Relation of obesity to circulating B-type natriuretic peptide concentrations in blacks: the Jackson Heart Study

Exploring the Mechanistic Link Between Obesity and Heart Failure

PURPOSE OF REVIEW

Among subtypes of cardiovascular disease, obesity has a potent and unique association with heart failure (HF) that is unexplained by traditional cardiovascular risk mediators. The concomitant rise in the prevalence of obesity and HF necessitates better understanding of their relationship to develop effective prevention and treatment strategies. The purpose of this review is to provide mechanistic insight regarding the link between obesity and HF by elucidating the direct and indirect pathways linking the two conditions.

RECENT FINDINGS

Several direct pathophysiologic mechanisms contribute to HF risk in individuals with excess weight, including hemodynamic alterations, neurohormonal activation, hormonal effects of dysfunctional adipose tissue, ectopic fat deposition with resulting lipotoxicity and microvascular dysfunction. Obesity further predisposes to HF indirectly through causal associations with hypertension, dyslipidemia, and most importantly, diabetes via insulin resistance. Low levels of physical activity and fitness further influence HF risk in the context of obesity. These various processes lead to myocardial injury and cardiac remodeling that are reflected by abnormalities in cardiac biomarkers and cardiac function on myocardial imaging. Understanding and addressing obesity-associated HF is a pressing clinical and public health challenge which can be informed by a deeper understanding of the complex pathways linking these two conditions together.

Body Composition Measures and N-terminal pro-B-type Natriuretic Peptide (NT-pro-BNP) in US Adults

BACKGROUND

The associations of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) with dual energy x-ray absorptiometry (DEXA)-derived measures of body mass and composition are largely unknown.

METHODS

We included participants aged ≥20 years from the 1999-2004 National Health and Nutrition Examination Survey with NT-pro-BNP and DEXA-derived body composition (fat and lean mass) measures. We used linear and logistic regression to characterize the associations of measures of body mass and composition (body mass index [BMI], waist circumference [WC], fat mass, and lean mass) with NT-pro-BNP, adjusting for cardiovascular risk factors.

RESULTS

We conducted sex-specific analyses among 9134 adults without cardiovascular disease (mean age 44.4 years, 50.8% women, and 72% White adults). The adjusted mean NT-proBNP values were lowest in the highest quartiles of BMI, WC, fat mass, and lean mass. There were large adjusted absolute differences in NT-pro-BNP between the highest and lowest quartiles of DEXA-derived lean mass, -6.26 pg/mL (95% confidence interval [CI], -8.99 to -3.52) among men and -22.96 pg/mL (95% CI, -26.83 to -19.09) among women. Lean mass exhibited a strong inverse association with elevated NT-pro-BNP ≥ 81.4 pg/mL (highest quartile) - odds ratio (OR) 0.58 (95% CI, 0.39-0.86) in men and OR 0.59 (95% CI, 0.47-0.73) in women for highest lean mass quartile vs. lowest quartile. Further adjustment for fat mass, BMI, or WC did not appreciably alter the inverse association of lean mass with NT-pro-BNP.

CONCLUSIONS

In a national sample of US adults, lean mass was inversely associated with NT-pro-BNP.

Discovery of another mechanism for the inhibition of particulate guanylyl cyclases by the natriuretic peptide clearance receptor

The cardiac natriuretic peptides (NPs) control pivotal physiological actions such as fluid and electrolyte balance, cardiovascular homeostasis, and adipose tissue metabolism by activating their receptor enzymes [natriuretic peptide receptor-A (NPRA) and natriuretic peptide receptor-B (NPRB)]. These receptors are homodimers that generate intracellular cyclic guanosine monophosphate (cGMP). The natriuretic peptide receptor-C (NPRC), nicknamed the clearance receptor, lacks a guanylyl cyclase domain; instead, it can bind the NPs to internalize and degrade them. The conventional paradigm is that by competing for and internalizing NPs, NPRC blunts the ability of NPs to signal through NPRA and NPRB. Here we show another previously unknown mechanism by which NPRC can interfere with the cGMP signaling function of the NP receptors. By forming a heterodimer with monomeric NPRA or NPRB, NPRC can prevent the formation of a functional guanylyl cyclase domain and thereby suppress cGMP production in a cell-autonomous manner.

Prospective Observational Study of N-terminal Pro-Brain Natriuretic Peptide Levels in Obese and Nonobese Women during Pregnancy

OBJECTIVE

N-terminal pro-brain natriuretic peptide (NT-proBNP), a marker of ventricular dysfunction, varies by body mass index (BMI) outside of pregnancy. This study aimed to determine whether obesity affects NT-proBNP levels in pregnancy.

STUDY DESIGN

This was a prospective observational study of healthy pregnant people in the third trimester (3TM) and postpartum (PP). Patients were excluded if they had significant medical comorbidities or if their fetuses had anomalies, growth restriction or aneuploidy. NT-proBNP was measured at 28 weeks (3TM), predelivery (PD), 1 to 2 days PP (immediate postpartum [IPP]), and 4 to 6 weeks PP (delayed postpartum [DPP]). LogNT-proBNP levels were analyzed using linear mixed effects models, including BMI < or ≥30, time, and time-by-BMI interactions.

RESULTS

Fifty-five people (28 [51%] with BMI ≥ 30 and 27 [49%] with BMI < 30) were enrolled. A greater proportion of obese than nonobese subjects developed hypertensive disorders of pregnancy (50 vs. 15%, p = 0.010) and obese patients had higher systolic blood pressures at all time points (p < 0.05). NT-proBNP levels (median [interquartile range] in pg/mL) were 18 (6-28) versus 26 (17-48) at 3TM, 16 (3-38) versus 43 (21-60) at PD, 58 (20-102) versus 63 (38-155) at IPP, and 33 (27-56) versus 23 (8-42) at DPP for obese compared with nonobese patients. In linear mixed effects models, logNT-proBNP was lower in obese patients at 3TM (β = -0.89 [95% confidence interval, CI: -1.51, -0.26]) and PD (β = -1.05 [95% CI: -1.72, -0.38]). The logNT-proBNP trends over time differed by BMI category, with higher values in obese patients at both PP time points compared with the 3TM (IPP β = 1.24 [95% CI: 0.75, 1.73]; DPP β = 1.08 [95% CI: 0.52, 1.63]), but only IPP for nonobese patients (β = 0.87 [95% CI: 0.36, 1.38]).

CONCLUSION

Obese patients had lower NT-proBNP levels than nonobese patients during pregnancy but not PP. The prolonged PP elevation in NT-proBNP in obese patients suggests that their PP cardiac recovery may be more prolonged.

KEY POINTS

· NT-proBNP levels are lower in obese than nonobese patients during pregnancy.. · Levels remain elevated in obese, but not nonobese, patients up to 4 to 6 weeks' postpartum.. · A lower threshold for concern regarding NT-proBNP levels may be needed in obese pregnant people..

Vitamin D Levels in Black Americans and the Association With Left Ventricular Remodeling and Incident Heart Failure With Preserved Ejectin Fraction: The Jackson Heart Study

BACKGROUND

In observational studies, a lower serum vitamin D₃ concentration has been associated with an increased risk of cardiovascular disease. However, the associations between serum vitamin D₃ levels and left ventricular (LV) structure and heart failure with preserved ejection fraction (HFpEF) have not been well-characterized among Black Americans. The prevalence of vitamin D₃ deficiency is higher among Black Americans than in other race/ethnicity groups. We hypothesized that serum vitamin D₃ levels are associated with LV concentric remodeling and incident HFpEF in Black Americans.

METHODS AND RESULTS

Among 5306 Black Americans in the Jackson Heart Study cohort, we investigated the relationships between serum vitamin D₃ levels and LV structure and function, evaluated with echocardiography, and incident HF hospitalization, categorized as either HF with reduced EF (HFrEF; an EF of <50%) or HFpEF (an EF of ≥50%). After adjustment for possible confounding factors, lower vitamin D₃ levels were associated with greater relative wall thickness (β for 1 standard deviation [SD] increase -0.003, 95% confidence interval -0.005 to -0.000). Over a median follow-up period of 11 years (range 10.2-11.0 years), 340 participants developed incident HF (7.88 cases per 1000 person-years), including 146 (43%) HFrEF and 194 (57%) HFpEF cases. After adjustment, higher serum vitamin D₃ levels were associated with decreased hazard for HF overall (hazard ratio for 1 SD increase 0.88, 95% confidence interval 0.78-0.99) driven by a significant association with HFpEF (hazard ratio for 1 SD increase 0.84, 95% confidence interval 0.71-0.99).

CONCLUSIONS

In this community-based Black American cohort, lower serum vitamin D₃ levels were associated with LV concentric remodeling and an increased hazard for HF, mainly HFpEF. Further investigation is required to examine whether supplementation with vitamin D₃ can prevent LV concentric remodeling and incident HFpEF in Black Americans.

Corin Missense Variants, Blood Pressure, and Hypertension in 11 322 Black Individuals: Insights From REGARDS and the Jackson Heart Study

Background

Corin enzyme contributes to the processing of inactive natriuretic peptides to bioactive hormones. In Black individuals, Corin gene variants (rs111253292 [Q568P] and rs75770792 [T555I]) have been previously reported to have a modest association with blood pressure (BP) and hypertension.

