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The INTERSALT Study, an international, collaborative, cross-sectional investigation of the relation between blood pressure and dietary and other factors, used quality-controlled, standardized procedures and assessment of multiple possible confounding factors to study 10 079 men and women in 52 population-based samples in 32 countries. In this study 24-h urinary excretion data were used as biochemical markers of intakes of sodium, potassium, and protein, with repeat examinations done in a randomly selected 8% of participants to assess reliability and correct for regression-dilution bias. INTERSALT showed that high salt intake, low potassium intake, excess alcohol consumption, and energy imbalance resulting in overweight are critically involved in the origins of the high blood pressure prevalent among a majority of adult populations. The findings also show that obtaining accurate estimates of associations between dietary intake and blood pressure requires large population-based samples, high-quality dietary information, control for multiple confounding variables, and modern multivariate methods of data analyses, including correction of observed associations for within-person variation in intake.

The INTERSALT Study is a standardized, worldwide epidemiologic study of large sample size (n = 10 079 men and women aged 20-59 y from 32 countries) that tested both within- and cross-population prior hypotheses on 24-h sodium excretion and blood pressure. For individuals, a significant, positive, independent linear relation between 24-h sodium excretion and systolic blood pressure (SBP) was found. With multivariate adjustment for underestimation, the estimated effect of a sodium intake higher by 100 mmol/d was higher SBP/DBP (diastolic blood pressure) by [approximately equals] 3-6/0-3 mm Hg. This relation prevailed for both men and women, for younger and older people, and for 8344 people without hypertension. In tests of prior cross-population hypotheses (n = 52), significant, independent relations were found between sample 24-h median urinary sodium excretion and sample median SBP and DBP, prevalence rate of hypertension, and slope of SBP and DBP from age 20 to 59 y (median sodium intake greater by 100 mmol/d was associated with a 30-y increase in SBP/DBP, ie, at the age of 55 y compared with 25 y, of 10-11/6 mm Hg. The INTERSALT results, which agree with findings from other diverse studies, including data from clinical observations, therapeutic interventions, randomized controlled trials, animal experiments, physiologic investigations, evolutionary biology research, anthropologic research, and epidemiologic studies, support the judgment that habitual high salt intake is one of the quantitatively important, preventable mass exposures causing the unfavorable population-wide blood pressure pattern that is a major risk factor for epidemic cardiovascular disease.

For men in the special intervention (SI) group of the Multiple Risk Factor Intervention Trial, the average decrease in *serum total cholesterol was 9.7 mg/dL (6.7%); for men in the usual care (UC) group, the average decrease was 9.7 mg/dL (3.8%). The difference between the two groups for plasma total cholesterol was 6.2 mg/dL. Plasma low-density-lipoprotein (LDL) cholesterol decreased 10.6 mg/dL (6.6%) in SI men and 5.4 mg/dL (3.4%) in UC men. Mean weight losses were 3.0 lb (1.36 kg) and 0.1 lb (0.05 kg) for SI and UC men, respectively. Change in blood total cholesterol was directly related to baseline concentration; for men with serum total cholesterol a [is greater than or equal to] 220 mg/dL, those in the SI group decreased their total cholesterol by 7.8% (design goal: 10%) and those in the UC group by 4.8% (expected: 0%). Change in dietary lipid intake (summarized by the Keys score) for SI men was significantly related to changes in blood total cholesterol, LDL cholesterol, and triglyceride, but not to change in high-density-lipoprotein (HDL) cholesterol. Controlled for weight change, coefficients for Keys score change were smaller but remained significantly related to each blood lipid except HDL cholesterol. Weight loss was associated with favorable effects on all blood lipids. Influences of change in diet and weight on blood lipids were quantitatively less for hypertensive men for serum total cholesterol, HDL cholesterol, and triglyceride than for nonhypertensive men. Nonsmokers had greater decreases than smokers in blood total cholesterol, LDL cholesterol, and triglyceride. Nutr 1997;65(supp):272S-88S.

