Predictors of racial differences in weight loss: the PROPEL trial

OBJECTIVE

Studies have consistently shown that African American individuals lose less weight in response to behavioral interventions, but the mechanisms leading to this result have been understudied.

METHODS

Data were derived from the PROmoting Successful Weight Loss in Primary CarE in Louisiana (PROPEL) study, which was a cluster-randomized, two-arm trial conducted in primary care clinics. In the PROPEL trial, African American individuals lost less weight compared with patients who belonged to other racial groups after 24 months. In the current study, counterfactual mediation analyses among 445 patients in the intervention arm of PROPEL were used to determine which variables mediated the relationship between race and weight loss. The mediators included treatment engagement, psychosocial, and lifestyle factors.

RESULTS

At 6 months, daily weighing mediated 33% (p = 0.008) of the racial differences in weight loss. At 24 months, session attendance and daily weighing mediated 35% (p = 0.027) and 66% (p = 0.005) of the racial differences in weight loss, respectively. None of the psychosocial or lifestyle variables mediated the race-weight loss association.

CONCLUSIONS

Strategies specifically targeting engagement, such as improving session attendance and self-weighing behaviors, among African American individuals are needed to support more equitable weight losses over extended time periods.

Clinical trial participation among underserved communities: Insights from the Louisiana Community Engagement Alliance

BACKGROUND

Diverse, equitable and inclusive participation in clinical research is needed to ensure evidence-based clinical practice and lessen disparities in health outcomes. Yet, clinical trial participation remains critically low in minoritized communities, particularly among Blacks. The Louisiana Community Engagement Alliance against COVID-19 Disparities (LA-CEAL) was launched in response to the disproportionate impact of COVID-19 on Black Louisianans to understand community barriers and preferences and increase inclusive participation in research. This study aims to understand perceptions regarding COVID-19 trial participation among underrepresented Louisianans.

METHODS

A rapid assessment integrating cross-sectional, surveys among federally qualified health center (FQHC) patients and community residents, and focus group discussions (FGDs) from community representatives was conducted in 2020-2021. Factors and perceptions underlying trial participation were identified using logistic regression models and thematic analyses, respectively.

RESULTS

Quantitative findings (FQHC: N=908, mean age=46.6 years, 66.4% Black; community: N=504, mean age=54.2 years, 93.7% Black) indicated that 0.9% and 3.6%, respectively, ever participated in a COVID-19 trial. Doctors/Healthcare providers were most trusted (FQHC=55.1%; community=59.3%) sources of information about trials. Advancing age was associated with increased odds of being very willing to participate (ORFQHC=1.03, 95% CI 1.02-1.05; ORCommunity=1.02, 95% CI 1.00-1.04). Qualitative data (6 FGDs, 29 attendees) revealed limited awareness, experimentation/exploitation-based fears, and minimal racial/ethnic representation among trialists as barriers to participation.

CONCLUSION

COVID-19 trial participation rates were low in our sample. Altruism was a key facilitator to participation; fear, mistrust, and low awareness were predominant barriers. Community-centered approaches, engaging informed providers and trusted community members, may facilitate inclusive trial participation.

The effect of mobile health technology on blood pressure control among patients with hypertension in Ghana and Nigeria

Background

More than half of patients with hypertension in sub-Saharan African do not achieve blood pressure control. This study determined the effect of mobile health technology on systolic blood pressure reduction and blood pressure (BP) control among patients with hypertension in Nigeria and Ghana.

Methods

A randomised control trial of 225 adults with hypertension attending two General/Medical Outpatient Clinics each in Nigeria and Ghana was randomized into intervention (n = 116) and control (n = 109) arm respectively. Patients in the intervention arm received messages twice weekly from a mobile app for six months in addition to the usual care while the control arm received usual care only. The study outcomes were systolic blood pressure (SBP) reduction and blood pressure control at six months, while the secondary outcome was medication adherence at six months. Data were collected at 0 and 6 months, it was analysed using SPSS-21 software at a significance level of p < 0.05. Binary logistic regression was used to generate the predictors of good blood pressure control.

Results

The mean age for the control and intervention were 60.2 ± 13.5 and 62.6 ± 10.8 years respectively; p-value = 0.300. The intervention group had greater reductions in SBP (-18.7mmHg vs -3.9mmHg; p < 0.001) and greater BP control rate (44.3% vs 24.8%; p-value 0.002).

Conclusions

The mobile health intervention resulted in significant SBP reduction rate and improvement in BP control rate in the 6th month. However, improvement in adherence level in the 3rd month and was not sustained in the 6th month. The addition of mobile health technology may be extended for use in the national hypertension control plan. Female gender, formal education and being in the intervention arm were predictors of blood pressure control.

Medication adherence and blood pressure control: A preliminary assessment of the role of health insurance in Nigeria and Ghana

Objectives

This study sought to assess the current impact of health insurance coverage on medication adherence and blood pressure control of patients being managed for hypertension in Ghana and Nigeria.

Methods

The study was a prospective study among 109 patients with hypertension in two health facilities with similar population dynamics in Ghana and Nigeria. Patients were systematically selected, categorized as having health insurance coverage or not, and followed up monthly for 6 months. The outcome variables (medication adherence and blood pressure control) were then measured and compared at 6 months. Analysis was done using Stata with level of significance set at p ⩽ 0.05.

Results

There was a 90% insurance coverage among participants from Ghana compared to 15% from Nigeria. National Health Insurance Authority enrolees in both countries had better blood pressure control and medication adherence compared to non-enrolees (adjusted odds ratio = 2.6 and 4.5, respectively).

Conclusion

National Health Insurance Authority enrolment was found to be poor among respondents in Nigeria compared to Ghana. Enrolment into the National health financing schemes in both countries led to better blood pressure control and medication adherence among patients with hypertension at primary health facilities. There is therefore the need for system strengthening to improve their sustainability.

Research Infrastructure Core Facilities at Research Centers in Minority Institutions: Part I-Research Resources Management, Operation, and Best Practices

Funded by the National Institutes of Health (NIH), the Research Centers in Minority Institutions (RCMI) Program fosters the development and implementation of innovative research aimed at improving minority health and reducing or eliminating health disparities. Currently, there are 21 RCMI Specialized (U54) Centers that share the same framework, comprising four required core components, namely the Administrative, Research Infrastructure, Investigator Development, and Community Engagement Cores. The Research Infrastructure Core (RIC) is fundamentally important for biomedical and health disparities research as a critical function domain. This paper aims to assess the research resources and services provided and evaluate the best practices in research resources management and networking across the RCMI Consortium. We conducted a REDCap-based survey and collected responses from 57 RIC Directors and Co-Directors from 98 core leaders. Our findings indicated that the RIC facilities across the 21 RCMI Centers provide access to major research equipment and are managed by experienced faculty and staff who provide expert consultative and technical services. However, several impediments to RIC facilities operation and management have been identified, and these are currently being addressed through implementation of cost-effective strategies and best practices of laboratory management and operation.

Evaluation of serum calcium differences in hypertensive crises and control patients: A randomly matched case-control study

The role of calcium in blood pressure has been widely studied among hypertensive patients; however, no study has explored the role of calcium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum calcium levels between hypertensive crises patients and a 1:1 random matched controls (age‐, sex‐, race‐, diabetes, and body mass index matched). This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented calcium level. The control group patients were required to be 18 years of age or older, have a documented calcium level, and have no diagnosis of hypertensive crises. The primary outcome of the study was to compare the mean serum calcium in patients with hypertensive crises vs patients without hypertensive crises. Five hundred and sixty‐six patients were included in the study: 283 patients in both the case group and control group. The primary outcome results showed that serum calcium concentration was not significantly different between the case group (8.99 ± 0.78 mg/dL) and control group (8.96 ± 0.75 mg/dL) (P = .606). This study found no significant difference in serum calcium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of calcium on blood pressure in hypertensive crises.

