Metabolic syndrome in African Americans: implications for preventing coronary heart disease

Non-cardiac and cardiac risk for ischemic stroke in young adults: The Stanford Y-CORE (Young Cardiovascular Outcomes and Risk Evaluation) study

BACKGROUND

The incidence of stroke is increasing in young to middle-aged adults. Assessing risk factors is important in this large population whose comorbidities may differ from older adults.

METHODS

In this retrospective cohort analysis of adults aged between 20 and 50 presenting to the Stanford Healthcare system from 1 January 2000 through 31 December 2021, with no prior history of stroke or transient ischemic attack, we studied the effects of 30 risk factors on the primary endpoint of incident ischemic stroke, defined by the presence of the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes for stroke and confirmed by brain imaging. The secondary endpoint was incident cerebrovascular events defined by the presence of ICD-10 codes for stroke or transient ischemic attacks (TIAs). Associations were measured with time-varying multivariable survival regression.

RESULTS

From an overall population of 1.3 million, we identified 540,999 individuals aged 20-50 years. Over the study period, 802 experienced the primary endpoint and 5734 the secondary endpoint. On multivariable analysis, non-cardiovascular risk factors were independently associated with the primary endpoint, adjusting for established cardiovascular risk factors, including sleep apnea [1.44, (1.19, 1.74)], bipolar disorder [1.88, (1.23, 2.86)], cancer [2.07 (1.71, 2.51)], and chronic kidney disease (CKD) [2.2, (1.73, 2.81)]. Other non-cardiovascular associations included ethno-racial subgroups of Black [2.05, (1.60, 2.64)], Pacific Islander [2.56, (1.70, 3.84)], and Hispanic [1.71, (1.37, 2.15)] versus white non-Hispanics. Combining non-cardiovascular risk factors significant on multivariable analysis with established cardiovascular factors significantly improved the C-index for de novo stroke to 0.814 over that obtained in either group alone (P < 0.05).

CONCLUSIONS

In this large population of young adults, several non-cardiovascular factors conferred risk for incident stroke independent of known cardiovascular risk factors and, in combination, significantly improved the prediction of incident stroke over those based on either group of factors alone. These findings may have implications for assessing risk in younger patients with distinct comorbidities.

Multilevel Mediators on the Associations of Neighborhood Social Environmental Factors and Severity of Metabolic Syndrome: The Jackson Heart Study

BACKGROUND

Neighborhood characteristics serve as risk factors for metabolic syndrome (MetS). However, the intermediary factors linking this relationship remain understudied. Thus, we investigated the sex-specific mediating role of C-reactive protein, physical activity (PA), and perceived stress in the associations of perceived neighborhood social environment (PNSE) with MetS severity among Black adults.

METHODS AND RESULTS

This cross-sectional study included 3185 adults (64% women) from exam 1 (2000-2004) of the Jackson Heart Study. MetS severity Z scores were calculated based on the Adult Treatment Panel III criteria formula. PNSE included neighborhood violence, problems, and social cohesion. Men and women were analyzed separately. A bootstrap resampling technique with 95% bias-corrected CI (95% BC CI) was used to evaluate whether C-reactive protein, PA, and perceived stress mediated the association between each PNSE and MetS severity, adjusting for covariates. All PNSE factors were directly related to MetS severity in women but not in men. In women, neighborhood problems were indirectly associated with MetS severity mediated through PA (β=0.02 [95% BC CI, 0.00-0.05]). In men, neighborhood violence, problems, and social cohesion were indirectly associated with MetS severity mediated through PA (β=0.05 [95% BC CI, 0.01-0.10]; β=0.03 [95% BC CI, 0.00-0.06]; and β=-0.04 [95% BC CI, -0.09 to -0.01], respectively). Neither C-reactive protein nor perceived stress mediated such associations in either women or men.

CONCLUSIONS

All PNSEs (violence, problems, and social cohesion) were directly related to MetS severity in women only. PA mediated the relationship between each PNSE and MetS in a sex-specific manner. Efforts focusing on local conditions are needed to better understand why such disparities exist for at-risk minoritized groups.

Changes in Lipid Profiles with the Progression of Pregnancy in Black Women

Background/Objectives: Lipid metabolism plays an important role in maternal health and fetal development. There is a gap in the knowledge of how lipid metabolism changes during pregnancy for Black women who are at a higher risk of adverse outcomes. We hypothesized that the comprehensive lipidome profiles would show variation across pregnancy indicative of requirements during gestation and fetal development. Methods: Black women were recruited at prenatal clinics. Plasma samples were collected at 8-18 weeks (T1), 22-29 weeks (T2), and 30-36 weeks (T3) of pregnancy. Samples from 64 women who had term births (≥37 weeks gestation) were subjected to "shotgun" Orbitrap mass spectrometry. Mixed-effects models were used to quantify systematic changes and dimensionality reduction models were used to visualize patterns and identify reliable lipid signatures. Results: Total lipids and major lipid classes showed significant increases with the progression of pregnancy. Phospholipids and glycerolipids exhibited a gradual increase from T1 to T2 to T3, while sphingolipids and total sterol lipids displayed a more pronounced increase from T2 to T3. Acylcarnitines, hydroxy acylcarnitines, and Lyso phospholipid levels significantly decreased from T1 to T3. A deviation was that non-esterified fatty acids decreased from T1 to T2 and increased again from T2 to T3, suggestive of a potential role for these lipids during the later stages of pregnancy. The fatty acids showing this trend included key fatty acids-non-esterified Linoleic acid, Arachidonic acid, Alpha-linolenic acid, Eicosapentaenoic acid, Docosapentaenoic acid, and Docosahexaenoic acid. Conclusions: Mapping lipid patterns and identifying lipid signatures would help develop intervention strategies to reduce perinatal health disparities among pregnant Black women.

Biological Basis of Breast Cancer-Related Disparities in Precision Oncology Era

Precision oncology is based on deep knowledge of the molecular profile of tumors, allowing for more accurate and personalized therapy for specific groups of patients who are different in disease susceptibility as well as treatment response. Thus, onco-breastomics is able to discover novel biomarkers that have been found to have racial and ethnic differences, among other types of disparities such as chronological or biological age-, sex/gender- or environmental-related ones. Usually, evidence suggests that breast cancer (BC) disparities are due to ethnicity, aging rate, socioeconomic position, environmental or chemical exposures, psycho-social stressors, comorbidities, Western lifestyle, poverty and rurality, or organizational and health care system factors or access. The aim of this review was to deepen the understanding of BC-related disparities, mainly from a biomedical perspective, which includes genomic-based differences, disparities in breast tumor biology and developmental biology, differences in breast tumors' immune and metabolic landscapes, ecological factors involved in these disparities as well as microbiomics- and metagenomics-based disparities in BC. We can conclude that onco-breastomics, in principle, based on genomics, proteomics, epigenomics, hormonomics, metabolomics and exposomics data, is able to characterize the multiple biological processes and molecular pathways involved in BC disparities, clarifying the differences in incidence, mortality and treatment response for different groups of BC patients.

Racial disparities in utilization of first-generation versus second-generation long-acting injectable antipsychotics in Medicaid beneficiaries with schizophrenia

BACKGROUND

Multiple studies report racial disparities in antipsychotic prescription patterns. This study assessed demographic and clinical factors associated with the utilization of first-generation (FG) versus second-generation (SG) long-acting injectable (LAI) antipsychotics.