This chapter relates food and nutrient intakes at baseline to other facets of reported dietary behavior, major risk factors, and sociodemographic characteristics of men in the Multiple Risk Factor Intervention Trial. Intakes of total fat (38.4% of energy), saturated fatty acids (14.2%), and dietary cholesterol (492 mg/d) were similar to amounts seen in the first and second National Health and Nutrition Examination Surveys in the 1970s and were generally lower than findings from studies in the 1960s. There were inverse relations between total serum cholesterol and intakes of total fat, saturated and monounsaturated fatty acids, and dietary cholesterol. These paradoxical associations were largely attributable to findings in the 21% of men who reported following a special diet, indicating that use of such a diet increases with severity of hypercholesterolemia. Fat intake was directly related to number of meals per week eaten away from home, and to cigarette smoking. Patterns of food and nutrient intake were similar for men stratified by baseline blood pressure and antihypertensive treatment. Intake of total energy and percentages from various dietary fats decreased with age, as did use of sucrose and caffeine. White men consumed more dairy products than did other ethnic groups, whereas black men consumed more eggs, sugars, and sweets. Asians had the highest intake of cereal foods. Those with more education ate less high-fat meat products, more fruit, and more polyunsaturated oils, but also more high-fat dairy products and less breads add cereals; they also drank more alcohol. Nutr 1997;65(suppl):228S-57S.

Various dietary assessment instruments were used in the Multiple Risk Factor Intervention Trial (MRFIT), either to assist with the special intervention program or to assess trial outcomes. For the latter purpose, the 24-h recall was the main method and was selected with the understanding that the single recall collected at baseline and at most annual visits -- considered by itself -- would be useful mainly for assessing groups rather than individuals. Major components of the data collection and analysis system developed for the 24-h recall included central training ad certification of nutritionists, a central nutrient coding system, and a food grouping system to assist interventionists in using recall data for counseling. Several additional nutritional assess methods were used for men in the special intervention group only to assist them in attaining the dietary goals. These goals consisted chiefly of reduced intake of saturated fat and cholesterol and a modest increase in intake of polyunsaturated fat; total fat intake was also decreased, primary for control of energy intake. Short-term success at attainment of these nutrition goals was evaluated by means of 3-d food records collected before the intervention and after the initial 10-wk intensive intervention period. The MRFIT nutrient goals, which became more vigorous at certain points in the trial, were translated into food patterns. Adherence to these food patterns was also assessed by scoring 3-d records and by subjective evaluation by nutritionists throughout the trial. Methods of collecting other trial data are also described in this chapter, Am J Clin Nutr 1997;65(suppl):196S-210S.

This chapter presents analyses of relations of dietary variables to blood pressure, systolic (SBP) and diastolic (DBP), for men in the special intervention (SI) and usual care (UC) groups in the Multiple Risk Factor Intervention Trial. For each dietary factor, analyses were done at baseline, for trial years 1-6, and for change from baseline to years 1-6. Analyses were done for all participants and for men receiving or not receiving antihypertensive drug treatment and were controlled for age, race, education, serum cholesterol, smoking, special diet status, and (for specific nutrients) body mass index and alcohol intake. Nutrient data for trial years 1-6, which are based on four or five dietary recalls per man, are more reliable than the baseline or change data, which are based on only one recall. therefore, this summary focuses on data for trial years 1-6, for SI and UC men pooled. Regression analyses confirmed direct independent relations of body mass index, alcohol intake, sodium, and ratio of sodium to potassium to SBP and DBP, and an inverse relation of potassium to SBP and DBP. Dietary starch was directly related to SBP and DBP, dietary saturated fatty acid and cholesterol and Keys score were directly related to DBP; dietary magnesium, fiber, and caffeine were inversely related to SBP and DBP; and dietary protein, polyunsaturated fatty acids, the ratio of polyunsaturated to saturated fatty acid, and other simple carbohydrates were inversely related to DBP. Method problems, all tending to produce underestimations, are also reviewed. Am J Clin Nutr 1997; 65(suppl):338S-65S.

