Rose Stamler

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.

Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations

Abstract Objectives: To assess further the relation in Intersalt of 24 hour urinary sodium to blood pressure of individuals and populations, and the difference in blood pressure from young adulthood into middle age. Design: Standardised cross sectional study within and across populations. Setting: 52 population samples in 32 countries. Subjects: 10 074 men and women aged 20-59. Main outcome measures: Association of sodium and blood pressure from within population and cross population multiple linear regression analyses with multivariate correction for regression dilution bias. Relation of sample median daily urinary sodium excretion to difference in blood pressure with age. Results: In within population analyses (n=10 074), individual 24 hour urinary sodium excretion higher by 100 mmol (for example, 170 v 70 mmol) was associated with systolic/diastolic blood pressure higher on average by 3/0 to 6/3 mm Hg (with and without body mass in analyses). Associations were larger at ages 40-59. In cross population analyses (n=52), sample median 24 hour sodium excretion higher by 100 mmol was associated with median systolic/diastolic pressure higher on average by 5-7/2-4 mm Hg, and estimated mean difference in systolic/diastolic pressure at age 55 compared with age 25 greater by 10-11/6 mm Hg. Conclusions: The strong, positive association of urinary sodium with systolic pressure of individuals concurs with Intersalt cross population findings and results of other studies. Higher urinary sodium is also associated with substantially greater differences in blood pressure in middle age compared with young adulthood. These results support recommendations for reduction of high salt intake in populations for prevention and control of adverse blood pressure levels. Key messages The within population findings were previously underestimated because of incomplete correction for the regression dilution problem Revised estimates of the within population association of sodium to blood pressure in Intersalt are concordant with the cross population findings for 52 samples Estimates of the effect of median sodium excretion higher by 100 mmol/day over a 30 year period (age 55 minus age 25) were a greater difference of 10-11 mm Hg in systolic blood pressure and 6 mm Hg in diastolic blood pressure These results lend further support to recommendations for mass reduction of high salt intake for the prevention and control of adverse blood pressure levels and high blood pressure in populations

Weight and blood pressure. Findings in hypertension screening of 1 million Americans

In the nationwide Community Hypertension Evaluation Clinic screening of more than 1 million people, the group classifying itself as overweight had prevalence rates of hypertension 50% to 300% higher than other screenees. Frequency of hypertension in overweight persons aged 20 to 39 years was double that of normal weight and triple that of underweight persons. Among those aged 40 to 64 years, the overweight group had a 50% higher hypertension prevalence rate than the normal-weight group and 100% higher than the underweight group. With each higher degree of blood pressure elevation, relative frequency of hypertension with overweight was larger. Thus this study confirms, in the largest group surveyed to date, similar findings in previous cross-sectional surveys. It is also consistent with data from longitudinal and intervention studies on the importance of overweight in relation to hypertension.

Alcohol and blood pressure: the INTERSALT study.

Abstract Objectives : To assess the relation between alcohol intake and blood pressure in men and women and in men at younger and older ages; to examine the influence of amount and pattern of alcohol consumption, as well as of acute effects, taking into account body mass index, smoking, and urinary sodium and potassium excretion. Design - Subjects reported alcohol consumption20for each of seven days before standardised blood pressure measurement, and whether they had consumed any alcohol in the 24 hours before measurement. Setting : 50 centres worldwide. Subjects : 4844 men and 4837 women aged 20-59. Main outcome measures : Effect of alcohol on blood pressure estimated by taking a weighted average of regression coefficients from centres. Acute effect assessed by examining mean differences in blood pressure of non- drinkers and of heavy drinkers who had and had not consumed alcohol in the 24 hours before measurement. Effect of pattern of consumption assessed by examining mean differences in blood pressure of non-drinkers compared with drinkers (i) whose intake was concentrated in fewer days or who were drinking more frequently, and (ii) whose alcohol intake varied little over the seven days or varied more substantially, as indicated by the standard deviation of daily consumption. Results : Of the 48 centres in which some people reported consuming at least 300 ml/week of alcohol, 35 had positive regression coefficients linking heavy alcohol consumption to blood pressure. Overall, alcohol consumption was associated with blood pressure, significantly at the highest intake. After account was taken of key confounders, men who drank 300-499 ml alcohol/week had systolic/diastolic blood pressure on average 2.7/1.6 mm Hg higher than non-drinkers, and men who drank >=500 ml alcohol/week had pressures of 4.6/3.0 mm Hg higher. For women, heavy drinkers (>=300 ml/week) had blood pressures higher by 3.9/3.1 mm Hg than non-drinkers. Heavy drinking and blood pressure were strongly associated in both sexes, and in men at both younger (20-39 years) and older (40-59 years) ages. In men who were heavy drinkers, episodic drinkers (those with great variation in daily alcohol consumption) had greater differences in blood pressure compared with non-drinkers than did regular drinkers of relatively constant amounts. Conclusion : The significant relation of heavy drinking (3-4 or more drinks/day) to blood pressure, observed in both men and women, and in younger and older men, was independent of and added to the effect on blood pressure of body mass index and urinary excretion of sodium and potassium. The findings indicate the usefulness of targeting those at higher risk as well as the general population to reduce the adverse effects of alcohol on blood pressure.