Methods and Results

We evaluated the association of Corin genotype with BP traits, prevalent hypertension, and incident hypertension among self‐identified 11 322 Black Americans in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study and the JHS (Jackson Heart Study) using multivariable‐adjusted regression modeling. Multivariable‐adjusted genotype‐stratified differences in NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) and BNP (B‐type natriuretic peptide) levels were assessed. Genotype‐stratified NPPA and NPPB expression differences in healthy organ donor left atrial and left ventricular heart tissue (N=15) were also examined. The rs111253292 genotype was not associated with systolic BP (β±SE, 0.42±0.58; −1.24±0.82), diastolic BP (0.51±0.33; −0.41±0.46), mean arterial pressure (0.48±0.38; −0.68±0.51), and prevalent hypertension (odds ratio [OR], 0.93 [95% CI, 0.80–1.09]; OR, 0.79 [95% CI, 0.61–1.01]) in both REGARDS and JHS, respectively. The rs75770792 genotype was not associated with systolic BP (0.48±0.58; −1.26±0.81), diastolic BP (0.52±0.33; −0.33±0.45), mean arterial pressure (0.50±0.38; −0.63±0.50), and prevalent hypertension (OR, 1.02 [95% CI, 0.84–1.23]; OR, 0.87 [95% CI, 0.67–1.13]) in both cohorts, respectively. The Corin genotype was also not associated with incident hypertension (OR, 1.35 [95% CI, 0.94–1.93]; OR, 0.95 [95% CI, 0.64–1.39]) in the study cohorts. The NT‐proBNP levels in REGARDS and BNP levels in JHS were similar between the Corin genotype groups. In heart tissue, the NPPA and NPPB expression was similar between the genotype groups.

Conclusions

Corin gene variants observed more commonly in Black individuals are not associated with differences in NP expression, circulating NP levels, and BP or hypertension as previously reported in candidate gene studies. Understanding the genetic determinants of complex cardiovascular traits in underrepresented populations requires further evaluation.

Relation of Glycemic Status with Unrecognized MI and the Subsequent Risk of Mortality: The Jackson Heart Study

Background

Almost 1/3 to 1/2 of initial myocardial infarctions (MI) may be silent or unrecognized (UMI), which forecasts future clinical events. Further, limited data exist to describe the potential risk for UMI in African-Americans. The relationship of glucose status with UMI was examined in the Jackson Heart Study: a cohort of African-American individuals.

Methods and results

At baseline, there were 5,073 participants with an initial 12-lead electrocardiogram (ECG) and fasting glucose measured. Of these participants, 106(2.1%) had a UMI, and 268(4.2%) had a recognized MI. This population consisted of 3,233 (63.7%) participants with normal fasting glucose (NFG), 533 (10.5%) with IFG, and 1,039 (20.4%) with DM. Logistic regression investigated the relationship between glucose status and UMI. Cox proportional hazard models determined the significance of all-cause mortality during follow-up by MI status. The sample was 65% female with a mean age of 55.3 ± 12.9 years. Over a mean follow-up of 10.4 years, there were 795 deaths. Relative to NFG, the crude odds ratio (OR) estimates for UMI at baseline with IFG and DM were 1.00(95% CI:0.48–2.14) and 3.22(2.15–4.81), respectively. With adjustment, DM continued to be significantly associated with UMI [2.30 (1.42–3.71)]. Overall, participants with a baseline UMI had an adjusted Hazard ratio (HR) of 2.00(1.39–2.78) of death compared to no prior MI. Compared to those with no MI, those with a recognizedMI had an adjusted HR of 1.70(1.31–2.17) for mortality.

Conclusions

DM is associated with UMI in African-Americans. Further, a UMI carried similar risk of death compared to those with a recognized MI.

Inverse Regulation of Serum Osteoprotegerin and B-Type Natriuretic Peptide Concentrations by Free Fatty Acids Elevation in Young Healthy Humans

Osteoprotegerin (OPG) and B-type natriuretic peptide (BNP) are cardiovascular risk factors, interrelated with each other, with possible associations with insulin sensitivity and glucose homeostasis. The aim of this study was to assess association between OPG and BNP concentrations in a young healthy population, their relation to insulin sensitivity and obesity and their regulation by hyperinsulinemia and serum free fatty acids (FFA) elevation. The study group consisted of 59 male volunteers, 30 of whom were of a normal weight (BMI < 25 kg/m²), and 29 were overweight/obese (BMI > 25 kg/m²). Insulin sensitivity was assessed with the 2-h hyperinsulinemic-euglycemic clamp (HEC). In the subgroup of 20 subjects, the clamp was prolonged to 6 h. After one week, another 6-h clamp, with concurrent Intralipid/heparin infusion, was performed. Serum OPG was positively associated with insulin sensitivity (p = 0.002) and negatively with BMI (p = 0.019) and serum BNP (p = 0.025). In response to 6-h hyperinsulinemia, circulating BNP decreased (p < 0.001). In response to HEC with Intralipid/heparin infusion, OPG decreased (p < 0.001) and BNP increased (p < 0.001). Our data show that OPG and BNP are differentially regulated by FFA, which suggests their association with lipid-induced insulin resistance. The assessment of these cardiovascular risk factors should take into account both long-term and short-term effects associated with insulin resistance.

Transthyretin V142I Genetic Variant and Cardiac Remodeling, Injury, and Heart Failure Risk in Black Adults

OBJECTIVES

This study evaluated the association of transthyretin (TTR) gene variant, in which isoleucine substitutes for valine at position 122 (V142I), with cardiac structure, function, and heart failure (HF) risk among middle-aged Black adults.

BACKGROUND

The valine-to-isoleucine substitution in the TTR protein is prevalent in Black individuals and causes cardiac amyloidosis.

METHODS

Jackson Heart Study participants without HF at baseline who had available data on the TTR V142I variant were included. The association of the TTR V142I variant with baseline echocardiographic parameters and repeated measures of high-sensitivity cardiac troponin-I (hs-cTnI) was assessed using adjusted linear regression models and linear mixed models, respectively. Adjusted Cox models, restricted mean survival time analysis, and Anderson-Gill models were constructed to determine the association of TTR V142I variant with the risk of incident HF, survival free of HF, and total HF hospitalizations.

RESULTS

A total of 119 of 2,960 participants (4%) were heterozygous carriers of the TTR V142I variant. The TTR V142I variant was not associated with measures of cardiac parameters at baseline but was associated with a greater increase in high-sensitivity troponin I (hs-TnI) levels over time. In adjusted Cox models, TTR V142I variant carriers had significantly higher risk of incident HF (HR: 1.80; 95% CI: 1.07-3.05; P = 0.03), lower survival free of HF (mean difference: 4.0 year; 95% CI: 0.6-6.2 years); P = 0.02), and higher risk of overall HF hospitalizations (HR: 2.12; 95% CI: 1.23-3.63; P = 0.007).

CONCLUSIONS

The TTR V142I variant in middle-aged Black adults is not associated with adverse cardiac remodeling but was associated with a significantly higher burden of chronic myocardial injury, and greater risk of incident HF and overall HF hospitalizations.

Soluble Urokinase Plasminogen Activator Receptor: Genetic Variation and Cardiovascular Disease Risk in Black Adults

BACKGROUND

suPAR (Soluble urokinase plasminogen activator receptor) has emerged as an important biomarker of coagulation, inflammation, and cardiovascular disease (CVD) risk. The contribution of suPAR to CVD risk and its genetic influence in Black populations have not been evaluated.

METHODS

We measured suPAR in 3492 Black adults from the prospective, community-based JHS (Jackson Heart Study). Cross-sectional associations of suPAR with lifestyle and CVD risk factors were assessed, whole-genome sequence data were used to evaluate genetic associations of suPAR, and relationships of suPAR with incident CVD outcomes and overall mortality were estimated over follow-up.

RESULTS

In Cox models adjusted for traditional CVD risk factors, estimated glomerular filtration rate, and CRP (C-reactive protein), each 1-SD higher suPAR was associated with a 21% to 31% increased risk of incident coronary heart disease, heart failure, stroke, and mortality. In the genome-wide association study, 2 missense (rs399145 encoding p.Thr86Ala, rs4760 encoding p.Phe272Leu) and 2 noncoding regulatory variants (rs73935023 within an enhancer element and rs4251805 within the promoter) of PLAUR on chromosome 19 were each independently associated with suPAR and together explained 14% of suPAR phenotypic variation. The allele frequencies of each of the four suPAR-associated genetic variants differ considerably across African and European populations. We further show that PLAUR rs73935023 can alter transcriptional activity in vitro. We did not find any association between genetically determined suPAR and CVD in JHS or a larger electronic medical record-based analyses of Blacks or Whites.

CONCLUSIONS

Our results demonstrate the importance of ancestry-differentiated genetic variation on suPAR levels and indicate suPAR is a CVD biomarker in Black adults.