METHODS

This retrospective, observational cohort analysis used claims data from the IBM MarketScan® Multi-State Medicaid database. The study included adults with an LAI claim between 01-January-2009 and 31-December-2018, an ICD-9-CM or ICD-10-CM diagnosis of schizophrenia, race recorded as Black or White, and ≥12 months of continuous enrollment before the index LAI. Descriptive analysis detailed the relationship between race and FG or SG LAI initiation. Multivariate logistic regression was used to assess potential associations with FG vs. SG LAI initiation, including clinical and demographic factors, comorbidities, and index year.

RESULTS

A total of 10,773 patients were included: 6659 (62 %) Black and 4114 (38 %) White. Black patients had a higher utilization of FG LAIs than White patients (46.8 % vs. 38.9 %) over the 10 years analyzed. Black patients were more likely to utilize FG LAIs than White patients (odds ratio: 1.47; 95 % CI: 1.34, 1.62) after controlling for index year and covariates (race, age, gender, insurance plan type, Quan-Charlson Comorbidity index score, comorbidities, prior medications). Significant predictors of FG LAI utilization were older age, type of baseline oral antipsychotic (FG vs SG), type of coverage (managed care vs fee for service), and greater comorbidity burden.

CONCLUSION

The utilization of FG LAIs was greater in Black compared to White Medicaid beneficiaries with schizophrenia over a 10-year period. These findings suggest that racial disparities exist in LAI initiation, with implications for differential quality of schizophrenia treatment.

Intersectional invisibility experiences of low-income African-American women in healthcare encounters

BACKGROUND

The disparities that Black/African-American women experience in health care are persistent and staggering. Findings from health outcomes research continue to demonstrate poorer outcomes for African-American women compared to women of other race/ethnicity in several conditions. These racial/ethnic and gender health disparities observed are complex, heavily nuanced and multi-factorial. To understand these, there is a need to apply an 'intersectionality' lens. Intersectionality refers to the experience of persons with multiple intersecting statuses. The objective of this exploratory study was to gain insight into the healthcare experiences of low-income African-American women.

METHODS

In-depth one-on-one interviews were conducted with 22 women and 2 focus group discussions with community leaders and advocates. Investigators conducted a thematic analysis of the transcripts.

RESULTS

The thematic analysis revealed four major themes, which tell the story of the intersectional invisibility experienced by low-income AA women in the healthcare system. These included (1) the perception of 'not feeling heard'; (2) patient as 'expert of her own body'; (3) disregard of patient preferences; and (4) the need for self-advocacy.

CONCLUSIONS

Black/African-American women, and particularly those with socioeconomic disadvantage, experience intersectional invisibility resulting from provider implicit bias, stereotypical assumptions, and systemic structures that enable discriminatory practices in healthcare delivery. Healthcare provider education that more explicitly addresses these biases and stereotypes should be complemented with system-level interventions that aim to dismantle the structural racism inherent in healthcare policies and practices.

Metabolic syndrome, associated factors and optimal waist circumference cut points: findings from a cross-sectional community-based study in the elderly population in Asmara, Eritrea

OBJECTIVE

The aim of the study was to investigate the prevalence of metabolic syndrome (MetSyn), associated factors, and optimal waist circumference (WC) cut points in a subset of the elderly population in Asmara, Eritrea.

DESIGN

A community-based cross-sectional study conducted between January and June 2018.

SETTING

Asmara, Eritrea.

PARTICIPANTS

Demographic, clinical biochemistry and anthropometric information were collected from a total of 319 elderly participants of African lineage (54.5% men vs 45.5% women).

MAIN OUTCOME MEASURES

Lipid profiles, fasting plasma glucose (FPG), anthropometric data, clinical profiles and demographic characteristic of patients were described. MetSyn was defined according to the International Diabetes Federation harmonised criteria.

RESULTS

The median age (IQR) of study participants was 67 (IQR: 63-72 years)-men 68 (IQR: 64-74) years versus women 65 (IQR: 62-70) years, p=0.002. The prevalence of MetSyn was 90 (28.4%). Abnormal values in MetSyn components were as follows: systolic blood pressure/diastolic blood pressure ≥130/85 mm Hg or use of hypertension medication 133 (41.7%); overweight/obesity, 55 (25.1%); abdominal obesity 129 (40.4); low-density lipoproptein cholesterol (LDL-C) >130 mg/dL, 139 (43.6%); total cholesterol >200 mg/dL, 152 (47.6%); non-high-density lipoproptein cholesterol (HDL-C)>130 mg/dL, 220 (69.0%) and FPG (≥100-125 mg/dL), 35 (12.7%) and FPG>125.17 (6.2%). Multivariate logistic regression analysis indicated that sex (females) (adjusted OR (aOR) 4.69, 95% CI 2.47 to 8.92); non-HDL-C (aOR 1.09, 95% CI 1.05 to 1.14); LDL-C >130 mg/dL (aOR 2.63, 95% CI 1.09 to 6.37) and body mass index (aOR 1.20, 95% CI 1.10 to 1.32) were independently associated with the presence of MetSyn. Optimal cut points for WC in men yielded a value of 85.50 cm, a sensitivity of 76.0%, a specificity of 61.0% and an area under receiver operating characteristics curve (AUROC) value of 74.0, 95% CI (65.7 to 82.4). For women, the WC at a cut point value of 80.50 cm yielded the highest Youden index (0.41) with a sensitivity of 80%, a specificity of 39%, and an AUROC of 73.4, 95% CI (64.8 to 82.5).

CONCLUSIONS

The MetSyn is highly prevalent in a subset of apparently healthy elderly population in Asmara, Eritrea. The findings support opportunistic and/or programmatic screening for CVD risk in the elderly during outpatient visits.

Increased Metabolic Burden Among Blacks: A Putative Mechanism for Disparate COVID-19 Outcomes

Mounting evidence shows a disproportionate COVID-19 burden among Blacks. Early findings indicate pre-existing metabolic burden (eg, obesity, hypertension and diabetes) as key drivers of COVID-19 severity. Since Blacks exhibit higher prevalence of metabolic burden, we examined the influence of metabolic syndrome on disparate COVID-19 burden. We analyzed data from a NIH-funded study to characterize metabolic burden among Blacks in New York (Metabolic Syndrome Outcome Study). Patients (n=1035) were recruited from outpatient clinics, where clinical and self-report data were obtained. The vast majority of the sample was overweight/obese (90%); diagnosed with hypertension (93%); dyslipidemia (72%); diabetes (61%); and nearly half of them were at risk for sleep apnea (48%). Older Blacks (age≥65 years) were characterized by higher levels of metabolic burden and co-morbidities (eg, heart disease, cancer). In multivariate-adjusted regression analyses, age was a significant (p≤.001) independent predictor of hypertension (OR=1.06; 95% CI: 1.04-1.09), diabetes (OR=1.03; 95% CI: 1.02-1.04), and dyslipidemia (OR=0.98; 95% CI: 0.97-0.99), but not obesity. Our study demonstrates an overwhelmingly high prevalence of the metabolic risk factors related to COVID-19 among Blacks in New York, highlighting disparate metabolic burden among Blacks as a possible mechanism conferring the greater burden of COVID-19 infection and mortality represented in published data.

