Abstract 55: Sodium Sensitivity, Sodium Resistance, and Incidence of Hypertension

Abstract

Background: Blood pressure responses to dietary sodium intake vary among individuals. However, it is unknown whether sodium sensitivity and sodium resistance predict incidence of hypertension. Methods: We conducted a feeding study, including a 7-day low-sodium diet (51.3 mmol/day) and a 7-day high-sodium diet (307.8 mmol/day), among 1,718 Chinese individuals with normal blood pressure in 2003-2005 and follow-up studies in 2008-2009 and 2011-2012. Three blood-pressure measurements and 24-hour urinary sodium excretion were obtained on each of 3 days during baseline, low- and high-sodium interventions, and follow-up visits. Latent class models were used to identify subgroups that share a similar underlying trajectory in blood-pressure responses to dietary sodium intake. Results: Three trajectories of systolic blood pressure responses to dietary sodium intake were identified (Figure). Mean (standard deviation) changes in systolic blood pressure were -13.7 (5.5), -4.9 (3.0), and 2.4 (3.0) mmHg during the low-sodium intervention, and 11.2 (5.3), 4.4 (4.1) and -0.2 (4.1) mmHg during the high-sodium intervention ( P< 0.001 for group differences) in high sodium-sensitive, moderate sodium-sensitive, and sodium-resistant groups, respectively. Compared to individuals with moderate sodium sensitivity, multiple-adjusted odds ratio (95% confidence intervals) for incident hypertension were 1.44 (1.03 to 1.99) for those with high sodium sensitivity and 1.42 (1.02 to 1.97) for those with sodium resistance ( P <0.001 for quadratic trend). Furthermore, a J-shaped association between systolic blood pressure responses to high sodium intake and incident hypertension was identified ( P <0.001). Similar results were observed for diastolic blood pressure. Conclusions: Individuals with either high sodium sensitivity or sodium resistance are at an increased risk for developing hypertension.

Advances in Genomics Research of Blood Pressure Responses to Dietary Sodium and Potassium Intakes

“…Although associations between salt resistance of blood pressure and clinical end points in humans are only just emerging, 10,27–29 functional studies of mice lacking guanylcyclase A and G protein-coupled P2Y receptors have provided not only compelling evidence but a genomic basis, for a salt-resistant model of hypertension. 30,31 Animal research has also long supported genetic mechanisms underlying salt sensitive hypertension.…”

“…Observational epidemiological research has pointed to high salt sensitivity of blood pressure as an important risk factor for hypertension and ASCVD. 10,[27][28][29] For example, a 2008 report by Barba et al 27 showed that 88% of individuals with high salt sensitivity developed hypertension compared with only 50% of those with lower salt sensitivity (P=0.02). Similarly, Morimoto et al 28 identified a 3-fold increased risk of cardiovascular events among persons with hypertension in the upper blood pressure response to high sodium compared with their counterparts in the lower 90th percentile (P<0.001).…”

“…[6][7][8] The extent to which individuals exhibit blood pressure responses to dietary sodium and potassium are heterogeneous, and emerging research has characterized both sensitivity and resistance phenotypes that associate with higher downstream hypertension risk. 9,10 Given the current challenges in diagnosing salt sensitivity in the clinical setting, the 2019 National Academies of Sciences, Engineering, and Medicine expert panel on Dietary Reference Intakes for Sodium and Potassium recognized the need for identification of molecular biomarkers, calling for genomics research to help characterize sodium sensitivity among individuals. 11 This research might hold promise for helping to one day identify individuals at high risk for hypertension and related sequelae and, more immediately, support the causal relation between blood pressure response phenotypes and their purported downstream consequences, including hypertension and ASCVD.…”