Reactivity as a predictor of subsequent blood pressure: racial differences in the Coronary Artery Risk Development in Young Adults (CARDIA) Study

Renal denervation ameliorated salt-induced hypertension by improving cardiac work, cardiac enzyme and oxidative balance in Sprague-Dawley rats

Background

Hypertension is associated with cardiovascular dysfunction, dysregulation of the antioxidant system and alteration of the level of some enzymes in the metabolic pathway. The possible modulatory effect of acute renal denervation (ARD) on cardiovascular function and the antioxidant system is still a subject of intense debate. This study sought to ascertain the ameliorative effects of ARD on cardiovascular parameters, antioxidant system, creatine kinase and lactate dehydrogenase levels.

Methods

Thirty-six Sprague-Dawley rats (5-6 weeks old) were divided into 6 groups of 6 animals each consisting of Normal Salt, High Salt, Normal Salt + Sham Denervation, High Salt + Sham Denervation, Normal Salt + Renal Denervation and High Salt + Renal Denervation. Induction of hypertension with 8 % salt in the diet lasted for 8 weeks. Renal or Sham denervation was thereafter done on selected groups. At the end of the experimental period, cardiovascular parameters, plasma antioxidant status, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) levels were assessed. Significance level was set at p < 0.05.

Results

Salt-loading significantly increased systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), rate pressure product (RPP) while reducing superoxide dismutase (SOD), reduced glutathione (GSH) and catalase (CAT). Acute renal denervation significantly (p < 0.0001) reduced SBP, DBP, MABP, RPP, LDH and norepinephrine level while increasing SOD, GSH and CAT. ARD did not significantly alter CK level.

Conclusion

Acute renal denervation, by reducing sympathetic activity, ameliorates cardiovascular and antioxidant functions as well as reduces LDH level without significantly altering CK level in salt-induced hypertension.

Twenty-Five-Year Changes in Office and Ambulatory Blood Pressure: Results From the Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Blood pressure (BP) measured in the office setting increases from early through later adulthood. However, it is unknown to what extent out-of-office BP derived via ambulatory BP monitoring (ABPM) increases over time, and which participant characteristics and risk factors might contribute to these increases.

METHODS

We assessed 25-year change in office- and ABPM-derived BP across sex, race, diabetes mellitus (DM), and body mass index (BMI) subgroups in the Coronary Artery Risk Development in Young Adults study using multivariable-adjusted linear mixed effects models.

RESULTS

We included 288 participants who underwent ABPM at the Year 5 Exam (mean [SD] age, 25.1 [3.7]; 45.8% men) and 455 participants who underwent ABPM at the Year 30 Exam (mean [SD] age, 49.5 [3.7]; 42.0% men). Office, daytime, and nighttime systolic BP (SBP) increased 12.8 (95% confidence interval [CI], 7.6-17.9), 14.7 (95% CI, 9.7-19.8), and 16.6 (95% CI, 11.4-21.8) mm Hg, respectively, over 25 years. Office SBP increased 6.5 (95% CI, 2.3-10.6) mm Hg more among black compared with white participants. Daytime SBP increased 6.3 (95% CI, 0.2-12.4) mm Hg more among participants with a BMI ≥25 vs. <25 kg/m2. Nighttime SBP increased 4.7 (95% CI, 0.5-8.9) mm Hg more among black compared with white participants, and 17.3 (95% CI, 7.2-27.4) mm Hg more among participants with vs. without DM.

CONCLUSIONS

Office- and ABPM-derived BP increased more from early through middle adulthood among black adults and participants with DM and BMI ≥25 kg/m2.

Internalized Shame and Social Stress-Induced Blood Pressure Patterns among Young Black Women

Background

The increasing prevalence of hypertension among young Black women warrants further exploration of hypertension risk factors in this population. Social cognitive pathways that increase hypertension risk have been understudied among Black women. Shame, an emotional response to social evaluative threats, may be important to understanding the contribution of social emotions to hypertension risk. The current study examined the association of internalized shame on systolic (SBP) and diastolic blood pressure (DPB) patterns of reactivity and recovery in a sample of Black women.

Methods

Black women (N=32) aged 18-22 were recruited from a public university in August 2019 and January 2020. Participants completed the Internalized Shame Scale, Self-Esteem subscale, and the Perceived Stress Scale. All participants completed the Trier Social Stress Test (TSST) and subsequent blood pressure readings were recorded at baseline and 1 min, 15 min, 30 min, 45 min, and 60 min post-TSST. Two separate repeated measures ANOVAs examined time and group effects of low shame (ISS score ≤ 39.9) vs high shame (ISS score ≥ 40) on blood pressure reactivity patterns.

Results

A significant effect of shame on DBP responses to the TSST was observed (P=.020). DBP for women in the low shame group peaked immediately following the TSST relative to baseline (M =81.2 mm Hg vs M =72.2 mm Hg) and remained stable during 60-minute recovery. DBP for women in the high shame group did not peak until 45 min post-TSST relative to baseline (M =84.2 mm Hg vs M =68.0 mm Hg) only slightly decreasing at 60 min post-TSST.

Implications

These results highlight the need to further examine the role of shame on hypertension risk among young Black women.

Social Determinants of Cardiovascular Health in African American Children With CKD: An Analysis of the Chronic Kidney Disease in Children (CKiD) Study

RATIONALE & OBJECTIVE

To identify differences in socioeconomic factors (SES) and subclinical cardiovascular disease (CVD) markers by race among Chronic Kidney Disease in Children (CKiD) participants and determine whether differences in CVD markers persist after adjusting for SES.

STUDY DESIGN

Analysis of 3,103 visits with repeated measures from 628 children (497 White participants; 131 African American participants) enrolled in the CKiD study.

SETTING & PARTICIPANTS

Children with mild-moderate CKD with at least 1 cardiovascular (CV) parameter (ambulatory blood pressure, left ventricular mass index [LVMI], or lipid profile) measured.

EXPOSURE

African American race.

OUTCOMES

Ambulatory hypertension, LVMI, triglycerides, high-density lipoprotein cholesterol.

ANALYTICAL APPROACH

Due to increased CV risks of glomerular disease, the analysis was stratified by CKD cause. Inverse probability weighting was used to adjust for SES (health insurance, household income, maternal education, food insecurity, abnormal birth history). Linear and logistic regression were used to evaluate association of race with CV markers.

RESULTS

African American children were disproportionately affected by adverse SES. African Americans with nonglomerular CKD had more instances of ambulatory hypertension and higher LVMI but more favorable lipid profiles. After adjustment for SES, age, and sex, the magnitude of differences in these CV markers was attenuated but remained statistically significant. Only LVMI differed by race in the glomerular CKD group, despite adjustment for SES.

