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INTERMAP: International Population Study on Macronutrients and BP

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005271
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : January 12, 2016
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Northwestern University

Brief Summary:
To investigate the relationship between dietary factors, especially macronutrients, and blood pressure in an international, multicenter observational study. A particular focus is to help elucidate the role of these dietary factors in accounting for the even more adverse blood pressure patterns of less educated population strata, especially in the United States, in both less educated Blacks and whites.

Condition or disease
Cardiovascular Diseases Heart Diseases Hypertension

Detailed Description:


Overall study findings are to be used to estimate favorable impact on blood pressure of multiple improvements in nutrition by populations. The investigators state that this should aid in making additional dietary recommendations toward the goal of primary prevention of hypertension and shifting blood pressure distributions downward to avoid excess risk associated with present levels generally above optimal.


INTERMAP's cross-sectional design is patterned after the tested INTERSALT model: a large sample size of 4,680 persons, half men and half women, ages 40-59 from 17 population samples of varied ethnicity, socioeconomic status (SES) and dietary habits in four countries (China, Japan, United Kingdom and the United States). There were eight United States INTERMAP centers. Specific aims involve elucidating influences on blood pressure of the amount and type of protein, lipids, carbohydrates, and also amino acids, calcium, magnesium, antioxidants, fiber, and caffeine. Primary hypotheses tested, with control for body mass index (BMI), intake of alcohol, age, sex, and other confounders are as follow: dietary protein is inversely related to blood pressure; inverse relations between education and blood pressure are significantly accounted for by education-related differences in dietary protein intake; there is a direct relation to blood pressure of dietary saturated fatty acids, cholesterol, Keys score, starch; there is an inverse relation of polyunsaturated fatty acids and polyunsaturated/saturated fatty acids. Randomly selected participants provide one timed 24-hr. urine collection for assessment of sodium, potassium, creatine, and urea, and complete four 24-hr. dietary recalls. Blood pressure was measured eight times at each of four clinic visits, with standardization and strict quality control of all procedures.

The study is coordinated by two Coordinating Centers--Northwestern University, Chicago and London School of Hygiene & Tropical Medicine. Urinary determinations are made at a Central Laboratory in Leuven, Belgium. Twenty-four hour dietary recalls are converted into nutrients with use of the Nutrition Data System of the University of Minnesota's Nutrition Coordinating Center. Data analyses to test hypotheses are done at the London Coordinating Center.

Recruitment and data collection began in July, 1996 through January, 1997. The main statistical analytic method is multivariate regression analysis. The study was renewed in FY 2000 and in FY 2004 to continue analysis of the data through August, 2009.

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Study Type : Observational
Actual Enrollment : 4680 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: INTERMAP: International Population Study on Macronutrients and BP
Study Start Date : July 1995
Actual Primary Completion Date : August 2009
Actual Study Completion Date : May 2015

Resource links provided by the National Library of Medicine

Primary Outcome Measures :
  1. Blood pressure measurement relative to diet. [ Time Frame: 15 years ]
    Ongoing comparisons of different nutrients, urinary sodium and blood pressure.

Biospecimen Retention:   Samples Without DNA
24 hour urine collection among all participants

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   40 Years to 59 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
The INTERMAP study population includes 4,680 men and women ages 40-59 who were recruited from 17 population samples of diverse ethnicity/ SES/ eating practices in four countries (China, Japan, UK, USA).

Inclusion Criteria:

  • Healthy individuals
  • Men and women
  • Age 40-59 years
  • Willing to collect 24 hour urine and return to clinic for second follow-up visit

Exclusion Criteria:

  • Existing disease
  • Unwilling to provide 24 hour urine collections
  • Unable to attend follow-up visits
  • Unable to recall dietary intake

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00005271

Sponsors and Collaborators
Northwestern University
National Heart, Lung, and Blood Institute (NHLBI)
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Principal Investigator: Lawrence Appel Johns Hopkins University
Principal Investigator: Daniel Jones University of Mississippi Medical Center
Principal Investigator: Darwin Labarthe University of Texas
Principal Investigator: Beatriz Rodriguez University of Hawaii at Manoa
Principal Investigator: Jeremiah Stamler Northwestern University
Principal Investigator: Linda Van Horn Northwestern University

Publications automatically indexed to this study by Identifier (NCT Number):

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Responsible Party: Northwestern University Identifier: NCT00005271    
Other Study ID Numbers: 1155
R01HL050490 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: January 12, 2016
Last Verified: January 2016
Additional relevant MeSH terms:
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Cardiovascular Diseases
Heart Diseases