The University of Virginia's Health System Department of Medicine – Division of Endocrinology and Metabolism is in search of healthy adults willing to participate in a study based on examining hypertension. This study is funded by the National Heart, Lung, and Blood Institute (NHLBI), a division under the National Health Institute (NIH).
The purpose of this study is to determine the cause of salt sensitivity on blood pressure. We hypothesize that people with a combination of genetic variations in two genes (regulating the sodium-bicarbonate co-transporter and G-protein coupled kinase in the kidney) are at risk for salt-sensitivity of blood pressure and salt-sensitive hypertension.
Why this study applies to you
High blood pressure, or hypertension, is defined as a systolic blood pressure over 139 mm Hg and diastolic blood pressure over 89 mm Hg. One-third of the world’s population has high blood pressure (hypertension) and it is responsible for almost 62% of deaths from stroke and 49% of deaths from coronary heart disease. Salt sensitivity is defined as in increase of blood pressure after a high salt meal. Salt sensitivity of blood pressure is equally devastating since it affects over 25% of the adult population and can reduce life expectancy by 20 years. However, the diagnosis of salt sensitivity cannot be performed in a doctor’s office setting due to its complexity and cost. Even individuals with normal or low blood pressure can be salt sensitive. The relationship between salt intake and cardiovascular risk is not linear, but rather fits a J-shaped curve relationship. Thus, a low-salt diet may not be beneficial to everyone and may paradoxically increase blood pressure in some individuals.
Accurate testing of salt sensitivity is not only laborious but also expensive, and with low patient compliance. Patients who have normal blood pressure but are salt-sensitive cannot be diagnosed in an office setting and there are no commercially available laboratory tests for salt sensitivity. Urinary surrogate markers for salt sensitivity are being developed and tested in our clinical study.
Our clinical study is designed to test the effect of two kidney gene variants on the degree of salt sensitivity of individuals. A polymorphism is one of many different forms of mutations in a single gene. We are looking for three polymorphisms in a protein called GRK4 that has been associated with hypertension and salt sensitivity. In addition, we are examining the effect of polymorphisms in a protein called NBCe2 that assists with sodium metabolism in the kidney. Polymorphisms in the gene for NBCe2 are associated with the increased likelihood of salt sensitivity. Clinical study participants that do not have any of these polymorphisms (controls) will be compared to individuals who express various combinations of these polymorphisms. As a volunteer for this study, we will test you for the presence of these polymorphisms at no charge and invite you to participate in a two week study with controlled dietary salt intake under our supervision, if you have the right genetic profile.
Enrolling in the study
The study is currently recruiting healthy participants with normal blood pressure. However, in order to qualify for this study, participants must be assessed and meet set inclusion and exclusion criteria. To learn more about inclusion criteria, click below.
Participants who meet general inclusion and exclusion criteria are eligible for the study. However, before entering into the two-week diet study, all participants must undergo two pre-study screenings to assess physical and genetic qualifications for the study. To learn more about what each screening consists of, click the button below.
Informed Consent Forms
It is our priority that all participants fully understand the purpose, benefits, and risks of the study. Participants are not obligated to stay in the study and may leave the study at their own will. To learn more about the purpose, benefits, risks, and more, click the button below.
Participants who meet our genetic and physical criteria will be recruited into our two-week diet study. Participants will be provided with two weeks of specially prepped food – one week of high salt diet and one week of low salt diet – that must be followed religiously in order to assess how the body reacts to different levels of sodium intake. To learn more about the diet and different food options, click the button below.
The study will be conducted within UVA facilities at their Clinical Research Unit (CRU). Click the button below for driving directions and more.
Still have questions about the study that have not been answered by the given information? Click on the button below to view frequently asked questions by other individuals that have showed interest in our study.