[Show abstract][Hide abstract] ABSTRACT: The diagnosis of metabolic syndrome (MetS) identifies individuals at risk for developing diabetes and cardiovascular disease (CVD). African Americans (AA) have high rates of CVD and subclinical vascular disease including arterial stiffness and microvascular dysfunction but have relatively low rates of MetS.
To evaluate the relationship between MetS and vascular function in a biracial cohort with the hypothesis that the diagnosis of MetS underestimates subclinical vascular disease in AA.
We measured components of MetS in a community-based cohort of 951 AA and white subjects (age 48.8 ± 11 years, 47% AA, 55% female).
Using digital pulse amplitude tonometry (EndoPAT), we estimated the reactive hyperemia index (RHI), a measure of microvascular endothelial function. Using applanation tonometry (Sphygmocor), central augmentation index (CAIx) and pulse wave velocity (PWV) were measured as indices of wave reflections and arterial stiffness, respectively.
MetS was present in 24.0% of subjects and was associated with increased PWV (p<0.001) and CAIx (p<0.001) and trend to lower RHI (p=0.068) in both races. However, in subjects without MetS, AA had lower RHI (p<0.001), higher PWV (p=0.003) and CAIx (p=0.002) compared to white subjects. Addition of an extra MetS criterion point for AA with hypertension eliminated the racial differences in PWV and CAIx, but not RHI.
Although MetS is associated with microvascular dysfunction and increased arterial stiffness in both racial groups, AA without MetS have greater vascular dysfunction compared to whites. Additional weighting for hypertension in AA attenuated the racial differences in subclinical disease associated with MetS.
The Journal of Clinical Endocrinology and Metabolism 07/2015; DOI:10.1210/JC.2014-4344 · 6.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Imagine a world where we are able to prevent and pre-empt the burden of cardiovascular, lung, and blood diseases; a world where we are able to capture the promise of personalized precision medicine, where each person receives the right treatment, tailored to their needs, at the right time. In this new world, what if we were able to realize a stroke-free generation of individuals living with sickle cell disease (SCD), what if we were able to eliminate health inequities (both domestic and global) with effective and rapid uptake of evidence-based practices and tools, and what if we could expand the frontiers of scientific knowledge and revolutionize how we diagnose, prevent, and treat disease by leveraging the power of big scientific data systems? This vision is not merely a collection of idle dreams; the boundless possibilities of this bold new world are well within our reach. (Am J Public Health. Published online ahead of print March 19, 2015: e1-e4. doi:10.2105/AJPH.2015.302605).
[Show abstract][Hide abstract] ABSTRACT: Background:
Low vitamin D and adiponectin levels are both associated with obesity and cardiovascular disease. Previous studies have indicated that vitamin D levels are directly associated with adiponectin, and that this association varies across body mass index (BMI) categories; stronger with increasing BMI. Few studies examined this association in African-Americans (AA), known to have lower levels of vitamin D and adiponectin, and in whites.
We assessed whether serum vitamin D is associated with serum adiponectin in a biracial population-based sample. Cross-sectional analyses were performed on 426 non-diabetic participants (218 whites and 208 AA) from the META-Health Study, a random sample from the metro Atlanta. Age-adjusted correlations and multivariable linear regression were used for analyses. We investigated the effect modification of the BMI categories of lean, overweight, and obese as defined by standard cut-points (25 and 30 kg/m(2)).
The mean (SD) age of our study sample was 50.5 (9) years. The mean (SD) levels of vitamin D were 27.4 (9.8) ng/mL in white women, 25.5 (9.3) ng/mL in white men, 16.9 (7.3) ng/mL in AA women, and 18.8 (7.3) ng/mL in AA men. The mean (SD) levels of adiponectin were 17.0 (17.1) μg/mL in white women, 9.9 (11.3) μg/mL in white men, 6.6 (4.8) μg/mL in AA women, and 9.4 (11.6) μg/mL in AA men. Among lean white women (n = 63), there was a significant direct association between vitamin D and adiponectin (β = 0.02, p = 0.04) after adjustment for age, systolic blood pressure, HDL-cholesterol, triglycerides, income, and season of blood drawing. On the contrary, in lean AA women (n = 23), there was a significant inverse association (β = -0.06, p = 0.01).
The association of vitamin D and adiponectin is dependent on race, gender, and BMI category. Among lean white women, there was a significant direct association, whereas in lean AA women the association was inverse. No association was present among obese individuals.
