Introduction to the Third International Conference on Preventive Cardiology, Oslo, Norway, June 27-July 1, 1993.
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Cardiovascular Diseases↗
Biomedical subjects
R Stamler
Publications and source records attributed to R Stamler.
Body mass index and associations of sodium and potassium with blood pressure in INTERSALT.
This report further examines the relation of body mass index (BMI) to associations of 24-hour urinary sodium, potassium, and sodium-potassium ratio with blood pressure in INTERSALT, a 52-center international study of electrolytes and blood pressure. Analyses without adjustment for BMI indicated average systolic pressure greater by 6.00 mm Hg per 100 mmol higher sodium and diastolic by 2.52 mm Hg. With adjustment for BMI, these values were reduced to 3.14 and 0.14 mm Hg, respectively. For the sodium-potassium ratio, blood pressure associations were stronger when not adjusted for BMI, and for potassium, adjustment generally had little effect. To explore possible interactions of these variables with BMI in relation to blood pressure, the 52 centers were divided into two groups of 26 based on whether the center median for BMI was less than or greater than or equal to 24.5 kg/m2, and individuals within each of the 52 centers were classified into lower- or higher-BMI groups based on individual BMI less than or greater than or equal to 24.1 kg/m2. Sodium and the sodium-potassium ratio were positively and significantly and potassium inversely and significantly related to systolic pressure in all four of these subgroups, and the sodium-potassium ratio and potassium were related to diastolic pressure in two and three subgroups, respectively. Electrolyte-blood pressure associations did not differ significantly between the two subgroups of centers or between the two subgroups based on individuals.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
A north-south comparison of blood pressure and factors related to blood pressure in the People's Republic of China: a report from the PRC-USA Collaborative Study of Cardiovascular Epidemiology.
OBJECTIVES: To compare blood pressures in northern (Beijing) and southern (Guangzhou) Chinese population samples aged 35-54 years, males and females, urban and rural, and to assess the role of blood pressure-related traits in explaining north-south differences. DESIGN: Cross-sectional surveys were conducted in 1983-1984 of northern and southern populations employed in industry (urban) or farming (rural). METHODS: In the north samples were selected from the Capital Iron and Steel Complex (urban) and Shijingshan district (rural); in the south samples from the Guangzhou Shipyard (urban) and Panyu County (rural) were used. RESULTS: The number of subjects surveyed in north and south were 4706 and 4179, respectively: 1500 and 1052 urban males, and 717 and 914 rural males; and 1300 and 1061 urban females, and 1189 and 1152 rural females, respectively. Average systolic (SBP) and diastolic (DBP) blood pressures, were consistently higher in the north than in the south. SBP and DBP were significantly and independently related to age, body mass index, heart rate, use of antihypertensive drugs, serum triglycerides level, alcohol use (males only) and inversely to cigarette smoking. Northerners were older, taller, heavier and had higher body mass index and triglycerides level than southerners. With adjustment of SBP and DBP for blood pressure-related traits, north-south blood pressure differences decreased, but remained significant for urban males, rural males and rural females, with sizeable differences for rural samples in particular. CONCLUSIONS: North-south differences in blood pressure in these samples are accounted for only partly by north-south differences in the cited blood pressure-related traits. The role of other traits requires assessment.
Adult↗
Correcting for regression dilution in INTERSALT.
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Blood Pressure↗
Blood pressure, systolic and diastolic, and cardiovascular risks. US population data.
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 abnormalities (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 (< 120/< 80 mm Hg); hence, they are at increased CVD risk, ie, the blood pressure problem involves most of the population, not only the substantial minority with clinical HBP. For middle-aged and older persons, SBP relates even more strongly to risk than DBP; at every DBP level, higher SBP results in greater CVD risk and curtailment of life expectancy. A great potential exists for improved health and increased longevity through control of the blood pressure problem. Its realization requires a strategy combining population wide and high-risk approaches, the former to prevent rise of blood pressure with age and to achieve primary prevention of HBP by nutritional-hygienic means; the latter to enhance detection, treatment, and control of HBP. The newly expanded goals of the NHBPEP, aimed at implementing this broader strategy for the solution of the blood pressure problem, merit active support from physicians and all health professionals.
Blood Pressure↗
Relationship of baseline major risk factors to coronary and all-cause mortality, and to longevity: findings from long-term follow-up of Chicago cohorts.
