Dietary Patterns, Sodium Intake and Blood Pressure (DASH - Sodium)

Hypertension Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00000608
• Other study ID #: 111
• Secondary ID: U01HL057139
• Status: Completed
• Phase: Phase 2
• First received: October 27, 1999
• Last updated: July 28, 2016
• Start date: February 1997
• Est. completion date: July 2002

Study information

• Verified date: January 2008
• Source: National Heart, Lung, and Blood Institute (NHLBI)
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

To compare the effects of three levels of dietary sodium and two patterns of diet (a control diet and an intervention diet high in fruits, vegetables, and low fat dairy products and low in fat) on blood pressure in individuals with higher than optimal blood pressure or with Stage 1 hypertension.. DASH - Sodium built on and extended the results of the NHLBI-initiated Dietary Approaches to Stop Hypertension (DASH) study.

Description:

BACKGROUND:

High blood pressure, defined as systolic blood pressure greater than or equal to 140 mm Hg or diastolic blood pressure greater than or equal to 90 mm Hg, or taking antihypertensive medication, affects 24 percent of the United States adult population or about 50 million people. Because the risk of cardiovascular disease and stroke increases with increasing blood pressure throughout the entire range of blood pressure levels, people with blood pressure above the optimal level of 120/80 are at increased risk of disease. Approximately 48 percent of the adult population have blood pressure either normal but above optimal levels or have Stage 1 hypertension, a prevalence which increases with age. To combat this highly prevalent condition, primary prevention through lifestyle modification represents a highly promising strategy for public health.

DASH - Sodium extended research from DASH trial to address several issues of relevance to clinical practice and public health and capitalized on the success of DASH by following the multicenter outpatient feeding study model. The model permitted a true test of efficacy because of high adherence and follow-up rates. In addition, the population studied across four geographic areas, encompassing individuals with diastolic blood pressure between 80-95 mm Hg and systolic blood pressure <160 mm Hg, was broadly representative, thus making the results generalizable to a large portion of the United States population.

DESIGN NARRATIVE:

The effects on blood pressure of three levels of sodium intake and two dietary patterns were compared. The combined impact of sodium reduction with dietary intervention was evaluated as a potential non-pharmacologic treatment alternative to drug therapy for stage one hypertension or for maintaining normal blood pressure levels. The two dietary patterns were a control diet that represented the typical American diet and an intervention diet (DASH diet) that was high in fruits, vegetables, included whole grains, poultry, fish, and nuts, and reduced in fats, red meat, sweets, and sugar-containing beverages and dairy products. The three levels of sodium were higher (current United States intake), intermediate (current recommended levels), and lower (potentially optimal levels). Participants were assigned to one of the two dietary patterns using a parallel group design and were fed at each sodium level using a randomized cross-over design.

Three eligibility pre-screening visits were followed by a two-week run-in feeding period and then a four-week intervention period at each of three sodium levels. During the run-in for the intervention feeding periods, all food was provided to participants. They were required to attend the clinic for at least one meal per day, five days per week, and to take home food to eat for other meals. Each of the four clinics recruited 100 participants. Blood pressure was measured once a week during the first of three weeks and five times during the last week. During the final feeding period, fasting blood was collected and 24-hour urine collections were analyzed for magnesium, potassium. calcium, sodium, and creatinine.

DASH - Sodium determined, separately by race, gender, and hypertension status: 1) the effects on blood pressure of three levels of dietary sodium within the context of both a control diet and the DASH diet; 2) the effect on blood pressure of the DASH diet, relative to the control diet, at each of the three levels of sodium intake. The study also assessed whether the effect on blood pressure of going from higher to lower sodium diets differs for participants in the control and DASH diets. Lastly, the study determined whether the blood pressure effect associated with reducing sodium from the higher to the intermediate level differs from the blood pressure effect associated with reducing sodium from the intermediate to the lower level, that is, testing whether the blood pressure effects of sodium are linear across sodium levels for each diet.

Recruitment and screening began in August 1997. The first cohort began the experimental diets in January 1998 and the last cohort completed the diets in November 1999. A total of 412 participants were enrolled into the study. Results were presented at the annual meeting of American Society of Hypertension in May 2000.

The study was renewed under R01HL57114 to to analyze the data of the trial The hypothesis to be tested is that genetic makeup modulates the BP effects of DASH diet and reduced sodium intake through one or more of the following mechanisms: 1) effects on vascular tone; 2) effects on mineralocorticoid regulation of sodium homeostasis; and 3) effects on non-classical regulation of sodium homeostasis.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 0
• Est. completion date: July 2002
• Est. primary completion date: July 2002
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 22 Years to 100 Years

Eligibility

Healthy adult men and women, ages 22 and older, who had a diastolic blood pressure of 80 to 95 mm Hg and a systolic blood pressure less than 160 mm Hg.