Ambient Stimuli Perpetuate Nighttime Sleep Disturbances in Hospital Patients With TBI

BACKGROUND AND OBJECTIVES

The effect of the ambient environment, sound, light, and movement, on the nighttime rest-activity of patients hospitalized with moderate-severe traumatic brain injury (TBI) is poorly understood. The purpose of this study was to examine how sound, light, and movement in these patients' hospital rooms may contribute to nighttime awakenings.

METHODS

An observational design was used with 18 adult participants on a neuroscience step-down unit diagnosed with moderate-severe TBI. For up to five consecutive nights, actigraphy was used to capture nighttime awakenings while a custom-made multisensory device captured sound, light, and movement exposures in the participant's room.

RESULTS

Participants were awake for 24% (or about 3 hr) of the time during the designated nighttime period of 8 pm to 8 am. Average nighttime exposures of sound was 52 dB, light was nine lumens, and movement, measured as a proportion, was 0.28% or 28%. With each stimuli exposure set at its average, there was a 20% probability of participant nighttime awakenings. Clinically meaningful reductions of movement in and out the participant's room and elevated sound significantly decreases the participant's probability of nighttime awakenings (p < .05), but reductions in light did not.

CONCLUSION

The ambient environment seems to impede restful sleep in immediate post-injury phase of patients with moderate-severe TBI.

Evaluation of serum magnesium differences in hypertensive crises and control patients: A randomly matched case-control study

Although the role of magnesium in blood pressure has been well studied among hypertensive patients, no study has explored the role of magnesium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum magnesium levels between hypertensive crises patients and matched controls (age‐, sex‐, race‐, and diabetes‐matched) in a 1:1 random match. This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented magnesium level. The control group patients were required to be 18 years of age or older, have no diagnosis of hypertensive crises, and have a documented magnesium level. The primary outcome of the study was to compare the mean serum magnesium in patients with hypertensive crises versus patients without hypertensive crises. Three hundred and fifty‐eight patients were included in the study: 179 patients in both the case group and control group. The primary outcome results showed that serum magnesium concentration was not significantly different between the case group (1.89 ± 0.29 mg/dl) and control group (1.90 ± 0.31 mg/dl) (p = .787). This study found no significant difference in serum magnesium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of magnesium on blood pressure in hypertensive crises.

A1C Reduction in Patients Who Declined Pharmacist-Led Diabetes Management Services

INTRODUCTION

The purpose of this research is to assess the mean change in A1C associated with patients who declined a pharmacy-led diabetes management program and to evaluate effects of predictor variables on the odds of achieving improved A1C in these patients.

STUDY DESIGN

Retrospective, single-center, single-group, cohort study.

METHODS

Patients 18 years or older with uncontrolled type 2 diabetes (defined as A1C ≥ 9%) who declined pharmacy-led diabetes management services were included in the study. The primary outcome of the study was to assess the mean change in A1C from time of phone call offering pharmacy management services (initial) to last observed A1C (final recorded A1C).

RESULTS

A total of 91 patients were included, 46 males and 45 females. The significant reduction in the mean change from baseline A1C to the final measured A1C was -0.59 (95% CI, -0.9327% to -0.2447%, P-value = 0.0010). This resulted in 8.79% of patients' final A1C falling into the range of < 7%.

CONCLUSION

Our study found a paradoxical reduction in A1C among patients who declined pharmacy-led diabetes management services, however, our study is limited by having no comparison group. Further research needs to be conducted to identify correlations between characteristics of patients declining diabetes management services in order to assist with identifying patient-specific methods for improving patient outcomes.

Weight Loss in Underserved Patients - A Cluster-Randomized Trial

BACKGROUND

Evidence of the effectiveness of treatment for obesity delivered in primary care settings in underserved populations is lacking.

METHODS

We conducted a cluster-randomized trial to test the effectiveness of a high-intensity, lifestyle-based program for obesity treatment delivered in primary care clinics in which a high percentage of the patients were from low-income populations. We randomly assigned 18 clinics to provide patients with either an intensive lifestyle intervention, which focused on reduced caloric intake and increased physical activity, or usual care. Patients in the intensive-lifestyle group participated in a high-intensity program delivered by health coaches embedded in the clinics. The program consisted of weekly sessions for the first 6 months, followed by monthly sessions for the remaining 18 months. Patients in the usual-care group received standard care from their primary care team. The primary outcome was the percent change from baseline in body weight at 24 months.

RESULTS

All 18 clinics (9 assigned to the intensive program and 9 assigned to usual care) completed 24 months of participation; a median of 40.5 patients were enrolled at each clinic. A total of 803 adults with obesity were enrolled: 452 were assigned to the intensive-lifestyle group, and 351 were assigned to the usual-care group; 67.2% of the patients were Black, and 65.5% had an annual household income of less than $40,000. Of the enrolled patients, 83.4% completed the 24-month trial. The percent weight loss at 24 months was significantly greater in the intensive-lifestyle group (change in body weight, -4.99%; 95% confidence interval [CI], -6.02 to -3.96) than in the usual-care group (-0.48%; 95% CI, -1.57 to 0.61), with a mean between-group difference of -4.51 percentage points (95% CI, -5.93 to -3.10) (P<0.001). There were no significant between-group differences in serious adverse events.

CONCLUSIONS

A high-intensity, lifestyle-based treatment program for obesity delivered in an underserved primary care population resulted in clinically significant weight loss at 24 months. (Funded by the Patient-Centered Outcomes Research Institute and others; PROPEL ClinicalTrials.gov number, NCT02561221.).

The Research Centers in Minority Institutions (RCMI) Translational Research Network: Building and Sustaining Capacity for Multi-Site Basic Biomedical, Clinical and Behavioral Research

The Research Centers in Minority Institutions (RCMI) program was established by the US Congress to support the development of biomedical research infrastructure at minority-serving institutions granting doctoral degrees in the health professions or in a health-related science. RCMI institutions also conduct research on diseases that disproportionately affect racial and ethnic minorities (ie, African Americans/Blacks, American Indians and Alaska Natives, Hispanics, Native Hawaiians and Other Pacific Islanders), those of low socioeconomic status, and rural persons. Quantitative metrics, including the numbers of doctoral science degrees granted to underrepresented students, NIH peer-reviewed research funding, peer-reviewed publications, and numbers of racial and ethnic minorities participating in sponsored research, demonstrate that RCMI grantee institutions have made substantial progress toward the intent of the Congressional legislation, as well as the NIH/NIMHD-linked goals of addressing workforce diversity and health disparities. Despite this progress, nationally, many challenges remain, including persistent disparities in research and career development awards to minority investigators. The continuing underrepresentation of minority investigators in NIH-sponsored research across multiple disease areas is of concern, in the face of unrelenting national health inequities. With the collaborative network support by the RCMI Translational Research Network (RTRN), the RCMI community is uniquely positioned to address these challenges through its community engagement and strategic partnerships with non-RCMI institutions. Funding agencies can play an important role by incentivizing such collaborations, and incorporating metrics for research funding that address underrepresented populations, workforce diversity and health equity.

Evaluation of Physician Prescribing Patterns For Antibiotics in the Treatment of Nonnecrotizing Skin and Soft Tissue Infections

PURPOSE

Skin and soft tissue infections (SSTIs) cause about 15 million cases of infection that result in more than 869,000 annual hospitalizations in the United States. Cellulitis accounted for 63% of all patients hospitalized with SSTIs between 2009 and 2011. The primary objective of this study was to evaluate physician adherence rates to evidence-based practice guidelines. Secondary objectives included evaluating antibiotic selection preferences and duration of therapy. The goal of the project was to generate data to inform the development of a hospital-based protocol for nonnecrotizing SSTI treatment.

METHODS

This study was a single-center, retrospective, electronic chart review of patients admitted to the hospital for nonnecrotizing SSTI. We reviewed charts of patients who were admitted with a diagnosis of cellulitis and abscess infection from August 2014 to August 2015.

