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Trial NCT00000511

Resource URI: http://static.linkedct.org/resource/trials/NCT00000511
linkedct:brief_title Polyunsaturates and KCL to Control Mild Hypertension
linkedct:condition <http://static.linkedct.org/resource/condition/13668>
linkedct:condition <http://static.linkedct.org/resource/condition/2312>
linkedct:condition <http://static.linkedct.org/resource/condition/5702>
linkedct:condition <http://static.linkedct.org/resource/condition/6238>
linkedct:criteria Mild hypertensives, ages 21 to 70, with no evidence of end-organ damage.. Untreated hypertensives.
linkedct:description BACKGROUND: The hypothesis that omega-3 fatty acids as well as magnesium and potassium in the diet lowered blood pressure in mild hypertensives needed further documentation, although preliminary and less well controlled studies had suggested such an effect was possible. In a previous study the investigators did not find a hypotensive effect of another polyunsaturated fatty acid, linoleic acid. In addition, findings of lower blood pressures in vegetarians and results obtained from a study in which vegetarian diets were fed to normotensives led to the conclusion that dietary factors other then linoleic acid were responsible for the possible hypotensive effect of vegetarian diets. The nutrients which were selected for further study, omega-3 fatty acids, magnesium and potassium, occur in higher amounts in vegetarian diets. Dietary supplementation with fish oils had only been done in a few studies with inconclusive results. However, the relationship of omega-3 fatty acids to the synthesis of prostacyclins, which are locally active vasodilators and which decrease with the excretion of the vasoconstrictor thromboxane, provide a possible mechanism for an effect of these compounds on blood pressure. The role of potassium in the control of blood pressure was first suggested from cross-cultural studies in which populations consuming high levels of potassium displayed lower rates of hypertension and a decrease in blood pressure with age. Cohort studies within this country have also shown a relationship between potassium intake or the ratio of potassium and sodium, as measured by urinary excretion and blood pressure. Most constantly it found that blood pressure differences between blacks and whites have been related to differences in potassium excretion. The results from human experimental studies involving potassium supplementation in normotensives and hypertensives have indicated mixed effects but blood pressure lowering was most consistently observed in subgroups with a family history of hypertension or those with higher blood pressure. DESIGN NARRATIVE: Trial 1: Subjects were randomized to a fish oil treatment group of 6 or 12 grams/day of omega-3 fatty acids or to a placebo group. At the end of 12 and 24 weeks, participants in the three groups were crossed-over to one of the other two treatments for an additional 12 weeks. Trial 2: Subjects were randomly assigned to one of four treatments: magnesium plus calcium supplementation; potassium plus calcium supplementation; magnesium plus potassium supplementation; matching placebos. The trial was double-blinded. Each of the treatments was administered for six months with measurements taken every three months. Trial 3: Similar to Trial 2. The primary endpoint in the three trials was change in diastolic blood pressure between baseline and the end of the studies based on an average of nine readings.
linkedct:download_date Information obtained from ClinicalTrials.gov on December 30, 2009
linkedct:eligibility_gender Both
linkedct:eligibility_healthy_volunteers No
linkedct:eligibility_maximum_age 70 Years
linkedct:eligibility_minimum_age 21 Years
linkedct:enrollment 0 (xsd:int)
linkedct:firstreceived_date October 27, 1999
linkedct:id NCT00000511
rdfs:label Trial NCT00000511
linkedct:lastchanged_date June 23, 2005
linkedct:lead_sponsor_agency National Heart, Lung, and Blood Institute (NHLBI)
linkedct:nct_id NCT00000511
linkedct:number_of_arms 0 (xsd:int)
linkedct:number_of_groups 0 (xsd:int)
linkedct:org_study_id 30
linkedct:overall_status Completed
linkedct:oversight <http://static.linkedct.org/resource/oversight/2918>
foaf:page <http://clinicaltrials.gov/show/NCT00000511>
linkedct:phase Phase 2
linkedct:reference <http://static.linkedct.org/resource/reference/48724>
linkedct:source National Heart, Lung, and Blood Institute (NHLBI)
linkedct:start_date December 1983
linkedct:study_design Treatment, Randomized, Crossover Assignment
linkedct:study_type Interventional
linkedct:summary To test the efficacy of omega-3 fatty acids, magnesium, calcium, and potassium supplementation in untreated mild hypertensives and magnesium and potassium supplementation in treated hypertensives. Three clinical trials were conducted in sequence over a four year period.
rdf:type linkedct:trials
linkedct:verification_date March 2005