Diet-dependent natriuretic peptide receptor C expression in adipose tissue is mediated by PPARγ via long-range distal enhancers

The cardiac natriuretic peptides (NPs) are well established as regulators of blood pressure and fluid volume, but they also stimulate adipocyte lipolysis and control the gene program of nonshivering thermogenesis in brown adipose tissue. The NP "clearance" receptor C (NPRC) functions to clear NPs from the circulation via peptide internalization and degradation and thus is an important regulator of NP signaling and adipocyte metabolism. It is well known that the Nprc gene is highly expressed in adipose tissue and dynamically regulated upon nutrition and environmental changes. However, the molecular basis for how Nprc gene expression is regulated is still poorly understood. Here, we identified the nuclear receptor transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) as a transcriptional regulator of Nprc expression in mouse adipocytes. During 3T3-L1 adipocyte differentiation, levels of Nprc expression increase in parallel with PPARγ induction. Rosiglitazone, a classic PPARγ agonist, increases, whereas siRNA knockdown of PPARγ reduces, Nprc expression in 3T3-L1 adipocytes. By using chromosome conformation capture and luciferase reporter assays, we demonstrate that PPARγ controls Nprc gene expression in adipocytes through its long-range distal enhancers. Furthermore, the induction of Nprc expression in adipose tissue during high-fat diet feeding is found to be associated with increased PPARγ enhancer activity. Our findings define PPARγ as a mediator of adipocyte Nprc gene expression and establish a new connection between PPARγ and the control of adipocyte NP signaling in obesity.

Physical Activity, Subclinical Myocardial Injury, and Risk of Heart Failure Subtypes in Black Adults

OBJECTIVES

This study sought to evaluate the independent associations and interactions between high-sensitivity cardiac troponin I (hs-cTnI) and physical activity (PA) with risk of heart failure (HF) subtypes, HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF).

BACKGROUND

Black adults are at high risk for developing HF. Physical inactivity and subclinical myocardial injury, as assessed by hs-cTnI concentration, are independent risk factors for HF.

METHODS

Black adults from the Jackson Heart Study without prevalent HF who had hs-cTnI concentration and self-reported PA assessed at baseline were included. Adjusted Cox models were used to evaluate the independent and joint associations and interaction between hs-cTnI concentrations and PA with risk of HFpEF and HFrEF.

RESULTS

Among 3,959 participants, 25.1% had subclinical myocardial injury (hs-cTnI ≥4 and ≥6 ng/l in women and men, respectively), and 48.2% were inactive (moderate-to-vigorous PA = 0 min/week). Over 12.0 years of follow-up, 163 and 150 participants had an incident HFpEF and HFrEF event, respectively. In adjusted analysis, higher hs-cTnI concentration (per 1-U log increase) was associated with higher risk of HFpEF (hazard ratio [HR]: 1.47; 95% confidence interval [CI]: 1.25 to 1.72]) and HFrEF (HR: 1.57; 95% CI: 1.35 to 1.83]). In contrast, higher PA (per 1-U log increase) was associated with a lower risk of HFpEF (HR: 0.93; 95% CI: 0.88 to 0.99]) but not HFrEF. There was a significant interaction between hs-cTnI and PA for risk of HFpEF (p interaction = 0.04) such that inactive participants with subclinical myocardial injury were at higher risk of HFpEF but active participants were not.

CONCLUSIONS

Among Black adults with subclinical myocardial injury, higher levels of PA were associated with attenuated risk of HFpEF.

Development and Validation of Machine Learning-Based Race-Specific Models to Predict 10-Year Risk of Heart Failure: A Multicohort Analysis

BACKGROUND

Heart failure (HF) risk and the underlying risk factors vary by race. Traditional models for HF risk prediction treat race as a covariate in risk prediction and do not account for significant parameters such as cardiac biomarkers. Machine learning (ML) may offer advantages over traditional modeling techniques to develop race-specific HF risk prediction models and to elucidate important contributors of HF development across races.

METHODS

We performed a retrospective analysis of 4 large, community cohort studies (ARIC [Atherosclerosis Risk in Communities], DHS [Dallas Heart Study], JHS [Jackson Heart Study], and MESA [Multi-Ethnic Study of Atherosclerosis]) with adjudicated HF events. The study included participants who were >40 years of age and free of HF at baseline. Race-specific ML models for HF risk prediction were developed in the JHS cohort (for Black race-specific model) and White adults from ARIC (for White race-specific model). The models included 39 candidate variables across demographic, anthropometric, medical history, laboratory, and electrocardiographic domains. The ML models were externally validated and compared with prior established traditional and non-race-specific ML models in race-specific subgroups of the pooled MESA/DHS cohort and Black participants of ARIC. The Harrell C-index and Greenwood-Nam-D'Agostino χ2 tests were used to assess discrimination and calibration, respectively.

RESULTS

The ML models had excellent discrimination in the derivation cohorts for Black (n=4141 in JHS, C-index=0.88) and White (n=7858 in ARIC, C-index=0.89) participants. In the external validation cohorts, the race-specific ML model demonstrated adequate calibration and superior discrimination (Black individuals, C-index=0.80-0.83; White individuals, C-index=0.82) compared with established HF risk models or with non-race-specific ML models derived with race included as a covariate. Among the risk factors, natriuretic peptide levels were the most important predictor of HF risk across both races, followed by troponin levels in Black and ECG-based Cornell voltage in White individuals. Other key predictors of HF risk among Black individuals were glycemic parameters and socioeconomic factors. In contrast, prevalent cardiovascular disease and traditional cardiovascular risk factors were stronger predictors of HF risk in White adults.

CONCLUSIONS

Race-specific and ML-based HF risk models that integrate clinical, laboratory, and biomarker data demonstrated superior performance compared with traditional HF risk and non-race-specific ML models. This approach identifies distinct race-specific contributors of HF.

Physical Activity, Inflammation, Coronary Artery Calcification, and Incident Coronary Heart Disease in African Americans: Insights From the Jackson Heart Study

OBJECTIVE

To examine associations between physical activity (PA), inflammation, coronary artery calcification (CAC), and incident coronary heart disease (CHD) in African Americans.

METHODS

Among Jackson Heart Study participants without prevalent CHD at baseline (n=4295), we examined the relationships between PA and high-sensitivity C-reactive protein, the presence of CAC (Agatston score ≥100), and incident CHD. Based on the American Heart Association's Life's Simple 7 metrics, participants were classified as having poor, intermediate, or ideal PA.

RESULTS

After adjustment for possible confounding factors, ideal PA was associated with lower high-sensitivity C-reactive protein levels (β, -0.15; 95% CI, -0.15 to -0.002) and a lower prevalence of CAC (odds ratio, 0.70; 95% CI, 0.51-0.96) compared with poor PA. During a median of 12.8 years of follow-up, there were 164 incident CHD events (3.3/1000 person-years). Ideal PA was associated with a lower rate of incident CHD compared with poor PA (hazard ratio, 0.55; 95% CI, 0.31-0.98).

CONCLUSION

In a large community-based African American cohort, ideal PA was associated with lower inflammation levels, a lower prevalence of CAC, and a lower rate of incident CHD. These findings suggest that promotion of ideal PA may be an important way to reduce the risk of subclinical and future clinical CHD in African Americans.

Relation of Low Normal Left Ventricular Ejection Fraction to Heart Failure Hospitalization in Blacks (From the Jackson Heart Study)

There is no clear consensus on a lower cutoff value for normal left ventricular ejection fraction (EF) and the prognostic implications of low normal EF (LNEF) are poorly understood, particularly in Blacks. Therefore, we investigated the association of LNEF and incident heart failure (HF) in a community-based cohort of Blacks. We studied 3,669 participants (mean age 54 years, 63% women) of the Jackson Heart Study without prevalent HF or coronary heart disease (CHD). Participants were divided into three groups: (1) Reduced EF (<50%), (2) LNEF (≥50%, <55%), and (3) Normal EF (≥55%). There were 197 cases of incident HF hospitalizations over a median follow-up of 10 years (interquartile range 9.4 to 10). After adjustment for conventional risk factors and incident CHD, the LNEF group had a higher rate of incident HF hospitalization than the Normal EF group (HR 1.58, 95% CI 1.04 to 2.38, p<0.05). Furthermore, this relation remained statistically significant after additionally adjusting for LV mass index but was not significant after adjusting for LV diastolic dysfunction grade. In participants with LNEF with incident HF, 63% developed HF with reduced EF and 37% developed HF with preserved EF. In conclusion, LNEF is associated with higher risk of incident HF hospitalization in comparison with normal EF in a community-based cohort of Blacks. In those with LNEF who went on to develop HF, most cases were HF with reduced EF. These findings suggest that strategies are needed for risk stratification and management to improve outcomes in patients with LNEF.

Associations of adiponectin and leptin with brain natriuretic peptide in African Americans: the Jackson Heart Study

Brain natriuretic peptide (BNP) is elevated in decompensated systolic and diastolic heart failure. The plasma levels of adipokines, such as adiponectin and leptin, may provide evidence for mechanistic differences in BNP concentrations. African-American-specific associations are limited in the literature. The objective of this study was to evaluate the associations of adiponectin and leptin with BNP among African Americans.