LIMITATIONS

Study design limits causal inference.

CONCLUSION

African American children with CKD are disproportionately affected by socioeconomic disadvantages compared with White children. The degree to which CV markers differ by race is influenced by disease etiology. African Americans with nonglomerular CKD have increased LVMI, more ambulatory hypertension, and favorable lipid profile, but attenuation in magnitude after adjustment for SES was observed. African Americans with glomerular CKD had increased LVMI, which persisted after SES adjustment. As many social determinants of health were not captured, future research should examine effects of systemic racism on CV health in this population.

Disparities in Hypertension Among African-Americans: Implications of Insufficient Sleep

PURPOSE OF REVIEW

Sleep deficiency has been proposed as a potential contributor to racial disparities in cardiovascular health. We present contemporary evidence on the unequal burden of insufficient sleep in Blacks/African-Americans and the repercussions for disparate risk of hypertension.

RECENT FINDINGS

The prevalence of insufficient sleep is high and rising and has been recognized as an important cardiovascular risk factor. Presumably due to a constellation of environmental, psychosocial, and individual determinants, these risks appear exacerbated in Blacks/African-Americans, who are more likely to experience short sleep than other ethnic/racial groups. Population-based data suggest that the risk of hypertension associated with sleep deficiency is greater in those of African ancestry. However, there is a paucity of experimental evidence linking short sleep duration to blood pressure levels in African-Americans. Blacks/African-Americans may be more vulnerable to sleep deficiency and to its hypertensive effects. Future research is needed to unequivocally establish causality and determine the mechanism underlying the postulated racial inequalities in sleep adequacy and consequent cardiovascular risk.

Thresholds for Ambulatory Blood Pressure Among African Americans in the Jackson Heart Study

BACKGROUND

Ambulatory blood pressure (BP) monitoring is the reference standard for out-of-clinic BP measurement. Thresholds for identifying ambulatory hypertension (daytime systolic BP [SBP]/diastolic BP [DBP] ≥135/85 mm Hg, 24-hour SBP/DBP ≥130/80 mm Hg, and nighttime SBP/DBP ≥120/70 mm Hg) have been derived from European, Asian, and South American populations. We determined BP thresholds for ambulatory hypertension in a US population-based sample of African American adults.

METHODS

We analyzed data from the Jackson Heart Study, a population-based cohort study comprised exclusively of African American adults (n=5306). Analyses were restricted to 1016 participants who completed ambulatory BP monitoring at baseline in 2000 to 2004. Mean SBP and DBP levels were calculated for daytime (10:00 am-8:00 pm), 24-hour (all available readings), and nighttime (midnight-6:00 am) periods, separately. Daytime, 24-hour, and nighttime BP thresholds for ambulatory hypertension were identified using regression- and outcome-derived approaches. The composite of a cardiovascular disease or an all-cause mortality event was used in the outcome-derived approach. For this latter approach, BP thresholds were identified only for SBP because clinic DBP was not associated with the outcome. Analyses were stratified by antihypertensive medication use.

RESULTS

Among participants not taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mm Hg were 134/85 mm Hg, 130/81 mm Hg, and 123/73 mm Hg, respectively. The outcome-derived thresholds for daytime, 24-hour, and nighttime SBP corresponding to a clinic SBP ≥140 mm Hg were 138 mm Hg, 134 mm Hg, and 129 mm Hg, respectively. Among participants taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mm Hg were 135/85 mm Hg, 133/82 mm Hg, and 128/76 mm Hg, respectively. The corresponding outcome-derived thresholds for daytime, 24-hour, and nighttime SBP were 140 mm Hg, 137 mm Hg, and 133 mm Hg, respectively, among those taking antihypertensive medication.

CONCLUSIONS

On the basis of the outcome-derived approach for SBP and regression-derived approach for DBP, the following definitions for daytime, 24-hour, and nighttime hypertension corresponding to clinic SBP/DBP ≥140/90 mm Hg are proposed for African American adults: daytime SBP/DBP ≥140/85 mm Hg, 24-hour SBP/DBP ≥135/80 mm Hg, and nighttime SBP/DBP ≥130/75 mm Hg, respectively.

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.

Subjective Stress and Coping Resources Interact to Predict Blood Pressure Reactivity in Black College Students

This study examined the effects of subjective stress and coping resources on blood pressure reactivity. Sixty-nine Black college students (mean age = 23.58 years) completed the Life Experiences and Stress Scale to explore the subjective stressfulness associated with life events, the Coping Orientations to Problems Experienced Scale to measure usual ways of coping, and a standardized serial addition laboratory challenge during which blood pressure was assessed. Multiple regression analyses revealed that the interactive effects of subjective stress and coping resources predicted diastolic blood pressure reactivity (both p < .025) but not systolic blood pressure reactivity (both p > .10). These significant interaction effects indicated that higher levels of problem-focused coping were related to more marked diastolic blood pressure changes under conditions of high subjective stress and that emotion-focused coping was associated with less exaggerated diastolic blood pressure changes under conditions of low subjective stress. These findings highlight the potential contribution of psychosocial factors to blood pressure reactivity in Blacks.

New insights on the risk for cardiovascular disease in African Americans: the role of added sugars

African Americans are at increased risk for cardiovascular and metabolic diseases, including obesity, high BP, diabetes, CKD, myocardial infarction, and stroke. Here we summarize the current risks and provide an overview of the underlying risk factors that may account for these associations. By reviewing the relationship between cardiovascular and renal diseases and the African-American population during the early 20th century, the historic and recent associations of African heritage with cardiovascular disease, and modern population genetics, it is possible to assemble strong hypotheses for the primary underlying mechanisms driving the increased frequency of disease in African Americans. Our studies suggest that underlying genetic mechanisms may be responsible for the increased frequency of high BP and kidney disease in African Americans, with particular emphasis on the role of APOL1 polymorphisms in causing kidney disease. In contrast, the Western diet, particularly the relatively high intake of fructose-containing sugars and sweetened beverages, appears to be the dominant force driving the increased risk of diabetes, obesity, and downstream complications. Given that intake of added sugars is a remediable risk factor, we recommend clinical trials to examine the reduction of sweetened beverages as a primary means for reducing cardiovascular risk in African Americans.

