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.
Behavioral: Low Sodium Diet
Behavioral: High Sodium Diet
Dietary Supplement: Potassium Supplementation
|Study Design:||Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
|Official Title:||Genetic Epidemiology Network of Salt Sensitivity|
- Blood pressure [ Time Frame: Measured at Day 21 ] [ Designated as safety issue: No ]
|Study Start Date:||October 2003|
|Primary Completion Date:||July 2005 (Final data collection date for primary outcome measure)|
Participants will follow a low sodium diet for Days 1 through 7, a high sodium diet for Days 7 through 14, and a high sodium diet plus potassium supplement regimen for Days 14 through 21.
Behavioral: Low Sodium Diet
3 grams of salt or 51.3 mmol of sodium per dayBehavioral: High Sodium Diet
18 grams of salt or 307.8 mmol of sodium per dayDietary Supplement: Potassium Supplementation
60 mmol potassium supplement
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00721721
|Chinese Academy of Medical Sciences|
|Principal Investigator:||Jiang He, MD, PhD||Tulane University|