Salt Sensitivity of Blood Pressure: 6 Nagging Questions
Salt sensitivity of blood pressure (SSBP) is still poorly understood. How much do you know about it? Find out, here.
References:
References1. Elijovich F, Weinberger MH, Anderson CA, et al. Salt sensitivity of blood pressure: a scientific statement from the American Heart Association. Hypertension. 2016;68:e7-e46. doi: 10.1161/HYP.0000000000000047. 2. Felder RA, White MJ, Williams SM, et al. Diagnostic tools for hypertension and salt sensitivity testing. Curr Opin Nephrol Hypertens. 2013;22:65-76. doi: 10.1097/MNH.0b013e32835b3693.3. Konerman MC, Hummel SL, et al. Sodium restriction in heart failure: benefit or harm? Curr Treat Options Cardiovasc Med. 2014;16:286. doi: 10.1007/s11936-013-0286-x.4. Ingelsson E, Björklund-Bodegård K, Lind L, et al. Diurnal blood pressure pattern and risk of congestive heart failure. JAMA. 2006;295:2859-66.5. Shin J, Kline S, Moore M, et al. Association of diurnal blood pressure pattern with risk of hospitalization or death in men with heart failure. J Card Fail. 2007;13:656-662.
Salt sensitivity of blood pressure (SSBP) is a poorly understood trait that affects whether, and to what degree, blood pressure in mammals, including humans, responds to sodium intake. As theories evolve about the molecular underpinnings of the SSBP phenotype, find out what you may or may not know already with our short, 6-question quiz.
1. Salt sensitivty refers to which of the following:
A. Increased blood pressure in response to increased salt intake.
B. Decreased blood pressure in response to increased salt intake.
C. Stable blood pressure in response to decreased salt intake.
D. Stable blood pressure in response to increased salt intake.
Answer A. Increased BP in response to increased salt intake. The simplest definition of salt sensitivity is increased blood pressure in response to increased salt intake. In persons who are salt-resistant, BP generally remains stable in response to increased or decreased salt intake. Genetic vulnerabilities as well as environmental factors (eg, low potassium intake and a poor quality diet) may be causative.
2. Which of the following groups is/are at increased risk for salt sensitivity?
A. Blacks
B. Overweight individuals
C. Hypertensive individuals
D. A and C
E. All of the above
Answer: C. A and C. Responses to variations in salt intake appear to be greater among blacks than among whites, among older vs younger individuals and in those with hypertension. Data are inconsistent for differences between genders, overweight vs normal weight individuals and people of Asian descent.1
3. Which of the following laboratory test can be used to directly measure salt sensitivity:
A. Plasma renin activity
B. Circulating BNP
C. 24-hr urinary excretion of sodium
D. None of the above
Answer: D. None of the above. Currently, no laboratory tests exist for direct measurement of salt sensitivity, nor is there consensus on how to evaluate the effect of salt intake on BP; 24-hour urinary excretion is preferred for estimating sodium intake in research studies, but has inherent variability and is impractical in the clinical context.1 Low plasma renin activity, circulating levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and endogenous ouabain have also been proposed, but their use is limited due to low sensitivity and specificity.2
4.The failure of BP to decline during sleep is a surrogate measure of salt sensitivity and may increase risk of heart failure.
A. True
B. False
Answer: A. True. BP non-dipping overnight is closely linked to salt-sensitivity and sometimes used as a surrogate for the condition.3 Non-dipping also has been linked to increased risk for heart failure,4 as well as heart failure hospitalization and death.4,5
5. Salt sensitivity is associated with which of the following conditions:
A. Insulin resistance
B. Chronic renal insufficiency
C. Sleep apnea
D. A and B
E. All of the above
Answer: D. All of the above. Salt sensitivity has been linked to several other hypertension-related conditions eg, central obesity, sleep apnea, insulin resistance, and chronic renal insufficiency. Research suggests ~12% of people in the US who have hypertension may also be salt sensitive, and 14% of people with normal BP may be salt sensitive.2