Study Design

Intervention Model: Parallel Assignment, Primary Purpose: Prevention

Related Conditions & MeSH terms

• Cardiovascular Diseases
• Heart Diseases
• Hypertension
• Vascular Diseases

Intervention

Behavioral:
• diet, fat-restricted

• diet, sodium-restricted

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
National Heart, Lung, and Blood Institute (NHLBI)

References & Publications (17)

Akita S, Sacks FM, Svetkey LP, Conlin PR, Kimura G; DASH-Sodium Trial Collaborative Research Group. Effects of the Dietary Approaches to Stop Hypertension (DASH) diet on the pressure-natriuresis relationship. Hypertension. 2003 Jul;42(1):8-13. Epub 2003 May 19. — View Citation

Ard JD, Coffman CJ, Lin PH, Svetkey LP. One-year follow-up study of blood pressure and dietary patterns in dietary approaches to stop hypertension (DASH)-sodium participants. Am J Hypertens. 2004 Dec;17(12 Pt 1):1156-62. — View Citation

Bray GA, Vollmer WM, Sacks FM, Obarzanek E, Svetkey LP, Appel LJ; DASH Collaborative Research Group. A further subgroup analysis of the effects of the DASH diet and three dietary sodium levels on blood pressure: results of the DASH-Sodium Trial. Am J Cardiol. 2004 Jul 15;94(2):222-7. Erratum in: Am J Cardiol. 2010 Feb 15;105(4):579. — View Citation

Conlin PR, Erlinger TP, Bohannon A, Miller ER 3rd, Appel LJ, Svetkey LP, Moore TJ. The DASH diet enhances the blood pressure response to losartan in hypertensive patients. Am J Hypertens. 2003 May;16(5 Pt 1):337-42. — View Citation

Erlinger TP, Miller ER 3rd, Charleston J, Appel LJ. Inflammation modifies the effects of a reduced-fat low-cholesterol diet on lipids: results from the DASH-sodium trial. Circulation. 2003 Jul 15;108(2):150-4. Epub 2003 Jul 7. — View Citation

Greenland P. Beating high blood pressure with low-sodium DASH. N Engl J Med. 2001 Jan 4;344(1):53-5. — View Citation

Harsha DW, Sacks FM, Obarzanek E, Svetkey LP, Lin PH, Bray GA, Aickin M, Conlin PR, Miller ER 3rd, Appel LJ. Effect of dietary sodium intake on blood lipids: results from the DASH-sodium trial. Hypertension. 2004 Feb;43(2):393-8. Epub 2004 Jan 5. — View Citation

Jürgens G, Graudal N; Dietary Approaches to Stop Hypertension. Subgroup results in the DASH-sodium trial. Ann Intern Med. 2002 Nov 5;137(9):772-3; author reply 772-3. — View Citation

Kennedy BM, Conlin PR, Ernst D, Reams P, Charleston JB, Appel LJ. Successfully recruiting a multicultural population: the DASH-Sodium experience. Ethn Dis. 2005 Winter;15(1):123-9. — View Citation

Lin PH, Aickin M, Champagne C, Craddick S, Sacks FM, McCarron P, Most-Windhauser MM, Rukenbrod F, Haworth L; Dash-Sodium Collaborative Research Group. Food group sources of nutrients in the dietary patterns of the DASH-Sodium trial. J Am Diet Assoc. 2003 Apr;103(4):488-96. — View Citation

Most MM, Craddick S, Crawford S, Redican S, Rhodes D, Rukenbrod F, Laws R; Dash-Sodium Collaborative Research Group. Dietary quality assurance processes of the DASH-Sodium controlled diet study. J Am Diet Assoc. 2003 Oct;103(10):1339-46. — View Citation

Obarzanek E, Proschan MA, Vollmer WM, Moore TJ, Sacks FM, Appel LJ, Svetkey LP, Most-Windhauser MM, Cutler JA. Individual blood pressure responses to changes in salt intake: results from the DASH-Sodium trial. Hypertension. 2003 Oct;42(4):459-67. Epub 2003 Sep 2. — View Citation

Phillips KM, Simpkins AH, Amanna KR, Wolf W, Stewart KK, Clark S, Kim KP, Beecher GR, Holden J. Long-term stability of nutrients in a frozen mixed food control material. Fresenius J Anal Chem. 2001 Jun;370(2-3):297-302. — View Citation

Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER 3rd, Simons-Morton DG, Karanja N, Lin PH; DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. N Engl J Med. 2001 Jan 4;344(1):3-10. — View Citation

Svetkey LP, Sacks FM, Obarzanek E, Vollmer WM, Appel LJ, Lin PH, Karanja NM, Harsha DW, Bray GA, Aickin M, Proschan MA, Windhauser MM, Swain JF, McCarron PB, Rhodes DG, Laws RL. The DASH Diet, Sodium Intake and Blood Pressure Trial (DASH-sodium): rationale and design. DASH-Sodium Collaborative Research Group. J Am Diet Assoc. 1999 Aug;99(8 Suppl):S96-104. — View Citation

Svetkey LP, Simons-Morton DG, Proschan MA, Sacks FM, Conlin PR, Harsha D, Moore TJ. Effect of the dietary approaches to stop hypertension diet and reduced sodium intake on blood pressure control. J Clin Hypertens (Greenwich). 2004 Jul;6(7):373-81. — View Citation

Vollmer WM, Sacks FM, Ard J, Appel LJ, Bray GA, Simons-Morton DG, Conlin PR, Svetkey LP, Erlinger TP, Moore TJ, Karanja N; DASH-Sodium Trial Collaborative Research Group. Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-sodium trial. Ann Intern Med. 2001 Dec 18;135(12):1019-28. — View Citation

* Note: There are 17 references in all — Click here to view all references