RESULTS

Vancomycin, piperacillin/tazobactam, and clindamycin were the initial empiric antibiotics used most frequently. The adherence rates to guideline-recommended empiric antibiotic therapy and duration of treatment were about 40% and 70%, respectively. The median duration of antibiotic therapy was 12 days. Male gender and presence of purulent discharge as independent variables led to poor adherence to guideline-recommended empiric antibiotic therapy (male versus female gender, 35% versus 50.8%; P = 0.045; purulent discharge [yes versus no], 23.9% versus 60.4%; P < 0.0001).

CONCLUSIONS

The results showed substantial noncompliance with guideline recommendations on empiric antibiotic selection for the treatment of nonnecrotizing SSTIs. There is a substantial opportunity for clinical pharmacist intervention in ensuring the efficient utilization of hospital resources to improve guideline compliance; promote appropriate antibiotic selection; reduce unnecessary antibiotic exposure; and reduce cost of hospitalization.

Development and Validation of Risk Prediction Models for Cardiovascular Events in Black Adults: The Jackson Heart Study Cohort

IMPORTANCE

Cardiovascular risk assessment is a fundamental component of prevention of cardiovascular disease (CVD). However, commonly used prediction models have been formulated in primarily or exclusively white populations. Whether risk assessment in black adults is dissimilar to that in white adults is uncertain.

OBJECTIVES

To develop and validate risk prediction models for CVD incidence in black adults, incorporating standard risk factors, biomarkers, and subclinical disease.

DESIGN, SETTING, AND PARTICIPANTS

The Jackson Heart Study (JHS), a longitudinal community-based study of 5301 black adults in Jackson, Mississippi. Inclusive study dates were the date of a participant's first visit (September 2000 to March 2004) to December 31, 2011. The median (75th percentile) follow-up was 9.1 (9.7) years. The dates of the analysis were August 2013 to May 2015. Measurements included standard risk factors, including age, sex, body mass index, systolic and diastolic blood pressure, ratio of fasting total cholesterol to high-density lipoprotein cholesterol, estimated glomerular filtration rate, antihypertensive therapy, diabetes mellitus, and smoking; blood biomarkers; and subclinical disease measures, including ankle-brachial index, carotid intimal-medial thickness, and echocardiographic left ventricular hypertrophy and systolic dysfunction.

MAIN OUTCOMES AND MEASURES

Incident CVD event was defined as the first occurrence of myocardial infarction, coronary heart disease death, congestive heart failure, stroke, incident angina, or intermittent claudication. Model performance was compared with the American College of Cardiology/American Heart Association (ACC/AHA) CVD risk algorithm and the Framingham Risk Score (FHS) refitted to the JHS data and evaluated in the Atherosclerosis Risk in Communities (ARIC) and Multi-Ethnic Study of Atherosclerosis cohorts.

RESULTS

The study cohort comprised 3689 participants with mean (SD) age at baseline was 53 (11) years, and 64.8% (n = 2390) were female. Over a median of 9.1 years, 270 participants (166 women) experienced a first CVD event. A simple combination of standard CVD risk factors, B-type natriuretic peptide, and ankle-brachial index (model 6) yielded modest improvement over a model without B-type natriuretic peptide and ankle-brachial index (C statistic, 0.79; 95% CI, 0.75-0.83 [relative integrated discrimination improvement, 0.22; 95% CI, 0.15-0.30]). However, the reclassification improvement was not substantially different between model 6 and the ACC/AHA CVD Pooled Cohort risk equations or between model 6 and the FHS. The models discriminated reasonably well in the ARIC and Multi-Ethnic Study of Atherosclerosis data (C statistic range, 0.70-0.77).

CONCLUSIONS AND RELEVANCE

Our findings using the JHS data in the present study are valuable because they confirm that current FHS and ACC/AHA risk algorithms work well in black individuals and are not easily improved on. A unique risk calculator for black adults may not be necessary.

Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL): Rationale, design and baseline characteristics

Underserved and minority populations suffer from a disproportionately high prevalence of obesity and related comorbidities. Effective obesity treatment programs delivered in primary care that produce significant weight loss are currently lacking. The purpose of this trial is to test the effectiveness of a pragmatic, high intensity lifestyle-based obesity treatment program delivered within primary care among an underserved population. We hypothesize that, relative to patients who receive usual care, patients who receive a high-intensity, health literacy- and culturally-appropriate lifestyle intervention will have greater percent reductions in body weight over 24 months. Eighteen clinics (N = 803 patients) serving low income populations with a high proportion of African Americans in Louisiana were randomized to the intervention or usual car. Patients in the intervention participate in a high-intensity lifestyle program delivered by health coaches employed by an academic health center and embedded in the primary care clinics. The program consists of weekly (16 in-person/6 telephone) sessions in the first six months, followed by sessions held at least monthly for the remaining 18 months. Primary care practitioners in usual care receive information on weight management and the current Centers for Medicare and Medicaid Services reimbursement for obesity treatment. The primary outcome is percent weight loss at 24 months. Secondary outcomes include absolute 24-month changes in body weight, waist circumference, blood pressure, fasting glucose and lipids, health-related quality of life, and weight-related quality of life. The results will provide evidence on the effectiveness of implementing high-intensity lifestyle and obesity counseling in primary care settings among underserved populations.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02561221.

A Patient-Held Smartcard With a Unique Identifier and an mHealth Platform to Improve the Availability of Prenatal Test Results in Rural Nigeria: Demonstration Study

BACKGROUND

Community-based strategies to test for HIV, hepatitis B virus (HBV), and sickle cell disease (SCD) have expanded opportunities to increase the proportion of pregnant women who are aware of their diagnosis. In order to use this information to implement evidence-based interventions, these results have to be available to skilled health providers at the point of delivery. Most electronic health platforms are dependent on the availability of reliable Internet connectivity and, thus, have limited use in many rural and resource-limited settings.

OBJECTIVE

Here we describe our work on the development and deployment of an integrated mHealth platform that is able to capture medical information, including test results, and encrypt it into a patient-held smartcard that can be read at the point of delivery without the need for an Internet connection.

METHODS

We engaged a team of implementation scientists, public health experts, and information technology specialists in a requirement-gathering process to inform the design of a prototype for a platform that uses smartcard technology, database deployment, and mobile phone app development. Key design decisions focused on usability, scalability, and security.

RESULTS

We successfully designed an integrated mHealth platform and deployed it in 4 health facilities across Benue State, Nigeria. We developed the Vitira Health platform to store test results of HIV, HBV, and SCD in a database, and securely encrypt the results on a Quick Response code embedded on a smartcard. We used a mobile app to read the contents on the smartcard without the need for Internet connectivity.

CONCLUSIONS

Our findings indicate that it is possible to develop a patient-held smartcard and an mHealth platform that contains vital health information that can be read at the point of delivery using a mobile phone-based app without an Internet connection.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03027258; https://clinicaltrials.gov/ct2/show/NCT03027258 (Archived by WebCite at http://www.webcitation.org/6owR2D0kE).

Clinical Effects of Cigarette Smoking: Epidemiologic Impact and Review of Pharmacotherapy Options

Cigarette smoking-a crucial modifiable risk factor for organ system diseases and cancer-remains prevalent in the United States and globally. In this literature review, we aim to summarize the epidemiology of cigarette smoking and tobacco use in the United States, pharmacology of nicotine-the active constituent of tobacco, and health consequence of cigarette smoking. This article also reviews behavioral and pharmacologic interventions for cigarette smokers and provides cost estimates for approved pharmacologic interventions in the United States. A literature search was conducted on Google Scholar, EBSCOhost, ClinicalKey, and PubMed databases using the following headings in combination or separately: cigarette smoking, tobacco smoking, epidemiology in the United States, health consequences of cigarette smoking, pharmacologic therapy for cigarette smoking, and non-pharmacologic therapy for cigarette smoking. This review found that efficacious non-pharmacologic interventions and pharmacologic therapy are available for cessation of cigarette smoking. Given the availability of efficacious interventions for cigarette smoking cessation, concerted efforts should be made by healthcare providers and public health professionals to promote smoking cessation as a valuable approach for reducing non-smokers' exposure to environmental tobacco smoke.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Perioperative Inotrope Therapy and Atrial Fibrillation Following Coronary Artery Bypass Graft Surgery: Evidence of a Racial Disparity

BACKGROUND AND OBJECTIVE

Following coronary artery bypass graft (CABG) surgery, mortality rates are significantly higher among black patients who experience postoperative atrial fibrillation (POAF). Perioperative inotropic therapy (PINOT) was associated with POAF in previous reports, but the extent to which race influences this association is unknown. In the present study, the relationship between PINOT, race, and POAF was examined in patients undergoing CABG surgery.