Socioeconomic differentials in mortality risk among men screened for the multiple risk factor intervention trial: I. White men

OBJECTIVES This study examined socioeconomic differentials in risk of death from a number of specific causes in a large cohort of White men in the United States. METHODS For 300 685 White men screened for the Multiple Risk Factor Intervention Trial between 1973 and 1975, data were collected on median income of White households in the zip code of residence, age, cigarette smoking, blood pressure, serum cholesterol, previous myocardial infarction, and drug treatment for diabetes. The 31 737 deaths that occurred over the 16-year follow-up period were grouped into specific causes and related to median White family income. RESULTS There was an inverse association between age- adjusted all-cause mortality and median family income. There was no attenuation of this association over the follow-up period, and the association was similar for the 22 clinical centers carrying out the screening. The gradient was seen for many-but not all-of the specific causes of death. Other risk factors accounted for some of the association between income and coronary heart disease and smoking-related cancers. CONCLUSIONS Socioeconomic position, as measured by median family income of area of residence, is an important determinant of mortality risk in White men.

INTERSALT study findings. Public health and medical care implications.

INTERSALT found a significant association between 24-hour urine sodium excretion and systolic blood pressure in individuals. There was also a significant association between sodium and slope (increase) of blood pressure with age across population samples. The weight of evidence from animal-experimental, clinical, intervention, and epidemiological data favors a causal relation. INTERSALT data from 52 centers in 32 countries permit an estimate of effect on average population blood pressure of lower sodium intake. Based on the sodium-blood pressure association in individuals, it was estimated that a habitual population sodium intake that was lower by 100 mmol/day (e.g., 70 vs. 170 mmol/day) would correspond to an average population systolic pressure that was lower by at least 2.2 mm Hg. This size difference in systolic blood pressure in major US and UK population studies is associated with 4% lower risk of coronary death and 6% lower risk of stroke death in middle age. If habitual diet is both lower in sodium and higher in potassium with lower alcohol intake and less obesity, INTERSALT data estimate average population systolic pressure would be lower by 5 mm Hg. This was calculated to correspond to a 9% lower risk of coronary death and a 14% lower risk of stroke death. INTERSALT cross-population data also suggest that, with a 100 mmol/day lower sodium intake over the life span, the average increase in population systolic pressure from age 25 to 55 years would be less by 9 mm Hg, corresponding at age 55 to a 16% lower risk of subsequent coronary death and 23% lower risk of stroke death. These findings have importance in long-term population strategy for reduction of cardiovascular mortality.

Nutritional Therapy for High Blood Pressure: Final Report of a Four-Year Randomized Controlled Trial— The Hypertension Control Program

A four-year trial assessed whether less severe hypertensives could discontinue antihypertensive drug therapy, using nutritional means to control blood pressure. Randomization was to three groups: group 1--discontinue drug therapy and reduce overweight, excess salt, and alcohol; group 2--discontinue drug therapy, with no nutritional program; or group 3--continue drug therapy, with no nutritional program. In groups 1 and 2 patients resumed drug therapy if pressure rose to hypertensive levels. Loss of at least 4.5 kg (10 + lb) was maintained by 30% of group 1, with a group mean loss of 1.8 kg (4 lb); sodium intake fell 36% and modest alcohol intake reduction was reported. At four years, 39% in group 1 remained normotensive without drug therapy, compared with 5% in group 2. Study findings demonstrated that nutritional therapy may substitute for drugs in a sizable proportion of hypertensives or, if drugs are still needed, can lessen some unwanted biochemical effects of drug treatment.