Effects of Nitrate Supplementation on Cardiovascular and Autonomic Reactivity in African-American Females

Previous studies have shown that beetroot juice (BJ) decreases systolic blood pressure (SBP) and oxygen demand. This study tests the hypothesis that a beetroot juice (BJ) treatment increases heart rate variability (HRV) measured by the average standard deviation of normal-normal electrocardiogram RR intervals (SDNN) and the low frequency (LF), mainly sympathetic, fast Fourier transform spectral index of HRV. The subjects were 13 healthy young adult African-American females. Placebo control orange juice (OJ) and BJ treatments were given on separate days. Blood nitric oxide [NO], SBP and RR intervals were measured at rest and at constant workloads set to 40% and 80% of the predetermined VO_2peak. Two hours after ingestion the BJ treatment increased [NO] and decreased SBP. BJ also increased SDNN at rest and at the 40% VO_2peak workload, without significant effects on LF. SDNN was significantly greater after the BJ than after the OJ treatment, across the two physical activity conditions and SDNN was (negatively) correlated with SBP. These results suggest that BJ decreases SBP and increases HRV at rest and during aerobic exercise. Similar results in subjects with prehypertension or hypertension could translate to a dietary nitrate treatment for hypertension.

Genome-wide association study identifies 8 novel loci associated with blood pressure responses to interventions in Han Chinese

BACKGROUND

Blood pressure (BP) responses to dietary sodium and potassium intervention and cold pressor test vary considerably among individuals. We aimed to identify novel genetic variants influencing individuals' BP responses to dietary intervention and cold pressor test.

METHODS AND RESULTS

We conducted a genome-wide association study of BP responses in 1881 Han Chinese and de novo genotyped top findings in 698 Han Chinese. Diet-feeding study included a 7-day low-sodium (51.3 mmol/d), a 7-day high-sodium (307.8 mmol/d), and a 7-day high-sodium plus potassium supplementation (60 mmol/d). Nine BP measurements were obtained during baseline observation and each intervention period. The meta-analyses identified 8 novel loci for BP phenotypes, which physically mapped in or near PRMT6 (P=7.29 × 10(-9)), CDCA7 (P=3.57 × 10(-8)), PIBF1 (P=1.78 × 10(-9)), ARL4C (P=1.86 × 10(-8)), IRAK1BP1 (P=1.44 × 10(-10)), SALL1 (P=7.01 × 10(-13)), TRPM8 (P=2.68 × 10(-8)), and FBXL13 (P=3.74 × 10(-9)). There was a strong dose-response relationship between the number of risk alleles of these independent single-nucleotide polymorphisms and the risk of developing hypertension during the 7.5-year follow-up in the study participants. Compared with those in the lowest quartile of risk alleles, odds ratios (95% confidence intervals) for those in the second, third, and fourth quartiles were 1.39 (0.97, 1.99), 1.72 (1.19, 2.47), and 1.84 (1.29, 2.62), respectively (P=0.0003 for trend).

CONCLUSIONS

Our study identified 8 novel loci for BP responses to dietary sodium and potassium intervention and cold pressor test. The effect size of these novel loci on BP phenotypes is much larger than those reported by the previously published studies. Furthermore, these variants predict the risk of developing hypertension among individuals with normal BP at baseline.

Nighttime blood pressure dipping in young adults and coronary artery calcium 10-15 years later: the coronary artery risk development in young adults study

Nighttime blood pressure (BP) dipping can be quantified as the ratio of mean nighttime (sleep) BP to mean daytime (awake) BP. People whose dipping ratio is ≥ 0.90 have been referred to as nondippers, and nondipping is associated with cardiovascular disease events. We examined the relationship between systolic nighttime BP dipping in young adults and the presence of coronary artery calcium (CAC) 10 to 15 years later using data from the ambulatory BP monitoring substudy of the Coronary Artery Risk Development in Young Adults Study. Among 239 participants with adequate measures of both nighttime and daytime readings and coronary artery calcium, the systolic BP dipping ratio ranged from 0.72 to 1.24 (mean, 0.88; SD, 0.06), and CAC was present 10 to 15 years later in 54 participants (22.6%). Compared with those whose systolic BP dipping ratio ranged from 0.88 to 0.92 (quartile 3), the 57 participants (23.9%) with less pronounced or absent dipping (ratio, 0.92-1.24; quartile 4) had an unadjusted odds ratio of 4.08 (95% CI, 1.48-11.2) for the presence of CAC. The 60 participants (25.1%) with a more pronounced dipping (ratio, 0.72-0.85; quartile 1) also had greater odds for presence of CAC (odds ratio, 4.76 [95% CI, 1.76-12.9]). When modeled as a continuous predictor, a U-shaped relationship between systolic BP dipping ratio and future CAC was apparent and persisted after adjustment for multiple potential confounders (P<0.001 for quadratic term). Both failure of systolic BP to dip sufficiently and "overdipping" during nighttime may be associated with future subclinical coronary atherosclerosis.

The relationship between cortisol, C-reactive protein and hypertension in African and Causcasian women: the POWIRS study

Research on the roles that C-reactive protein (CRP) and other risk factors such as cortisol and obesity play in the diagnosis of cardiovascular disease (CVD) in African and Caucasian women has become increasingly imperative when one considers the prevalence of hypertension in these groups. CRP and cortisol have been associated with an increased prevalence of hypertension and obesity. Cortisol has also been linked with both hypertension and the hypothalamic-pituitary-adrenal (HPA) response. African women have previously presented with an increased vascular reactivity. Conversely, Caucasian women have displayed an increased central cardiac reactivity. We included African (n = 102) and Caucasian (n = 115) women in the study, matched for age and body mass index. Elevated CRP levels were observed in African women compared to Caucasian women. A trend of hypocortisolism was exhibited in both hypertensive ethnic groups. Systolic blood pressure (SBP) and a vascular marker, arterial compliance (Cw), predicted hypertension in African women. Conversely, in Caucasian women, only SBP predicted hypertension. These results suggest the apparently diverse roles that dysregulation by the HPA axis, in conjunction with the respective cardiac and vascular responses in both Caucasian and African women, can play in future cardiovascular risk for these groups.

State anxiety is associated with cardiovascular reactivity in young, healthy african americans

Although several studies have shown that enhanced cardiovascular reactivity can predict hypertension development in African Americans, these findings have not been consistent among all studies examining reactivity and hypertension susceptibility. This inconsistency may be explained by the influence of anxiety (state and trait) on the blood pressure response to stress. Therefore, this study sought to determine whether anxiety is associated with blood pressure response to cold pressor (CP) and anger recall (AR) stress tests in young healthy African Americans. Modeling using state and trait anxiety revealed that state anxiety predicts systolic (SBP) and diastolic blood pressure DBP response to CP and AR (P ≤ 0.02). Interestingly, state anxiety predicted heart rate changes only to CP (P < 0.01; P = 0.3 for AR). Although trait anxiety was associated with SBP response to AR and not CP, it was not a significant predictor of reactivity in our models. We conclude that anxiety levels may contribute to the variable blood pressure response to acute stressors and, therefore, should be assessed when performing cardiovascular reactivity measures.

