure calibrated by magnetic resonance. PWVs over the aortic arch and descending aorta were measured by magnetic resonance in a subsample (n=47). Mean (SE) aPWV(AG) in South Asians (n=68; age 55±10 years), at known higher coronary disease risk than other groups, was 0.5 m/s (0.2 m/s) higher than in African Caribbeans (n=67; 55±10 years), at lowest coronary disease risk here, and Europeans (n=63; 57±8 years), adjusted for age, systolic blood pressure, and diabetes mellitus (P=0.01). By magnetic resonance, PWV over the descending aorta in South Asians was 0.7 m/s (0.3 m/s) and 0.8 m/s (0.3 m/s) higher than in African Caribbeans and Europeans, respectively; PWV over the aortic arch was not different. South Asians and African Caribbeans had 21 nmol/L (3 nmol/L) and 14 nmol/L (3 nmol/L) lower mean (SE) 25(OH)D than Europeans (P<0.001). Unlike aldosterone, 25(OH)D was negatively correlated with aPWV(AG) adjusted for age and systolic blood pressure, as well as weakened or removed ethnic differences in aPWV(AG) in regression models. These data suggest that aortic stiffness as aPWV parallels coronary disease risk in ethnic groups, descending aortic but not arch PWV has this feature, and serum 25(OH)D is an independent negative correlate of aPWV and may partly account for ethnicity-related differences in aPWV and coronary disease risk.

Associations of endothelial dysfunction and arterial stiffness with intradialytic hypotension and hypertension

Intradialytic hypotension and hypertension are both independently associated with mortality among persons with end-stage renal disease on hemodialysis. Endothelial dysfunction and arterial stiffness are two possible mechanisms underlying these phenomena, but their association with hemodynamic instability during dialysis has not been evaluated. Thirty patients were recruited from chronic dialysis units at San Francisco General Hospital and San Francisco Veterans Affairs Medical Center. Endothelial dysfunction was assessed with flow-mediated dilation of the brachial artery after upper arm occlusion. Arterial stiffness was assessed using carotid-femoral pulse wave velocity measured by tonometry. Intradialytic hypotension and hypertension were defined as the average decrease in systolic blood pressure (SBP) over 1 week, as well as the frequency over 1 month of hypotension or hypertension. Every 5% decrease in flow-mediated dilation was associated with a 7.5 mmHg decrease in SBP after adjustment for phosphorus, body mass index, atherosclerosis, and ultrafiltration (P=0.02). Every 5 m/s increase in pulse wave velocity was associated with an 8 mmHg increase in SBP after adjustment for predialysis SBP and ultrafiltration (P=0.03). Over 1 month, every 5% lower flow-mediated dilation was associated with a 10% higher frequency of hypotension (P=0.09), and every 5 m/s increase in pulse wave velocity was associated with an 15% higher frequency of hypertension (P=0.02). In a cross-sectional analysis of 30 dialysis patients, endothelial dysfunction and arterial stiffness were independently associated with intradialytic hypotension and intradialytic hypertension, respectively. Elucidating these potential mechanisms of hemodynamic instability during dialysis may facilitate development of treatment strategies specific to this pathophysiology.

Ethnicity and arterial stiffness in Brazil

BACKGROUND

The impact of increased central arterial stiffness as a predictor of morbidity and mortality, independently of other cardiovascular (CV) risk factors, has been established. The main aim of the present work was to investigate the association of ethnicity on arterial stiffness in different ethnic groups from the Brazilian population.

METHODS

A total of 1,427 individuals from the general population were randomly selected from the Vitoria City metropolitan area and 588 Amerindians from a native community in Brazil. The ethnicity of the general population was classified by a standard questionnaire as Caucasian descent, African descent, or Mulattos (considered racially mixed subjects). Pulse wave velocity (PWV) was measured with a noninvasive automatic device (Complior, Colson; Garges les Gonesses, France).

RESULTS

Hemodynamic data of PWV, systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) was higher in African descent individuals than in the other groups (P < 0.001). These results were still observed after adjustment for age and mean arterial pressure (P < 0.001). In addition, studying only normotensive individuals, PWV adjusted levels were higher in African descent individuals, and lower in Amerindians when compared with other ethnic groups (P < 0.01), showing, without the possible confounder effects of time and severity of hypertension or medication use, that PWV is associated with ethnicity in our population.

CONCLUSION

The study of different ethnic groups from a highly admixtured population was able to demonstrate an association between ethnicity and arterial stiffness.

The ageing cardiovascular system

The increase in the ageing population has generated much interest and research into what constitutes normal ageing. By identifying normal ageing processes it is hoped it will be possible to distinguish risk factors for the development of abnormal or premature ageing.

