Effects of Lifestyle Modification on Telomerase Gene Expression in Hypertensive Patients: A Pilot Trial of Stress Reduction and Health Education Programs in African Americans.

BACKGROUND: African Americans suffer from disproportionately high rates of hypertension and cardiovascular disease. Psychosocial stress, lifestyle and telomere dysfunction contribute to the pathogenesis of hypertension and cardiovascular disease. This study evaluated effects of stress reduction and lifestyle modification on blood pressure, telomerase gene expression and lifestyle factors in African Americans. METHODS: Forty-eight African American men and women with stage I hypertension who participated in a larger randomized controlled trial volunteered for this substudy. These subjects participated in either stress reduction with the Transcendental Meditation technique and a basic health education course (SR) or an extensive health education program (EHE) for 16 weeks. Primary outcomes were telomerase gene expression (hTERT and hTR) and clinic blood pressure. Secondary outcomes included lifestyle-related factors. Data were analyzed for within-group and between-group changes. RESULTS: Both groups showed increases in the two measures of telomerase gene expression, hTR mRNA levels (SR: p< 0.001; EHE: p< 0.001) and hTERT mRNA levels (SR: p = 0.055; EHE: p< 0.002). However, no statistically significant between-group changes were observed. Both groups showed reductions in systolic BP. Adjusted changes were SR = -5.7 mm Hg, p< 0.01; EHE = -9.0 mm Hg, p < 0.001 with no statistically significant difference between group difference. There was a significant reduction in diastolic BP in the EHE group (-5.3 mm Hg, p< 0.001) but not in SR (-1.2 mm Hg, p = 0.42); the between-group difference was significant (p = 0.04). The EHE group showed a greater number of changes in lifestyle behaviors. CONCLUSION: In this pilot trial, both stress reduction (Transcendental Meditation technique plus health education) and extensive health education groups demonstrated increased telomerase gene expression and reduced BP. The association between increased telomerase gene expression and reduced BP observed in this high-risk population suggest hypotheses that telomerase gene expression may either be a biomarker for reduced BP or a mechanism by which stress reduction and lifestyle modification reduces BP. TRIAL REGISTRATION: ClinicalTrials.gov NCT00681200.

Obesity and Cardiovascular Diseases in a High-Risk Population: Evidence-Based Approach to CHD Risk Reduction.

BACKGROUND: Obesity is becoming a worldwide public health problem and it is expected to worsen as its prevalence is increasing in children and adolescents. This report examined the distribution of major cardiovascular disease (CVD) risk factors and the effect of life-style changes on coronary heart disease (CHD) risk prediction in a high risk obese African Americans. METHODS: We examined the baseline distribution of CVD risk factors in 515 obese African Americans, with mean BMI of 42.9 ± 6.8 kg/m2, and prospectively the effect of a 6-month low-salt, low-fat diet and aerobic-exercise intervention program on risk reduction. RESULTS: Prevalence of hypertension, dyslipidemia, and diabetes mellitus were 57%, 27% and 24% respectively. Metabolic syndrome was present in 36% and 39% met two features of the syndrome. The 10-year risk prediction for developing CHD ranged from 4% to 17% for women and 6% to 29% for men. After 6 months of life-style changes, many of the risk factors improved, and the CHD risk scores decreased from 6% to 4% in the women and 16% to 13% in the men. CONCLUSION: The high prevalence and increasing incidence of obesity and associated cardiovascular risk emphasizes the need to focus on obesity reduction in this high risk population.

Effect of intensive blood pressure control on cardiovascular remodeling in hypertensive patients with nephrosclerosis.

Pulse pressure (PP), a marker of arterial system properties, has been linked to cardiovascular (CV) complications. We examined (a) association between unit changes of PP and (i) composite CV outcomes and (ii) development of left-ventricular hypertrophy (LVH) and (b) effect of mean arterial pressure (MAP) control on rate of change in PP. We studied 1094 nondiabetics with nephrosclerosis in the African American Study of Kidney Disease and Hypertension. Subjects were randomly assigned to usual MAP goal (102-107 mmHg) or a lower MAP goal (≤92 mmHg) and randomized to beta-blocker, angiotensin converting enzyme inhibitor, or calcium channel blocker. After covariate adjustment, a higher PP was associated with increased risk of CV outcome (RR = 1.28, CI = 1.11-1.47, P < 0.01) and new LVH (RR = 1.26, CI = 1.04-1.54, P = 0.02). PP increased at a greater rate in the usual than in lower MAP groups (slope ± SE: 1.08 ± 0.15 versus 0.42 ± 0.15 mmHg/year, P = 0.002), but not by the antihypertensive treatment assignment. Observations indicate that control to a lower MAP slows the progression of PP, a correlate of cardiovascular remodeling and complications, and may be beneficial to CV health.