Autonomic responses to stress in Black versus Caucasian Africans: the SABPA study

Underlying mechanisms of increased pressor responses to stress in Blacks are poorly understood. Cardiovascular regulation of normotensive Black (n=43) and Caucasian (n=90) Africans was studied during a cold pressor and color-word conflict test. Autonomic evaluation was performed by spectral analysis. Higher diastolic pressor and heart rate responses to the cold pressor test were observed in Black compared to Caucasian Africans. Autonomic efferent outflow to stress was comparable between groups. Transient downregulation of baroreflex during stress was evident in Blacks but not in Caucasians. Greater diastolic pressor responses were related to a higher cardiac reactivity, a baroreflex desensitization, and higher stress perception in Black Africans. Thus, increased stress perception may facilitate cardiac and diastolic hyperreactivity, indirectly affecting baroreflex function in Black Africans.

Diurnal blood pressure pattern and development of prehypertension or hypertension in young adults: the CARDIA study

Nondippers (people whose sleep systolic blood pressure [SBP] fails to decrease >10% from daytime SBP) have increased risk of cardiovascular disease. The prevalence of nondipping in younger adults has not been well studied, nor has its value for predicting hypertension. We examined the prevalence of nondipping in a substudy of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. We used Cox regression to estimate the hazard ratio (HR) conferred by nondipping for incident prehypertension or hypertension (preHTN/HTN) over 15 years. Of the 264 nonhypertensive participants at baseline, 118 (45%) were nondippers. Blacks were more likely than whites to be nondippers (52% versus 33%, P = .004). The incidence rate of preHTN/HTN was 29.2/1000 person-years among dippers and 36.2/1000 person-years among nondippers. Compared with those in the lowest quartile of nighttime to daytime SBP, those in the highest quartile were more likely to develop preHTN/HTN (HR 1.61; P = .06), but this relationship was attenuated after adjustment (HR 1.34; P = .27). Our results demonstrate that nondipping is common in young, nonhypertensive adults, and is more common in blacks than whites. Nondipping might predate a meaningful clinically detected increase in BP in some people, but more research in larger study samples is needed.

Pre-pregnancy stress reactivity and pregnancy outcome

Stress has been proposed as a cause of preterm birth (PTB) and small-for-gestational age (SGA), but stress does not have the same effects on all women. It may be that a woman's reaction to stress relates to her pregnancy health, and previous studies indicate that higher reactivity is associated with reduced birthweight and gestational age. The objective of this study was to examine the relationship between pre-pregnancy cardiovascular reactivity to stress and pregnancy outcome. The sample included 917 women in the Coronary Artery Risk Development in Young Adults Study who had cardiovascular reactivity measured in 1987-88 and at least one subsequent singleton livebirth within an 18-year period. Cardiovascular reactivity was measured using a video game, star tracing and cold pressor test. Gestational age and birthweight were based on the women's self-report, with PTB defined as birth <37 weeks' gestation and SGA as weight <10th percentile for gestational age. Linear and Poisson regression and generalised estimating equations were used to model the relationship between reactivity to stress and birth outcomes with control for confounders. Few associations were seen between reactivity and pregnancy outcomes. Higher pre-pregnancy diastolic blood pressure (adjusted relative risk 1.14; 95% confidence interval [CI] 0.98, 1.34) and mean arterial pressure reactivity (1.15; 0.98, 1.36) were associated with risk of PTB at first pregnancy, while SGA was associated with lower systolic blood pressure reactivity (0.76; 0.60, 0.95). No associations were seen with other measures of reactivity. Contrary to hypothesis, the association between heart rate reactivity and PTB in first pregnancy was stronger in whites (adjusted relative risk 1.39; 1.03, 1.88) than in blacks (1.00; 0.83, 1.20; P for interaction = 0.08). Similar results were found for mean arterial pressure. No strong associations were found between higher pre-pregnancy stress reactivity and SGA or PTB, and stress reactivity did not have a stronger association with birth outcomes in blacks than whites.

Variables influencing heart rate

In both physiologic and pathological conditions, instantaneous heart rate value is the result of a rather complex interplay. It constantly varies under the influence of a number of factors: nonmodifiable and modifiable ones. Pharmacologic blockade with beta-adrenergic antagonists and/or with parasympathetic antagonists such as atropine have permitted the identification of the mechanisms of autonomic nervous regulation of heart rate in a variety of physiologic and pathological conditions. The analysis of heart rate and blood pressure variability has yielded additional information on the autonomic control of the circulation, which has proven to have diagnostic and prognostic implications in a number of clinically relevant conditions such as hypertension, acute myocardial infarction, heart failure, and predisposition to sudden cardiac death. This article will summarize, based on available epidemiologic and clinical studies, the key variables influencing heart rate and heart rate variability in view of the known association between heart rate and cardiovascular disease.

The Relationship of Low Birth Weight to Blood Pressure, Cortisol Levels, and Reactivity in African American Adolescents: A Pilot Study

Epidemiological studies show a relationship between low birth weight (LBW) and adult cardiovascular disease. Blood pressure and cortisol hyper-responsiveness during physiologic stress may function as biological markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol levels with induced physiologic stress to LBW. Forty-eight adolescents, 14 to 16 years old, were tested for blood pressure and cortisol levels at rest and in response to a physiological stressor. A history of LBW was obtained. Multivariate repeated measures analysis and chi-square analyses were used to determine the changes in blood pressure and cortisol.Forty-eight African American adolescents, mean age 14.98 years (SD = 0.33), completed the study. Thirteen adolescents (27%) reported LBW. Although not statistically significant, systolic and diastolic pressures were 6 mmHg and 2 mmHg, respectively, higher in the LBW group when compared with the normal birth weight (NBW) group (p = 0.33 and p = 0.21, and 6 (46%) had elevated blood pressures (p = 0.005)). Blood pressure changes, cardiovascular reactivity, elevated blood, or all of these were significantly higher in LBW African American adolescents (p = 0.006). Cardiovascular reactivity was not significant (p = 0.208)). The mean average cortisol levels were (18.8 nmol/dL (SD = 11.0) but comparable (p = 0.72)). The number of LBW adolescents with cortisol reactivity was significantly higher that in the NBW group (p = 0.041). This study adds support to the association of LBW to biological markers of hypertension in childhood.

