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.