METHODS AND SETTING

Clinical records were examined from a prospectively maintained cohort of 11,855 patients (median age 64 yrs; 70% male; 16% black) undergoing primary isolated CABG at a large cardiovascular institute in the southeastern region of the United States. Relative risk (RR) and 95% confidence intervals (CIs) were computed using log-binomial regression.

MAIN RESULTS

The association between PINOT and POAF was significantly increased among black patients (adjusted RR 1.7, CI 1.4-2.0) compared with white patients (adjusted RR 1.3, CI 1.2-1.4) (p_interaction  = 0.013).

CONCLUSIONS

These findings suggest that PINOT may be disproportionately associated with POAF among black patients undergoing CABG surgery. Additional studies are needed to examine further the potential underlying mechanisms of this association.

Psychosocial Correlates of Nocturnal Blood Pressure Dipping in African Americans: The Jackson Heart Study

BACKGROUND

African Americans exhibit a lower degree of nocturnal blood pressure (BP) dipping compared with Whites, but the reasons for reduced BP dipping in this group are not fully understood. The aim of this study was to identify psychosocial factors associated with BP dipping in a population-based cohort of African Americans.

METHODS

This cross-sectional study included 668 Jackson Heart Study (JHS) participants with valid 24-hour ambulatory BP data and complete data on psychosocial factors of interest including stress, negative emotions, and psychosocial resources (e.g., perceived support). The association of each psychosocial factor with BP dipping percentage and nondipping status (defined as <10% BP dipping) was assessed using linear and Poisson regression models, respectively, with progressive adjustment for demographic, socioeconomic, biomedical, and behavioral factors.

RESULTS

The prevalence of nondipping was 64%. Higher depressive symptoms, higher hostility, and lower perceived social support were associated with a lower BP dipping percentage in unadjusted models and after adjustment for age, sex, body mass index, and mean 24-hour systolic BP (P < 0.05). Only perceived support was associated with BP dipping percentage in fully adjusted models. Also, after full multivariable adjustment, the prevalence ratio for nondipping BP associated with 1 SD (7.1 unit) increase in perceived support was 0.93 (95% CI: 0.88-0.99). No other psychosocial factors were associated with nondipping status.

CONCLUSIONS

Lower perceived support was associated with reduced BP dipping in this study. The role of social support as a potentially modifiable determinant of nocturnal BP dipping warrants further investigation.

Perceptions of Obesity Treatment Options Among Healthcare Providers and Low-Income Primary Care Patients

BACKGROUND

Primary care is a key component of medical care delivery and has a role to play in reducing obesity in the United States. The purpose of this study was to explore attitudes and perceptions about obesity in low-income primary care patients and to identify preferences for weight management interventions from the patient and healthcare provider perspectives.

METHODS

A convenience sample of 28 patients and 6 healthcare providers from across the state of Louisiana participated in 1 of 5 structured focus groups. Demographic information was collected from both the patients and healthcare providers using survey instruments.

RESULTS

Patients and healthcare providers were more similar than dissimilar in their perceptions of obesity in that both groups selected referral to a nutritionist, use of medication, and prescribed exercise as the top 3 strategies that would have the greatest impact on losing weight. Referral to a nutritionist was selected as the easiest strategy to implement.

CONCLUSION

Receiving feedback from both patients and healthcare providers gives researchers the opportunity to acquire useful knowledge that may be beneficial in designing and conducting interventions suitable for patients desiring to lose weight, especially those in primary care settings.

Differential increase in prevalence estimates of inadequate sleep among black and white Americans

BACKGROUND

The National Health Interview Survey (NHIS) was used to ascertain whether increases in inadequate sleep differentially affected black and white Americans. We tested the hypothesis that prevalence estimates of inadequate sleep were consistently greater among blacks, and that temporal changes have affected these two strata differentially.

METHODS

NHIS is an ongoing cross-sectional study of non-institutionalized US adults (≥18 years) providing socio-demographic, health risk, and medical factors. Sleep duration was coded as very short sleep [VSS] (<5 h), short sleep [SS] (5-6 h), or long sleep [LS] (>8 h), referenced to 7-8 h sleepers. Analyses adjusted for NHIS' complex sampling design using SAS-callable SUDAAN.

RESULTS

Among whites, the prevalence of VSS increased by 53% (1.5% to 2.3%) from 1977 to 2009 and the prevalence of SS increased by 32% (19.3% to 25.4 %); prevalence of LS decreased by 30% (11.2% to 7.8%). Among blacks, the prevalence of VSS increased by 21% (3.3% to 4.0%) and the prevalence of SS increased by 37% (24.6 % to 33.7%); prevalence of LS decreased by 42% (16.1% to 9.4%). Adjusted multinomial regression analysis showed that odds of reporting inadequate sleep for whites were: VSS (OR = 1.40, 95% CI = 1.13-1.74, p < 0.001), SS (OR = 1.34, 95 % CI = 1.25-1.44, p < 0.001), and LS (OR = 0.94, 95% CI = 0.85-1.05, NS). For blacks, estimates were: VSS (OR = 0.83, 95% CI = 0.60-1.40, NS), SS (OR = 1.21, 95% CI = 1.05-1.50, p < 0.001), and LS (OR = 0.84, 95% CI = 0.64-1.08, NS).

CONCLUSIONS

Blacks and whites are characteristically different regarding the prevalence of inadequate sleep over the years. Temporal changes in estimates of inadequate sleep seem dependent upon individuals' race/ethnicity.

Increased Long-Term Mortality among Black CABG Patients Receiving Preoperative Inotropic Agents

The aim of this study was to examine racial differences in long-term mortality after coronary artery bypass grafting (CABG), stratified by preoperative use of inotropic agents. Black and white patients who required preoperative inotropic support prior to undergoing CABG procedures between 1992 and 2011 were compared. Mortality probabilities were computed using the Kaplan-Meier product-limit method. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 15,765 patients underwent CABG, of whom 211 received preoperative inotropic agents within 48 hours of surgery. Long-term mortality differed by race (black versus white) among preoperative inotropic category (inotropes: adjusted HR = 1.6, 95% CI = 1.009–2.4; no inotropes: adjusted HR = 1.15, 95% CI = 1.08–1.2; P_interaction < 0.0001). Our study identified an independent preoperative risk-factor for long-term mortality among blacks receiving CABG. This outcome provides information that may be useful for surgeons, primary care providers, and their patients.

Clinical correlates and prognostic significance of change in standardized left ventricular mass in a community-based cohort of African Americans

Background

Though left ventricular mass (LVM) predicts cardiovascular events (CVD) and mortality in African Americans, limited data exists on factors contributing to change in LVM and its prognostic significance. We hypothesized that baseline blood pressure (BP) and body mass index (BMI) and change in these variables over time are associated with longitudinal increases in LVM and that such increase is associated with greater incidence of CVD.

Methods and Results

We investigated the clinical correlates of change in standardized logarithmically transformed‐LVM indexed to height2.7 (log‐LVMI) and its association with incident CVD in 606 African Americans (mean age 58±6 years, 66% women) who attended serial examinations 8 years apart. Log‐LVMI and clinical covariates were standardized within sex to obtain z scores for both visits. Standardized log‐LVMI was modeled using linear regression (correlates of change in standardized log‐LVMI) and Cox proportional hazards regression (incidence of CVD [defined as coronary heart disease, stroke, heart failure and intermittent claudication]). Baseline clinical correlates (standardized log‐LVM, BMI, systolic BP) and change in systolic BP over time were significantly associated with 8‐year change in standardized log‐LVMI. In prospective analysis, change in standardized LVM was significantly (P=0.0011) associated with incident CVD (hazards ratio per unit standard deviation change log‐LVMI 1.51, 95% CI 1.18 to 1.93).