A review of neuroimaging studies of stressor-evoked blood pressure reactivity: emerging evidence for a brain-body pathway to coronary heart disease risk

An individual's tendency to show exaggerated or otherwise dysregulated cardiovascular reactions to acute stressors has long been associated with increased risk for clinical and preclinical endpoints of coronary heart disease (CHD). However, the 'brain-body' pathways that link stressor-evoked cardiovascular reactions to CHD risk remain uncertain. This review summarizes emerging neuroimaging research indicating that individual differences in stressor-evoked blood pressure reactivity (a particular form of cardiovascular reactivity) are associated with activation patterns in corticolimbic brain areas that are jointly involved in processing stressors and regulating the cardiovascular system. As supported empirically by activation likelihood estimates derived from a meta-analysis, these corticolimbic areas include divisions of the cingulate cortex, insula, and amygdala--as well as networked cortical and subcortical areas involved in mobilizing hemodynamic and metabolic support for stress-related behavioral responding. Contextually, the research reviewed here illustrates how behavioral medicine and health neuroscience methods can be integrated to help characterize the 'brain-body' pathways that mechanistically link stressful experiences with CHD risk.

Heightened resting neural activity predicts exaggerated stressor-evoked blood pressure reactivity

Individuals who express relatively large-magnitude or "exaggerated" blood pressure (BP) reactions to behavioral stressors are presumably at increased risk for cardiovascular disease. As shown by recent neuroimaging studies, individuals who express exaggerated stressor-evoked BP reactivity also express heightened neural activity in corticolimbic brain areas that centrally regulate the cardiovascular system. These studies, however, have exclusively examined BP reactivity and concomitant neural activity during stressor exposure. If exaggerated BP reactivity originates in part from a centrally regulated and dispositional cardiovascular response tendency, then heightened resting (prestressor) corticolimbic activity may predict the subsequent expression of exaggerated stressor-evoked BP reactivity. To test this hypothesis, perfusion MRI was used to quantify resting regional cerebral blood flow (an indirect metabolic measure of neural activity) in men (n=19) and women (n=20) aged 20 to 37 years who subsequently performed cognitive stressor tasks to evoke BP reactivity. Individuals who expressed larger task-induced rises in systolic and diastolic BP also expressed higher resting regional cerebral blood flow in 4 functionally related corticolimbic areas: the dorsal and perigenual anterior cingulate, medial prefrontal, and insular cortices. Specifically, resting regional cerebral blood flow in these areas accounted, respectively, for 40% and 31% of the variance in systolic (P=0.001) and diastolic (P=0.008) BP reactivity, after accounting for total resting cerebral blood flow, resting BP, task performance, and task-related ratings of unpleasantness, arousal, and perceived psychological control. Heightened resting corticolimbic activity may represent a neurobiological correlate of an individual's predisposition for exaggerated stressor-evoked BP reactivity and possibly related cardiovascular risk.

Genetic influences on blood pressure response to the cold pressor test: results from the Heredity and Phenotype Intervention Heart Study

OBJECTIVES

Blood pressure (BP) response to the cold pressor test (CPT) has been found to predict the development of hypertension and cardiovascular disease in prospective studies. The determinants of BP response to the CPT, including the role of genetic factors, however, are largely unknown. Additionally, to our knowledge, no study has examined the genetics of BP recovery from the CPT, including whether shared genetic factors influence both reactivity and recovery.

METHODS

As part of the Heredity and Phenotype Intervention Heart Study, we administered a 2.5 min hand CPT to 835 participants from 18 extended Amish families. We estimated the heritability of BP reactivity and recovery (measured by the incremental area under the curve) and the genetic correlations between baseline, reactivity, and recovery BP phenotypes.

RESULTS

After adjusting for relevant covariates, including baseline BP, the heritability estimates for both systolic BP (SBP) and diastolic BP (DBP) reactivity and recovery differed significantly from zero (P < 0.01), with 12-25% of the total variation in BP response attributable to additive genetic effects. The genetic correlations between baseline DBP and response phenotypes were not significantly different from zero, whereas the genetic correlation between DBP reactivity and recovery (0.74) was significantly different from zero and 1 (P < 0.005). The genetic correlation between SBP reactivity and recovery was similar (0.81; P < 0.05).

CONCLUSION

We conclude that, independent of baseline BP, BP response to CPT is heritable, and that both shared and unshared genetic factors influence BP reactivity and recovery, thus stressing the importance of identifying genetic variants that influence both traits.

Impact of ethnicity and gender differences on angiographic coronary artery disease prevalence and in-hospital mortality in the American College of Cardiology-National Cardiovascular Data Registry

BACKGROUND

Although populations referred for coronary angiography are increasingly diverse, there is limited information on coronary artery disease (CAD) prevalence and in-hospital mortality other than for predominately white male patients.

METHODS AND RESULTS

We examined gender and ethnic differences in CAD prevalence and in-hospital mortality in a prospective cohort of patients referred for angiographic evaluation of stable angina (n=375,886) or acute coronary syndromes (ACS; unstable angina or myocardial infarction, n=450,329) at 388 US hospitals participating in the American College of Cardiology-National Cardiovascular Data Registry, an angiographic registry. Univariable and multivariable (with covariates that included risk factors, symptoms, and comorbidities) logistic regression models were used to estimate significant CAD, defined as > or = 70% stenosis, and in-hospital mortality. Within stable angina and ACS cohorts, 7% of patients were black, 2% were Hispanic, 0.3% were Native American, 1% were Asian, and 90% were white, respectively. In stable angina, the risk-adjusted OR for significant CAD was 0.34 for women compared with men (P<0.0001), with black women having the lowest risk-adjusted odds (P<0.0001) compared with other females. Among ACS patients, the risk-adjusted OR of significant CAD was 0.47 for women compared with men (P<0.0001); similarly, black women had the lowest risk-adjusted odds (P<0.0001) compared with other females. Higher in-hospital mortality was reported for white women presenting with stable angina (P<0.00001). White women had a 1.34-fold (95% CI 1.21 to 1.48) higher risk-adjusted odds ratio for mortality than white men with stable angina (P<0.0001), with higher rates noted for white women who were older or had significant CAD (both P<0.0001). Lower utilization of elective coronary revascularization, aspirin, and glycoprotein IIb/IIIa inhibitors (all P<0.0001) may have contributed to higher in-hospital mortality for white women. In ACS, higher in-hospital mortality was reported for Hispanic (P=0.015) and white (P<0.0001) women; however, neither white (P=0.51) or Hispanic (P=0.13) women had higher in-hospital risk-adjusted mortality.