METHODS

Linear and logistic regressions were used to test the associations between adiponectin, leptin, and plasma BNP in 3738 participants of the Jackson Heart Study (JHS), a single-site prospective cohort study of African Americans in Jackson, Mississippi.

RESULTS

A direct relationship of adiponectin was observed in multiple multivariate-adjusted linear models: in men (β = 0.41-0.47), and in women (β = 0.32-0.38). Those in the highest quartile of adiponectin expression were twice as likely to have elevated BNP levels after adjustment [odds ratio 2.66 (95% confidence interval, 1.66-4.34)]. An inverse relationship of leptin with BNP was observed (β = -0.15) but attenuated after adjustment for aldosterone, renin, and adiponectin.

CONCLUSIONS

Different linear associations of adiponectin and leptin with BNP were observed. Odds of elevated adiponectin were observed with elevated BNP in multivariate-adjusted models. This paradoxical relationship of adiponectin and plasma BNP is possibly explained through adiponectin resistance.

Interferon gamma-induced protein 10 (IP-10) and cardiovascular disease in African Americans

Biomarkers of chronic inflammation (such as C-reactive protein) have long been associated with cardiovascular disease and mortality; however, biomarkers involved in antiviral cytokine induction and adaptive immune system activation remain largely unexamined. We hypothesized the cytokine interferon gamma inducible protein 10 (IP-10) would be associated with clinical and subclinical cardiovascular disease and all-cause mortality in African Americans. We assessed these associations in the Jackson Heart Study (JHS) cohort and the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. There was a modest association of IP-10 with higher odds of left ventricular hypertrophy (OR = 1.20 (95% confidence interval (CI) 1.03, 1.41) per standard deviation (SD) higher natural log-transformed IP-10 in JHS). We did not observe associations with ankle brachial index, intima-media thickness, or arterial calcification. Each SD higher increment of ln-transformed IP-10 concentration was associated with incident heart failure (hazard ratio (HR) 1.26; 95% CI 1.11, 1.42, p = 4x10-4) in JHS, and with overall mortality in both JHS (HR 1.12 per SD, 95% CI 1.03, 1.21, p = 7.5x10-3) and REGARDS (HR 1.31 per SD, 95% CI 1.10, 1.55, p = 2.0 x 10-3), adjusting for cardiovascular risk factors and C-reactive protein. However, we found no association between IP-10 and stroke or coronary heart disease. These results suggest a role of IP-10 in heart failure and mortality risk independent of C-reactive protein. Further research is needed to investigate how the body's response to chronic viral infection may mediate heart failure and overall mortality risk in African Americans.

Racial Differences in Malignant Left Ventricular Hypertrophy and Incidence of Heart Failure: A Multicohort Study

BACKGROUND

A malignant subphenotype of left ventricular hypertrophy (LVH) has been described, in which minimal elevations in cardiac biomarkers identify individuals with LVH at high risk for developing heart failure (HF). We tested the hypothesis that a higher prevalence of malignant LVH among blacks may contribute to racial disparities in HF risk.

METHODS

Participants (n=15 710) without prevalent cardiovascular disease were pooled from 3 population-based cohort studies, the ARIC Study (Atherosclerosis Risk in Communities), the DHS (Dallas Heart Study), and the MESA (Multi-Ethnic Study of Atherosclerosis). Participants were classified into 3 groups: those without ECG-LVH, those with ECG-LVH and normal biomarkers (hs-cTnT (high sensitivity cardiac troponin-T) <6 ng/L and NT-proBNP (N-terminal pro-B-type natriuretic peptide) <100 pg/mL), and those with ECG-LVH and abnormal levels of either biomarker (malignant LVH). The outcome was incident HF.

RESULTS

Over the 10-year follow-up period, HF occurred in 512 (3.3%) participants, with 5.2% in black men, 3.8% in white men, 3.2% in black women, and 2.2% in white women. The prevalence of malignant LVH was 3-fold higher among black men and women versus white men and women. Compared with participants without LVH, the adjusted hazard ratio for HF was 2.8 (95% CI, 2.1-3.5) in those with malignant LVH and 0.9 (95% CI, 0.6-1.5) in those with LVH and normal biomarkers, with similar findings in each race/sex subgroup. Mediation analyses indicated that 33% of excess hazard for HF among black men and 11% of the excess hazard among black women was explained by the higher prevalence of malignant LVH in blacks. Of black men who developed HF, 30.8% had malignant LVH at baseline, with a corresponding population attributable fraction of 0.21. The proportion of HF cases occurring among those with malignant LVH, and the corresponding population attributable fraction, were intermediate and similar among black women and white men and lowest among white women.

CONCLUSIONS

A higher prevalence of malignant LVH may in part explain the higher risk of HF among blacks versus whites. Strategies to prevent development or attenuate risk associated with malignant LVH should be investigated as a strategy to lower HF risk and mitigate racial disparities.

Independent Impact of Gynoid Fat Distribution and Free Testosterone on Circulating Levels of N-Terminal Pro-Brain Natriuretic Peptide (NT-proBNP) in Humans

Background: Natriuretic peptides (NPs), including brain natriuretic peptide (BNP), are neurohormones involved in the regulation of water-sodium balance and the maintenance of cardiovascular homeostasis. A higher concentration of NPs is observed in females, but the mechanism behind this difference has not been fully elucidated. Methods: Randomly chosen 255 volunteers from the general population were examined. Overall, 196 people without severe cardiovascular disease were included (mean age 48 years, 35.7% male). A comprehensive assessment was performed, including anthropometric measurements, N-terminal pro-brain natriuretic peptide (NT-proBNP), total testosterone (TT) and sex hormone-binding globulin (SHBG) concentration, transthoracic echocardiography (ECHO), and body composition analysis by direct dual-energy X-ray absorptiometry (DEXA). The univariate analysis adjusted by the known affecting factors determined which measurements were independently associated with NT-proBNP concentration. Results: NT-proBNP concentration was positively associated with gynoid fat mass, gynoid/total fat (G/TF) mass index, SHBG and negatively with android/gynoid (A/G) fat mass index, TT and calculated free testosterone (CFT) concentrations. Furthermore, body composition parameters remained independently associated with NT-proBNP levels even after adjusting for CFT and SHBG. Conclusion: In the population without severe cardiovascular disease, the NT-proBNP concentration is independently associated with lower availability of testosterone and higher gynoid fat distribution, which may explain higher NPs levels in females.

Prediabetes and Risk for Cardiovascular Disease by Hypertension Status in Black Adults: The Jackson Heart Study

OBJECTIVE

Recent studies have suggested that prediabetes is associated with an increased risk for cardiovascular disease (CVD) only among individuals with concomitant hypertension.

RESEARCH DESIGN AND METHODS

We analyzed the association between prediabetes and CVD by hypertension status among 3,313 black adults in the Jackson Heart Study (JHS) without diabetes or a history of CVD at baseline (2000-2004). Prediabetes was defined as fasting plasma glucose between 100 and 125 mg/dL or hemoglobin A1c between 5.7 and 6.4% (39 and 46 mmol/mol). Hypertension was defined as systolic/diastolic blood pressure ≥140/90 mmHg and/or self-reported antihypertensive medication use. Participants were followed for incident CVD events and all-cause mortality through 31 December 2014.

RESULTS

Overall, 35% of JHS participants did not have prediabetes or hypertension, 18% had prediabetes alone, 22% had hypertension alone, and 25% had both prediabetes and hypertension. Compared with participants without either condition, the multivariable-adjusted hazard ratios for CVD events among participants with prediabetes alone, hypertension alone, and both prediabetes and hypertension were 0.86 (95% CI 0.51, 1.45), 2.09 (1.39, 3.14), and 1.93 (1.28, 2.90), respectively. Among participants with and without hypertension, there was no association between prediabetes and an increased risk for CVD (0.78 [0.46, 1.34] and 0.94 [0.70, 1.26], respectively). No association was present between prediabetes and all-cause mortality among participants with or without hypertension.

CONCLUSIONS

Regardless of hypertension status, prediabetes was not associated with an increased risk for CVD or all-cause mortality in this cohort of black adults.

Racial differences in the association of NT-proBNP with risk of incident heart failure in REGARDS

BACKGROUND

Black individuals have lower natriuretic peptide levels and greater risk of heart failure (HF) than white individuals. Higher N-terminal-pro-B-type natriuretic peptide (NT-proBNP) is associated with increased risk of incident HF, but little information is available in black individuals. We examined race-specific differences in 1) the association of NT-proBNP with incident HF and 2) the predictive ability of NT-proBNP for incident HF across body mass index (BMI) and estimated glomerular filtration rate (eGFR) categories.

METHODS

In a prospective case-cohort study, baseline NT-proBNP was measured among 687 participants with incident HF and 2,923 (weighted 20,075) non-case randomly selected participants. Multivariable Cox proportional hazard modeling was used to assess the objectives of our study. Global Wald Chi-square score estimated from multivariable Cox models was used to assess predictive ability of NT-proBNP across BMI and eGFR categories.