This review discusses biological, structural and mechanical changes in the cardiovascular system with ageing that are thought to increase the risk of cardiovascular disease with ageing. Contributory factors are thought to be genetic and lifestyle related. Measurements of biological as opposed to chronological ageing such as vascular stiffness are explored as a possible useful predictor of cardiovascular morbidity and mortality, indicating its possible utilization as a non-invasive screening tool in older people.

The identification of those at risk of cardiovascular disease and modification of risk factors may minimize interactions of the ageing process and therefore reduce the incidence of cardiovascular disease within the UK population.

Disparities in vascular surgery: is it biology or environment?

Disparities in health care are well documented for several racial, ethnic, and gender groups. In peripheral arterial disease, differences in prevalence, treatment selection, treatment outcomes, and resulting quality of life have negative effects on some minority groups and women. It may be easy to document disparities, but it is harder to understand their underlying causes. Are there biologic differences between members of racial and ethnic groups that influence disease presentation and outcomes? Or is the socioeconomic environment that surrounds them the true driver of observed differences? This article reviews the evidence for racial and gender disparities in vascular surgery and presents some potential mechanisms that may explain the disparities.

Aortic PWV in chronic kidney disease: a CRIC ancillary study

BACKGROUND

Aortic pulse wave velocity (PWV) is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end-stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease (CKD) who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV.

METHODS

We performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in CKD.

RESULTS

PWV measurements were obtained in 2,564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were <7.7 m/s, 7.7-10.2 m/s, and >10.2 m/s with an overall mean (+/- s.d.) value of 9.48 +/- 3.03 m/s (95% confidence interval = 9.35-9.61 m/s). Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function.

CONCLUSIONS

The large size of this unique cohort, and the targeted enrollment of CKD participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure.

Hypertensive target organ damage in Ghanaian civil servants with hypertension

Background

Low levels of detection, treatment and control of hypertension have repeatedly been reported from sub Saharan Africa, potentially increasing the likelihood of target organ damage.

Methods

A cross-sectional study was conducted on 1015 urban civil servants aged≥25 years from seven central government ministries in Accra, Ghana. Participants diagnosed to have hypertension were examined for target organ involvement. Hypertensive target organ damage was defined as the detection of any of the following: left ventricular hypertrophy diagnosed by electrocardiogram, reduction in glomerular filtration rate, the presence of hypertensive retinopathy or a history of a stroke.

Results

Of the 219 hypertensive participants examined, 104 (47.5%) had evidence of target organ damage. The presence of target organ damage was associated with higher systolic and diastolic blood pressure levels. The odds of developing hypertensive target organ damage was five to six times higher in participants with blood pressure (BP)≥180/110 mmHg compared to those with BP<140/90 mmHg, and there was a trend to higher odds of target organ damage with increasing BP (p = 0.001). Women had about lower odds of developing target organ damage compared to men.

Conclusions

The high prevalence of target organ damage in this working population associated with increasing blood pressure, emphasises the need for hypertension control programs aimed at improving the detection of hypertension, and importantly addressing the issues inhibiting the effective treatment and control of people with hypertension in the population.

Racial differences in central blood pressure and vascular function in young men

Young African-American men have altered macrovascular and microvascular function. In this cross-sectional study, we tested the hypothesis that vascular dysfunction in young African-American men would contribute to greater central blood pressure (BP) compared with young white men. Fifty-five young (23 yr), healthy men (25 African-American and 30 white) underwent measures of vascular structure and function, including carotid artery intima-media thickness (IMT) and carotid artery β-stiffness via ultrasonography, aortic pulse wave velocity, aortic augmentation index (AIx), and wave reflection travel time (Tr) via radial artery tonometery and a generalized transfer function, and microvascular vasodilatory capacity of forearm resistance arteries with strain-gauge plethysmography. African-American men had similar brachial systolic BP (SBP) but greater aortic SBP ( P < 0.05) and carotid SBP ( P < 0.05). African-American men also had greater carotid IMT, greater carotid β-stiffness, greater aortic stiffness and AIx, reduced aortic Tr and reduced peak hyperemic, and total hyperemic forearm blood flow compared with white men ( P < 0.05). In conclusion, young African-American men have greater central BP, despite comparable brachial BP, compared with young white men. Diffuse macrovascular and microvascular dysfunction manifesting as carotid hypertrophy, increased stiffness of central elastic arteries, heightened resistance artery constriction/blunted resistance artery dilation, and greater arterial wave reflection are present at a young age in apparently healthy African-American men, and conventional brachial BP measurement does not reflect this vascular burden.