CONCLUSIONS

The likelihood for significant CAD at coronary angiography and for in-hospital mortality varied significantly by ethnicity and gender. Future clinical practice guidelines should be tailored to gender subsets of the population, in particular for black women, to improve the efficient use of angiographic laboratories and to target at-risk populations of women and men.

The association of low birth weight and physiological risk factors of hypertension in African American adolescents

Low birth weight (LBW) has been associated with increased blood pressure and the development of cardiovascular disease including hypertension. Elevated blood pressure, cortisol, and hyperresponsiveness during physiologic stress may function as hypertension biological markers. We examined the association of blood pressure and cortisol levels during induced physiologic stress with LBW in an African American adolescent population (n = 106).

METHODS AND RESULTS

Birth weight was obtained from parents. Blood pressure and cortisol levels were measured at rest and in response to an induced physiological stressor. Compared with normal birth weight group (n = 73), the LBW group (n = 33) demonstrated elevated (+4 mm Hg) diastolic pressure (P = .002) and cortisol hyperresponsiveness (P = .05). Seventy-nine percent of LBW adolescents had elevated blood pressure and/or cardiovascular reactivity (P = .04), and 39% had elevated blood pressures.

CONCLUSIONS

Low birth weight African American adolescents demonstrated physiological risk factors for hypertension, and these findings add support to the association between LBW and the development of hypertension.

Laboratory-based blood pressure recovery is a predictor of ambulatory blood pressure

The recovery phase of the stress response is an individual difference characteristic that may predict cardiovascular risk. The purpose of this study was to examine whether laboratory-based blood pressure (BP) recovery predicts ambulatory BP (ABP). One hundred and eighty-two participants underwent a standard laboratory stress protocol, involving a 20-min baseline rest period, and four stressors presented in a counterbalanced order, each followed by a 10-min recovery period. Participants also wore an ABP monitor for 24h during a typical workday. Hierarchical regression analyses showed that BP recovery accounted for significant additional variance for daytime SBP (p<0.001), nighttime SBP (p<0.001), daytime DBP (p<0.001), and nighttime DBP (p<0.001), after controlling for baseline and reactivity BP. Results suggest that persistence of the BP response following stress may be a more salient characteristic of the stress response in understanding its potential impact on longer term cardiovascular regulation.

Longitudinal relationship of parental hypertension with body mass index, blood pressure, and cardiovascular reactivity in children

OBJECTIVE

To investigate whether parental hypertension (HTN) affects children's body mass index (BMI) and cardiovascular reactivity (CVR) over time.

STUDY DESIGN

A longitudinal study of 315 students (black: 23 females, 19 males; white: 142 females, 131 males) was conducted in the public schools of Obion County, Tennessee, between 1987 and 1992. BMI and BMI z scores were calculated. The CVR task was a series of video games (taking approximately 10 minutes to play) given to the same students in their third-, fourth-, fifth-, seventh-, and eighth-grade years. CVR was defined as the change in blood pressure (delta_BP) or heart rate (delta_HR) between before playing and while playing the video game. Positive parental history of HTN (27.6%) was defined as at least 1 parent with HTN. Multivariable regression analyses were performed to estimate the effects of parental HTN on children's BMI and CVR over time.

RESULTS

Children with parental HTN had significant higher BMI, BMI z score, and R_BP than did children without parental HTN (BMI: 21.6 vs 19.9, P = .001; BMI z score: 1.6 vs 1.1, P = .003; R_SBP: 112.6 vs 110.4 mm Hg, P = .01; R_DBP 62.7 vs 60.6 mm Hg, P = .003) after adjustment for covariates. Increased CVR was observed in children with parental HTN compared with children without parental HTN but was statistically significant only for SBP (delta_SBP: 17.2 vs 14.9 mm Hg; P = .01) after adjustment for covariates.

CONCLUSIONS

Parental HTN independently predicted children's BMI, BMI z score, resting BP, and BP reactivity.

The relationship of blood pressure and cortisol reactivity to family history of hypertension of African American adolescents

Ethnicity and family history of hypertension (FHH) have been associated with the development of hypertension. Blood pressure and cortisol reactivity during physiologic stress are hypothesized to function as biologic markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol reactivity physiologic to FHH in a selected sample of African American adolescents.

METHODS

Demographic data and physiologic measurements were obtained from 48 African American adolescents (14-17 years). Reactivity was induced by a cold pressor test of hand immersion in cold water. chi, t tests, and multivariate repeated-measures analysis were used to determine relationships.

RESULTS

Thirty-one (65%) subjects reported an FHH. Thirty (63%) subjects demonstrated cardiovascular reactivity. Although the mean systolic blood pressure was 4 mm Hg higher, t tests indicated no significance between group in systolic blood pressure (P = .32), diastolic pressure (P = .73), and cortisol (P =.81). Blood pressure reactivity of the FHH group was significantly different than the no family history group (P = .0338). Cortisol levels for the total group were markedly elevated (19 nmol/dL) and there was no significant difference in reactivity.

CONCLUSION

African American adolescents with FHH demonstrate increased blood pressure reactivity. Cortisol levels were elevated for all participants. This study adds support to the association of blood pressure reactivity, a biologic marker of HTN and FHH.

Sequelae of systemic hypertension in alcohol abstainers, light drinkers, and heavy drinkers

A link exists between alcohol intake and increased blood pressure (BP), with many studies showing increased hypertension prevalence in heavy drinkers. The harmful and beneficial effects of alcohol can confound the study of the long-term risks of alcohol-related hypertension. We therefore studied cardiovascular sequelae separately in heavy drinkers, light drinkers, and abstainers among 127,212 subjects with BP and alcohol intake ascertained at 1978 to 1985 health examinations. Subsequent cardiovascular end points included mortality risk, hospitalization risk, and outpatient diagnosis of hypertension. Analyses were performed for all subjects and stratified by 5 alcohol-drinking categories (from never drinkers to >or=3 drinks/day). With <120/80 mm Hg as the referent, Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals for 3 higher BP categories (120 to 129/80 to 84, 130 to 139/85 to 89, and >or=140/90 mm Hg). The covariates were age, gender, race, body mass index, education, and smoking. The risk of all outcomes was progressively higher for increasing BP categories, with a similarly increased risk for abstainers, light drinkers, and heavy drinkers. The interaction tests for alcohol and BP were not statistically significant for the mortality and hospitalization outcomes. Interpretation was limited by an inability to separate subjects with increased BP from alcohol consumption from those with other etiologies. In conclusion, the data indicate that the risks of hypertension are similar regardless of the amount of alcohol consumption.