RESULTS

In the multivariable model, a doubling of NT-proBNP concentration was associated with greater risk of incident HF among white individuals [hazard ratio (HR): 1.73; 95% CI: 1.55-1.94] than black individuals (HR: 1.51; 95% CI: 1.34-1.70); Pinteraction by race = 0.024. Higher NT-proBNP was the strongest predictor of incident HF across all BMI and eGFR categories among white individuals. By contrast, among black individuals with obesity (BMI ≥ 30 kg/m2) or eGFR < 60 mL/min/1.73 m2, the predictive ability of NT-proBNP for incident HF was attenuated.

CONCLUSIONS

The magnitude of the association of higher NT-proBNP with incident HF risk was greater among white individuals than black individuals. The diminished ability of NT-proBNP to predict the risk of HF in black population with obesity or impaired kidney function highlights the need of further investigations.

Race-based demographic, anthropometric and clinical correlates of N-terminal-pro B-type natriuretic peptide

BACKGROUND

Population studies have shown that black race is a natriuretic peptide (NP) deficiency state. We sought to assess whether the effects of age, sex, body mass index (BMI) and estimated glomerular filtration rate (eGFR) on N-terminal-pro-B-type NP (NT-proBNP) levels differ in white and black individuals.

METHODS

The study population consisted of a stratified random cohort from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. The study outcomes were the effects of age, sex, BMI and eGFR on NT-proBNP levels independent of socioeconomic and cardiovascular disease factors. Multivariable regression analyses were used to assess the effects of age, sex, BMI and eGFR on NT-proBNP levels in blacks and whites.

RESULTS

Of the 27,679 participants in the weighted sample, 54.7% were females, 40.6% were black, and the median age was 64 years. Every 10-year higher age was associated with 38% [95% confidence interval (CI): 30%-45%] and 34% (95% CI: 22%-43%) higher NT-proBNP levels in whites and blacks, respectively. Female sex was associated with 31% (95% CI: 20%-43%) higher NT-proBNP levels in whites and 28% (95% CI: 15%-45%) higher in blacks. There was a significant linear inverse relationship between BMI and NT-proBNP in whites and a non-linear inverse relationship in blacks. Whites and blacks had a non-linear inverse relationship between eGFR and NT-proBNP. However, the non-linear relationship between NT-proBNP and eGFR differed by race (p = 0.01 for interaction).

CONCLUSIONS

The association of age and sex with NT-proBNP levels was similar in blacks and whites but the form of the BMI and eGFR relationship differed by race.

Sex-specific associations of obesity and N-terminal pro-B-type natriuretic peptide levels in the general population

BACKGROUND

Obese subjects have lower natriuretic peptide levels, but males and females have different anthropometric characteristics and fat distribution. Whether obesity-associated lowering of natriuretic peptides differs among males and females is unknown. Therefore, we investigated sex-specific associations of obesity and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels among adults in the general population.

METHODS AND RESULTS

Using 8260 participants (50.1% females) from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort, we evaluated the relationship of NT-proBNP levels with obesity-associated parameters, i.e. waist circumference (WC), body mass index (BMI) and body weight in the overall population, and in males and females separately. NT-proBNP levels were higher in females (median, interquartile range: 50.5, 28.2-87.0 ng/L) than in males (24.3, 10.1-54.6 ng/L; P < 0.001). In the overall population, NT-proBNP levels were significantly lower in heavier individuals and displayed a 'U-shaped' relationship with increasing WC, but were not associated with BMI. After sex stratification, there was no significant association between NT-proBNP concentrations and anthropometric measures in females. However, in males increasing WC and BMI were associated with higher NT-proBNP levels (P < 0.05) while increasing body weight was associated with slightly lower NT-proBNP levels (P < 0.05). Age strongly confounded the association of NT-proBNP levels with obesity, and age-associated increases in NT-proBNP were significantly higher in males than in females (P < 0.001). In multivariable adjusted analyses, the inverse association of obesity and NT-proBNP levels was also significantly modified by sex: NT-proBNP levels were lower with increasing WC, BMI and body weight among females compared with males (P_interaction  < 0.05). After also accounting for BMI, abdominal obesity was associated with lower NT-proBNP levels in females, but not in males (P_interaction  < 0.001).

CONCLUSIONS

Natriuretic peptide deficiency in obesity mostly pertains to females with abdominal obesity, whereas the relationship between obesity and natriuretic peptides appears to be more complex in males.

Intentional and unintentional medication non-adherence in African Americans: Insights from the Jackson Heart Study

BACKGROUND

Non-adherence to medications is common and leads to suboptimal outcomes. Non-adherence can be intentional (e.g., deciding to skip dosages) or unintentional (e.g., forgetting), yet few studies have distinguished these reasons. An improved understanding of the reasons for non-adherence could inform the development of effective interventions.

METHODS AND RESULTS

We analyzed data from African Americans in the Jackson Heart Study who were prescribed medications for one or more chronic conditions. Participants were grouped by patient-reported adherence with non-adherence categorized as being intentional, unintentional or both. We used modified Poisson regression models to examine the factors associated with types of non-adherence. Of 2933 participants taking medication, 2138 (72.9%) reported non-adherence with 754 (35.3%) reporting only unintentional non-adherence, 263 (12.3%) only intentional non-adherence, and 1121 (52.4%) both. Factors independently associated with intentional non-adherence included female sex and depressive symptoms while factors associated with unintentional non-adherence included younger age and separated relationship status. Unintentional and intentional non-adherence was more common among participants taking anti-arrhythmic and anti-asthmatic medications, respectively. Higher levels of global perceived stress was associated with both types of non-adherence. The adjusted models for intentional and unintentional non-adherence had c-statistics of 0.65 and 0.66, respectively, indicating modest discrimination.

CONCLUSION

Specific patient factors and individual medication classes were associated with distinct patterns of intentional and unintentional non-adherence, yet the overall modest discrimination of the models suggests contributions from other unmeasured factors. These findings provide a construct for understanding reasons for non-adherence and provide rationale to assess whether personalized interventions can improve adherence.

Cigarette Smoking and Incident Heart Failure: Insights From the Jackson Heart Study

BACKGROUND

Cigarette smoking has been linked with several factors associated with cardiac dysfunction. We hypothesized that cigarette smoking is associated with left ventricular (LV) structure and function, and incident heart failure (HF) hospitalization.

METHODS

We investigated 4129 (never smoker n=2884, current smoker n=503, and former smoker n=742) black participants (mean age, 54 years; 63% women) without a history of HF or coronary heart disease at baseline in the Jackson Heart Study. We examined the relationships between cigarette smoking and LV structure and function by using cardiac magnetic resonance imaging among 1092 participants, cigarette smoking and brain natriuretic peptide levels among 3325 participants, and incident HF hospitalization among 3633 participants with complete data.

RESULTS

After adjustment for confounding factors, current smoking was associated with higher mean LV mass index and lower mean LV circumferential strain (P<0.05, for both) in comparison with never smoking. Smoking status, intensity, and burden were associated with higher mean brain natriuretic peptide levels (all P<0.05). Over 8.0 years (7.7-8.0) median follow-up, there were 147 incident HF hospitalizations. After adjustment for traditional risk factors and incident coronary heart disease, current smoking (hazard ratio, 2.82; 95% confidence interval, 1.71-4.64), smoking intensity among current smokers (≥20 cigarettes/d: hazard ratio, 3.48; 95% confidence interval, 1.65-7.32), and smoking burden among ever smokers (≥15 pack-years: hazard ratio, 2.06; 95% confidence interval, 1.29-3.3) were significantly associated with incident HF hospitalization in comparison with never smoking.

CONCLUSIONS

In blacks, cigarette smoking is an important risk factor for LV hypertrophy, systolic dysfunction, and incident HF hospitalization even after adjusting for effects on coronary heart disease.

Synthesis, secretion, function, metabolism and application of natriuretic peptides in heart failure

As a family of hormones with pleiotropic effects, natriuretic peptide (NP) system includes atrial NP (ANP), B-type NP (BNP), C-type NP (CNP), dendroaspis NP and urodilatin, with NP receptor-A (guanylate cyclase-A), NP receptor-B (guanylate cyclase-B) and NP receptor-C (clearance receptor). These peptides are genetically distinct, but structurally and functionally related for regulating circulatory homeostasis in vertebrates. In humans, ANP and BNP are encoded by NP precursor A (NPPA) and NPPB genes on chromosome 1, whereas CNP is encoded by NPPC on chromosome 2. NPs are synthesized and secreted through certain mechanisms by cardiomyocytes, fibroblasts, endotheliocytes, immune cells (neutrophils, T-cells and macrophages) and immature cells (embryonic stem cells, muscle satellite cells and cardiac precursor cells). They are mainly produced by cardiovascular, brain and renal tissues in response to wall stretch and other causes. NPs provide natriuresis, diuresis, vasodilation, antiproliferation, antihypertrophy, antifibrosis and other cardiometabolic protection. NPs represent body's own antihypertensive system, and provide compensatory protection to counterbalance vasoconstrictor-mitogenic-sodium retaining hormones, released by renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS). NPs play central roles in regulation of heart failure (HF), and are inactivated through not only NP receptor-C, but also neutral endopeptidase (NEP), dipeptidyl peptidase-4 and insulin degrading enzyme. Both BNP and N-terminal proBNP are useful biomarkers to not only make the diagnosis and assess the severity of HF, but also guide the therapy and predict the prognosis in patients with HF. Current NP-augmenting strategies include the synthesis of NPs or agonists to increase NP bioactivity and inhibition of NEP to reduce NP breakdown. Nesiritide has been established as an available therapy, and angiotensin receptor blocker NEP inhibitor (ARNI, LCZ696) has obtained extremely encouraging results with decreased morbidity and mortality. Novel pharmacological approaches based on NPs may promote a therapeutic shift from suppressing the RAAS and SNS to re-balancing neuroendocrine dysregulation in patients with HF. The current review discussed the synthesis, secretion, function and metabolism of NPs, and their diagnostic, therapeutic and prognostic values in HF.