Stroke in young adults: Current trends, opportunities for prevention and pathways forward

Cardiovascular disease remains a major contributor to morbidity and mortality in the US and elsewhere, and stroke is a leading cause of disability worldwide. Despite recent success in diminishing stroke incidence in the general US population, in parallel there is now a concerning propensity for strokes to happen at younger ages. Specifically, the incidence of stroke for US adults 20-44 years of age increased from 17 per 100,000 US adults in 1993 to 28 per 100,000 in 2015. Occurrence of strokes in young adults is particularly problematic as these patients are often affected by physical disability, depression, cognitive impairment and loss of productivity, all of which have vast personal, social and economic implications. These concerning trends among young adults are likely due to increasing trends in the prevalence of modifiable risk factors amongst this population including hypertension, hyperlipidemia, obesity and diabetes, highlighting the importance of early detection and aggressive prevention strategies in the general population at early ages. In parallel and compounding to the issue, troublesome trends are evident regarding increasing rates of substance abuse among young adults. Higher rates of strokes have been noted particularly among young African Americans, indicating the need for tailored prevention and social efforts targeting this and other vulnerable groups, including the primordial prevention of risk factors in the first place, reducing stroke rates in the presence of prevalent risk factors such as hypertension, and improving outcomes through enhanced healthcare access. In this narrative review we aim to emphasize the importance of stroke in young adults as a growing public health issue and increase awareness among clinicians and the public health sector. For this purpose, we summarize the available data on stroke in young adults and discuss the underlying epidemiology, etiology, risk factors, prognosis and opportunities for timely prevention of stroke specifically at young ages. Furthermore, this review highlights the gaps in knowledge and proposes future directions moving forward.

Circulating microRNAs and endothelial cell migration rate are associated with metabolic syndrome and fitness level in postmenopausal African American women

Postmenopausal African American women are at elevated risk for metabolic syndrome (MetS), which predisposes them to cardiovascular disease and other chronic diseases. Circulating microRNAs (ci-miR) are potential mediators of cardiometabolic diseases also impacted by cardiorespiratory fitness (CRF) level. Using real-time quantitative PCR, we compared the expression of vascular-related ci-miRs (miR-21-5p, miR-92a-3p, miR-126-5p, miR-146a-5p, miR-150-5p, miR-221-3p) in sedentary, overweight/obese, postmenopausal African American women based on 1) presence (n = 31) or absence (n = 42) of MetS and 2) CRF level (VO2peak ) (Very Low < 18.0 mL·kg-1 ·min-1 [n = 31], Low = 18.0-22.0 mL·kg-1 ·min-1 [n = 24], or Moderate >22.0 mL·kg-1 ·min-1 [n = 18]). Endothelial migration rate in response to subjects' serum was assessed to determine the effect of circulating blood-borne factors on endothelial repair. Ci-miR-21-5p was the only ci-miR that differed between women with MetS compared to those without MetS (0.93 ± 0.43 vs. 1.28 ± 0.71, P = 0.03). There were borderline significant differences (P = 0.06-0.09) in ci-miR-21-5p, 126-5p, and 221-3p levels between the CRF groups, and these three ci-miRs correlated with VO2peak (r = -0.25 to -0.28, P < 0.05). Endothelial migration rate was impaired in response to serum from women with MetS compared to those without after 16-24 h. Serum from women with Moderate CRF induced greater endothelial migration than the Very Low and Low CRF groups after 4 and 16-24 h, that was also not different from a young, healthy reference group. Ci-miR-21-5p is lower in postmenopausal African American women with MetS, while ci-miRs-21-5p, 126-5p, and 221-3p are associated with CRF. Factors which impair endothelial cell migration rate are present in serum of women with MetS, though having Moderate CRF may be protective.

The effect of metabolic risk factors on cancer mortality among blacks and whites

BACKGROUND

Previous data showed that metabolic syndrome (MS) and its components are associated with cancer mortality. However, whether the association varies by race is unclear. To examine the association between metabolic risk factors and cancer death in non-Hispanic whites (whites) and non-Hispanic blacks (blacks) in the US.

METHODS

We used data from National Health and Nutrition Examination Survey III (NHANES III) [1988-1994], a nationwide survey conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention in the US. We included a total of 18,001 participants aged ≥20 years in the study. We ascertained cancer death from NHANES III mortality follow-up study, which linked with the National Death Index and provides follow-up from the date of baseline NHANES III [1988-1994] through December 2006. MS was defined as the presence of at least three of five risk factors [i.e., elevated triglycerides (TG) (≥150 mg/dL), impaired fasting blood glucose (≥100 mg/dL), increased waist circumference (≥88 cm for women and ≥102 cm for men), elevated blood pressure (BP) (≥130 mmHg systolic BP or ≥85 mmHg diastolic BP) and, reduced high density lipoprotein (HDL) cholesterol (<50 mg/dL)]. The interaction between race and MS and its components against total cancer mortality was first tested. Cox proportional hazards regression was then used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for total cancer mortality in relation to each MS individual component, and a MS composite score in whites and blacks, separately.

RESULTS

We found a statistically significant interaction between MS and race as well as MS components and race in their effect on cancer death. In adjusted models, elevated BP was significantly associated with a 41% increased risk of total cancer death in blacks (HR 1.41; 95% CI, 1.10-1.80) while in whites, the risk of cancer death increased 29% with central obesity (HR 1.29; 95% CI, 1.05-1.59), 26% with low HDL (HR 1.26; 95% CI, 1.04-1.52), and 45% with impaired fasting glucose (HR 1.45; 95% CI, 1.19-1.76).

CONCLUSIONS

The relationship between metabolic risk factors and total cancer mortality differed by race in the US. In blacks, high BP was associated with an increased risk for cancer death while in whites, central obesity, low HDL, and especially impaired fasting glucose were positively associated with cancer death.

The Metabolic Syndrome and Its Components in African-American Women: Emerging Trends and Implications

The Metabolic Syndrome (MetS) is recognized as a predictor of cardiovascular outcomes and type 2 diabetes (T2DM). The MetS is a constellation of clinical and metabolic risk factors that include abdominal obesity, dyslipidemia, glucose intolerance, and hypertension. There are ethnic and racial differences in the prevalence of MetS and its components. In general, African-Americans have lower prevalence of MetS when compared to whites, but suffer disproportionately from higher cardiovascular mortality and T2DM. Specifically, African-American women (AAW) have higher rates of T2DM and cardiovascular mortality despite a more favorable lipid and lipoprotein profile. This is paradoxical. However, there is a general upward trend in the prevalence of MetS in the US. The reasons are debatable, but could be multifactorial, including genetics and environmental factors. Thus, there is a need to understand the increasing trend in the MetS, its components, and the associated outcomes for AAW. Therefore, the purpose of this mini review is to (1) understand the increasing prevalence of MetS and its components in AAW and (2) provide suggestions for future prevention of cardiovascular disease and T2DM in AAW.