This chapter describes dietary composition according to cigarette smoking status at baseline and changes in smoking status during follow-up for men in the special intervention (SI) and usual care (UC) groups of the Multiple Risk Factor Intervention Trial. Five patterns of smoking behavior were defined: 1) sustained nonsmoking, 2) early (years 1-2 of the trial) sustained quitting, 3) late (years 3-6 of the trial) sustained quitting, 4) recidivism, and 5) continued smoking. SI men who quit smoking showed greater favorable changes in dietary lipid composition and micronutrient intake than did continued smokers, and these changes were in many instances as great as favorable changes made by nonsmokers. On the other hand, SI men who quit smoking gained an average of 3.8 lb (1.7 kg), in contrast with nonsmokers who lost an average of 6.4 lb (2.9 kg). The gain by SI quitters was, however, less than that by UC quitters, who gained 6.5 lb (3.0 kg). Moreover, despite weight gain, net change in high-density-lipoprotein (HDL) cholesterol for SI quitters was positive. With the associated decrease in low-density-lipoprotein (LDL) cholesterol, early SI quitters had the most improvement in ratio of LDL to HDL among all subgroups. Thus, unfavorable nutritional patterns of smokers put them at double jeopardy regarding cardiovascular and other chronic diseases; additionally, long-term risks can be improved not only by smoking cessation but also by achievement of healthier eating patterns. Am J Clin Nutr 1997;65(suppl):374S-402S.

This chapter summarizes weight and body mass index findings of the Multiple Risk Factor Intervention Trial and then focuses on relations of food group and nutrient intakes to weight change during follow-up. Results were qualitatively similar for the special intervention (SI) and usual care groups. Weight change was related both to dietary composition averaged over follow-up recalls and to changes from baseline. Greater weight loss compared with little change or gain was related to greater reductions from baseline and lower percentages of energy reported at follow-up from refined sucrose, total fat, and saturated and monounsaturated fatty acids. Greater weight loss was also associated with greater reductions in and lower intakes of cholesterol and energy. In both groups, these patterns reflected lower percentages of energy from medium-fat dairy products, eggs, highly saturated visible fats, crackers and snacks, refined sugars and sweets, and additionally for SI men, lower percentages of energy from high-fat meats, dairy products, and baked goods and desserts. In both groups weight loss was related to increased or higher percentages of energy from total and non-sucrose simple carbohydrates, and to fiber intake, and for SI men, to higher percentages of energy from starch. These nutrient patterns involved higher percentages of energy from low-fat dairy products, breads and cereals, fruit, and vegetables, and for SI men, from low-fat baked goods and desserts. Overall, substantial weight loss was associated with a diet of lower energy density and with higher intakes of several essential micronutrients. Am J Clin Nutr 1997;65(suppl): 366S-73S.

This chapter addresses relations between intake of fiber -- total, soluble, and insoluble -- and blood lipids in the Multiple Risk Factor Intervention Trial through use of baseline data (single measurement), averages of four to five 24-h recalls and blood lipid determinations collected during annual follow-up examinations, and change from baseline to follow-up. No significant associations were observed at baseline. Consistent highly significant inverse associations were seen in analyses of follow-up measurements. Results from change data were of intermediate strength and consistency. These variations were in all likelihood due to the low reliability of a single 24-h recall at baseline for determination of dietary intake and change in intake for individuals. From follow-up data, plasma total and low-density-lipoprotein (LDL) cholesterol concentrations were lower by [is nearly equal] 5 mg/dL for men in the special intervention group in quintile 5 of total fiber intake (25 g/d) compared with men in quintile 1 (8 g/d), after adjustment for average body mass index and intake of alcohol, saturated and polyunsaturated fatty acids, and dietary cholesterol. Results were similar for men in the usual care group. There were no adverse effects on high-density-lipoprotein cholesterol, nor any consistent associations with plasma triglycerides. Thus, increasing dietary fiber can provide additional reduction in blood total and LDL cholesterol and consequent improvement in the lipid profile, over and above the beneficial effects of a fat-modified diet. Am J Clin Nutr 1997;65(suppl):327S-37S.