The metabolically healthy but obese phenotype in African Americans.

Obesity has become one of the leading public health concerns in the United States and worldwide. While obesity is associated with the metabolic syndrome, some obese individuals do not possess the constellation of the metabolic abnormalities and are referred to as metabolically healthy but obese (MHO) persons. Limited data exist on the prevalence and characteristics of the MHO in African Americans. The authors studied 126 obese African Americans and defined the MHO phenotype as an individual with a body mass index ≥30 kg/m(2) , high-density lipoprotein cholesterol ≥40 mg/dL, absence of type 2 diabetes mellitus, and absence of arterial hypertension. The correlates of the MHO phenotype with anthropometrical and metabolic indices were examined, as well as the effect of age on these correlates. Results showed that 36 (28.5%) of the individuals were identified with the MHO phenotype. Waist circumference (WC) and waist-to-hip ratio (WHR) were significantly lower (P<.05) in MHO than in non-MHO patients. While there were significant lower levels of low-density lipoprotein and triglycerides in MHO among patients younger than 40 years, the significance was lost among patients 40 years or older. This study indicates that increased WC and WHR may be early premetabolic syndrome markers in obese individuals and should warrant aggressive risk factor reduction therapy to prevent future development of related cardiovascular conditions.

Nocturnal blood pressure nondipping in obese African-Americans.

OBJECTIVES: Nondipping pattern of circadian blood pressure (BP) is associated with increased cardiovascular morbidity and mortality; however, limited data are available among obese African-Americans. We, therefore, aimed to evaluate the pattern of circadian BP variation and to identify clinical conditions associated with nondipping in this population. METHODS: A total of 211 obese African-Americans enrolled in a weight-reduction program underwent 24-h ambulatory BP monitoring. Nondipping was defined as a nocturnal BP reduction of less than 10%. RESULTS: Systolic BP (SBP) nondipping was present in 158 participants (74.9%) and diastolic BP (DBP) nondipping was present in 93 participants (44.1%). In multivariate logistic regression analyses, diabetes was associated with SBP nondipping (adjusted OR, 2.53; CI: 1.16-5.76; P=0.02), and increasing BMI (5 kg/m) was associated with DBP nondipping (adjusted OR, 1.46; CI: 1.17-1.83; P=0.001). In linear regression analyses, BMI was positively correlated to office, 24-h, daytime, and night-time SBP (P=0.03, 0.01, 0.03, and 0.005, respectively) and office, 24-h, daytime, and night-time PP (P=0.01, P<0.001, 0.001, and P=0.003, respectively). CONCLUSION: This study demonstrated an excessively high prevalence of nondippers and independent associations between diabetes and SBP nondipping and between BMI and DBP nondipping in an obese African-American population.

The relationship between flow-mediated dilatation of the brachial artery and intima-media thickness of the carotid artery to Framingham risk scores in older African Americans.

The objective of this study was to investigate the relationship of flow-mediated dilatation and intima-media thickness (IMT) with coronary risk in African Americans (AAs). Endothelial dysfunction and IMT of carotid arteries are considered early steps in atherosclerotic disease process and have been used as surrogate markers of subclinical atherosclerosis. Data were collected on 106 AAs with a mean age of 64.0+/-6.6 years. Carotid artery IMT was measured with B-mode ultrasonography, as was brachial artery diameter at rest, during reactive hyperemia, and after nitroglycerin. Percent change in flow-mediated dilatation (%FMD) was defined as 100x(diameter during reactive hyperemia - resting diameter)/resting diameter. Percent change in nitroglycerin-mediated dilatation (%NMD) was defined as 100x(diameter with nitroglycerin-resting diameter)/resting diameter. The Framingham 10-year risk score (FRS) was calculated for each patient using the National Cholesterol Education Program (NCEP) risk score calculator and participants were categorized into 3 groups with FRS as <10%, 10% to 20%, and >20%. Thirty-eight participants had risk scores <10%, 26 had 10% to 20%, and 42 >20%. There was a significant inverse relation between %FMD and FRS (P<.0001) and between %NMD and FRS (P<.001). IMT was not statistically different among the risk groups. Endothelial dysfunction assessed by FMD significantly correlates inversely with FRS in AAs. FMD, an index of arterial compliance, appears to be a sensitive and reliable index of cardiovascular disease.