Changes in social support over time in a faith-based physical activity intervention

African-American women report higher levels of chronic conditions and church attendance relative to the overall US population. Therefore, efforts have increased over the past decade to design church-based health promotion programs. The present study compared changes in religiosity, religious social support and general social support across time within a church-based physical activity study. In a clustered randomized controlled trial, 31 churches and ∼15 African-American women per church were recruited to participate. Churches were randomized to one of three 10-month programs to promote physical activity: faith-integrated (FI), non-faith integrated (NFI) or self-guided control program (C). Comparisons were made between baseline and 10-month time points to assess differences over time. A significant reduction in general social support was observed across all groups. Private religious practices and religious emotional support received increases in C and FI, respectively. Prior research findings and the current study highlight difficulty in demonstrating strong, unilateral changes in religiosity, social support and health. Additional research is needed to identify more accurate measures of these concepts. Findings from the current study have implications for the role of social support in future church-based health promotion studies.

Low-dose spironolactone ameliorates insulin resistance and suppresses elevated plasminogen activator inhibitor-1 during gestational testosterone exposure

CONTEXT

Elevated gestational circulating testosterone has been associated with pathological pregnancies that increase the risk of development of cardiometabolic disorder in later life.

OBJECTIVE

We hypothesised that gestational testosterone exposure, in late pregnancy, causes glucose deregulation and atherogenic dyslipidaemia that would be accompanied by high plasminogen activator inhibitor-1 (PAI-1). The study also hypothesise that low-dose spironolactone treatment would ameliorate these effects.

METHODS

Pregnant Wistar rats received vehicle, testosterone (0.5 mg/kg; sc), spironolactone (0.5 mg/kg, po) or testosterone and spironolactone daily between gestational days 15 and 19.

RESULTS

Gestational testosterone exposure led to increased HOMA-IR, circulating insulin, testosterone, 1-h post-load glucose, atherogenic dyslipidaemia, PLR, PAI-1 and MDA. However, all these effects, except that of circulating testosterone, were ameliorated by spironolactone.

CONCLUSIONS

These results demonstrate that low-dose spironolactone ameliorates glucose deregulation and atherogenic dyslipidaemia during elevated gestational testosterone exposure, at least in part, by suppressing elevated PAI-1.

Hypertension in Obese Black Women is Not Caused by Increased Sympathetic Vascular Tone

Background

Black women have one of the highest prevalence rates of hypertension and obesity in the United States. We previously reported that sympathetic activation induced by obesity is a significant contributor to hypertension in white patients. It is unknown whether sympathetic activity similarly contributes to hypertension in obese black women.

Methods and Results

We studied 42 obese women (16 white, body mass index 36±4 kg/m², 44% with hypertension; 26 black, body mass index 35±4 kg/m², 46% with hypertension). Antihypertensive medications were discontinued for 2 weeks before the day of the study. All patients underwent complete autonomic blockade with trimethaphan at a dosage of 4 mg/min. Resting sympathetic activity determined from muscle sympathetic nerve recordings was similar between obese black women with hypertension and those with normotension. In whites, sympathetic activity was elevated in obese patients with hypertension compared with normotension; the decrease in mean arterial blood pressure produced by trimethaphan was greater in obese white patients with hypertension compared with those with normotension (−26.8±9.7 mm Hg versus −14.8±7.9 mm Hg, P=0.02). In contrast, there was no difference in the depressor responses induced by trimethaphan between obese black women with hypertension and those with normotension (−15.5±10.5 mm Hg versus −12.3±10.2 mm Hg, P=0.45). Mean arterial blood pressure remained elevated in obese blacks with hypertension compared with those with normotension during trimethaphan infusion (83.7±15.0 mm Hg versus 71.7±9.8 mm Hg, P=0.02). Heart rate increased similarly with trimethaphan between white (P=0.11) and black (P=0.76) women with hypertension and normotension.

Conclusions

These findings suggest that sympathetic activity does not contribute to hypertension in obese black women and provide further evidence for racial differences in hypertension mechanisms.

Is self-reported physical functioning associated with incident cardiometabolic abnormalities or the metabolic syndrome?

BACKGROUND

Physical functioning may be an important pre-clinical marker of chronic disease, used as a tool to identify patients at risk for future cardiometabolic abnormalities. This study evaluated if self-reported physical functioning was associated with the development of cardiometabolic abnormalities or their clustering (metabolic syndrome) over time.

METHODS

Participants (n = 2,254) from the Study of Women's Health Across the Nation who reported physical functioning on the Short Form health survey and had a metabolic syndrome assessment (elevated fasting glucose, blood pressure, triglycerides and waist circumference; reduced HDL cholesterol) in 2000 were included. Discrete survival analysis was used to assess the 10-year risk of developing metabolic syndrome or a syndrome component through 2010.

RESULTS

At baseline, the prevalence of metabolic syndrome was 22.0%. Women with substantial limitations (OR = 1.60; 95% CI: 1.12, 2.29) in physical functioning were significantly more likely to develop the metabolic syndrome compared with women reporting no limitations. Self-reported physical functioning was significantly associated with incident hypertension and increased waist circumference.

CONCLUSIONS

Simple screening tools for cardiometabolic risk in clinical settings are needed. Self-reported physical functioning assessments are simple tools that may allow healthcare providers to more accurately predict the course of chronic conditions.

Obesity, weight gain, and ovarian cancer risk in African American women

Although there is growing evidence that higher adiposity increases ovarian cancer risk, little is known about its impact in African American (AA) women, the racial/ethnic group with the highest prevalence of obesity. We evaluated the impact of body mass index (BMI) 1 year before diagnosis and weight gain since age 18 years on ovarian cancer risk in a population-based case-control study in AA women in 11 geographical areas in the US. Cases (n = 492) and age and site matched controls (n = 696) were identified through rapid case ascertainment and random-digit-dialing, respectively. Information was collected on demographic and lifestyle factors, including self-reported height, weight at age 18 and weight 1 year before diagnosis/interview. Multivariable logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential covariates. Obese women had elevated ovarian cancer risk, particularly for BMI ≥ 40 kg/m(2) compared to BMI <25 (OR = 1.72, 95% CI: 1.12-2.66; p for trend: 0.03). There was also a strong association with weight gain since age 18 (OR: 1.52; 95% CI: 1.07-2.16; p for trend: 0.02) comparing the highest to lowest quartile. In stratified analyses by menopausal status, the association with BMI and weight gain was limited to postmenopausal women, with a 15% (95% CI: 1.05-1.23) increase in risk per 5 kg/m(2) of BMI and 6% (95% CI: 1.01-1.10) increase in risk per 5 kg of weight gain. Excluding hormone therapy users essentially did not change results. Obesity and excessive adult weight gain may increase ovarian cancer risk in post-menopausal AA women.

Cardiorespiratory Fitness and Metabolic Syndrome in Postmenopausal African-American Women

We examined the association of cardiorespiratory fitness with metabolic syndrome in overweight/obese postmenopausal African-American women. Pooled baseline data on 170 African-American women from 2 exercise trials were examined. Metabolic syndrome was defined as at least 3 of the following: abdominal obesity, glucose intolerance, hypertension, low high-density lipoprotein cholesterol (HDL-C), and high triglycerides. Cardiorespiratory fitness (VO2peak) was determined using the Bruce treadmill protocol and categorized as: Very Low (VLCRF<18 mL·kg(-1) min(-1)), Low (LCRF=18.0-220-22-22.0 mL·kg(-1) min(-1)), and Moderate (MCRF>22.0 mL·kg(-1) min(-1)). Associations of metabolic syndrome with cardiorespiratory fitness were analyzed using one-way ANOVA and linear regression. VO2peak was significantly lower in the VLCRF compared to the MCRF group. Lower cardiorespiratory fitness was associated with higher prevalence of metabolic syndrome, abdominal obesity, hypertriglyceridemia, and low HDL among overweight/obese postmenopausal African-American women. In fully adjusted models, higher waist circumference and triglycerides were associated with lower VO2peak levels (P<0.01) and higher HDL-C was associated with higher VO2peak levels (P=0.03). Overweight/obese postmenopausal African-American women with very low cardiorespiratory fitness are more likely to have metabolic syndrome, higher body mass index, and unhealthier levels of certain metabolic syndrome components than women with moderate cardiorespiratory fitness.

