Racial Differences in Natriuretic Peptide Levels: The Dallas Heart Study

Abstract

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.

Keywords: deficiency; hypertension; natriuretic peptides; race.

Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Odds of low Nt-proBNP levels in black compared with white participants in the Dallas Heart Study, overall and in selected subgroups

Odds ratios (95% CI) for low Nt-proBNP (defined as the lowest sex-specific quartile: ≤ 7.3 pg/ml for men; ≤ 19.4 pg/ml for women) for black compared with white individuals. Models are adjusted for race/ethnicity, age, sex, heart rate, anti-hypertensive medication use, systolic blood pressure, diabetes mellitus, body mass index, estimated glomerular filtration rate, urine microalbumin, education, and income. Analyses including HOMA-IR are restricted to individuals without diabetes mellitus. HOMA-IR = homeostatic assessment model for insulin resistance. For lean mass subgroup analyses, models included lean and fat mass in place of BMI. BMI = body mass index

Figure 2. Central illustration. Consequences of natriuretic peptide deficiency

Natriuretic peptides are cardiac derived hormones that affect target organs resulting in cardiometabolic protective effects. Relative deficiencies of natriuretic peptides are associated with adverse phenotypes.