The focus here is on relationships between major risk factors and long-term mortality from coronary heart disease (CHD) and all causes, and on longevity, in Chicago cohorts: 25-year follow-up for Peoples Gas (PG) men aged 25-39 (n = 1,119), 30-year follow-up for PG men aged 40-59 (n = 1,235), 24-year follow-up for Western Electric (WE) men aged 40-55 (n = 1,882); also 15-year follow-up for five cohorts of the Chicago Heart Association (CHA) Study: men aged 25-39 (n = 7,873), 40-59 (n = 8,515), 60-74 (n = 1,490), and women aged 40-59 (n = 7,082) and 60-74 (n = 1,243); also 12-year findings for very low risk men (n = 11,098) and other men (n = 350,564) screened for the Multiple Risk Factor Intervention Trial (MRFIT). With a high degree of consistency, multivariate analyses showed independent positive relationships of baseline serum cholesterol, blood pressure and cigarette use to risk of death from CHD and all causes. For the WE cohort, with baseline nutrient data, dietary cholesterol was also independently related to these mortality risks. Combined risk factor impact was strong for both men and women of all baseline ages. Thus, for WE men, favorable compared to observed levels of serum cholesterol, blood pressure, cigarette use and dietary cholesterol were estimated to result in 24-year risk of CHD death 69% lower, all-cause death 42% lower and longevity 9 years greater. For CHA middle-aged and older women, favorable baseline levels of serum cholesterol, blood pressure and cigarette use were estimated to yield 15-year-CHD risk lower by about 60% and longevity greater by about 5 years. For MRFIT, very low risk men (serum cholesterol < 182 mg/dl, systolic/diastolic blood pressure < 120/<80), nonsmokers, nondiabetic, no previous heart attack), compared to all others, observed 12-year death rates were lower by 89% for CHD, 79% for stroke, 86% for all cardiovascular diseases, 30% for cancers, 21% for other causes, 53% for all causes, and longevity was estimated to be more than 9 years longer. These findings indicate great potentials for prevention of the CHD epidemic and for increased longevity with health for men and women, through improved life-styles and consequent lower risk factor levels.
Adult↗
Serum cholesterol. Doing the right thing.
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Adult↗
Blood pressure and life style in the People's Republic of China: three samples in the INTERSALT Study.
In INTERSALT, the International Cooperative Study on Electrolytes and Blood Pressure, three centres located in the People's Republic of China (PRC) had distinctive patterns of BP and of life style variables that, in INTERSALT overall, were found to relate to BP. The PRC centres had low body mass index (BMI) and alcohol consumption but high urinary sodium and sodium/potassium ratio (Na/K). Compared with 45 other INTERSALT centres, average BMI was 22.7 vs. 25.4 and alcohol consumption was 32% vs. 61%, with heavy drinking 3% vs. 14%. However, Na/K in the PRC was 6.7 vs. 3.2 in the other centres. This combination of factors may underlie the BP pattern observed. While mean BP in the PRC was lower than in the 45 centres (-7.0 mmHg SBP, -5.6 mmHg for DBP), this was counterbalanced by other findings. Upward slope of systolic pressure with age was 45% greater for the PRC than the other centres and 24% greater for diastolic pressure. As a result, although percentage hypertensive for ages 20-49 years for the PRC was half that in the 45 centres (6% vs. 12%), by age 50-59 years the prevalence was 31% in the PRC and 38% in the other centres. Hypertension prevalence in Tianjin, with highest Na/K in INTERSALT (7.6) was 40% for ages 50-59 years. While sample size in individual centres does not provide power to demonstrate aetiological relationships, these findings permit formulation of the following hypothesis: although lower body mass and lower alcohol intake may counteract to some degree impact of high salt intake, such intake over decades eventually takes its toll on BP.
Adult↗
Population based data on urinary excretion of calcium, magnesium, oxalate, phosphate and uric acid in children from Cimitile (southern Italy).
Population based data on 24-h urinary excretion of calcium, oxalate, magnesium, phosphate, uric acid and creatinine were collected from 220 children (aged 3-16 years) living in Cimitile, Campania, southern Italy. Mean excretion rates for 7 days were correlated with age, body weight, body mass index and height. The prevalence of hypercalciuria (greater than 4 mg/kg body weight) and of hyperoxaluria (greater than 60 mg/day) were 9.1% and 1.8%, respectively. The same 20 children were also identified as hypercalciuric when a calcium/creatinine ratio of greater than 0.15 was considered. No significant differences between boys and girls were found in the urinary excretion of the five constituents implicated in urolithiasis. The study data provide additional childhood reference values for urinary excretion of compounds related to stone formation.
Adolescent↗
Higher blood pressure in adults with less education. Some explanations from INTERSALT.