Prenatal Testosterone Exposure Leads to Gonadal Hormone-Dependent Hyperinsulinemia and Gonadal Hormone-Independent Glucose Intolerance in Adult Male Rat Offspring

Elevated testosterone levels during prenatal life lead to hyperandrogenism and insulin resistance in adult females. This study evaluated whether prenatal testosterone exposure leads to the development of insulin resistance in adult male rats in order to assess the influence of gonadal hormones on glucose homeostasis in these animals. Male offspring of pregnant rats treated with testosterone propionate or its vehicle (control) were examined. A subset of male offspring was orchiectomized at 7 wk of age and reared to adulthood. At 24 wk of age, fat weights, plasma testosterone, glucose homeostasis, pancreas morphology, and gastrocnemius insulin receptor (IR) beta levels were examined. The pups born to testosterone-treated mothers were smaller at birth and remained smaller through adult life, with levels of fat deposition relatively similar to those in controls. Testosterone exposure during prenatal life induced hyperinsulinemia paralleled by an increased HOMA-IR index in a fasting state and glucose intolerance and exaggerated insulin responses following a glucose tolerance test. Prenatal androgen-exposed males had more circulating testosterone during adult life. Gonadectomy prevented hyperandrogenism, reversed hyperinsulinemia, and attenuated glucose-induced insulin responses but did not alter glucose intolerance in these rats. Prenatal androgen-exposed males had decreased pancreatic islet numbers, size, and beta-cell area along with decreased expression of IR in gastrocnemius muscles. Gonadectomy restored pancreatic islet numbers, size, and beta-cell area but did not normalize IRbeta expression. This study shows that prenatal testosterone exposure leads to a defective pancreas and skeletal muscle function in male offspring. Hyperinsulinemia during adult life is gonad-dependent, but glucose intolerance appears to be independent of postnatal testosterone levels.

Genome-wide significant loci: how important are they? Systems genetics to understand heritability of coronary artery disease and other common complex disorders

Genome-wide association studies (GWAS) have been extensively used to study common complex diseases such as coronary artery disease (CAD), revealing 153 suggestive CAD loci, of which at least 46 have been validated as having genome-wide significance. However, these loci collectively explain <10% of the genetic variance in CAD. Thus, we must address the key question of what factors constitute the remaining 90% of CAD heritability. We review possible limitations of GWAS, and contextually consider some candidate CAD loci identified by this method. Looking ahead, we propose systems genetics as a complementary approach to unlocking the CAD heritability and etiology. Systems genetics builds network models of relevant molecular processes by combining genetic and genomic datasets to ultimately identify key "drivers" of disease. By leveraging systems-based genetic approaches, we can help reveal the full genetic basis of common complex disorders, enabling novel diagnostic and therapeutic opportunities.

The paradox of atrial fibrillation in African Americans

The reported lower prevalence and incidence of atrial fibrillation (AF) despite the higher prevalence of AF risk factors in African Americans compared to Caucasian whites has been referred to as the paradox of AF in African Americans. In this report we highlight this paradox and address potential explanations using data from several US populations studies. These possible explanations include limited methodology to detect AF patterns that are harder to detect (e.g. paroxysmal/intermittent AF or atrial flutter) coupled with the possibility of African Americans having more of these patterns, differential access to health care with African Americans having less access and subsequently less detected AF, survival bias with Caucasian whites living longer and subsequently having more AF, and finally differential impact of AF risk factors with Caucasian whites being more affected or African Americans less affected by AF risk factors whether this is genetically determined or via other unknown predispositions.

Physically active, low-income African American women: an exploration of activity maintenance in the context of sociodemographic factors associated with inactivity

Increasing physical activity among low-income African American women is an important target for addressing racial and economic disparities in chronic conditions and related risk factors. While barriers to physical activity for women have been examined empirically, successful strategies for navigating those barriers among physically active, low-income women have not been thoroughly explored. Informed by grounded theory, we conducted in-depth individual interviews between 2007-2010 with 14 low-income African American women who were physically active at nationally recommended levels for one year or more. We analyzed the data using thematic analysis techniques. Key themes emerged in three main categories: motivation for maintaining active lifestyle, strategies for maintaining physical activity, and challenges to maintaining physical activity. Important motivations included getting or staying healthy, social connections, and gratification. Two planning strategies emerged: flexibility and freedom. Critical challenges included financial constraints, physical strain and history of sedentary relapse. The motivations, strategies and challenges reported by low-income African American women who successfully maintained an active lifestyle provided important information for developing effective health promotion strategies for their inactive and underactive counterparts. A qualitative, asset-based approach to physical activity research contributes rich data to bridge the gap between epidemiological knowledge and community health improvement.

In an urban neighborhood, who is physically active and where?

Previous research has shown differences in adult physical activity (PA) levels within urban population, in what types of activities they participated, and where they were active. A sample of 514 urban Philadelphia adult residents was surveyed about level and location of PA. A majority (55.6%) of survey participants reported being vigorously or moderately active or walking enough to meet PA guidelines. A significantly higher proportion of men (vs. women), younger (vs. older) adults and people who were employed (vs. unemployed) met the PA guidelines. Most participants (87.5%) reported walking at least once within the previous week, while 79.3% reported engaging in moderate or vigorous activity. Of the participants who reported being moderately or vigorously active, 64.0% were physically active in indoors only, 22.6% were active in outdoors only, and 13.4% were active in both indoors and outdoors. Significantly fewer black women were active outdoors, compared to all other race/sex combinations (odds ratio = 0.43, p-value < 0.01). In this diverse sample of urban residents, outdoor PA was significantly less frequently reported than indoor PA, particularly for Black women. These findings could help inform urban PA interventions.

The relationship of oxidative stress, adiposity and metabolic risk factors in healthy Black and White American youth

What is already known about this subject African Americans are disproportionately affected by obesity and other metabolic risk factors in comparison to White Americans. Increasing prevalence of obesity has been associated with concomitant increases in childhood hypertension, dyslipidaemia and type 2 diabetes. Oxidative stress is associated with obesity in both adults and children. What this study adds Oxidative stress is positively associated with total body fat and truncal fat, but not with body mass index (BMI) or BMI z-score in healthy youth. Oxidative stress is associated with diastolic blood pressure in African American but not in White American healthy youth.

BACKGROUND

Oxidative stress is elevated in obese youth, but less is known regarding racial disparities in the relationship of oxidative stress with metabolic risk factors.

OBJECTIVES

To determine the relationship between oxidative stress and metabolic risk factors, adiposity, leptin, adiponectin and cardiovascular fitness (VO2PEAK ) in healthy African American and White American youth.