Conclusions

In our community‐based sample of African Americans, baseline BMI and BP, and change in BP on follow‐up were key determinants of increase in standardized log‐LVMI, which in turn carried an adverse prognosis, underscoring the need for greater control of BP and weight in this group.

Tipping the scales on obesity: church-based health promotion for African American women

Research suggests that over 80% of U.S. adult African American (AA) women are at risk for hypertension, cardiovascular disease, and diabetes. In 2011-2012, 56.6% of non-Hispanic Black women were obese (BMI ≥ 30 kg/m2). Project TEACH--Transforming, Empowering, and Affecting Congregation Health was designed to determine the effectiveness of a faith-based, culturally competent, nutrition and exercise program targeting AA women in a church setting.

The association between individual and combined components of metabolic syndrome and chronic kidney disease among African Americans: the Jackson Heart Study

Introduction

Approximately 26.3 million people in the United States have chronic kidney disease and many more are at risk of developing the condition. The association between specific metabolic syndrome components and chronic kidney disease in African American individuals is uncertain.

Methods

Baseline data from 4,933 participants of the Jackson Heart Study were analyzed. Logistic regression models were used to estimate the odds and 95% confidence intervals of chronic kidney disease associated with individual components, metabolic syndrome, the number of components, and specific combinations of metabolic syndrome components.

Results

Metabolic syndrome was common with a prevalence of 42.0%. Chronic kidney disease was present in 19.4% of participants. The prevalence of metabolic components was high: elevated blood pressure (71.8%), abdominal obesity (65.8%), low fasting high density lipoprotein cholesterol (37.3%), elevated fasting glucose (32.2%) and elevated triglycerides (16.2%). Elevated blood pressure, triglycerides, fasting blood glucose, and abdominal obesity were significantly associated with increased odds of chronic kidney disease. Participants with metabolic syndrome had a 2.22-fold (adjusted odds ratio (AOR) 2.22; 95% CI, 1.78–2.78) increase in the odds of chronic kidney disease compared to participants without metabolic syndrome. The combination of elevated fasting glucose, elevated triglycerides, and abdominal obesity was associated with the highest odds for chronic kidney disease (AOR 25.11; 95% CI, 6.94–90.90).

Conclusion

Metabolic syndrome as well as individual or combinations of metabolic syndrome components are independently associated with chronic kidney disease in African American adults.

Joint effects of smoking and sedentary lifestyle on lung function in African Americans: the Jackson Heart Study cohort

This study examined: (a) differences in lung function between current and non current smokers who had sedentary lifestyles and non sedentary lifestyles and (b) the mediating effect of sedentary lifestyle on the association between smoking and lung function in African Americans. Sedentary lifestyle was defined as the lowest quartile of the total physical activity score. The results of linear and logistic regression analyses revealed that non smokers with non sedentary lifestyles had the highest level of lung function, and smokers with sedentary lifestyles had the lowest level. The female non-smokers with sedentary lifestyles had a significantly higher FEV1% predicted and FVC% predicted than smokers with non sedentary lifestyles (93.3% vs. 88.6%; p = 0.0102 and 92.1% vs. 86.9%; p = 0.0055 respectively). FEV1/FVC ratio for men was higher in non smokers with sedentary lifestyles than in smokers with non sedentary lifestyles (80.9 vs. 78.1; p = 0.0048). Though smoking is inversely associated with lung function, it seems to have a more deleterious effect than sedentary lifestyle on lung function. Physically active smokers had higher lung function than their non physically active counterparts.

Gene-environment interaction between SCN5A-1103Y and hypokalemia influences QT interval prolongation in African Americans: the Jackson Heart Study

BACKGROUND

African-American ancestry, hypokalemia, and QT interval prolongation on the electrocardiogram are all risk factors for sudden cardiac death (SCD), but their interactions remain to be characterized. SCN5A-1103Y is a common missense variant, of African ancestry, of the cardiac sodium channel gene. SCN5A-1103Y is known to interact with QT-prolonging factors to promote ventricular arrhythmias in persons at high risk for SCD, but its clinical impact in the general African-American population has not been established.

METHODS

We genotyped SCN5A-S1103Y in 4,476 participants of the Jackson Heart Study, a population-based cohort of African Americans. We investigated the effect of SCN5A-1103Y, including interaction with hypokalemia, on QT interval prolongation, a widely-used indicator of prolonged myocardial repolarization and predisposition to SCD. We then evaluated the two sub-components of the QT interval: QRS duration and JT interval.

RESULTS

The carrier frequency for SCN5A-1103Y was 15.4%. SCN5A-1103Y was associated with QT interval prolongation (2.7 milliseconds; P < .001) and potentiated the effect of hypokalemia on QT interval prolongation (14.6 milliseconds; P = .02). SCN5A-1103Y had opposing effects on the two sub-components of the QT interval, with shortening of QRS duration (-1.5 milliseconds; P = .001) and prolongation of the JT interval (3.4 milliseconds; P < .001). Hypokalemia was associated with diuretic use (78%; P < .001).

CONCLUSIONS

SCN5A-1103Y potentiates the effect of hypokalemia on prolonging myocardial repolarization in the general African-American population. These findings have clinical implications for modification of QT prolonging factors, such as hypokalemia, in the 15% of African Americans who are carriers of SCN5A-1103Y.

Improving health outcomes of children through effective parenting: model and methods

This article reports on the design, development, testing and presentation of preliminary evidence of a translational, culturally relevant parenting education model, titled Smart and Secured Children (SSC). SSC, a quality parenting curriculum, prepares disparate African American parents as leaders for transforming their parenting behaviors and leading their peers and community in changing existing parenting culture. The article recommends expanded utility of identified promising processes, approaches and practices to engage African American parents to lead in addressing health inequity conditions in their families and communities. It adds to the growing scientific literature on the association between parent–child relationship quality and a wide variety of children physical, emotional and social outcomes. SSC applied principles of developmental theories; community based participatory research (CBPR), and iterative Delphi method between the community stakeholders, parents and researchers. The delivery approach of SSC was revamped from professional-led to parent-led content presentation and delivery methods using a conversational learning approach, referred to as ‘conversepedia’. Parents’ leadership development training and delivery of this curriculum in social supportive groups improved their mental wellbeing, parenting capacity and leadership skills. Parents do matter and can choose positive influence in their lives and are capable of reversing negative peer influence.

Correlates of isolated nocturnal hypertension and target organ damage in a population-based cohort of African Americans: the Jackson Heart Study

BACKGROUND

African Americans have higher rates of nocturnal hypertension and less nocturnal blood pressure (BP) dipping compared with whites. Although nocturnal hypertension is associated with increased cardiovascular morbidity and mortality, its clinical significance among those with normal daytime BP is unclear. This paper reports the prevalence and correlates of isolated nocturnal hypertension (INH) in a population-based cohort of African Americans enrolled in the Jackson Heart Study (JHS).

METHODS

The study sample included 425 untreated, normotensive and hypertensive JHS participants who underwent 24-hour ambulatory BP monitoring (ABPM), echocardiography, and 24-hour urine collection. Multiple logistic regression and 1-way analysis of variance models were used to test the hypothesis that those with INH have worse target organ damage reflected by greater left ventricular (LV) mass and proteinuria compared with normotensive participants.

RESULTS

Based on 24-hour ABP profiles, 19.1% of participants had INH. In age and sex-adjusted models, participants with INH had greater LV mass compared with those who were normotensive (P = 0.02), as well as about 3 times the odds of LV hypertrophy and proteinuria (Ps < 0.10). However, multivariable adjustment reduced the magnitude and statistical significance of each of these differences.

