Sodium Excretion and Cardiovascular Structure and Function in the Nonhypertensive Population: The Korean Genome and Epidemiology Study

Abstract

BACKGROUND The effect of sodium intake on the cardiovascular system remains controversial. The purpose of this study is to investigate the relation between sodium intake and cardiovascular structure and function in the nonhypertensive population. METHODS We performed a cross-sectional analysis in 1,586 nonhypertensive subjects who participated in the Korean Genome Epidemiology Study (2007-2008). Sodium intake was assessed by estimating the 24-hour urinary sodium excretion from a spot urine sample. Changes in cardiovascular structure and function were assessed by using tissue Doppler echocardiography, the carotid intima-media thickness (CIMT), and the brachial-ankle pulse wave velocity (baPWV). RESULTS Systolic and diastolic blood pressures increased with increasing tertiles of estimated 24-hour urinary sodium excretion. In multivariate analyses adjusting for covariates, there were stepwise decreases in the baPWV (P = 0.003) and CIMT (P = 0.001) values as the estimated 24-hour urinary sodium excretion increased, whereas no significant differences in left ventricular (LV) structural and functional parameters were observed across the tertiles of estimated 24-hour urinary sodium excretion. Multiple linear regression analyses revealed that the estimated 24-hour urinary sodium excretion was independently and inversely associated with baPWV (P < 0.001) and CIMT (P = 0.001), but not with LV parameters. CONCLUSIONS In the nonhypertensive population, urinary sodium excretion was inversely related to baPWV and CIMT. However, there were no associations between urinary sodium excretion and LV structure or function.