METHODS

A marker of oxidative stress (F2 -isoprostane), validated markers of metabolic risk factors, fitness and body composition were measured in African American (n = 82) and White American (n = 76) youth (8-17 years old) recruited over a range of BMI percentiles (4th to 99th).

RESULTS

F2 -isoprostane concentration was positively correlated with percentage body fat (r = 0.198) and percentage truncal fat (r = 0.173), but was not different between African American and White American males and females (P = 0.208). African American youth had significantly higher mean systolic and diastolic blood pressure (P = 0.023 and P = 0.011, respectively), body weight, BMI percentile and Tanner stage. After adjusting for gender, age, BMI and Tanner stage, African American youth varied from White Americans in the association of F2 -isoprostane with diastolic blood pressure (P = 0.047), but not with systolic blood pressure, triglycerides, VO2PEAK or homeostatic model assessment for insulin resistance (all P > 0.05).

CONCLUSIONS

Oxidative stress, as measured by urinary F2 -isoprostane concentrations, was positively associated with percent body fat and truncal fat in youth. Oxidative stress levels were similar among African American and White American youth. Among markers of the metabolic syndrome, a significant difference between African American and White American youth was demonstrated only in the association of oxidative stress with diastolic blood pressure.

The impact of cardiovascular disease and risk factor treatment on ethnic disparities in kidney transplant

There is limited data on the use of cardiovascular disease (CVD) risk factor medications following renal transplant, especially when comparing use across ethnicities. The aim of this study was to compare the incidence, treatment, and impact of CVD between ethnicities in kidney transplant recipients. This was a retrospective cohort study of adults who underwent transplant between 2000 and 2008 within our academic medical transplant center. Pediatrics, multiorgan transplants, and those lost to follow-up were excluded. Data collection included all transplant and sociodemographic characteristics, medication use, CVD risk factor management, and follow-up events, including acute rejection, graft loss, and death. A total of 987 patients were included and followed for a mean of 6.7 ± 3.0 years. The baseline demographics revealed black patients were equally likely to have preexisting CVD (24% vs 25%, P = .651), but more likely to have preexisting diabetes (35% vs 23%, P < .001) or hypertension (97% vs 94%, P = .029). Black patients had poorer treatment of CVD risk factors, with lower rates of control of diabetes (35% vs 51%, P < .05) and dyslipidemia (37% vs 42%, P < .05). Black renal transplant recipients who had preexisting CVD had reduced graft survival rates compared to white patients (10-year rate 50% vs 60%, P = .033), but similar rates of graft survival were found in those without CVD (10-year rate 70% vs 71% in white patients, P = .483). CVD is common in transplant recipients, with black patients having higher rates and poorer control of diabetes and dyslipidemia.

Metabolic Syndrome Derived from Principal Component Analysis and Incident Cardiovascular Events: The Multi Ethnic Study of Atherosclerosis (MESA) and Health, Aging, and Body Composition (Health ABC)

Background. The NCEP metabolic syndrome (MetS) is a combination of dichotomized interrelated risk factors from predominantly Caucasian populations. We propose a continuous MetS score based on principal component analysis (PCA) of the same risk factors in a multiethnic cohort and compare prediction of incident CVD events with NCEP MetS definition. Additionally, we replicated these analyses in the Health, Aging, and Body composition (Health ABC) study cohort. Methods and Results. We performed PCA of the MetS elements (waist circumference, HDL, TG, fasting blood glucose, SBP, and DBP) in 2610 Caucasian Americans, 801 Chinese Americans, 1875 African Americans, and 1494 Hispanic Americans in the multiethnic study of atherosclerosis (MESA) cohort. We selected the first principal component as a continuous MetS score (MetS-PC). Cox proportional hazards models were used to examine the association between MetS-PC and 5.5 years of CVD events (n = 377) adjusting for age, gender, race, smoking and LDL-C, overall and by ethnicity. To facilitate comparison of MetS-PC with the binary NCEP definition, a MetS-PC cut point was chosen to yield the same 37% prevalence of MetS as the NCEP definition (37%) in the MESA cohort. Hazard ratio (HR) for CVD events were estimated using the NCEP and Mets-PC-derived binary definitions. In Cox proportional models, the HR (95% CI) for CVD events for 1-SD (standard deviation) of MetS-PC was 1.71 (1.54–1.90) (P < 0.0001) overall after adjusting for potential confounders, and for each ethnicity, HRs were: Caucasian, 1.64 (1.39–1.94), Chinese, 1.39 (1.06–1.83), African, 1.67 (1.37–2.02), and Hispanic, 2.10 (1.66-2.65). Finally, when binary definitions were compared, HR for CVD events was 2.34 (1.91–2.87) for MetS-PC versus 1.79 (1.46–2.20) for NCEP MetS. In the Health ABC cohort, in a fully adjusted model, MetS-PC per 1-SD (Health ABC) remained associated with CVD events (HR = 1.21, 95%CI 1.12–1.32) overall, and for each ethnicity, Caucasian (HR = 1.24, 95%CI 1.12–1.39) and African Americans (HR = 1.16, 95%CI 1.01–1.32). Finally, when using a binary definition of MetS-PC (cut point 0.505) designed to match the NCEP definition in terms of prevalence in the Health ABC cohort (35%), the fully adjusted HR for CVD events was 1.39, 95%CI 1.17–1.64 compared with 1.46, 95%CI 1.23–1.72 using the NCEP definition. Conclusion. MetS-PC is a continuous measure of metabolic syndrome and was a better predictor of CVD events overall and in individual ethnicities. Additionally, a binary MetS-PC definition was better than the NCEP MetS definition in predicting incident CVD events in the MESA cohort, but this superiority was not evident in the Health ABC cohort.

Anthropometric measures, presence of metabolic syndrome, and adherence to physical activity guidelines among African American church members, Dallas, Texas, 2008

INTRODUCTION

The low prevalence of physical activity among African Americans and high risk of cardiovascular disease lends urgency to assessing the association between metabolic syndrome, abdominal obesity, and adherence to current physical activity guidelines. Few studies have examined this association among African American adults.

METHODS

We examined the association between demographic characteristics, anthropometric measures, and metabolic syndrome and adherence to the 2008 Department of Health and Human Services guidelines for moderate and vigorous physical activity. Participants were 392 African American church members from congregations in Dallas, Texas. Physical activity levels were assessed via a validated questionnaire (7-Day Physical Activity Recall), and metabolic syndrome was determined on the basis of the American Heart Association/National Heart, Lung, and Blood Institute diagnostic criteria. We used bivariate and multinomial logistic regression to examine the associations.

RESULTS

Meeting guidelines for vigorous physical activity was significantly and independently associated with the absence of metabolic syndrome among women (odds ratio, 4.71; 95% confidence interval, 1.63-13.14; P = .003), after adjusting for covariates. No association was found between meeting moderate or vigorous physical activity guidelines and metabolic syndrome among men. Meeting physical activity guidelines was not associated with body mass index or waist circumference among this sample of predominantly overweight and obese African American church members.

CONCLUSION

Results indicate that meeting the 2008 guidelines for vigorous physical activity is associated with the absence of metabolic syndrome among African American women. This finding might suggest the need to integrate vigorous physical activity into interventions for African American women as a preventive therapy for cardiovascular risk. 