Quantitative genetic analysis of blood pressure reactivity to orthostatic tilt using principal components analysis

Blood pressure (BP) reactivity to orthostatic tilt may be predictive of cardiovascular disease. However, the genetic and environmental influences on BP reactivity to tilt have not been well examined. Identifying different influences on BP at rest and BP during tilt is complicated by the intercorrelation among multiple measurements. In this study, we use principal components analysis (PCA) to reduce multivariate BP data into components that are orthogonal. The objective of this study is to characterize and examine the genetic architecture of BP at rest and during head-up tilt (HUT). Specifically, we estimate the heritability of individual BP measures and three principal components (PC) derived from multiple BP measurements during HUT. Additionally, we estimate covariate effects on these traits. The study sample consisted of 444 individuals, distributed across four large families. HUT consisted of 70 degrees head-up table tilting while strapped to a tilt table. BP reactivity (deltaBP) was defined as BP during HUT minus BP while supine. Three PC extracted from the PCA were interpreted as 'general BP' (PC1), 'pulse pressure' (PC2) and 'BP reactivity' (PC3). Variance components methods were used to estimate the heritabilities of resting BP, HUT BP, deltaBP, as well as the three BP PC. Significant (P<0.05) heritabilities were found for all BP measurements, except for systolic deltaBP at 1 and 3 min, and diastolic deltaBP at 2 min. Significant genetic effects were also found for the three PC. Each of these orthogonal components is significantly influenced by somewhat different sets of covariates.

Perceived racism and vascular reactivity in black college women: moderating effects of seeking social support

This quasi-experimental study explored the association of perceived racism and seeking social support to vascular reactivity in a college sample of 110 Black women. Perceived racism and seeking social support were assessed via self-report, and vascular reactivity was measured before and during a standardized speaking task. Hierarchical regression analyses indicated that perceived racism was positively related to changes in systolic blood pressure. These analyses also indicated that seeking social support moderated the relationship between perceived racism and systolic blood pressure changes. This interaction effect persisted after controlling for several potential confounders. Follow-up regression analyses showed that perceived racism was positively associated with reactivity among participants who were low in seeking social support. A significant relationship was not observed between perceived racism and systolic blood pressure changes among participants who were high in seeking social support. Perceived racism and seeking social support were not significantly associated with changes in diastolic blood pressure. These findings highlight the importance of examining psychosocial factors that may mitigate the hypothesized relationship between perceived racism and reactivity.

Stress management for African American women with elevated blood pressure: a pilot study

This article reports the results of a pilot study testing the effects of two stress management interventions on blood pressure (BP) and stress-related variables in employed African American women. Thirty-three women with mean age 44.8 +/- 7.6 years were randomly assigned to a cognitive mediation group (n=10), a relaxation group (n=12), or a delayed treatment control group (n=11). The participants in the two stress management groups participated in a 10-week intervention; the delayed treatment control group received BP monitoring during the 10-week period. Measures included BP, the State-Trait Anger Expression Inventory, Personal Strain, and Coping Resources. Although no significant Group x Time effects were found in BP, anger, or personal strain, several of the outcome measures appear to be sensitive and showed cell means in the hypothesized direction. Further study of the effects of stress management interventions on BP and stress, with a larger sample, is warranted.

Chronic stress influences ambulatory blood pressure in adolescents

BACKGROUND

High ambulatory blood pressure (ABP) predicts cardiovascular events, even after controlling for clinic BP and other established risk factors.

PURPOSE

This study examined whether chronic or discrete stress in the past year was associated with greater ABP in adolescents.

METHOD

Participants were 217 male and female Black and White adolescents who wore ABP monitors on 2 consecutive school days and completed a survey of life events.

RESULTS

Report of discrete, negative events was not associated with ABP. Adolescents experiencing greater numbers of chronic, negative life events exhibited greater systolic blood pressure (SBP), independent of ethnicity; sex; body mass index; and location, position, physical activity, and consumption of food/caffeine/nicotine at time of measurement. Greater numbers of chronic, negative events were associated with greater diastolic blood pressure (DBP) among boys. When resting clinic BP was introduced into the model, the main effect of chronic, negative life events on ambulatory SBP became nonsignificant, whereas the effect of chronic, negative life events on male adolescents' DBP persisted.

CONCLUSIONS

Chronic stress is associated with greater ambulatory SBP among male and female adolescents and with greater ambulatory DBP among male adolescents. The latter association persisted after controlling for clinic BP, suggesting that males may be more vulnerable to chronic stress as a determinant of BP regulation than females early in life.

Hemodynamic profile, compensation deficit, and ambulatory blood pressure

This study hypothesized that physiologically grounded patterns of hemodynamic profile and compensation deficit would be superior to traditional blood pressure reactivity in the prediction of daily-life blood pressure. Impedance cardiography-derived measures and beat-to-beat blood pressure were monitored continuously in 45 subjects during baseline and four tasks. Ambulatory blood pressure measures were obtained combining data from one work day and one off day. The mediating effects of gender and family history of hypertension were considered. Only gender was significantly associated with hemodynamic profile. Regression analysis indicated that typical reactivity measures failed to predict everyday life blood pressure. After controlling for gender and baseline blood pressure, hemodynamic patterns during specific tasks proved to be strong predictors, overcoming limitations of previous reactivity models in predicting real-life blood pressure.

Violence exposure and optimism predict task-induced changes in blood pressure and pulse rate in a normotensive sample of inner-city black youth

OBJECTIVE

This investigation examined the association of violence exposure (home and neighborhood) and optimism to task-induced changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse rate (PR).

METHODS

Drawn from a larger investigation, the convenience sample for this study consisted of 172 normotensive black youth (mean age = 11.5 years, standard deviation = 1.3). Violence exposure and optimism were self-reported by participants, and task-induced changes in SBP, DBP, and PR were measured with an automated monitor during two sequentially administered digit-forward and digit-backward tasks.

RESULTS

Hierarchical regression analyses revealed that violence exposure was inversely related to task-induced changes in SBP (p = .010) and DBP (p = .005). Optimism was not an independent predictor of blood pressure or PR changes (p-s > .32). The final step of these hierarchical analyses indicated that the effects of violence exposure and optimism interacted to predict task-induced changes in SBP (p = .013) and PR (p = .003). Follow-up regression analyses indicated that violence exposure was inversely related to task-induced changes in SBP among participants high in optimism and was positively associated with PR reactivity in participants low in optimism.