This chapter explores relations between reported intakes of dietary carbohydrates and measurements of plasma lipids at baseline and during trial years 1-6 of the Multiple Risk Factor Intervention Trial. With control for dietary lipids, alcohol, and other factors, total carbohydrate intake at baseline was inversely related to baseline plasma total cholesterol and high-density-lipoprotein (HDL) cholesterol: starch and other simple carbohydrates were unrelated to plasma lipids and sucrose was inversely related to HDL cholesterol. During trial years 1-6, men assigned to the special intervention group increased their intake of starch and other simple carbohydrates as they decreased their fat intake, and lowered their intakes of refined and processed sucrose. Total carbohydrate intake of these men was inversely related to total, low-density-lipoprotein (LDL), and HDL cholesterol. Starch and sucrose intakes were also inversely related to HDL cholesterol. In contrast, intake of other simple carbohydrates was directly related to HDL, and inversely related to plasma total and LDL cholesterol. For men in the highest quintile of intake of other simple carbohydrates compared with men in the lowest quintile, plasma total cholesterol was lower by 3.6 mg/dL, LDL cholesterol was lower by 4.3 mg/dL, and HDL cholesterol was higher by 1.6 mg/dL. Findings were generally similar for men in the usual care group. Am J Clin Nutr 1997;65(supple):314S-26S.

This chapter presents changes in dietary intake reported by men in the special intervention (SI) and usual care (UC) groups from baseline through 6 y of follow-up in the Multiple Risk Factor Intervention Trial. Changes in nutrients by SI men after 1 y of following the intensive intervention program were as follows: reduced intake of total fat (from 6.4% to 8.6% of 34.3% of energy), saturated fatty acids (14.2% to 10.4% of energy), and cholesterol (448 to 263 mg/d), and increased intake of polyunsaturated fatty acids (from 6.4% to 8.6% of energy). These changes were maintained and did not increase through the remaining 5 y. UC men reported small changes in similar directions. Most of the change in saturated fatty acid intake by SI participants was from high-fat meat and high- and medium-fat dairy products. Reduction in dietary cholesterol was achieved primarily by substantial decreases in intake of eggs and high-fat meats. Several baseline factors were associated with amount of dietary change in SI men. Greater changes were seen in men with higher baseline serum cholesterol concentrations, in those not consuming a special diet, in nonsmokers followed by lighter smokers, in hypertensive than in non-hypertensive men, in older participants, in white than in black men, in moderate drinkers than in nondrinkers or those consuming [is greater than or equal to] 22 drinks/wk, and in those with no 'stressful life events' than in those reporting one or more life events. Am J Clin Nutr 1997;65(suppl):258S-71S.

The selection process in the Multiple Risk Factor Intervention Trial caused relations between risk factors to differ between participants who were randomly assigned into the study add the screening population. Cigarette smoking, blood pressure, and serum cholesterol were moderately inversely related to each other in the randomly assigned population whereas these relations in the unselected population were direct and small in magnitude. This problem was addressed by covariate adjustment in analyses. The selection process also created an artificially high initial mean concentration of serum cholesterol, the mean plasma concentration at the second screening was 15 mg/dL lower than at the first screening. Most of this difference is attributable to regression to the mean. To account for this problem, emphasis was placed on change in plasma cholesterol over time, calculated from the second-screening measurement. Examination of the reliability of nutrient-biochemical relations are subject to considerable regression-dilution bias. The ratios of 'within' to 'between' components of variability were typically between one and four. Analyses in which multiple follow-up measures were averaged are emphasized in this monograph. Men assigned to the special intervention group reported considerable reductions in total energy intake, which was not consistent with observed weight loss. The most likely explanation for this is underreporting or underconsumption the day before the recall. To partially adjust for this, nutrient data are often expressed both in absolute units and as nutrient densities. Am J Clin Nutr 1997;65(suppl):211S-27S.

Geoge Davey Smith and Andrew Phillips raise some issues concerning methods used in correcting for regression dilution in Intersalt but offer no judgment on the crucial issue of the strength [...]

In the United States population, black men have higher prevalence rates of electrocardiographic (ECG) higH QRS voltage, more ST-segment and T-wave abnormalities, and more ECG left ventricular hypertrophy (LVH) than do white men. Reasons for these differences have not been fully elucidated. The prevalence rate of ECG LVH and associated characteristics were compared in black and white men in the Chicago Heart Association Detection Project in industry population study. Data were from 1,391 black men and 19,126 white men (age range 20 to 64 years) employed by 84 Chicago organizations. ECG LVH was defined by the presence of both high QRS (Minnesota code 3.3) and ST-T abnormality (code 4.1-4.3 or 5.1-5.3). Black men had a significantly higher prevalence rate of ECG LVH than did white men in each 15-year age group (15.9 vs 2.4, 14.6 vs 2.8, and 35.7 vs 12.5/1,000 in the 20- to 34-, 35- to 49-, and 50-to 64-year age groups, respectively; p

