INTERMAP: International Population Study on Macronutrients and BP

January 11, 2016 updated by: Northwestern University
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.

Study Overview

Status

Completed

Conditions

Detailed Description

BACKGROUND:

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.

DESIGN NARRATIVE:

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.

Study Type

Observational

Enrollment (Actual)

4680

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

40 years to 59 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

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).

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Cross-Sectional

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood pressure measurement relative to diet.
Time Frame: 15 years
Ongoing comparisons of different nutrients, urinary sodium and blood pressure.
15 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Northwestern University

Collaborators

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • 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 and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 1995

Primary Completion (Actual)

August 1, 2009

Study Completion (Actual)

May 1, 2015

Study Registration Dates

First Submitted

May 25, 2000

First Submitted That Met QC Criteria

May 25, 2000

First Posted (Estimate)

May 26, 2000

Study Record Updates

Last Update Posted (Estimate)

January 12, 2016

Last Update Submitted That Met QC Criteria

January 11, 2016

Last Verified

January 1, 2016

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1155
  • R01HL050490 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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