CONCLUSIONS

INH was associated with increased LV mass compared with normo tension in a population-based cohort of African Americans enrolled in the JHS. There were trends toward a greater likelihood of LV hyper trophy and proteinuria among participants with INH vs. those who were normotensive. The clinical significance of the noted target organ damage should be explored in this population.

The associations of multiple dimensions of discrimination and abdominal fat in African American adults: the Jackson Heart Study

BACKGROUND

Discrimination may be adversely associated with abdominal obesity, but few studies have examined associations with abdominal fat.

PURPOSE

The purpose of this study was to examine whether discrimination was independently associated with visceral (VAT) and subcutaneous (SAT) fat and whether these associations differed by sex and age.

METHODS

Participants self-reported experiences of everyday and lifetime discrimination. The main reason for and the coping response to these experiences were also reported. VAT and SAT were quantified by computed tomography.

RESULTS

In fully adjusted models, higher reports of everyday discrimination were associated with greater SAT, but not VAT, volumes in men only: SAT increased by 3.6 (standard error = 1.8) cm(3) for each unit increase in the everyday discrimination score. In women, higher reports of lifetime non-racial discrimination were associated with greater VAT (71.6 ± 32.0, P < 0.05) and SAT (212.6 ± 83.6, P < 0.05), but these relationships were attenuated after controlling for body mass index.

CONCLUSIONS

These cross-sectional findings do not fully support the independent hypothesis of discrimination and abdominal fat. Additional investigations involving longitudinal designs are warranted.

The contribution of stress to the social patterning of clinical and subclinical CVD risk factors in African Americans: the Jackson Heart Study

It is often hypothesized that psychosocial stress may contribute to associations of socioeconomic position (SEP) with risk factors for cardiovascular disease (CVD). However, few studies have investigated this hypothesis among African Americans, who may be more frequently exposed to stressors due to social and economic circumstances. Cross-sectional data from the Jackson Heart Study (JHS), a large population-based cohort of African Americans, were used to examine the contributions of stressors to the association of SEP with selected cardiovascular (CVD) risk factors and subclinical atherosclerotic disease. Among women, higher income was associated with lower prevalence of hypertension, obesity, diabetes and carotid plaque and lower levels of stress. Higher stress levels were also weakly, albeit positively, associated with hypertension, diabetes, and obesity, but not with plaque. Adjustment for the stress measures reduced the associations of income with hypertension, diabetes and obesity by a small amount that was comparable to, or larger, than the reduction observed after adjustment for behavioral risk factors. In men, high income was associated with lower prevalence of diabetes and stressors were not consistently associated with any of the outcomes examined. Overall, modest mediation effects of stressors were observed for diabetes (15.9%), hypertension (9.7%), and obesity (5.1%) among women but only results for diabetes were statistically significant. No mediation effects of stressors were observed in men. Our results suggest that stressors may partially contribute to associations of SEP with diabetes and possibly hypertension and obesity in African American women. Further research with appropriate study designs and data is needed to understand the dynamic and interacting effects of stressors and behaviors on CVD outcomes as well as sex differences in these effects.

Social patterning of cumulative biological risk by education and income among African Americans

OBJECTIVES

We examined the social patterning of cumulative dysregulation of multiple systems, or allostatic load, among African Americans adults.

METHODS

We examined the cross-sectional associations of socioeconomic status (SES) with summary indices of allostatic load and neuroendocrine, metabolic, autonomic, and immune function components in 4048 Jackson Heart Study participants.

RESULTS

Lower education and income were associated with higher allostatic load scores in African American adults. Patterns were most consistent for the metabolic and immune dimensions, less consistent for the autonomic dimension, and absent for the neuroendocrine dimension among African American women. Associations of SES with the global allostatic load score and the metabolic and immune domains persisted after adjustment for behavioral factors and were stronger for income than for education. There was some evidence that the neuroendocrine dimension was inversely associated with SES after behavioral adjustment in men, but the immune and autonomic components did not show clear dose-response trends, and we observed no associations for the metabolic component.

CONCLUSIONS

Findings support our hypothesis that allostatic load is socially patterned in African American women, but this pattern is less consistent in African American men.

Association of adiponectin with left ventricular mass in blacks: the Jackson Heart Study

BACKGROUND

Blacks have a higher prevalence of left ventricular hypertrophy than whites. Several population-based studies have reported an inverse association between adiponectin and left ventricular mass (LVM); however, the relationship between adiponectin levels and LVM has yet to be defined in blacks. The Jackson Heart Study cohort provides an opportunity to test the hypothesis that the inverse association between adiponectin and LVM may be modified by risk factors common among blacks.

METHODS AND RESULTS

The study population included 2649 black Jackson Heart Study participants (mean age 51±12 years, 63% women, 51% obese, 54% with hypertension, and 16% with diabetes). Multiple linear and spline regression was used to assess the association, with adjustment for demographic, clinical, and behavioral covariates. Among all the participants, there was a statistically significant but modest inverse association between adiponectin and LVM index. Hypertension and insulin resistance emerged as statistically significant effect modifiers of this relationship. The inverse association present among the normotensive participants was explained by obesity measures such as the body mass index. Among participants with both hypertension and insulin resistance, there was a significant direct association between adiponectin and the LVM index after multivariable adjustment (β=1.55, P=0.04, per 1-SD increment in the adiponectin log value).

CONCLUSIONS

The association between serum adiponectin and LVM among blacks in the Jackson Heart Study cohort was dependent on hypertension and insulin resistance status. Normotensive blacks exhibited an inverse adiponectin-LVM association, whereas participants with hypertension and insulin resistance had a direct association.

Age is positively associated with high-density lipoprotein cholesterol among African Americans in cross-sectional analysis: the Jackson Heart Study

BACKGROUND

African Americans have historically had high high-density lipoprotein cholesterol (HDL-C) compared with other races and ethnicities.

OBJECTIVE

We sought to characterize whether there is a cross-sectional association between age and HDL-C in a contemporary community-based study of African Americans.

METHODS

Cross-sectional data were modeled by logistic regression for predictors of HDL-C among African Americans, ages 35-74, participating in the baseline examination of a community-based study of cardiovascular disease in Jackson, Mississippi, during 2000-2004. After excluding persons taking lipid-lowering medications, hormone replacement therapy, oral contraceptives, or thyroid replacement, the analytical data set comprised 2420 persons (1370 women, 1050 men).

RESULTS

HDL-C had a significant positive association with age after controlling for serum triglycerides, sex, waist circumference, percent dietary calories from carbohydrates, alcohol use, and leisure physical activity. Sex was a significant effect modifier of this relationship, whereby the increase in HDL-C with age was steeper for women than for men.

CONCLUSIONS

Cross-sectional analysis found a positive association of HDL-C with age while controlling for triglycerides. Careful evaluation of longitudinal data will be needed to confirm whether this is a true effect of aging, or a cohort or survivor effect.

SCN5A variation is associated with electrocardiographic traits in the Jackson Heart Study

BACKGROUND

Understanding variation in the normal electric activity of the heart, assessed by the ECG, may provide a starting point for studies of susceptibility to serious arrhythmias such as sudden cardiac death during myocardial infarction or drug therapy. Recent genetic association studies of one ECG trait, the QT interval, have identified common variation in European-descent populations, but little is known about the genetic determinants of ECG traits in populations of African descent.

METHODS AND RESULTS

To identify genetic risk factors, we have undertaken a candidate gene study of ECG traits in collaboration with the Jackson Heart Study, a longitudinal study of 5301 blacks ascertained from the Jackson, Mississippi, area. Nine quantitative ECG traits were evaluated: P, PR, QRS, QT, and QTc durations, heart rate, and P, QRS, and T axes. We genotyped 72 variations in the predominant sodium channel gene expressed in heart, SCN5A, encoding the Na(v)1.5 voltage-gated sodium channel in 4558 subjects. Both rare and common variants in this gene have previously been associated with inherited arrhythmia syndromes and variable conduction. Adjusting for age, sex, and European ancestry, we performed tests of association in 3054 unrelated participants and identified 14 significant associations (P<1.0×10(-4)), of which 13 are independent, based on linkage disequilibrium. These variants explain up to 2% of the variation in ECG traits in the Jackson Heart Study.