An inverse association between social class and disease has frequently been reported; education, an indicator of social class, was negatively related to blood pressure in several studies. Reasons are not clear. INTERSALT, an international study on electrolytes and blood pressure, obtained data on years of education for 10,079 adults in 52 centers in 32 countries. Data presented here are for 47 centers, omitting five where the population in the sample had no education or no differences in educational level. Regression coefficients were calculated for the education-blood pressure association in each center. An inverse association was found for men in 28 centers and for women in 38. Center coefficients were combined to give a studywide estimate of that association. When adjusted only for age, systolic pressure in men was 1.3 mm Hg higher for 10 fewer years of education (p less than 0.05) and for women 4.5 mm Hg higher (p less than 0.001). However, when adjusted also for five lifestyle factors (24-hour sodium and potassium excretion, body mass index, alcohol intake, and smoking), these estimates were reduced by about one half, and the inverse association was no longer significant for men. Similar findings were obtained for diastolic pressure. Those with less education had on average higher sodium excretion, lower potassium excretion, greater body mass, and higher alcohol intake, all factors tending to increase blood pressure. Improvement of these factors, which help explain the differences in blood pressure related to years of education, has the potential to reduce the blood pressure disadvantage associated with lower socioeconomic status.
Adult↗
Age-related changes of urinary urea. Epidemiological study in children from southern Italy living in Cimitile.
Urinary urea was measured, under normal living conditions, in children aged 3-16 years, from Cimitile, a small town near Naples in Southern Italy. Urinary urea correlated with age, height, weight, body mass index and body surface area, and was independent from sex. Urinary urea also correlated with urinary creatinine, uric acid, oxalate, sodium and phosphate. Protein intake assessed from urea excretion was 2.66 +/- 0.66 g/kg at 3 years of age and 1.49 +/- 0.31 g/kg at 16 years, and exceeded Italian standards for recommended intake. Also, the height and weight of the children living in Cimitile, with few exceptions, were in excess of national reference standards.
Adolescent↗
Implications of the INTERSALT study.
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Blood Pressure↗
Findings of the International Cooperative INTERSALT Study.
INTERSALT, an international cooperative study on electrolytes and other factors related to blood pressure, found, in within-population analyses involving 10,079 persons, a significant positive association between 24-hour urinary sodium excretion and systolic blood pressure and between the sodium/potassium ratio and systolic blood pressure. These significant findings were derived from analyses for individuals from all 52 centers and from the 48 centers remaining when persons from four low sodium centers were excluded. Potassium excretion of individuals was significantly and independently related inversely to their systolic blood pressure. For men and women, both separate and combined, the relation between sodium and systolic blood pressure was stronger for older than younger adults, perhaps reflecting the result of longer exposure with age or diminished capacity to handle a sodium load. Relations between electrolyte excretion and diastolic blood pressure in individuals were weaker than for systolic blood pressure. Body mass index and heavy alcohol consumption of individuals were strongly and independently related to blood pressure. In cross-population analyses with n = 52 or n = 48, sample median sodium excretion was significantly and independently related to the slope of systolic blood pressure and diastolic blood pressure with age. Other ecological analyses yielded inconsistent results. Four isolated populations showed low sodium excretion, low sodium/potassium excretion, low body mass index, and low alcohol consumption; sample median blood pressures were low, there was little or no upward slope of blood pressure with age, and high blood pressure was rare or nonexistent.
Adult↗
Why do lean hypertensives have higher mortality rates than other hypertensives? Findings of the Hypertension Detection and Follow-up Program.
Specific causes of death were analyzed for 10,908 participants in the Hypertension Detection and Follow-up Program, to explore possible explanations for the observed excess 8.3-year mortality from all causes in hypertensives with low body mass. Although the cardiovascular mortality rate among men in the lowest decile of body mass (body mass index 21.96 or less) was 50% higher than that of men in the median class (body mass index 26.4-28.8), death rate for noncardiovascular deaths was more than 2 1/2 times higher in men with lean versus median body mass. The pattern was similar among women. Among noncardiovascular causes, striking differences in mortality rates between lean hypertensives and those of average body mass were observed for cirrhotic death (relative risk of 12+ in men and 11+ in women), for nonmalignant respiratory disease in men (relative risk of 7+), for violent death (both sexes), and for malignant neoplasms in men. Prevalence of smoking was almost twice as high in the lowest compared with the median body mass group; among the lean, excess deaths, particularly noncardiovascular deaths, were concentrated among smokers. Thus, male smokers in the lowest decile of body mass constituted only 3% of the study population, but contributed 8% of all deaths, 11% of all noncardiovascular deaths, and 22% of all cirrhotic deaths. A larger proportion of deaths occurred early in follow-up in the lean versus other hypertensives, suggesting occult disease among the lean at baseline. There was no evidence that more severe or treatment-resistant hypertension was present in or could explain excess mortality among the hypertensives with low body mass. The inference from the findings is not that overweight is protective for hypertensives nor that excess risk is due to leanness per se. Rather, a reasonable hypothesis, particularly from findings on specific causes of death, is that excess mortality in lean hypertensives is due to deleterious lifestyles, particularly smoking and excess alcohol intake, contributing to both leanness and risk of death.
Adult↗
Blood pressure levels, related factors, and hypertension control status of Japanese and Americans.
