The Sodium-Potassium Blood Pressure Trial in Children (NaKS), is a clinical trial in a healthy, free living population of children and adolescents. It is designed to test the hypotheses that a reduction in dietary sodium and/or an increase in potassium intake will decrease the rate of rise in blood pressure during normal maturation in children and adolescents with high normal blood pressure. Screening was conducted in 19,452 students in grades 5-8 in Minneapolis and St. Paul between January 1986 and May 1987. After screening, 3,223 students were found to have blood pressures that fulfilled the initial eligibility criteria for the study, and of these, 643 (20.0%) attended the orientation meeting, i.e., the first clinic visit. A total of four clinic visits, designed to test the willingness and capability of the potential participants to comply with the study protocol were conducted prior to randomization. At the conclusion of the four prerandomization visits, 243 children (7.5% of the initially eligible children) agreed to be randomized to one of four trial groups: low-sodium diet; potassium supplement administration; placebo-treated control group; and a no-treatment control group (to test the effect of acclimatization on blood pressure measurements) that will not be seen after randomization until the 4-year termination of the study. The first participants was randomized into the study on June 17, 1986, and the last on December 29, 1987. The potassium and placebo capsules are administered double-masked. Participants will be examined and receive intervention instruction four times yearly for 4 years counted from the date of their randomization. All groups were comparable with regard to distribution of school district, sex, and race and with respect to baseline physical characteristics. Results from this study will provide information about the feasibility and effect of dietary intervention during childhood and adolescence on the prevention of essential hypertension.
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We wish to thank all of the children and their parents for their participation in the study. Jean Heberle supervised the school screening and Cathy Pinther-Evans and Janell Miersch are supervising the clinic logistics. Software development and data management is conducted by Ching-Ping Hong. The dietary intervention was developed and is directed by Vikki Mullenbach. Capsule adherence is supervised by Florine Campbell. All secretarial assistance is provided by Lauri Schafer. This work was supported by grant #HL 34659 from the National Heart, Lung, and Blood Institute.
- Clinical trial