Racial (black-white) divergence in the association between adiponectin and arterial stiffness in asymptomatic young adults: the Bogalusa heart study

BACKGROUND

Adiponectin, an adipocytokine with beneficial biological functions relevant to cardiovascular (CV) diseases, and arterial stiffness, an indicator of vascular function, are considered to be important correlates of CV disease risk. Although racial (black-white) divergences in adiponectin and arterial stiffness are known, information is scant regarding the association between these two parameters among asymptomatic young adults within each race.

METHODS

As part of the Bogalusa Heart Study, arterial stiffness was examined noninvasively in terms of aorta-femoral pulse wave velocity (af-PWV) in 991 black and white nondiabetic subjects (72% white, 43% male) aged 24-44 years.

RESULTS

In a multivariate regression model by race that included adiponectin, age, sex, waist circumference, mean arterial pressure, heart rate, homeostasis model assessment of insulin resistance, low- and high-density lipoprotein cholesterols, triglycerides, and cigarette smoking, the significant predictors of af-PWV, in the order of entry, were: mean arterial pressure, age, smoking, and heart rate in both races, followed by adiponectin (inverse relation) in blacks. Further, after adjusting for mean arterial pressure, age, smoking, and heart rate, the odds ratio of finding excess af-PWV (top decile vs. the rest) in individuals with low adiponectin levels (bottom quartile vs. the rest) was significantly higher in blacks (OR: 2.5; 95% CI: 1.1-5.5), but not in whites (OR: 0.9; 95% CI: 0.5-1.9).

CONCLUSIONS

These findings suggest that the status of hypoadiponectinemia is an independent correlate of excess arterial stiffness in asymptomatic young black adults.

Heritability of arterial stiffness in black and white American youth and young adults

BACKGROUND

Our objectives were to examine the heritability of arterial stiffness measured as pulse-wave velocity (PWV), and its dependence on ethnicity, gender, and blood pressure (BP).

METHODS

As part of the Georgia Cardiovascular Twin Study, we measured aorto-radial (radial) and aorto-dorsalis-pedis (foot) PWV in 702 twins (41% black; 49% male) aged 12 to 30 years (mean age, 17.7 +/- 3.3 years), including monozygotic and dizygotic pairs of the same as well as opposite gender. Ethnicity and gender effects on genetic and environmental contributions to PWV were estimated by genetic model fitting.

RESULTS

Diastolic BP was the most important hemodynamic predictor. The best-fitting models showed no ethnicity or gender differences in estimates of genetic and environmental influence, and indicated substantial heritabilities of 0.43 (95% confidence interval, 0.30 to 0.54) and 0.53 (95% confidence interval, 0.42 to 0.62) for radial and foot PWV, respectively. Over a quarter of these heritabilities (0.19 for radial PWV; 0.14 for foot PWV) could be attributed to genes that also influenced diastolic BP, as based on multivariate models.

CONCLUSIONS

Individual differences in the arterial stiffness of youth and young adults are substantially heritable, and >25% of this heritability is explained by genes that also influence diastolic BP. Heritability estimates do not show any differences between blacks and whites or males and females.

Markers of vascular disease do not differ in black and white hemodialysis patients despite a different risk profile

Increased aortic stiffness, as measured by pulse wave velocity (PWV) and augmentation index (Aix), and vascular calcification have been associated with an unfavourable cardiovascular outcome in hemodialysis patients. However, the majority of data have been published in white patients and epidemiological data are discordant on the fate of patients of different races. In this cross sectional study we measured PWV and Aix by applanation tonometry and coronary artery and thoracic aorta calcium score (CAC and AoC) by electron beam tomography (EBT) in 81 Blacks and 61 Whites on maintenance hemodialysis. Vascular stiffness measurements and EBT scans were performed within a week of each other. There was no difference between races in age, systolic blood pressure or gender distribution. Blacks had a more frequent history of hypertension (100% versus 89%; P=0.002), lower prevalence of dyslipidemia (30% versus 66%; P<0.001), higher PTH levels (geometric mean 607 pg/ml versus 245 pg/ml; P=0.039), received calcium based phosphate binders less frequently (37% versus 60%, P=0.007) and calcium antagonists more frequently than Whites (54% versus 28%; P=0.003). Nonetheless, the unadjusted and risk adjusted PWV and Aix, as well as CAC and AoC were not statistically different between races. In this dialysis cohort there was no difference in markers of vasculopathy between black and white patients despite differences in baseline clinical characteristics. Epidemiological data from the general population indicate that Blacks have lower calcium scores and stiffer vessels than Whites. Some studies in the renal populations suggest a better and others a similar survival of Blacks and Whites on hemodialysis. Our findings raise the important question of the prognostic significance of markers of vasculopathy in patients of different races and with different risk profiles.