Effect of diet and exercise on pulse pressure and cardiac function in morbid obesity: analysis of 24-hour ambulatory blood pressure.

Blood pressure is a major risk factor for cardiovascular events, although the role of pulse pressure, an independent predictor of arterial stiffness, has recently been emphasized. This study examines the baseline relationship between body mass index (BMI) and blood pressure indexes in 215 obese African Americans enrolled in a diet-exercise program. The subject population was 77% female, with a mean +/- SD age of 46.7+/-10.7 years and a mean BMI of 42.5+/-7.5 kg/m2. In addition, the authors prospectively examined the effect of weight loss on cardiovascular parameters in a subset of 25 participants. The results show a closer significant correlation between pulse pressure and BMI (b=1.97 kgm-1; p=0.001) than between systolic blood pressure and BMI (b=1.58 kgm-1; p=0.020). After 3 months of diet and exercise, average reductions were as follows: BMI, 4.2 kg/m2 (p<0.01); systolic blood pressure, 7.2 mm Hg (p<0.01); pulse pressure, 4.8 mm Hg (p<0.01); and cardiac output, 975 mL/min (p<0.01). Compliance index increased by 0.1 mL/mm Hg/m2 (p=0.03). The results highlight the potential value to cardiovascular health of a modest reduction in body weight in obese individuals.

Obese African Americans: the prevalence of dyslipidemia, hypertension, and diabetes mellitus.

CONTEXT: The prevalence of the cardiovascular disease risk factors, dyslipidemia, hypertension, and diabetes mellitus, is increased in the setting of obesity. OBJECTIVE: To determine whether the prevalence of these risk factors increases with increasing body mass index in an obese cohort, or whether there is a threshold for their appearance. DESIGN AND SETTING: Individuals with body mass index > or = 30 kg/m2 joined a weight reduction program in the Howard University General Clinical Research Center. PARTICIPANTS: Five hundred fifteen African Americans (aged 12-74 years, mean body mass index of 42.8 +/- 8.5 kg/m2). OUTCOME MEASURES: The cohort was divided by incremental increases in body mass index of 4.99 kg/m2, and the prevalence rates of hypertension (blood pressure > or = 140/90 mm Hg), dyslipidemia (total cholesterol > 200 mg/dL, or low-density lipoprotein > 130 mg/dL, or elevated ratio of total or low-density to high-density lipoprotein cholesterol) and diabetes mellitus (fasting blood glucose > or = 126 mg/dL or random blood glucose > 200 mg/dL) were determined for each group. RESULTS: The cohort prevalence rates were: dyslipidemia, 27.0%; hypertension, 56.9%; and diabetes mellitus, 24.1%. These rates are higher than those found in the African-American population by the third National Health and Nutrition Examination Survey. After adjusting for age and sex, there were no significant differences in the prevalence rates of these risk factors according to increasing body mass index, suggesting a threshold of between 30 kg/m2-34.99 kg/m2 for maximal appearance of these risk factors. CONCLUSION: The incidence rates of dyslipidemia, hypertension, and diabetes mellitus do not increase with a greater degree of obesity above a body mass index of 34.99 kg/m2.

Response of lipoprotein(a) levels to therapeutic life-style change in obese African-Americans.

Lipoprotein(a) (Lp(a)) is regarded as an independent risk factor for Atherosclerotic cardiovascular disease. The objectives of this study were: to determine the effects of diet and exercise on Lp(a) and to evaluate the relation of Lp(a) with the lipid profile (total serum cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol). Baseline Lp(a), body mass index (BMI) and the lipid profiles were measured in 343 Obese (BMI >30kg/m(2)) African-Americans. After a 3-month intervention of diet and exercise by 105 participants, their lipids were re-measured. Baseline Lp(a) levels ranged from 1.2 to 280mg/dl. Lp(a) was inversely associated with triglyceride (P<0.05). After the intervention, Lp(a) and HDL increased by a mean of 20 and 5%, respectively. Total cholesterol, triglycerides, LDL and BMI decreased by 7, 10, 11 and 8%, respectively. Women taking estrogen replacement had a negligible change in Lp(a) while participants taking HMG-CoA reductase inhibitors had an increase in Lp(a) levels by 30%.