CONCLUSIONS

These results suggest that SCN5A variation contributes to ECG trait distributions in blacks, and these same variations may be risk or protective factors associated with susceptibility to arrhythmias.

The relation of diabetes, impaired fasting blood glucose, and insulin resistance to left ventricular structure and function in African Americans: the Jackson Heart Study

OBJECTIVE

We assessed the relation of diabetes and insulin resistance (IR) on left ventricular (LV) structure and function in African Americans.

RESEARCH DESIGN AND METHODS

Among those receiving echocardiograms in cycle 1 of the Jackson Heart Study, we assessed the sex-specific relation of fasting blood glucose (FBG), diabetes, and IR to LV structure and function, adjusting for age, systolic blood pressure, antihypertensive medications, and BMI.

RESULTS

Among 2,399 participants, LV mass index (P(women) = 0.0002 and P(men) = 0.02), posterior wall thickness (P(women) = 0.01 and P(men) = 0.05), and interventricular septal wall thickness (P(women) = 0.01) were related to FBG categories. Among those with normal FBG and no diabetes, concentric remodeling and low ejection fraction in women and LV mass index and posterior wall thickness in men were related to IR.

CONCLUSIONS

In the largest study of its kind in a community-based cohort of African Americans, we found a relation of FBG category and IR to LV structure and function.

Geographic representation of the jackson heart study cohort to the African-American population in Jackson, Mississippi

Recent advances in geographic information systems software and multilevel methodology provide opportunities for more extensive characterization of "at-risk" populations in epidemiologic studies. The authors used age-restricted, geocoded data from the all-African-American Jackson Heart Study (JHS), 2000-2004, to demonstrate a novel use of the Lorenz curve and Gini coefficient to determine the representativeness of the JHS cohort to the African-American population in a geographic setting. The authors also used a spatial binomial model to assess the geographic variability in participant recruitment across the Jackson, Mississippi, Metropolitan Statistical Area. The overall Gini coefficient, an equality measure that ranges from 0 (perfect equality) to 1 (perfect inequality), was 0.37 (95% confidence interval (CI): 0.30, 0.45), indicating moderate representation. The population of sampled women (Gini coefficient = 0.34, 95% CI: 0.30, 0.39) tended to be more representative of the underlying population than did the population of sampled men (Gini coefficient = 0.49, 95% CI: 0.35, 0.61). Representative recruitment of JHS participants was observed in predominantly African-American and mixed-race census tracts and in the center of the study area, the area nearest the examination clinic. This is of critical importance as the authors continue to explore novel approaches to investigate the geographic variation in disease etiology.

The triglyceride/high-density lipoprotein cholesterol ratio fails to predict insulin resistance in African-American women: an analysis of Jackson Heart Study

BACKGROUND

Compared to whites, insulin-resistant African Americans have worse outcomes. Screening programs that could identify insulin resistance early enough for intervention to affect outcome often rely on triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels. Racial differences in TG and HDL-C may compromise the efficacy of these programs in African Americans. A recommendation currently exists to use the TG/HDL-C ratio ≥2.0 to predict insulin resistance in African Americans. The validity of this recommendation needs examination. Therefore, our aim was to determine the ability of TG/HDL-C ratio to predict insulin resistance in African Americans.

METHODS

In 1,903 African Americans [895 men, 1,008 women, age 55 ± 12 years, mean ± standard deviation (SD), range 35-80 years, body mass index (BMI) 31.0 ± 6.4 kg/m(2), range 18.5-55 kg/m(2)] participating in the Jackson Heart Study, a population-based study of African Americans, Jackson, Mississippi tricounty region, insulin resistance was defined by the upper quartile (≥4.43) of homeostasis model assessment of insulin resistance (HOMA-IR). An area under the receiver operating characteristic curve (AUC-ROC) of >0.70 was required for prediction of insulin resistance by TG/HDL-C. The optimal test cutoff was determined by the Youden index.

RESULTS

HOMA-IR was similar in men and women (3.40 ± 2.03 vs. 3.80 ± 2.46, P = 0.60). Women had lower TG (94 ± 49 vs. 109 ± 65 mg/dL P < 0.001) and TG/HDL-C (1.9 ± 1.4 vs. 2.7 ± 2.1, P < 0.001). For men, AUC-ROC for prediction of insulin resistance by TG/HDL-C was: 0.77 ± 0.01, mean ± standard error (SE), with an optimal cutoff of ≥2.5. For women, the AUC-ROC was 0.66 ± 0.01, rendering an optimal cutoff indefinable. When women were divided in two groups according to age, 35-50 years and 51-80 years, the results did not change.

CONCLUSIONS

In African-American men, the recommended TG/HDL-C threshold of 2.0 should be adjusted upward to 2.5. In African-American women, TG/HDL-C cannot identify insulin resistance. The Jackson Heart Study can help determine the efficacy of screening programs in African-Americans.

Fine-mapping in African Americans of 8 recently discovered genetic loci for plasma lipids: the Jackson Heart Study

BACKGROUND

Genome-wide association studies in cohorts of European descent have identified novel genomic regions as associated with lipids, but their relevance in African Americans remains unclear.

METHODS AND RESULTS

We genotyped 8 index single nucleotide polymorphisms (SNPs) and 488 tagging SNPs across 8 novel lipid loci in the Jackson Heart Study, a community-based cohort of 4605 African Americans. For each trait, we calculated residuals adjusted for age, sex, and global ancestry and performed multivariable linear regression to detect genotype-phenotype association with adjustment for local ancestry. To explore admixture effects, we conducted stratified analyses in individuals with a high probability of 2 African ancestral alleles or at least 1 European allele at each locus. We confirmed 2 index SNPs as associated with lipid traits in African Americans, with suggestive association for 3 more. However, the effect sizes for 4 of the 5 associated SNPs were larger in the European local ancestry subgroup compared with the African local ancestry subgroup, suggesting that the replication is driven by European ancestry segments. Through fine-mapping, we discovered 3 new SNPs with significant associations, 2 with consistent effect on triglyceride levels across ancestral groups: rs636523 near DOCK7/ANGPTL3 and rs780093 in GCKR. African linkage disequilibrium patterns did not assist in narrowing association signals.

CONCLUSIONS

We confirm that 5 genetic regions associated with lipid traits in European-derived populations are relevant in African Americans. To further evaluate these loci, fine-mapping in larger African American cohorts and/or resequencing will be required.

Fine mapping of the association with obesity at the FTO locus in African-derived populations

Genome-wide association studies have identified many common genetic variants that are associated with polygenic traits, and have typically been performed with individuals of recent European ancestry. In these populations, many common variants are tightly correlated, with the perfect or near-perfect proxies for the functional or true variant showing equivalent evidence of association, considerably limiting the resolution of fine mapping. Populations with recent African ancestry often have less extensive and/or different patterns of linkage disequilibrium (LD), and have been proposed to be useful in fine-mapping studies. Here, we strongly replicate and fine map in populations of predominantly African ancestry the association between variation at the FTO locus and body mass index (BMI) that is well established in populations of European ancestry. We genotyped single nucleotide polymorphisms that are correlated with the signal of association in individuals of European ancestry but that have varying degrees of correlation in African-derived individuals. Most of the variants, including one previously proposed as functionally important, have no significant association with BMI, but two variants, rs3751812 and rs9941349, show strong evidence of association (P = 2.58 x 10(-6) and 3.61 x 10(-6) in a meta-analysis of 9881 individuals). Thus, we have both strongly replicated this association in African-ancestry populations and narrowed the list of potentially causal variants to those that are correlated with rs3751812 and rs9941349 in African-derived populations. This study illustrates the potential of using populations with different LD patterns to fine map associations and helps pave the way for genetically guided functional studies at the FTO locus.