Frontiers in Public Health 10/2014; 2:193. DOI:10.3389/fpubh.2014.00193
[Show abstract][Hide abstract] ABSTRACT: Vitamin D deficiency has been implicated as a potential risk factor for cardiovascular disease. The high rate of vitamin D deficiency (<30 ng/ml) exhibited by African Americans may account for some of the excess prevalence of cardiovascular morbidity and mortality in this vulnerable US population. Vitamin D supplementation may reduce the risk of cardiovascular disease by ameliorating the onset and progression of arterial stiffness, a strong predictor of cardiovascular mortality, usually assessed by pulse wave velocity and augmentation index. Very few prospective studies have evaluated the effect of vitamin D supplementation on the inflammatory and oxidative stress mediators of arterial stiffness.
In a double blind randomized placebo controlled study we evaluated the effect of a monthly dose of 100,000IU of vitamin D3 for three months on the level of serum 25(OH)D, intact parathyroid hormone (PTH), urinary isoprostane, adipocyte cytokine expression and arterial stiffness among 130 overweight and obese (BMI > 25) African Americans with elevated blood pressure (130 - 150/85 - 100 mmHg) and low serum vitamin D level (10 - 25 ng/ml).
There was a significant increase in the serum 25(OH)D levels to a mean level of 34.5 ng/ml (SD = 7.1) with the intervention (p < 0.001). The increase in 25(OH)D levels was associated with a significant decrease in the serum level of intact PTH (p = 0.02), mean urinary isoprostane (p = 0.02) and adipocyte cytokine expression. Although the increase in the 25(OH)D levels was not associated with any significant change in the Pulse Wave Velocity (PWV) in the overall study sample, it was associated with a significant decrease in the augmentation index among the participants with the highest tertile of urinary isoprostane (p = 0.007).
We concluded that vitamin D supplementation increased serum 25(OH)D levels, decreased intact PTH level and the levels of select inflammatory and oxidative stress mediators of arterial stiffness. Longer term prospective studies are warranted to evaluate the effect of high dose vitamin D supplementation on arterial stiffness.
Health 06/2014; 2014(12). DOI:10.4236/health.2014.612185 · 0.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To assess the associations of social determinants on cardiovascular health among White and Black residing in Stroke Belt (urban) and Stroke Buckle (rural) regions of the South.
A cross-sectional observational analysis based on a random digit-dial telephone survey of a representative sample of White and Black adults residing in urban and rural Georgia conducted from 2004-2005. Separate logistic regression analyses examined the effects of social determinants on cardiovascular health within and between White and Black women and within and between urban and rural residential location. The main outcome measure was poor cardiovascular health defined as > or = 2 self-reported clinical cardiovascular disease risk factors (hypertension, diabetes, elevated cholesterol, overweight or obese). Social determinants were defined as socioeconomic status (SES), general daily stress, racial discrimination, and stress due to exposure to racial discrimination. Significance was established as a two-tailed P < .05.
A total of 674 White and Black women aged 18-90 years were included in the sample. Results showed Black women with lower SES had worse cardiovascular health than White women in both rural and urban areas (rural odds ratio [OR] 2.68; confidence interval [CI] 1.44, 4.90; P = .001; urban OR = 2.92; CI = 1.62, 5.23; P = .0003). White women reporting high or very high exposure to general daily stress where more likely to have worse cardiovascular health than White women reporting very little to no daily stress (OR = 2.85; CI = 1.49, 5.44; P = .001).
Our findings demonstrate the importance of social determinants associated with cardiovascular health. Tailored cardiovascular risk reduction intervention is needed among lower SES Black women in Stroke Belt and Buckle regions of the South, as well as stress-reduction intervention among White women in the South.
[Show abstract][Hide abstract] ABSTRACT: Background: Compared with European Americans, African Americans (AAs) exhibit lower levels of the cardio-metabolically protective adiponectin even after accounting for adiposity measures. Because few studies have examined in AA the association between adiponectin and genetic admixture, a dense panel of ancestry informative markers (AIMs) was used to estimate the individual proportions of European ancestry (PEA) for the AAs enrolled in a large community-based cohort, the Jackson Heart Study (JHS). We tested the hypothesis that plasma adiponectin and PEA are directly associated and assessed the interaction with a series of cardio-metabolic risk factors.