Blood pressure levels and related factors in Japanese, US whites and US blacks aged 30 to 74 years were compared, using data from the similarly designed national survey of each country in a similar period, i.e., the National Survey on Circulatory Disorders of Japan, 1980 (10,897 persons from all over Japan) and the second National Health and Nutrition Survey of the US, 1976 to 1980 (NHANES-II) (16,204 persons from all over the USA). Data collection methods were judged to be comparable. Data were stratified by age (30-39, 40-49, 50-59, 60-69, 70-74 yrs) and sex. Age-specific and age-adjusted mean systolic BPs of Japanese were generally higher than those of US whites; mean diastolic pressures were similar in the two populations in both men and women. Mean weight and body mass index (BMI) and their standard deviations were lower for Japanese than Americans. In US blacks, BP was higher than in Japanese or in US whites for diastolic in men, and for both systolic and diastolic in women. Systolic BP levels of black men were between those of Japanese and US whites. At specific levels of BMI, Japanese systolic BPs were markedly higher than those of US whites in all age-sex groups, and diastolic pressures were higher in Japanese than in US whites, slightly so at younger ages and more so at ages 60 and over in both sexes. The proportions of all persons with high BP who were receiving antihypertensive treatment and who were controlled were similar in most age-sex groups of the Japanese and US white populations; they were lower in US black men and higher in US black women. In linear regression analyses of BP on BMI controlled for age, slopes were similar for Japanese and Americans. However, given the lower mean BMI and smaller BMI standard deviation (less overweight), partial correlation coefficients between BMI and BP were smaller for Japanese than Americans. These results indicate that overweight plays a lesser role in Japanese than Americans in producing high prevalence rates of hypertension and that other factors are critically involved (e.g., intake of sodium, potassium, calcium, alcohol).
Adult↗
Sodium-lithium countertransport and systolic blood pressure response to exercise.
This study examined the relationship between erythrocyte sodium-stimulated lithium countertransport (Na-Li CT) and systolic blood pressure (SBP) response to exercise in 22 white normotensive men (mean age 40.6 years) completing a submaximal (85% of target heart rate) graded exercise tolerance test. These men were assessed to be at risk of hypertension on the basis of a high normal diastolic blood pressure (DBP; 80-89 mmHg), being overweight and having a rapid resting pulse rate. Na-Li CT was positively and significantly associated with the maximal SBP reached during exercise (P less than 0.01) and the lowest SBP achieved during post-exercise supine rest (P less than 0.01). The relationship with resting blood pressure was not significant. Standing DBP was the only resting blood pressure measurement significantly associated with Na-Li CT (P less than 0.05). We found an association between Na-Li CT, a membrane sodium transport system associated with blood pressure and hypertension, and the maximal SBP reached during exercise, a blood pressure measurement predictive of future hypertension, in people with normotensive resting blood pressure. This suggests that altered membrane sodium transport may occur before the establishment of hypertension, and supports the possibility that Na-Li CT may be a risk factor for this disease.
Adult↗
Multiple risk factors in hypertension: results from the Gubbio study.
The association between hypertension and a number of cardiovascular disease risk factors was assessed in the large population sample of Gubbio, a town in central Italy that dates back to medieval times. The data confirm those of previous studies showing that hypertension is strongly associated with other metabolic abnormalities, such as markedly overweight subjects, hyperuricaemia, hyperglycaemia, hypercholesterolaemia, that may be related to the aetiopathogenesis of high blood pressure and, in addition, compound the risk of major clinical cardiovascular events in people with hypertension. The findings are therefore relevant for prevention strategies. In addition, the association between erythrocyte sodium-stimulated lithium countertransport and hypertension is being studied.
Adult↗
Primary prevention of hypertension by nutritional-hygienic means. Final report of a randomized, controlled trial.
A 5-year trial involving 201 men and women with high-normal blood pressure at baseline demonstrated the ability to reduce the incidence of hypertension in participants randomized to nutritional-hygienic intervention compared with a control group. The incidence of hypertension was 8.8% among 102 intervention group participants vs 19.2% among 99 control group members. The odds ratio for the incidence of hypertension in the control group was 2.4. Mean trial blood pressure also was lower in the intervention compared with the control group (-1.2 and -1.9 mm Hg, respectively, for diastolic blood pressure at work-site and office visits and -1.3 and -2.0 mm Hg, respectively, for systolic blood pressure at the two sites). Net weight loss in the intervention group averaged 2.7 kg during the trial; sodium intake was reduced by 25% and reported alcohol intake decreased by 30%. The majority of intervention participants also reported an increase in physical activity. Effect on blood pressure was related particularly to degree of weight loss. Results indicate that even a moderate reduction in risk factors for hypertension among hypertension-prone individuals contributes to the primary prevention of the disease.
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