The relation of C--reactive protein to chronic kidney disease in African Americans: the Jackson Heart Study

Background

African Americans have an increased incidence and worse prognosis with chronic kidney disease (CKD - estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m²) than their counterparts of European-descent. Inflammation has been related to renal disease in non-Hispanic whites, but there are limited data on the role of inflammation in renal dysfunction in African Americans in the community.

Methods

We examined the cross-sectional relation of log transformed C-reactive protein (CRP) to renal function (eGFR by Modification of Diet and Renal Disease equation) in African American participants of the community-based Jackson Heart Study's first examination (2000 to 2004). We conducted multivariable linear regression relating CRP to eGFR adjusting for age, sex, body mass index, systolic and diastolic blood pressure, diabetes, total/HDL cholesterol, triglycerides, smoking, antihypertensive therapy, lipid lowering therapy, hormone replacement therapy, and prevalent cardiovascular disease events. In a secondary analysis we assessed the association of CRP with albuminuria (defined as albumin-to-creatinine ratio > 30 mg/g).

Results

Participants (n = 4320, 63.2% women) had a mean age ± SD of 54.0 ± 12.8 years. The prevalence of CKD was 5.2% (n = 228 cases). In multivariable regression, CRP concentrations were higher in those with CKD compared to those without CKD (mean CRP 3.2 ± 1.1 mg/L vs. 2.4 ± 1.0 mg/L, respectively p < 0.0001). CRP was significantly associated with albuminuria in sex and age adjusted model however not in the multivariable adjusted model (p > 0.05).

Conclusion

CRP was associated with CKD however not albuminuria in multivariable-adjusted analyses. The study of inflammation in the progression of renal disease in African Americans merits further investigation.

Clinical correlates and heritability of QT interval duration in blacks: the Jackson Heart Study

BACKGROUND

Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of the QT interval and estimate its heritability in the Jackson Heart Study.

METHODS AND RESULTS

The Jackson Heart Study comprises a sample of blacks residing in Jackson, Miss, of whom 5302 individuals with data at the baseline examination were available for study. Jackson Heart Study participants on QT-altering medications, with bundle-branch block, paced rhythm, atrial fibrillation/flutter, or other arrhythmias were excluded, resulting in a sample of 4660 individuals eligible for analyses. The relation between QT and potential covariates was tested using multivariable stepwise linear regression. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routine in a subset of 1297 Jackson Heart Study participants in 292 families; the remaining sample included unrelated individuals. In stepwise multivariable linear regression analysis, covariates significantly associated with QT interval duration included R-R interval, sex, QRS duration, age, serum potassium, hypertension, body mass index, coronary heart disease, diuretic use, and Sokolow-Lyon voltage (P < or = 0.01 for all). The heritability of QT interval duration in the age-, sex-, and R-R interval-adjusted model and in the fully adjusted model was 0.41 (SE, 0.07) and 0.40 (SE, 0.07; P < 10(-11) for both), respectively.

CONCLUSIONS

There is substantial heritability of adjusted QT interval in blacks, supporting the need for further investigation to identify its genetic determinants.

Epidemiology, heritability, and genetic linkage of C-reactive protein in African Americans (from the Jackson Heart Study)

C-reactive protein (CRP) has been studied largely in white non-Hispanic cohorts. There is limited information on CRP's range of values, heritability, and relation to cardiovascular disease risk factors in African Americans. The aim of this study was to evaluate the distribution, clinical correlates, heritability, and genetic linkage of log-transformed CRP in participants in the middle-aged to elderly African American cohort in the community-based Jackson Heart Study. The distribution and correlates of CRP were analyzed for the entire study cohort who underwent the first examination (2001 to 2004). Heritability was estimated for the family cohort nested within the larger Jackson Heart Study (246 families, n = 1,317). The relation between CRP and cardiovascular disease risk factors was tested with multivariable stepwise regression analyses. Heritability was estimated using a variance-components method. Linkage analysis was performed using the multipoint variance-components approach. The study sample consisted of 4,919 participants (mean age 55 +/- 13 years, 63% women); the median CRP concentration was 2.7 mg/L. In stepwise models, traditional risk factors explained 23.8% of CRP's variability, with body mass index (partial R(2) = 13.6%) explaining 57.1% of the variability of CRP due to traditional risk factors. The heritability of CRP (adjusted for age, gender, and body mass index) was 0.45. The strongest linkage evidence for CRP was observed on chromosome 11 (11p13 to 11p11.2), with a logarithm of odds score of 2.72. In conclusion, in this large population-based cohort of African Americans, circulating CRP concentration was heritable and associated with several traditional cardiovascular risk factors, particularly body mass index.

Toward resolution of cardiovascular health disparities in African Americans: design and methods of the Jackson Heart Study

OBJECTIVE

The design, overall methods, and major phenotypes for the all-African-American Jackson Heart Study (JHS) are detailed.

METHODS

Participants were enrolled from the three counties that make up the Jackson, Mississippi metropolitan area. Relatives of selected participants were recruited to develop a large, nested family cohort. Participants provided extensive medical and social history, had an array of physical and biochemical measurements and diagnostic procedures, and provided genomic DNA.

RESULTS

Data and biologic materials have been collected from 5302 adult African Americans, including 1499 members of 291 families. Participants have a high prevalence of diabetes, hypertension, obesity, and related disorders.

DISCUSSION

The JHS dataset and biologic materials (serum, DNA, and cryopreserved cells) offer a valuable resource for the study of diseases that are of particular importance to African Americans.

Recruiting African-American research participation in the Jackson Heart Study: methods, response rates, and sample description

OBJECTIVE

The sampling and recruitment methods, response rate, and cohort description for the all-African-American Jackson Heart Study (JHS) are detailed.

METHODS

Four subsamples of participants residing in the Jackson, Mississippi metropolitan statistical area (MSA) were included: random, volunteer, ARIC (continuing from Atherosclerosis Risk in Communities study), and family. A community-driven recruitment model was developed, and community representatives guided recruitment.

RESULTS

96% (n=5,302) of target enrollment was achieved with diversity in sex, education, and income. The JHS cohort provides a sample of African-American adults for longitudinal investigation.

DISCUSSION

Cohort recruitment was challenging. The JHS experiences provide useful lessons for observational epidemiological studies recruiting African-American research participation. Co-participation of researchers and researched in study design and realistic evidence of community benefit were crucial to recruitment success.

Interaction between Potassium-Depleting Diuretics and Lovastatin in Hypercholesterolemic Ambulatory Care Patients

Objective:

To evaluate the potential impact of potassium-depleting diuretics on the efficacy of lovastatin.

Design:

A retrospective study of ambulatory patients taking lovastatin and thiazide or loop diuretics was conducted.

Setting:

Ambulatory care patients with coexisting hypercholesterolemia and hypertension from a Veterans Affairs Medical Center.

Participants:

A total of 32 patients were studied, 13 of whom had been taking lovastatin before diuretics were added. Another 19 patients had been receiving diuretics before lovastatin was initiated. The changes in their total cholesterol from baseline were recorded and analyzed.

Main Outcome Measures:

In all the patients taking lovastatin and diuretics concurrently, total cholesterol concentrations dropped initially, followed by a rise despite continuation of therapy with lovastatin. The reason for this initial drop in total cholesterol following 1 month of concurrent therapy is the subject of further investigation in a prospective study.

Results:

Regardless of the order of administration of the lipid-lowering and antihypertensive drugs, serum cholesterol rose 20% from its nadir.

Conclusions:

Patients taking potassium-depleting diuretics and a hepatic hydroxymethylglutaryl-coenzyme A reductase enzyme inhibitor (lovastatin) concurrently do not seem to benefit substantially from the lipid-lowering effect of lovastatin, probably because of a functional antagonism of the lipid-lowering effect of lovastatin by potassium-depleting diuretics.