Analyzing Genetic Factors Involved in Blood Pressure Changes Due to Salt and Potassium Intake (The GenSalt Study)
Condition: Blood Pressure
Study type: Interventional
Phase: Phase 3

Summary: 
      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.
    

Detailed description: 
      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).
    

Intervention name(s): Low Sodium Diet; High Sodium Diet; Potassium Supplementation
Intervention type(s): Behavioral; Behavioral; Dietary Supplement
Intervention description(s): 3 grams of salt or 51.3 mmol of sodium per day; 18 grams of salt or 307.8 mmol of sodium per day; 60 mmol potassium supplement
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Dietary Sodium; Dietary Potassium; Genes; Genomics