Increased Proximal Aortic Diameter is Associated With Risk of Cardiovascular Events and All-Cause Mortality in Blacks The Jackson Heart Study

BACKGROUND

Enlargement of the proximal aorta is associated with aortic wall tissue remodeling, including fragmentation of the elastin fibers, increased synthesis of collagen, and calcification, all of which are associated with aortic wall stiffening. We hypothesized that the proximal aortic diameter (AoD) is associated with cardiovascular events in a community-based cohort of blacks.

METHODS AND RESULTS

We investigated the associations between AoD and cardiovascular events among 3018 black participants (mean age, 55.9 years; 69% women) without past history of cardiovascular disease in the Jackson Heart Study. AoD was measured using echocardiography at the level of the sinuses of Valsalva at end diastole. Cardiovascular event was defined as incident myocardial infarction, fatal coronary artery disease, stroke, or heart failure hospitalization. Cox proportional hazards regression models were used to evaluate the association between baseline AoD and cardiovascular events. Over a median follow-up of 8.3 years, there were 258 cardiovascular events (incident rate, 10.5 per 1000 person-years). After adjustment for traditional risk factors, increased AoD was significantly associated with cardiovascular events (hazard ratio per 1-cm increase, 1.72; 95% CI, 1.10-2.69; P<0.05). Participants in the top AoD quintile had a higher incidence of cardiovascular events compared to those not in the top quintile (hazard ratio, 1.47; 95% CI, 1.11-1.94; P<0.005) after adjustment for risk factors.

CONCLUSIONS

Greater AoD was associated with an increased risk of cardiovascular events in a community-based cohort of blacks. AoD may be useful as a predictor of incident cardiovascular events and further investigation is warranted.

Biomarkers in cardiovascular disease: Statistical assessment and section on key novel heart failure biomarkers

Cardiovascular disease (CVD) is a leading cause of death worldwide and continues to increase in prevalence compared to previous decades, in part because of the aging of the world population. Atherosclerotic CVD starts at a very young age and progresses over time allowing sufficient time for screening and early detection of the condition. Advances in biomarker research and developments related to CVD over the past 30 years have led to more sensitive screening methods, a greater emphasis on its early detection and diagnosis, and improved treatments resulting in more favorable clinical outcomes in the community. However, the use of biomarkers for different purposes in CVD remains an important area of research that has been explored by scientists over the years and many new developments are still underway. Therefore, a detailed description of all CVD biomarkers that are currently been used or investigated for future use in the field of cardiovascular medicine is out of scope for any review article. In the present review, we do not intend to replicate the information from previous exhaustive review on biomarkers, but highlight key statistical and clinical issues with an emphasis on methods to evaluate the incremental yield of biomarkers, including their clinical utility, a prerequisite before any putative novel biomarker is utilized in clinical practice. In addition, we will summarize information regarding recent novel heart failure biomarkers in current practice, which are undergoing scrutiny before they can be available for clinical use, and their impact on clinical outcomes.

Associations Between Blood Pressure and Outcomes Among Blacks in the Jackson Heart Study

BACKGROUND

In 2014, new hypertension guidelines liberalized blood pressure goals for persons 60 years and older. Little is known about the implications for blacks.

METHODS AND RESULTS

Using data from 2000 through 2011 for 5280 participants in the Jackson Heart Study, a community-based black cohort in Jackson, Mississippi, we examined whether higher blood pressure was associated with greater risk of mortality and heart failure hospitalization, and whether the risk was the same across age groups. We investigated associations between baseline blood pressure and both mortality and heart failure hospitalization. We also tested for interactions between age and blood pressure in the mortality model. Median systolic and diastolic blood pressures at baseline were 125 mm Hg (25th-75th percentile, 114-137 mm Hg) and 79 mm Hg (72-86 mm Hg), respectively. Median follow-up was 9 years for mortality and 7 years for heart failure hospitalization. After multivariable adjustment, every 10 mm Hg increase in systolic blood pressure was associated with greater risks of mortality (hazard ratio, 1.12; 95% CI, 1.06-1.17) and heart failure hospitalization (1.07; 95% CI, 1.00-1.14). The mortality risk per 10 mm Hg increase in systolic blood pressure was greater in participants younger than 60 years (1.26; 95% CI, 1.13-1.42) than among participants 60 years and older (1.09; 95% CI, 1.03-1.15).

CONCLUSIONS

Adults in all age groups were at greater risk of mortality as systolic blood pressure increased. In the context of the 2014 hypertension guidelines, these findings should be considered when determining treatment goals in black patients.

Capacity-Building for Career Paths in Public Health and Biomedical Research for Undergraduate Minority Students: A Jackson Heart Study Success Model

OBJECTIVE

This article chronicles the building of individual student capacity as well as faculty and institutional capacity, within the context of a population-based, longitudinal study of African Americans and cardiovascular disease. The purpose of this article is to present preliminary data documenting the results of this approach.

DESIGN

The JHS Scholars program is designed, under the organizational structure of the Natural Sciences Division at Tougaloo College, to provide solid preparation in quantitative skills through: good preparation in mathematics and the sciences; a high level of reading comprehension; hands-on learning experiences; and mentoring and counseling to sustain the motivation of the students to pursue further studies.

SETTING

This program is on the campus of a private Historically Black College in Mississippi.

PARTICIPANTS

The participants in the program are undergraduate students.

MAIN OUTCOME MEASURES

Data, which included information on major area of study, institution attended, degrees earned and position in the workforce, were analyzed using STATA 14.

RESULTS

Of 167 scholars, 46 are currently enrolled, while 118 have graduated. One half have completed graduate or professional programs, including; medicine, public health, pharmacy, nursing, and biomedical science; approximately one-fourth (25.4 %) are enrolled in graduate or professional programs; and nearly one tenth (9.3%) completed graduate degrees in law, education, business or English.

CONCLUSIONS

These data could assist other institutions in understanding the career development process that helps underrepresented minority students in higher education to make career choices on a path toward public health, health professions, biomedical research, and related careers.

Higher BNP levels within physiological range correlate with beneficial nonfasting lipid profiles in the elderly: a cross-sectional study

Background

Emerging studies indicate that B-type natriuretic peptide (BNP), a well-known biomarker for heart failure, also plays pivotal roles in metabolic control. Circulating BNP levels progressively increase as ages grow older. However, the association between BNP levels and lipid metabolism in the elderly remains unknown.

Methods

A total of 680 eligible volunteers (male/female: 334/346) aged between 60 and 80 years old without overt heart failure (BNP <100 pg/ml) were enrolled. Random nonfasting venous samples were obtained for biochemical analysis. The subjects were stratified based on BNP quartiles: BNP Q1 (range: 2.2–9.0 pg/ml), Q2 (9.1–20.4 pg/ml), Q3 (20.5–44.4 pg/ml) and Q4 (44.6–99.7 pg/ml). Difference of metabolic parameters was compared among the subjects grouped by BNP quartiles. Univariate correlation and multiple linear regression were performed to analyze the association between BNP levels and metabolic parameters. The odds ratios (OR) and 95 % confidence intervals (CI) for dyslipidemia in subjects within BNP Q1-3 relative to subjects within BNP Q4 were calculated.

Results

Circulating BNP levels positively correlated with age, while negatively correlated with body mass index (BMI), eGFR and non-HDL. Subjects with lower BNP quartiles had significantly elevated prevalence of dyslipidemia, including hypertriglyceridemia, hyper-LDL-emia and hypercholesterolemia. The OR of hypertriglyceridemia and hypercholesterolemia for subjects within BNP Q1-2 significantly increased relative to BNP Q4.

Conclusions

The elderly people with higher BNP levels have significantly reduced risks for nonfasting dyslipidemia. Verification of the cause-effect relationship between BNP and dyslipidemia may bring therapeutic implications.

