Analyzing Genetic Factors Involved in Blood Pressure Changes Due to Salt and Potassium Intake (The GenSalt Study)
Analyzing Genetic Factors Involved in Blood Pressure Changes Due to Salt and Potassium Intake (The GenSalt Study)
High blood pressure is a serious health problem. In terms of diet recommendations, people
 with this condition are encouraged to eat a low sodium and high potassium diet. It is
 believed that genetics may play a role in the development of high blood pressure and may
 affect changes in blood pressure levels, including changes brought on by sodium and
 potassium. This study will identify genetic factors that may influence blood pressure changes
 due to increased salt or potassium intake in people with mildly elevated blood pressure and
 in their family members.
High blood pressure is one of the most common health problems among adults. If left
 untreated, it can lead to heart failure, kidney failure, or stroke. Common causes include
 stress, diet, diabetes, kidney disease, or obesity. Typical treatments include taking
 medication, losing weight, and quitting smoking. It is also recommended that people with high
 blood pressure or those at risk of developing high blood pressure modify their diets to
 decrease sodium intake and increase potassium intake. Research has shown that genetics may
 play a role in the development of high blood pressure and may affect fluctuations of blood
 pressure levels, including blood pressure changes brought on by sodium and potassium. This
 study will identify and analyze the genetic factors that may be responsible for blood
 pressure changes due to dietary salt and potassium intake. Blood samples collected in this
 study may also be used for future genetic research on blood pressure.

 This study will enroll people who have mildly elevated blood pressure and their siblings,
 spouses, and children. Participants will first take part in a 3-day observation period. At a
 Day 1 study visit, participants' weight, height, waist size, and blood pressure will be
 measured. There will be three separate blood pressure measurements. Study staff will then
 interview participants to collect information on family and personal medical history,
 cigarette smoking habits, alcohol consumption, physical activity, and diet. Finally, blood
 samples will be collected. For 24 hours after the first study visit, participants will
 collect their urine. At study visits on Days 2 and 3, participants will undergo three blood
 pressure measurements and a cold pressor test, which measures blood pressure at different
 body temperatures. Participants will also collect a urine sample each night.

 After the 3-day observation period, participants will take part in a 3-week treatment period.
 Each day, all participants will eat breakfast, lunch, and dinner in the study kitchen. For
 Days 1 through 7, participants will eat a low sodium diet; for Days 7 through 14,
 participants will eat a high sodium diet; and for Days 14 through 21, participants will eat a
 high sodium diet and receive potassium supplements. Blood pressure will be measured three
 times per day and urine will be collected at several times during this period. Blood samples
 will be collected at the end of each week.

 Parents of participants will also be enrolled in this study, and they will complete the same
 study procedures that participants complete during the 3-day observation period except for
 the urine collection.

 The study completion date listed in this record was obtained from the "Completed Date"
 entered in the Query View Report System (QVR).
Inclusion Criteria:

 Inclusion Criteria for Primary Participants:

 -  Between 18 and 60 years old

 -  Systolic blood pressure level of 130 to 160 mm Hg and/or diastolic blood pressure
 level of 85 to 100 mm Hg

 -  Both parents (2-generation nuclear family) or at least one parent (at least a
 3-generation family) is available and willing to participate in the study

 -  At least one sibling meets eligibility criteria for participation

 Inclusion Criteria for Sibling/Spouse/Child Participants:

 -  Siblings and spouses must be between 18 and 60 years old; children must be more than
 16 years old

 -  Lives in the same village as the main study participant

 Exclusion Criteria for All Participants:

 -  Current stage 2 hypertension (systolic blood pressure level greater than or equal to
 160 mm Hg and/or diastolic blood pressure level greater than or equal to 100 mm Hg)

 -  Current or recent (i.e., less than 1 month before the screening visit) use of
 antihypertensive medications or medications that affect blood pressure

 -  Secondary hypertension

 -  History of clinical cardiovascular disease, including heart attack, congestive heart
 failure, stroke, and peripheral arterial disease

 -  Chronic kidney failure or urinary albumin concentration of greater than or equal to 20
 mg/dL

 -  Current diabetes (i.e., fasting serum glucose level greater than or equal to 126
 mg/dL) or use of insulin or oral hypoglycemic agents

 -  Peptic ulcer disease requiring treatment in the 2 years before study entry

 -  Liver disease requiring treatment in the 2 years before study entry

 -  Pregnant

 -  Heavy alcohol drinker (i.e., more than 14 drinks per week)

 -  Currently adhering to a low sodium diet