Methods: Plasma specimens from 1439 JHS participants were analyzed by ELISA for adiponectin levels. Using pseudo-ancestral population genotype data from the HapMap Consortium, PEA was estimated with a panel of up to 1447 genome-wide preselected AIMs by a maximum likelihood approach. Interaction assessment, stepwise linear and cubic multivariable-adjusted regression models were used to analyze the cross-sectional association between adiponectin and PEA.
Results: Among the study participants (62% women; mean age 48 ± 12 years), the median (interquartile range) of PEA was 15.8 (9.3)%. Body mass index (BMI) (p = 0.04) and insulin resistance (p = 0.0001) modified the association between adiponectin and PEA. Adiponectin was directly and linearly associated with PEA (β = 0.62 ± 0.28, p = 0.03) among non-obese (n = 673) and insulin sensitive participants (n = 1141; β = 0.74 ± 0.23, p = 0.001), but not among those obese or with insulin resistance. No threshold point effect was detected for non-obese participants.
Conclusions: In a large AA population, the individual proportion of European ancestry was linearly and directly associated with plasma adiponectin among non-obese and non insulin-resistant participants, pointing to the interaction of genetic and metabolic factors influencing adiponectin levels.
Frontiers in Genetics 02/2014; 5:22. DOI:10.3389/fgene.2014.00022
[Show abstract][Hide abstract] ABSTRACT: Background
The purpose of this study was to assess the effects of a comprehensive lifestyle intervention on modifiable cardiovascular risk factors among high-risk African Americans.
The study included a randomized treatment/controlled intervention trial among 136 African Americans residing in Atlanta, GA who were overweight and had elevated blood pressure. The treatment group was exposed to 3-months of a multi-component intervention and the control to an abbreviated 6-week intervention after the completion of the treatment group’s intervention. The main outcomes included mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP), mean waist circumference, mean body mass index (BMI), mean number of times exercise per week, mean number of servings of fruits and vegetables per day, and mean level of daily stress. Data were collected at baseline and at 6-month follow-up. Separate linear regressions were used with an established significance level of p < 0.05.
Results revealed significant net improvement in treatment group when compared to controls in waist circumference, BMI, times weekly exercise, servings of fruit and vegetables per day (p < 0.001, 0.04, 0.02, 0.002, respectively). Diastolic blood pressure also significantly improved within the treatment group for overall hypertensives from baseline to 6-month follow-up (90.9 mmHg to 83.1 mmHg, p = 0.002).
These results show that a comprehensive lifestyle intervention can improve cardiovascular risk factor profile among high risk African Americans. Caregivers should encourage patients to participate in such programs and public health policymakers should allocate resources to community based health oriented organizations to implement comprehensive lifestyle program.
Open Journal of Preventive Medicine 12/2013; 3(9):526-533. DOI:10.4236/ojpm.2013.39071
[Show abstract][Hide abstract] ABSTRACT: Objectives
Psychological stress may play a role in metabolic syndrome. A consequence of metabolic syndrome is endothelial dysfunction, which is also influenced by psychological stress. We sought to compare the effect of consciously resting meditation (CRM), a sound based meditation, with a control intervention of health education (HE) on endothelial function in the setting of metabolic syndrome.Methods
Sixty-eight black Americans with metabolic syndrome risk factors (age, 30-65 years) were randomized to either CRM (n = 33) or HE (n = 35); interventions were matched for frequency and duration of sessions and lasted 12 months. Endothelial function was assessed by brachial artery flow-mediated dilation at baseline and at 6 and 12 months. Arterial elasticity, metabolic risk factors, and psychosocial and behavioral variables were secondary end points.ResultsAlthough flow-mediated dilation improved in the CRM group for 12 months, this increase was not significantly higher than that in the HE group (p = .51 for the interaction between group and time). Non-endothelium-dependent dilation and arterial elasticity did not change in either group. Most metabolic syndrome risk factors showed beneficial trends in the CRM group only. A risk factor score counting the number of metabolic syndrome components decreased in the CRM group only (p = .049 for the interaction between treatment group and time).Conclusions
Among black Americans with metabolic syndrome risk factors, CRM, did not improve endothelial function significantly more than a control intervention of HE. CRM resulted in favorable trends in metabolic syndrome risk factors, which were examined as secondary outcomes.
Psychosomatic Medicine 06/2013; 75(6). DOI:10.1097/PSY.0b013e31829ac4f4 · 3.47 Impact Factor