Using Natriuretic Peptides for Selection of Patients in Acute Heart Failure Clinical Trials

Acute heart failure (AHF) is a complex syndrome with presentations ranging from hypotensive cardiogenic shock to hypertensive emergency with pulmonary edema. Most patients with AHF present with worsening of chronic HF signs and symptoms over days to weeks, and significant heterogeneity exists. It can, therefore, be challenging to characterize the overall population. The complexity of defining the AHF phenotype has been cited as a contributing cause for neutral results in most pharmacologic trials in patients with AHF. Dyspnea has been a routine inclusion criterion for AHF for over a decade, but the utility of current instruments for dyspnea assessment has been called into question. Furthermore, the threshold of clinical severity that prompts patient admission of an HF clinic visit may vary substantially across regions in global trials. Therefore, the inclusion of cardiac-specific biomarkers has been incorporated into AHF trials as 1 strategy to support inclusion of the target patient population and potentially enrich the population with patients at risk for clinical outcomes. In conclusion, we discuss strategies to support appropriate patient selection in AHF trials with an emphasis on using biomarker criteria that may improve the likelihood of success with future AHF clinical trials.

Natural interpretations in Tobit regression models using marginal estimation methods

The Tobit model, also known as a censored regression model to account for left- and/or right-censoring in the dependent variable, has been used in many areas of applications, including dental health, medical research and economics. The reported Tobit model coefficient allows estimation and inference of an exposure effect on the latent dependent variable. However, this model does not directly provide overall exposure effects estimation on the original outcome scale. We propose a direct-marginalization approach using a reparameterized link function to model exposure and covariate effects directly on the truncated dependent variable mean. We also discuss an alternative average-predicted-value, post-estimation approach which uses model-predicted values for each person in a designated reference group under different exposure statuses to estimate covariate-adjusted overall exposure effects. Simulation studies were conducted to show the unbiasedness and robustness properties for both approaches under various scenarios. Robustness appears to diminish when covariates with substantial effects are imbalanced between exposure groups; we outline an approach for model choice based on information criterion fit statistics. The methods are applied to the Genetic Epidemiology Network of Arteriopathy (GENOA) cohort study to assess associations between obesity and cognitive function in the non-Hispanic white participants.

Facing Morbid Obesity: How to Approach It

Obesity is a major public health problem, with a prevalence of 10% to 20% in Western Europe. Morbid obesity, characterized by body mass index >40 kg/m(2), showed an increased prevalence in the last 30 years. Obesity is associated with reduced economic and social opportunities, reduced quality of life, and is a determinant of several "intermediate risk factors," leading to an increased mortality and a loss in life expectancy. The rising prevalence of morbid obesity increased the demand for bariatric surgery, also called "metabolic surgery": after these interventions, there is a decrease in metabolic comorbidities, cardiovascular (CV) risk, and total mortality. In this review, we update the evaluation of morbid obese patients from the physical examination to the metabolic, CV and respiratory assessments in order to correctly stratify the CV risk and provide the best treatment. To obtain these achievements, multidisciplinary work has to be carried out with a team involving several experts with different skills.

Natriuretic Peptides and Cardiometabolic Health

Natriuretic peptides are cardiac-derived hormones with a range of protective functions, including natriuresis, diuresis, vasodilation, lusitropy, lipolysis, weight loss, and improved insulin sensitivity. Their actions are mediated through membrane-bound guanylyl cyclases that lead to production of the intracellular second-messenger cyclic guanosine monophosphate. A growing body of evidence demonstrates that genetic and acquired deficiencies of the natriuretic peptide system can promote hypertension, cardiac hypertrophy, obesity, diabetes mellitus, the metabolic syndrome, and heart failure. Clinically, natriuretic peptides are robust diagnostic and prognostic markers, and augmenting natriuretic peptides is a target for therapeutic strategies in cardiometabolic disease. This review will summarize current understanding and highlight novel aspects of natriuretic peptide biology.

Insulin resistance is associated with increased concentrations of NT-proBNP in rheumatoid arthritis: IL-6 as a potential mediator

We examined the hypothesis that insulin resistance (IR) decreases circulating concentrations of N-terminal (NT)-probrain natriuretic peptide (BNP). Obesity, despite being a risk factor for heart failure (HF), is paradoxically associated with lower concentrations of BNP, a marker of myocardial stress. Low BNP in obesity is postulated to be due to IR; however, it has been difficult to define the role of IR independent of obesity. IR in rheumatoid arthritis (RA) is increased, independent of obesity, thus allowing potential mechanistic insights into the relationship between IR and BNP. We measured demographic factors, traditional cardiovascular risk factors, body mass index (BMI), markers of inflammation (interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor α (TNFα)), NT-proBNP, and IR by the homeostatic model assessment (HOMA) in 140 patients with RA and 82 control subjects. Patients with heart failure and coronary artery disease were excluded. We used multiple linear regression models to examine the relationship between HOMA and NT-proBNP in RA and controls and in RA alone, the additional effect of inflammation. As previously reported, NT-proBNP concentrations were higher in RA (median 80.49 pg/mL, IQR (23.67-167.08 pg/mL)) than controls (17.84 pg/mL (3.28-36.28 pg/mL)) (P < 0.001), and the prevalence of IR, defined by HOMA > 2.114, was higher among RA than controls (53 % vs. 15%, P > 0.001). HOMA was positively correlated with NT-proBNP (rho = 0.226, P = 0.007) in RA, but not in controls (rho = -0.154, P = 0.168). In a multivariable model adjusted for age, race, and sex, we found that increasing HOMA was statistically associated with increasing NT-proBNP concentrations in RA (P = 0.001), but not controls (P = 0.543) (P for interaction = 0.036). In RA subjects, when IL-6 was further included in the model, IL-6 (P = 0.0014), but not HOMA (P = 0.43), remained significantly associated with NT-proBNP, suggesting that IL-6 may be mechanistically involved in the relationship between IR and NT-proBNP in RA. We conclude that in patients with RA, insulin resistance is associated with higher, rather than the expected lower, concentrations of NT-proBNP and that this may be related to increased IL-6.

Racial Differences in Natriuretic Peptide Levels: The Dallas Heart Study

OBJECTIVES

The purpose of this study was to assess whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels differ according to race/ethnicity.

BACKGROUND

Natriuretic peptides (NP) are hormones with natriuretic, diuretic, and vasodilatory effects. Experimental NP deficiency promotes salt-sensitive hypertension and cardiac hypertrophy, conditions that are more common among black individuals.

METHODS

We examined plasma NT-proBNP levels according to race/ethnicity in 3,148 individuals (51% black, 31% white, 18% Hispanic) free of prevalent cardiovascular disease in the Dallas Heart Study. NT-proBNP values in the bottom sex-specific quartile were defined as low. Multivariable linear and logistic regression analyses were performed adjusting for clinical covariates and magnetic resonance imaging measurements of cardiac structure and function.

RESULTS

Hypertension was present in 41%, 25%, and 16% of black, white, and Hispanic individuals, respectively. Unadjusted NT-proBNP levels were lowest in black (median: 24 pg/ml; interquartile range [IQR]: 10 to 52 pg/ml) as compared with Hispanic (30 pg/ml; IQR: 14 to 59 pg/ml) and white individuals (32 pg/ml; IQR: 16 to 62 pg/ml), p < 0.0001. In multivariable-adjusted models, black individuals still had significantly lower NT-proBNP levels (-39% [95% confidence interval: -46% to -31%]; p < 0.0001) and greater odds of having low NT-proBNP (odds ratio: 2.46 [95% confidence interval: 1.86 to 3.26]), compared with white individuals. In contrast, NT-proBNP levels did not significantly differ between Hispanic and white individuals (p = 0.28). The finding of lower NT-proBNP levels in black individuals was similar when analyses were restricted to healthy participants without cardiovascular risk factors.

CONCLUSIONS

In this multiethnic cohort, NT-proBNP levels differ substantially according to race/ethnicity. Despite a higher prevalence of hypertension, black individuals had significantly lower NP levels than white and Hispanic individuals. A relative NP "deficiency" among black individuals may lead to greater susceptibility to salt retention and hypertension.

Higher serum concentrations of N-terminal pro-B-type natriuretic peptide associate with prevalent hypertension whereas lower associate with incident hypertension

Background

The role of the natriuretic peptides (NPs) in hypertension is complex. Thus, a higher blood NP concentration is a robust marker of pressure-induced cardiac damage in patients with hypertension, whereas genetically elevated NP concentrations are associated with a reduced risk of hypertension and overweight individuals presumably at high risk of hypertension have lower NP concentrations.

Objective

To investigate the associations between serum N-terminal pro-B-type natriuretic peptide (NT-proBNP), used as a surrogate marker for active BNP, and prevalent as well as 5-year incident hypertension in a Danish general population sample.

Methods

Cross-sectional and prospective population-based study.

Results

At baseline, among 5,307 participants (51.3% women, mean age 46.0±7.9 years) with a complete set of data, we recorded 1,979 cases with prevalent hypertension (PHT). Among 2,389 normotensive participants at baseline with a complete set of data, we recorded 324 cases with incident hypertension (IHT) on follow-up 5 years later. In models adjusted for age, sex, lifestyle, social, dietary, anthropometric, pulmonic, lipid, metabolic and renal risk factors, as well as heart rate and baseline blood pressure (only incident model), one standard deviation increase in baseline log-transformed NT-proBNP concentrations was on one side associated with a 21% higher risk of PHT (odds ratio [OR]: 1.21 [95% confidence interval (CI): 1.13-1.30], P<0.001), and on the other side with a 14% lower risk of IHT (OR: 0.86 [95%CI:0.76-0.98], P = 0.020).