Characteristics of prepared food sources in low-income neighborhoods of Baltimore City

The food environment is associated with obesity risk and diet-related chronic diseases. Despite extensive research conducted on retail food stores, little is known about prepared food sources(PFSs). We conducted an observational assessment of all PFSs(N = 92) in low-income neighborhoods in Baltimore. The most common PFSs were carry-outs, which had the lowest availability of healthy food choices. Only a small proportion of these carry-outs offered healthy sides, whole wheat bread, or entrée salads (21.4%, 7.1%, and 33.9%, respectively). These findings suggest that carry-out-specific interventions are necessary to increase healthy food availability in low-income urban neighborhoods.

Metabolic syndrome in African Americans: views on making lifestyle changes

This study explores African American adults' understanding of metabolic syndrome (MetS) and their motivations for making lifestyle changes. African Americans have a greater risk for components of MetS, such as hypertension. Three focus groups were conducted with African American adults (n = 11) with MetS. Content analysis revealed five themes: Threat of Poor Health, Building Trust With Providers, Gaining Social Support, Seeking Culturally Acceptable Alternatives, and Getting on Track and Staying on Track. Lifestyle interventions for African Americans with MetS need to focus on building trust, developing self-monitoring skills, social support, and identifying low-cost/convenient opportunities for physical activity.

Amlodipine/Atorvastatin single-pill therapy for blood pressure and lipid goals in African Americans: influence of the metabolic syndrome and type 2 diabetes mellitus

African Americans with diabetes +/- the metabolic syndrome are at high risk for cardiovascular disease. This subanalysis of the Clinical Utility of Caduet in Simultaneously Achieving Blood Pressure and Lipid End Points (CAPABLE) trial studied attainment of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) goals by 8 flexibly titrated doses (5/10-10/80 mg) of amlodipine/atorvastatin single pill in 494 African Americans with hypertension and dyslipidemia, according to the presence of diabetes +/- the metabolic syndrome. In 169 diabetic patients, the metabolic syndrome was associated with poorer BP goal attainment (38.5% vs 48.5% in diabetic patients without the metabolic syndrome). Among diabetic patients (+/- the metabolic syndrome) 61% to 62% reached LDL-C goal. More than 60% of patients with diabetes uncontrolled for LDL-C were maintained on suboptimal atorvastatin therapy (mean final dose: 29.9 mg vs maximum of 80 mg). Reluctance to intensify therapy to attain accepted targets in high-risk individuals suggests a degree of clinical inertia not explained by objective evidence of dose-dependent intolerance.

Atrial fibrillation and ethnicity: the known, the unknown and the paradox

Current understanding of the pathophysiology and epidemiology of atrial fibrillation (AF) is based primarily on studies in White populations of European ancestry with limited data on the non-White populations. Many traditional and novel risk factors for AF have been already established. However, little is known about the differential impact of these AF risk factors in non-White versus White populations. Few studies have compared the prevalence and incidence of AF in Black versus White individuals, and still fewer extended this comparison to other races and ethnicities. These few studies consistently reported that Black individuals have lower AF burden compared with their White counterparts. These findings are not consistent with the reported high stroke rates in Black populations and the strong association between stroke and AF. In this perspective we argue that differential AF underascertainment among different racial and ethnic groups may be the key in explaining this paradox of racial/ethnic distribution of AF. Results from recent publications suggest that Black individuals would have higher rates of AF if more sensitive AF detection methods are used. Although these findings do not reach the level of definitive evidence, they may support the need for rethinking the epidemiology of AF across races and ethnicities in the context of the limited methodology available to detect AF, as well as the questionable assumption that the ability to diagnose AF across different racial/ethnic groups is the same.

The sensitivity of the method used to detect atrial fibrillation in population studies affects group-specific prevalence estimates: ethnic and regional distribution of atrial fibrillation in the REGARDS study

BACKGROUND

Among African-Americans, and in southern US states, the rates of stroke are high but the reported prevalences of atrial fibrillation (AF) are low. We hypothesized that the reported ethnic and regional distributions of AF are affected by the sensitivity of the methods that were used to detect AF in previous reports.

METHODS

A total of 18,833 black and white participants from the US national REasons For Geographic And Racial Differences In Stroke (REGARDS) study were included in this analysis. Levels of sensitivity to detect AF, from least to most sensitive, were created for combinations of self-report (SR) and ECG methods, as follows: (1) SR plus ECG, (2) ECG alone, (3) SR alone, and (4) SR or ECG. Geographic regions were dichotomized as Stroke Belt (the southern US states) and non-Stroke Belt. Logistic regression analysis estimated the odd ratios of AF associated with the Stroke Belt and black ethnicity for each diagnostic combination.

RESULTS

Residence in the Stroke Belt was significantly associated with AF when diagnosed by SR plus ECG (multivariable-adjusted OR, 0.66; 95% CI, 0.47 to 0.92), but not when diagnosed with SR or ECG (OR, 0.95; 95% CI, 0.85 to 1.06). Similarly, for the 4 methods used to detect AF, the strength of the association between black ethnicity and AF progressively decreased with increasing test sensitivity (ORs: 0.20, 0.40, 0.70, 0.71, respectively).

CONCLUSIONS

The association of AF with residence in the Stroke Belt and black ethnicity was inversely related to the sensitivity of the method used to detect AF: as test sensitivity increased, the association became attenuated. This may partially explain the lower reported prevalence of AF in populations and regions with higher stroke rates.

Adaptive variation regulates the expression of the human SGK1 gene in response to stress

The Serum and Glucocorticoid-regulated Kinase1 (SGK1) gene is a target of the glucocorticoid receptor (GR) and is central to the stress response in many human tissues. Because environmental stress varies across habitats, we hypothesized that natural selection shaped the geographic distribution of genetic variants regulating the level of SGK1 expression following GR activation. By combining population genetics and molecular biology methods, we identified a variant (rs9493857) with marked allele frequency differences between populations of African and European ancestry and with a strong correlation between allele frequency and latitude in worldwide population samples. This SNP is located in a GR-binding region upstream of SGK1 that was identified using a GR ChIP-chip. SNP rs9493857 also lies within a predicted binding site for Oct1, a transcription factor known to cooperate with the GR in the transactivation of target genes. Using ChIP assays, we show that both GR and Oct1 bind to this region and that the ancestral allele at rs9493857 binds the GR-Oct1 complex more efficiently than the derived allele. Finally, using a reporter gene assay, we demonstrate that the ancestral allele is associated with increased glucocorticoid-dependent gene expression when compared to the derived allele. Our results suggest a novel paradigm in which hormonal responsiveness is modulated by sequence variation in the regulatory regions of nuclear receptor target genes. Identifying such functional variants may shed light on the mechanisms underlying inter-individual variation in response to environmental stressors and to hormonal therapy, as well as in the susceptibility to hormone-dependent diseases.

