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| ID | Type | Description | Link |
|---|---|---|---|
| F31AG033994 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institute on Aging (NIA) | NIH |
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The investigators hypothesize that reducing salt in the diet will improve the function of blood vessels in middle aged and older adults with moderately elevated systolic blood pressure, by increasing the amount of BH4 and nitric oxide in your blood vessels and reducing the amount of oxidative stress.
The improvement in blood vessel function will be determined over a 10 week period. Subjects will be randomly assigned to either a 'low salt' condition (placebo pills + 1200 mg dietary sodium) or a 'normal salt' condition (2300 mg sodium chloride pills + 1200 mg dietary sodium) and monitored for 5 weeks. After the initial set of 5 weeks, the subjects are switched into the opposite condition, completing the cross-over study design. During weeks 1-4 and 6-9, subjects are monitored weekly with 24 hour urine collections and diet logs. The assessment of the primary outcome (blood vessel function) is completed during weeks 5 and 10. BH4 and ascorbic acid are also administered during weeks 5 and 10 to measure the effects of sodium intake on endogenous BH4 levels and vascular oxidative stress.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Normal sodium | Other | Subjects on a 1200 mg sodium diet are given 2300 mg sodium in the form of slow sodium tablets to bring them back up to a normal salt intake. Subjects then cross-over to the low sodium condition in the second half of the study. |
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| Low sodium | Other | Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. Subjects then cross-over to the normal sodium condition in the second half of the study. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Slow sodium tablets | Drug | The normal salt condition is maintained with 2300 mg / day in the form of slowly released salt (NaCl) tablets. |
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| Measure | Description | Time Frame |
|---|---|---|
| Improved Flow Mediated Dilation | FMD is analyzed at weeks 5 and 10 or after each condition in this cross-over study design. Subjects are randomly assigned to a low salt or normal salt condition for the first set of 5 weeks and then crossed over to the other condition for the second set of 5 weeks. | Week 5 (after first condition of low salt or normal salt), Week 10 (after second condition, opposite to first) |
| Measure | Description | Time Frame |
|---|---|---|
| Vascular Oxidative Stress | Change in FMD following acute infusion of ascorbic acid (a dose known to scavenge superoxide) is measured at the end of 5 weeks of sodium condition (low and normal intake) as an index of vascular oxidative. | Immediately following acute infusion of ascorbic acid on Weeks 5 and 10 |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Kristen L Jablonski, PhD | University of Colorado, Boulder | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Clinical Translational Research Center | Boulder | Colorado | 80309 | United States |
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| Label | URL |
|---|---|
| Integrative Physiology of Aging Laboratory Website | View source |
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| ID | Title | Description |
|---|---|---|
| FG000 | Slow Sodium Tablets (Start) | Subjects on a 1200 mg sodium diet are given 2300 mg sodium in the form of slow sodium tablets to bring them back up to a normal salt intake. Subjects then cross over to the opposite condition in the second half of the study. |
| FG001 | Placebo | Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. Subjects then cross over to the opposite condition in the second half of the study. |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
11 Men and 6 post-menopausal women were enrolled.
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| ID | Title | Description |
|---|---|---|
| BG000 | Slow Sodium Tablets (Start) | Subjects on a 1200 mg sodium diet are given 2300 mg sodium in the form of a slow sodium tablets to bring them back up to a normal salt intake. This is administered through 10 tablets day. Subjects then cross-over to the placebo arm in the second half of the study. |
| BG001 |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Improved Flow Mediated Dilation | FMD is analyzed at weeks 5 and 10 or after each condition in this cross-over study design. Subjects are randomly assigned to a low salt or normal salt condition for the first set of 5 weeks and then crossed over to the other condition for the second set of 5 weeks. | All subjects are analyzed under each condition because of the cross-over design. | Posted | Mean | Standard Deviation | percentage dilation | Week 5 (after first condition of low salt or normal salt), Week 10 (after second condition, opposite to first) |
|
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Normal Sodium | Subjects on a 1200 mg sodium diet are given 2300 mg sodium in the form of slow sodium tablets to bring them back up to a normal salt intake. |
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Due to the complexity, burden, and, in some cases, invasiveness of the study design and procedures, only a limited number of subjects could be studied.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. Kristen Jablonski | University of Colorado Denver | 303-724-4842 | KRISTEN.NOWAK@UCDENVER.EDU |
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| ID | Term |
|---|---|
| D006973 | Hypertension |
| ID | Term |
|---|---|
| D014652 | Vascular Diseases |
| D002318 | Cardiovascular Diseases |
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| placebo | Other | Placebo tablets are administered to maintain the low sodium condition. |
|
| BH4 Bioavailability |
Change in FMD following acute oral tetrahydrobiopterin (BH4) is measured at the end of 5 weeks of sodium condition (low and normal intake) as an index of BH4 bioavailability. |
| Immediately following acute administration of BH4 on Weeks 5 and 10 |
| Placebo (Start) |
Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. Subjects then cross over to the slow sodium tablet arm in the second half of the study. |
| BG002 | Total | Total of all reporting groups |
| years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. |
|
|
| Secondary | Vascular Oxidative Stress | Change in FMD following acute infusion of ascorbic acid (a dose known to scavenge superoxide) is measured at the end of 5 weeks of sodium condition (low and normal intake) as an index of vascular oxidative. | Ascorbic acid is missing in one participant due to a failed i.v. | Posted | Mean | Standard Deviation | percentage dilation | Immediately following acute infusion of ascorbic acid on Weeks 5 and 10 |
|
|
|
| Secondary | BH4 Bioavailability | Change in FMD following acute oral tetrahydrobiopterin (BH4) is measured at the end of 5 weeks of sodium condition (low and normal intake) as an index of BH4 bioavailability. | BH4 could not be administered to 3 participants due to canceled visits. | Posted | Mean | Standard Deviation | percentage dilation | Immediately following acute administration of BH4 on Weeks 5 and 10 |
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|
|
| 0 |
| 17 |
| 0 |
| 17 |
| EG001 | Low Sodium | Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. | 0 | 17 | 0 | 17 |
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