Conclusions

Higher serum concentrations of NT-proBNP associate with PHT whereas lower concentrations associate with IHT. This suggests that a lower amount of circulating BNP, resulting in diminished vasodilation and natriuresis, could be involved in the pathogenesis of hypertension in its early stages.

Genome-wide association analysis of plasma B-type natriuretic peptide in blacks: the Jackson Heart Study

BACKGROUND

Numerous experimental studies suggest that B-type natriuretic peptide (BNP) is cardioprotective; however, in clinical studies, higher plasma BNP concentrations have been associated with incident cardiovascular disease and higher left ventricular mass. Genetic association studies may allow us to determine the true causal directions without confounding by compensatory mechanisms.

METHODS AND RESULTS

We performed a meta-analysis of 2 genome-wide association results from a total of 2790 blacks. We assumed an additive genetic model in an association analysis of imputed 2.5 million single-nucleotide polymorphism dosages with residuals generated from multivariable-adjusted logarithmically transformed BNP controlling for relevant covariates and population stratification. Two loci were genome-wide significant, a candidate gene locus NPPB (rs198389, P=1.18×10(-09)) and a novel missense variant in the KLKB1 locus (rs3733402, P=1.75×10(-11)) that explained 0.4% and 1.9% of variation in log BNP concentration, respectively. The observed increase in BNP concentration was proportional to the number of effect allele copies, and an average of 8.1 pg/mL increase was associated with 2 allele copies. In a companion study, single-nucleotide polymorphisms in this loci were cross-checked with genome-wide association results for the aldosterone/renin ratio in individuals of European ancestry, and rs3733402 was genome-wide significant (P<5.0×10(-8)), suggesting possible shared genetic architecture for these 2 pathways. Other statistically significant relations for these single-nucleotide polymorphisms included the following: rs198389 with systolic blood pressure in blacks (COGENT consortium) and rs198389 and rs3733402 with left ventricular mass in whites (EchoGEN consortium).

CONCLUSIONS

These findings improve our knowledge of the genetic basis of BNP variation in blacks, demonstrate a possible shared allelic architecture for BNP with aldosterone-renin ratio, and motivate further studies of underlying mechanisms.

Ventricular conduction and long-term heart failure outcomes and mortality in African Americans: insights from the Jackson Heart Study

BACKGROUND

QRS prolongation is associated with adverse outcomes in mostly white populations, but its clinical significance is not well established for other groups. We investigated the association between QRS duration and mortality in African Americans.

METHODS AND RESULTS

We analyzed data from 5146 African Americans in the Jackson Heart Study stratified by QRS duration on baseline 12-lead ECG. We defined QRS prolongation as QRS≥100 ms. We assessed the association between QRS duration and all-cause mortality using Cox proportional hazards models and reported the cumulative incidence of heart failure hospitalization. We identified factors associated with the development of QRS prolongation in patients with normal baseline QRS. At baseline, 30% (n=1528) of participants had QRS prolongation. The cumulative incidences of mortality and heart failure hospitalization were greater with versus without baseline QRS prolongation: 12.6% (95% confidence interval [CI], 11.0-14.4) versus 7.1% (95% CI, 6.3-8.0) and 8.2% (95% CI, 6.9-9.7) versus 4.4% (95% CI, 3.7-5.1), respectively. After risk adjustment, QRS prolongation was associated with increased mortality (hazard ratio, 1.27; 95% CI, 1.03-1.56; P=0.02). There was a linear relationship between QRS duration and mortality (hazard ratio per 10 ms increase, 1.06; 95% CI, 1.01-1.12). Older age, male sex, prior myocardial infarction, lower ejection fraction, left ventricular hypertrophy, and left ventricular dilatation were associated with the development of QRS prolongation.

CONCLUSIONS

QRS prolongation in African Americans was associated with increased mortality and heart failure hospitalization. Factors associated with developing QRS prolongation included age, male sex, prior myocardial infarction, and left ventricular structural abnormalities.

B-type natriuretic peptides improve cardiovascular disease risk prediction in a cohort of women

BACKGROUND

Although N-terminal pro-B-type natriuretic peptide (NT-proBNP) has a strong relationship with incident cardiovascular disease (CVD), few studies have examined whether NT-proBNP adds to risk prediction algorithms, particularly in women.

OBJECTIVES

This study sought to evaluate the relationship between NT-proBNP and incident CVD in women.

METHODS

Using a prospective case-cohort within the WHI (Women's Health Initiative) observational study, we selected 1,821 incident cases of CVD (746 myocardial infarctions, 754 ischemic strokes, 160 hemorrhagic strokes, and 161 other cardiovascular [CV] deaths) and a randomly selected reference cohort of 1,992 women without CVD at baseline.

RESULTS

Median levels of NT-proBNP were higher at study entry among incident cases (120.3 ng/l [interquartile range (IQR): 68.1 to 219.5 ng/l]) than among control subjects (100.4 ng/l [IQR: 59.7 to 172.6 ng/l]; p < 0.0001). Women in the highest quartile of NT-proBNP (≥140.8 ng/l) were at 53% increased risk of CVD versus those in the lowest quartile after adjusting for traditional risk factors (1.53 [95% confidence interval (CI): 1.21 to 1.94]; p for trend <0.0001). Similar associations were observed after adjustment for Reynolds Risk Score covariables (1.53 [95% CI: 1.20 to 1.95]; p for trend <0.0001); the association remained in separate analyses of CV death (2.66 [95% CI: 1.48 to 4.81]; p for trend <0.0001), myocardial infarction (1.39 [95% CI: 1.02 to 1.88]; p for trend = 0.008), and stroke (1.60 [95% CI: 1.22 to 2.11]; p for trend <0.0001). When added to traditional risk covariables, NT-proBNP improved the c-statistic (0.765 to 0.774; p = 0.0003), categorical net reclassification (0.08; p < 0.0001), and integrated discrimination (0.0105; p < 0.0001). Similar results were observed when NT-proBNP was added to the Reynolds Risk Score.

CONCLUSIONS

In this multiethnic cohort of women with numerous CV events, NT-proBNP modestly improved measures of CVD risk prediction.

Metabolic rather than body composition measurements are associated with lower serum natriuretic peptide concentrations in normal weight and obese men

BACKGROUND

Several studies have shown that obese persons have lower circulating natriuretic peptide (NP) concentrations. The cause of the relative NP deficiency seen in obese persons is poorly understood, although variation in body composition and metabolic abnormalities has been suggested to play a role. Thus, the aim of this study was to assess whether variation in circulating NP concentrations would be associated with differences in metabolic disturbances rather than with differences in body composition.

METHODS

In 27 normal weight men (body mass index (BMI) = 20.0-24.9kg/m(2)) and 103 obese men (BMI ≥ 30kg/m(2)), we determined body composition (total, android, and gynoid fat mass) by dual energy x-ray absorptiometry scanning, and we measured fasting serum concentrations of midregional proatrial NP (MR-proANP) and insulin, as well as fasting plasma glucose concentrations.

RESULTS

Mean weight ± SD was 74.9±6.7kg in the normal weight men and 106.1±10.8kg in obese men. Applying multiple regressions, adjusting for age and weight status (normal weight vs. obese), serum MR-proANP concentrations were significantly inversely associated with serum insulin concentrations (β = -0.39; P < 0.0001) and plasma glucose concentrations (β = -0.21; P = 0.02) but not with total (β = 0.00), android (β = -0.01), or gynoid (β = 0.03) fat mass percentage (P > 0.76). No significant interaction effects between metabolic measurements or body composition measurements and weight status on MR-proANP concentrations were found (P > 0.08).

CONCLUSIONS

In normal weight and obese men, lower circulating NP concentrations are associated with higher insulin and glucose concentrations and not with the proportion of total fat mass or the distribution of fat mass.

The role of natriuretic peptides for the diagnosis of left ventricular dysfunction

Natriuretic peptides (NPs) are entered in current guidelines for heart failure (HF) diagnosis and management because of their high specificity and sensibility in screening patients with acute dyspnea. Due to their availability and relatively low cost, they became the first step examinations in HF patients evaluation at hospital admission together with clinical and chest radiography examination. NPs are released following any cardiac haemodynamic stress due to volume or pressure overload and should be considered as a mirror of cardiac condition helping in recognizing patients with poor outcome. Moreover, the exact role of NPs in early HF stages, in isolated diastolic dysfunction, and in general population is questioned. Several promising reports described their potential role; however, the wide cut-off definition, inclusion criteria, and intrinsic measurement biases do not actually consent to their clinical application in these settings. A multimodality strategy including both NPs and imaging studies appears to be the best strategy to define the cardiac dysfunction etiology and its severity as well as to identify patients with higher risk. In this review, we describe the current and potential role of NPs in patients with asymptomatic cardiac insufficiency, evaluating the requirement to obtain a better standardization for imaging as for laboratory criteria.