INTERMAP: International Population Study on Macronutrients and BP

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.

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.

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).

• Cardiovascular Diseases
• Heart Diseases
• Hypertension

• Stamler J, Elliott P, Dennis B, Dyer AR, Kesteloot H, Liu K, Ueshima H, Zhou BF; INTERMAP Research Group. INTERMAP: background, aims, design, methods, and descriptive statistics (nondietary). J Hum Hypertens. 2003 Sep;17(9):591-608.
• Beevers DG, Stamler J. Background to the INTERMAP study of nutrients and blood pressure. J Hum Hypertens. 2003 Sep;17(9):589-90. No abstract available.
• Dennis B, Stamler J, Buzzard M, Conway R, Elliott P, Moag-Stahlberg A, Okayama A, Okuda N, Robertson C, Robinson F, Schakel S, Stevens M, Van Heel N, Zhao L, Zhou BF; INTERMAP Research Group. INTERMAP: the dietary data--process and quality control. J Hum Hypertens. 2003 Sep;17(9):609-22.
• Zhou BF, Stamler J, Dennis B, Moag-Stahlberg A, Okuda N, Robertson C, Zhao L, Chan Q, Elliott P; INTERMAP Research Group. Nutrient intakes of middle-aged men and women in China, Japan, United Kingdom, and United States in the late 1990s: the INTERMAP study. J Hum Hypertens. 2003 Sep;17(9):623-30.
• Dyer AR, Elliott P, Stamler J, Chan Q, Ueshima H, Zhou BF; INTERMAP Research Group. Dietary intake in male and female smokers, ex-smokers, and never smokers: the INTERMAP study. J Hum Hypertens. 2003 Sep;17(9):641-54.
• Stamler J, Elliott P, Appel L, Chan Q, Buzzard M, Dennis B, Dyer AR, Elmer P, Greenland P, Jones D, Kesteloot H, Kuller L, Labarthe D, Liu K, Moag-Stahlberg A, Nichaman M, Okayama A, Okuda N, Robertson C, Rodriguez B, Stevens M, Ueshima H, Horn LV, Zhou B. Higher blood pressure in middle-aged American adults with less education-role of multiple dietary factors: the INTERMAP study. J Hum Hypertens. 2003 Sep;17(9):655-775.
• Stamler J, Elliott P, Chan Q. INTERMAP Appendix Tables, Tables of Contents (Tables A). J Hum Hypertens. 2003 Sep;17(9):665-758. No abstract available.
• Stamler J, Elliott P, Chan Q. INTERMAP Appendix Tables, Tables of Contents (Tables B). J Hum Hypertens. 2003 Sep;17(9):759-75. No abstract available.
• Conway R, Robertson C, Dennis B, Stamler J, Elliott P; INTERMAP Research Group. Standardised coding of diet records: experiences from INTERMAP UK. Br J Nutr. 2004 May;91(5):765-71.
• Zhao L, Stamler J, Yan LL, Zhou B, Wu Y, Liu K, Daviglus ML, Dennis BH, Elliott P, Ueshima H, Yang J, Zhu L, Guo D; INTERMAP Research Group. Blood pressure differences between northern and southern Chinese: role of dietary factors: the International Study on Macronutrients and Blood Pressure. Hypertension. 2004 Jun;43(6):1332-7. Epub 2004 Apr 26.
• Dyer AR, Greenland P, Elliott P, Daviglus ML, Claeys G, Kesteloot H, Chan Q, Ueshima H, Stamler J. Estimating laboratory precision of urinary albumin excretion and other urinary measures in the international study on macronutrients and blood pressure. Am J Epidemiol. 2004 Aug 1;160(3):287-94.
• Dyer AR, Greenland P, Elliott P, Daviglus ML, Claeys G, Kesteloot H, Ueshima H, Stamler J. Evaluation of measures of urinary albumin excretion in epidemiologic studies. Am J Epidemiol. 2004 Dec 1;160(11):1122-31.
• Daviglus ML, Greenland P, Stamler J, Elliott P, Appel LJ, Carnethon MR, Chan Q, Claeys G, Kesteloot H, Miura K, Nakagawa H, Pirzada A, Steffen L, Yan LL, Zhou B, Dyer AR. Relation of nutrient intake to microalbuminuria in nondiabetic middle-aged men and women: International Population Study on Macronutrients and Blood Pressure (INTERMAP). Am J Kidney Dis. 2005 Feb;45(2):256-66.
• Elliott P, Stamler J, Dyer AR, Appel L, Dennis B, Kesteloot H, Ueshima H, Okayama A, Chan Q, Garside DB, Zhou B. Association between protein intake and blood pressure: the INTERMAP Study. Arch Intern Med. 2006 Jan 9;166(1):79-87.

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