CONCLUSIONS

The youth in this study have intact mechanisms for buffering blood pressure responses to violence exposure, especially those who are more optimistic about their future-a person factor whose moderating effects might wane with advancing age.

Race/ethnicity, income, major risk factors, and cardiovascular disease mortality

OBJECTIVES

We explored differences between Black and White men for cardiovascular disease (CVD) mortality across major risk factor levels.

METHODS

Major CVD risk factors were measured among 300,647 White and 20,223 Black men aged 35 to 57 years who were screened for the Multiple Risk Factor Intervention Trial (MRFIT). Hazard ratios for CVD deaths for Black and White men over 25 years of follow-up were calculated for subgroups stratified according to risk factor levels.

RESULTS

CVD was responsible for 2518 deaths among Black men and 30,772 deaths among White men. The age-adjusted Black-to-White CVD hazard ratio was 1.35 (95% confidence interval [CI]=1.29, 1.40); the risk- and income-adjusted ratio was 1.05 (95% CI=1.01, 1.10). CVD mortality rates were dramatically lower in cases of favorable risk profiles. However, fully adjusted Black-to-White CVD hazard ratios within groups at low, intermediate, high, and very high levels of overall risk were 1.76, 1.20, 1.10, and 0.94, respectively. Similar gradients were evident for individual risk factors.

CONCLUSIONS

Higher CVD mortality rates among Black men were largely mediated by risk factors and income. These data underscore the need for sustained primordial risk factor prevention among Black men.

Ethnic differences in the prognostic value of stress technetium-99m tetrofosmin gated single-photon emission computed tomography myocardial perfusion imaging

OBJECTIVES

This study was designed to evaluate the differential prognostic value of gated single-photon emission computed tomographic imaging (SPECT) imaging in an ethnically diverse multicenter registry.

BACKGROUND

Ethnic minority patient populations have reportedly higher coronary heart disease mortality with greater comorbidity and a clustering of risk factors at a significantly younger age when compared with Caucasian, non-Hispanic patients. Despite our increasingly diverse population, the predictive accuracy of cardiac imaging in ethnic minority patients is ill-defined.

METHODS

A total of 7,849 patients were prospectively enrolled in a registry of patients undergoing exercise (44%) or pharmacologic stress (56%) technetium-99m tetrofosmin SPECT. Scans were scored using a 20-segment myocardial model with a 5-point severity index. Multivariable Cox proportional hazards models were employed to assess time to death or myocardial infarction.

RESULTS

A total of 1,993 African-American, 464 Hispanic, and 5,258 Caucasian non-Hispanic patients underwent SPECT imaging. African-American and Hispanic patients more often had a history of stroke, peripheral arterial disease, angina, heart failure, diabetes, hypertension, and smoking at a younger age. Moderate or severely abnormal SPECT scans were noted in 21%, 17%, and 13% of African-American, Hispanic, and Caucasian non-Hispanic patients, respectively (p < 0.0001). Cardiovascular death rates were highest for ethnic minority patients (p < 0.0001). Annual rates of ischemic heart disease death ranged from 0.2% to 3.0% for Caucasian non-Hispanic and 0.8% to 6.5% for African-American patients with low-risk to severely abnormal SPECT scans (p < 0.0001). For post-stress ejection fraction <45%, annualized risk-adjusted death rates were 2.7% for Caucasian non-Hispanic patients versus 8.0% and 14.0% for African-American and Hispanic patients (p < 0.0001).

CONCLUSIONS

The current results from a large observational registry reveal that exercise and pharmacologic stress SPECT effectively predicts major cardiovascular events in a large cohort of African-American and Hispanic patients evaluated for suspected myocardial ischemia. These results provide further evidence that ethnic minority patient populations have a worsening outcome related to cardiovascular disease.

Essential hypertension, progressive renal disease, and uric acid: a pathogenetic link?

Hypertension and hypertension-associated ESRD are epidemic in society. The mechanisms responsible for renal progression in mild to moderate hypertension and those groups most at risk need to be identified. Historic, epidemiologic, clinical, and experimental studies on the pathogenesis of hypertension and hypertension-associated renal disease are reviewed and an overview/hypothesis for the mechanisms involved in renal progression is presented. There is increasing evidence that hypertension may exist in one of two forms/stages. The first stage, most commonly observed in early or borderline hypertension, is characterized by salt-resistance, normal or only slightly decreased GFR, relatively normal or mild renal arteriolosclerosis, and normal renal autoregulation. This group is at minimal risk for renal progression. The second stage, characterized by salt-sensitivity, renal arteriolar disease, and blunted renal autoregulation, defines a group at highest risk for the development of microalbuminuria, albuminuria, and progressive renal disease. This second stage is more likely to be observed in blacks, in subjects with gout or hyperuricemia, with low level lead intoxication, or with severe obesity/metabolic syndrome. The two major mechanistic pathways for causing impaired autoregulation at mild to moderate elevations in BP appear to be hyperuricemia and/or low nephron number. Understanding the pathogenetic pathways mediating renal progression in hypertensive subjects should help identify those subjects at highest risk and may provide insights into new therapeutic maneuvers to slow or prevent progression.

Moderating effects of perceived racism on john henryism and blood pressure reactivity in black female college students

BACKGROUND

Relative to other ethnic groups in the United States Blacks have disproportionately higher rates of hypertension. Research suggest that perceived racism might moderate the relation between such Pearson variables as John Henryism and cardiac/vascular functioning.

PURPOSE

This study examined the possible moderating influence of perceived racism on the John Henryism reactivity relation in a sample of 117 Black female college students (M age = 26.10 years, SD = 8.83).

METHODS

Blood pressure was measured before and during a speaking task. John Henryism and perceived racism were assessed via self-report.

RESULTS

Hierarchial regression analyses revealed that John Henryism was inversely related to systolic blood pressure reactivity (p = .007). These analyses also indicated that John Henryism and perceived racism interacted to predict both systolic (p = .007) and diastolic blood pressure reactivity (p = .0005). Follow-up regression analyses indicated that John Henryism was unrelated to systolic and diastolic blood pressure reactivity for women high in perceived racism (ps > .62) and was inversely associated with systolic and diastolic blood pressure reactivity for women low in perceived racism (ps < .01).

CONCLUSIONS

The findings highlight the importance of examining the potential moderating effects of ethnically relevant situation factors when exploring the relation of John Henryism to blood pressure reactivity.