Mortality differences between black and white men in the USA: contribution of income and other risk factors among men screened for the MRFIT

BACKGROUND Studies of underlying differences in adult mortality between black and white individuals in the USA have been constrained by limitations of data or small study size. We investigated the extent to which differences in socioeconomic position between black and white men contribute to differences in all-cause and cause-specific mortality. METHODS 361,662 men were screened for the Multiple Risk Factor Intervention Trial between 1973 and 1975, in 22 sites. Median family income of households by zipcode (postal) area of residence was available for 20,224 black and 300,685 white men as well as data on age, cigarette smoking, blood pressure, serum cholesterol, previous heart attack, and treatment for diabetes. We classified deaths during 16 years of follow-up into specific causes and compared differences in death rates between black men and white men, before and after adjustment for differences in income and other risk factors. FINDINGS Age-adjusted relative risk of death (black vs white) was 1.47 (95% CI 1.42-1.53). Adjustment for diastolic blood pressure, serum cholesterol, cigarette smoking, medication for diabetes, and previous admission to hospital for heart attack decreased the relative risk to 1.40 (1.35-1.46). Adjustment for income but not the other risk factors decreased the risk to 1.19 (1.14-1.24) and adjustment for other risk factors did not alter this estimate. For cardiovascular death, relative risk on adjustment for income was decreased from 1.36 to 1.09; for cancer from 1.47 to 1.25; and for non-cardiovascular and non-cancer deaths from 1.71 to 1.26. For some specific causes of death, including prostate cancer, myeloma, and hypertensive heart disease, the higher death rates among black men did not seem to reflect differences in income. Rates of death for suicide and melanoma were lower among black than white men, as were those for coronary heart disease after adjustment for income. INTERPRETATION Socioeconomic position is the major contributor to differences in death rates between black and white men. Differentials in mortality from some specific causes do not simply reflect differences in income, however, and more detailed investigations are needed of how differences are influenced by environmental exposures, lifetime socioeconomic conditions, lifestyle, racism, and other sociocultural and biological factors.

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.

Inverse Relation of Dietary Protein Markers With Blood Pressure Findings for 10 020 Men and Women in the INTERSALT Study

BACKGROUND The purpose of this study was to assess relations to blood pressure (BP) in individuals of markers of dietary protein in their 24-hour urine collections. METHODS AND RESULTS INTERSALT (INTERnational study of SALT and blood pressure) was a cross-sectional study of 10020 men and women aged 20 to 59 years in 52 population-based samples in 32 countries worldwide, with quality-controlled standardized procedures and assessment of multiple possible confounders. Three measurements of dietary protein in 24-hour urine of each individual participant were studied: total nitrogen and urea as indexes of total protein intake, and sulfate as an index of sulfur-containing dietary amino acids. Repeat examination was performed in a random 8% of participants to assess reliability and to correct for regression-dilution bias. Significant independent inverse relationships were found between BP (systolic and diastolic) and both 24-hour urinary total nitrogen and urea nitrogen, with adjustment for age, sex, alcohol intake, body mass, and 24-hour urinary sodium, potassium, calcium, and magnesium. With adjustment for regression-dilution bias, it was estimated that systolic and diastolic BP were on average 3.0 and 2.5 mm Hg lower, respectively, for persons with dietary total protein intake 30% above the overall mean than for those whose dietary protein intake was 30% below the overall mean (12.94 versus 6.96 g/d urinary total nitrogen, equivalent to 81 versus 44 g/d dietary protein, respectively). For the association of these markers with diastolic BP, results were similar for younger (20- to 39-year-old) and older (40- to 59-year-old) persons and for women and men. For their relation to systolic BP, regression coefficients were larger both for those aged 40 to 59 years than for those aged 20 to 39 years and for women than for men. Nonsignificant inverse relations were recorded for urinary sulfate and BP. CONCLUSIONS These INTERSALT findings lend support to the hypothesis that higher dietary protein intake has favorable influences on BP.