Age-related changes in dorsal root ganglia, circulating and vascular calcitonin gene-related peptide (CGRP) concentrations in female rats: effect of female sex steroid hormones

The aim of the present study is to investigate whether immunoreactive (I) calcitonin gene-related peptide (CGRP) content is decreased in plasma and mesenteric arteries (resistance arteries) in middle-aged rats and if so, whether sex steroid hormones enhance I-CGRP in middle-aged female rats. We also examined whether vascular CGRP receptor components, calcitonin receptor like receptor (CRLR) and receptor activity modifying protein 1 (RAMP1) are elevated by sex steroid hormones treatment in middle-aged female rats. Young adult (3 months old) and middle-aged (10-12 months old) ovariectomized rats were treated subcutaneously with estradiol-17beta (E2; 2 mg), progesterone (P4; 5 mg), E2+P4 (2 mg+20 mg) or placebo (control). Radioimmunoassay and Western blot analysis were performed to measure I-CGRP content and CGRP receptor components in dorsal root ganglia (DRG), in resistance arteries and in plasma. Immunofluorescent staining methods were employed to determine cellular localization of CRLR, RAMP1 in resistance arteries. Our data demonstrated that I-CGRP content was significantly (p<0.05) lower in the plasma and resistance arteries of middle-aged female rats compared to young controls. Both RAMP1 and CRLR were concentrated in vascular endothelium and the underlying smooth muscle cells. RAMP1 but not CRLR appeared to be decreased in middle-aged rat vasculature. Chronic perfusion of sex steroid hormones to ovariectomized rats: 1 significantly (p<0.05) elevated I-CGRP in the DRG and in the plasma, and (2) significantly elevated RAMP1 (p<0.05) but did not alter CRLR in resistance arteries. These data suggest that female sex steroid treatment enhances I-CGRP and its receptors, and thus regulate the blood pressure in aged female rats.

Cross sectional study of childhood obesity and prevalence of risk factors for cardiovascular disease and diabetes in children aged 11-13

Background

Childhood obesity levels are rising with estimates suggesting that around one in three children in Western countries are overweight. People from lower socioeconomic status and ethnic minority backgrounds are at higher risk of obesity and subsequent CVD and diabetes.

Within this study we examine the prevalence of risk factors for CVD and diabetes (obesity, hypercholesterolemia, hypertension) and examine factors associated with the presence of these risk factors in school children aged 11–13.

Methods and design

Participants will be recruited from schools across South Wales. Schools will be selected based on catchment area, recruiting those with high ethnic minority or deprived catchment areas. Data collection will take place during the PE lessons and on school premises. Data will include: anthropometrical variables (height, weight, waist, hip and neck circumferences, skinfold thickness at 4 sites), physiological variables (blood pressure and aerobic fitness (20 metre multi stage fitness test (20 MSFT)), diet (self-reported seven-day food diary), physical activity (Physical Activity Questionnire for Adolescents (PAQ-A), accelerometery) and blood tests (fasting glucose, insulin, lipids, fibrinogen (Fg), adiponectin (high molecular weight), C-reactive protein (CRP) and interleukin-6 (IL-6)). Deprivation at the school level will be measured via information on the number of children receiving free school meals. Townsend deprivation scores will be calculated based on the individual childs postcode and self assigned ethnicity for each participating child will be collected. It is anticipated 800 children will be recruited. Multilevel modeling will be used to examine shared and individual factors associated with obesity, stratified by ethnic background, deprivation level and school.

Discussion

This study is part of a larger project which includes interviews with older children regarding health behaviours and analysis of existing cohort studies (Millennium cohort study) for factors associated with childhood obesity.

The project will contribute to the evidence base needed to develop multi-dimensional interventions for addressing childhood obesity.

Physical Activity and Fitness in African Americans: Implications for Cardiovascular Health

The prevalence of cardiovascular disease (CVD), obesity, diabetes mellitus, hypertension, and physical inactivity is significantly higher in African Americans. The higher prevalence of these important risk factors is thought to be largely responsible for the higher CVD mortality rate in blacks. Limited evidence suggests that the aerobic power of African Americans may be inherently lower than that of whites. This apparent deficiency may be explained, in part, by differences in muscle oxidative capacity but is poorly understood. Studies have shown a lower prevalence of overweight/obesity, the metabolic syndrome, and insulin resistance with higher levels of physical activity/fitness. Training studies have shown that increasing physical activity and/or fitness positively affects metabolic risk factors, body composition, and insulin sensitivity. The few studies of African Americans suggest that they respond to exercise training in a manner similar to whites. Controlling blood pressure of hypertensive blacks at levels comparable with that of whites could result in more than 7000 fewer deaths from CVD. Physical fitness has been shown to be negatively associated with blood pressure in African Americans, but results from interventional studies have been equivocal. Some evidence suggests that increased physical activity and/or fitness may reduce the blood pressure response to submaximal exercise and other stressors in African Americans. Blacks have higher levels of high-density lipoprotein cholesterol (HDL-C) and lower levels of total cholesterol, triglycerides, and small dense low-density lipoprotein particles. Studies suggest that the blood lipid response to exercise training is similar between African Americans and whites. There may be an intensity threshold of 75% of age-predicted maximal heart rate to elicit significant changes in HDL-C. More research is needed to explore the association between physical activity/fitness and CVD risk factors in this population.

Endothelial dysfunction in African-Americans

The journey of atherosclerosis begins with endothelial dysfunction and culminates into its most fearful destination producing ischemia, myocardial infarction and death. The excess cardiovascular disease morbidity and mortality in African-Americans is one of the major public health problems. In this review, we discuss vascular endothelial dysfunction as a key element for excess cardiovascular disease burden in this target population. It can be logical window of future atherosclerotic outcomes, and further efforts should be made to detect it at the earliest in African American individuals even if they are appearing healthy as the therapeutic interventions if instituted early, might prevent the subsequent cardiac events.

An international matched cohort study of the contribution of metabolic impairments to subclinical atherosclerosis in United Kingdom and Jamaican African-Caribbeans

BACKGROUND

A gradient of increased vascular risk exists across the African diaspora. We hypothesised that increased insulin resistance with environmental transition contributes to this risk.

METHODS

The study was undertaken in 73 healthy African-Caribbeans in the UK and 151 age and sex matched African-Caribbeans in Jamaica. Body mass index (BMI), fasting insulin, insulin resistance, carotid intima media thickness (CIMT) and endothelium dependent vasodilatation (EDV) were compared. CIMT was measured ultrasonographically in the distal 1cm of both common carotid arteries. EDV was measured the absolute change from baseline in the Reflection index (RI) of the digital volume pulse during intravenous infusion of albuterol (DeltaRI(ALB)).

RESULTS

UK African-Caribbeans had greater CIMT (mean difference 0.124 [95% C.I. 0.075-0.173] mm, p<0.0001) and decreased EDV (mean difference in DeltaRI(ALB) 5.1 [95% C.I. 2.5-7.6] percentage points, p<0.0001). This was associated with higher insulin concentrations (mean difference 1.6 [95% C.I. 1.3-4.1] microU/mL, p=0.038) and greater HOMA score (2.8 versus 2.0; p=0.035) despite no significant differences in BMI (28.8 versus 27.6; p=0.168) or the waist to hip ratio (0.86 versus 0.85; p=0.188). HOMA scores correlated positively with CIMT (r=0.35, p=0.01) and negatively with DeltaRI(ALB) (r=-0.17; p=0.02) in UK, but not in Jamaican, African-Caribbeans. A significant interaction was seen between HOMA and UK domicile for CIMT (p<0.0001) and between fasting insulin and UK domicile for DeltaRI(ALB) (p<0.0001).

CONCLUSIONS

Increased insulin resistance, associated with living in a nutritionally enriched environment, may contribute to early subclinical atherosclerosis in UK African-Caribbeans.