Dietary assessment plays a crucial role in our ability to detect relationships between dietary exposure and disease causation. Nutritional problems are at the root of major mass diseases that are impediments to progress toward national and international health goals. This is true for chronic undernutrition and famine as well as many of the chronic diseases afflicting middle-aged and elderly people in industrialized and developing countries. High-quality dietary assessment provides a sound scientific foundation for the primary prevention of mass diseases, whereas inadequate assessment can produce false-negative results and result in apparent inconsistencies between cross-population and within-population findings for a particular disease. The critical role of dietary assessment in the elucidation of disease causation is discussed with regard to high blood pressure, heart disease, breast cancer, and several other major chronic diseases. Improved approaches to dietary assessment need to be made more widely known, not only among research scientists and health practitioners, but also among policymakers who require high-quality dietary data for establishing nutrition goals and making policy decisions.

The National High Blood Pressure Education Program (NHBPEP) was launched 20 years ago based on data from population studies and clinical trials that showed high blood pressure (HBP) was a major unsolved - but soluble - mass public health problem. The present review summarizes recent data from US prospective population studies on blood pressure - systolic (SBP), diastolic (DBP) - and cardiovascular risk. The outcome variables include blood pressure-related risks, primarily incidence and mortality from coronary heart disease, stroke, other and all cardiovascular diseases (CVD); also cardiac abnormalites (roentgenographic, electrocardiographic, echocardiographic); also, all-cause mortality and life expectancy. Data accrued during the past 20 years confirm that SBP and DBP have continuous, graded, strong, independent, etiologically significant relationships to the outcome variables. These relationships are documented for young, middle-aged, and older men and for middle-aged and older women of varying socioeconomic backgrounds and ethnicity. Among persons aged 35 years or more, most have SBP/DBP above optimal (

* Background. - With increased efforts to lower serum cholesterol levels, it is important to quantify associations between serum cholesterol level and causes of death other than coronary heart disease, for which an etiologic relationship has been established. Methods. - For an average of 12 years, 350 977 men aged 35 to 57 years who had been screened for the Multiple Risk Factor Intervention Trial were followed up following a single standardized measurement of serum cholesterol level and other coronary heart disease risk factors; 21 499 deaths were identified. Results. - A strong, positive, graded relationship was evident between serum cholesterol level measured at initial screening and death from coronary heart disease. This relationship persisted over the 12-year follow-up period. No association was noted between serum cholesterol level and stroke. The absence of an association overall was due to different relationships of serum cholesterol level with intracranial hemorrhage and non hemorrhagic stroke. For the latter, a positive, graded association with serum cholesterol level was evident. For intracranial hemorrhage, cholesterol levels less than 4.14 mmol/L (

Diastolic blood pressure reflects the pressure during the relaxation phase of the heart cycle. Mild hypertension is characterized by diastolic blood pressures between 90 and 104 millimeters of mercury (mm Hg). This is the most common type of hypertension in the United States, and is responsible for most deaths due to hypertension-related coronary artery disease (CAD). Drug therapy for mild hypertension reduces the incidence of stroke by 40 percent, but only causes a 14 percent reduction in (CAD). The benefits of antihypertensive treatment will be assessed in the Treatment of Mild Hypertension Study (TOMHS), which is currently underway. Specifically, TOMHS will examine the long-term effectiveness of therapy without medication and treatment with one of five drug regimens for mild hypertension plus therapy without drugs. The study will evaluate six types of agents, including the beta blocker acebutolol, the calcium antagonist amlodipine, the diuretic chlorthalidone, the alpha-1 antagonist doxazosin, the angiotensin-converting enzyme inhibitor enalapril, and a placebo. All participants of the study will receive counselling on nutrition and hygiene to reduce weight, decrease sodium and alcohol intake, and increase physical activity. The patients will be routinely monitored for changes in blood pressure, drug side effects, quality of life, disorders of heart electrical activity, and abnormalities in findings from echocardiography (which uses sound waves to visualize the heart). They will also be assessed for the incidence of cardiovascular or heart-related events, including death. (Consumer Summary produced by Reliance Medical Information, Inc.)