Pulse pressure-I. Level and associated factors in four Chicago epidemiologic studies

Hypertension: trends in prevalence, incidence, and control

Hypertension is the leading cause of cardiovascular disease worldwide. Prior to 1990, population data suggest that hypertension prevalence was decreasing; however, recent data suggest that it is again on the rise. In 1999-2002, 28.6% of the U.S. population had hypertension. Hypertension prevalence has also been increasing in other countries, and an estimated 972 million people in the world are suffering from this problem. Incidence rates of hypertension range between 3% and 18%, depending on the age, gender, ethnicity, and body size of the population studied. Despite advances in hypertension treatment, control rates continue to be suboptimal. Only about one third of all hypertensives are controlled in the United States. Programs that improve hypertension control rates and prevent hypertension are urgently needed.

Pulse pressure--a review of mechanisms and clinical relevance

The goal of this study was to review the origin, clinical relevance and treatment of pulse pressure (PP). Elevated PP is increasingly being recognized as a risk factor for cardiovascular, particularly coronary, disease. Pulse pressure is discussed in terms of both Windkessel and distributive models of the arterial circulation. Pulse pressure arises from the interaction of cardiac ejection (stroke volume) and the properties of the arterial circulation. An increased stiffness of the aorta and large arteries leads to an increase in PP through a reduction in arterial compliance and effects on wave reflection. A number of factors are known to influence arterial wall behavior and, therefore, PP. In addition to the effects of aging and blood pressure on arterial wall elasticity, there is some evidence that atherosclerosis, per se, amplifies these effects. Thus, the relationship between PP and coronary disease may be bidirectional. A number of dietary and lifestyle interventions have been shown to modify large artery behavior. These include aerobic exercise training and consumption of n-3 fatty acids. Conversely, strength training is associated with an increase in arterial stiffness and a higher PP. The effects of antihypertensive medication have been extensively studied, but many studies are difficult to interpret because of concomitant change in blood pressure, and to a lesser degree, heart rate. However a number of studies do suggest direct arterial wall effects, particularly for angiotensin-converting enzyme inhibitors. A distributed compliance model of the arterial circulation provides a framework for understanding the causes, effects and potential treatment of elevations in PP.

Effect of reduced alcohol consumption on blood pressure in untreated hypertensive men

Fifty-four untreated, mildly hypertensive men whose daily alcohol consumption was > or = 28 ml ethanol and who drank at least 4 times per week took part in a randomized, controlled crossover trial. The purpose of the trial was to test the effects of alcohol reduction on blood pressure. After a 2-week familiarization period, the participants were assigned to either a reduced alcohol drinking group or a usual drinking group for 3 weeks (experimental period 1). The situation was then reversed for the next 3 weeks (experimental period 2). The participants were requested to limit their daily alcohol consumption to zero or reduce it as much as possible for the reduced alcohol consumption period. The self-reported alcohol consumption was 56.1 +/- 3.6 (SEM) ml/day during the usual alcohol drinking period and 26.1 +/- 3.0 ml/day during the period of reduced alcohol consumption. Systolic and diastolic blood pressures in the intervention group were found by analysis of variance to be significantly lower (2.6-4.8 and 2.2-3.0 mm Hg, respectively) than those in the control group during experimental period 2 for systolic blood pressure and experimental period 1 for diastolic blood pressure. Significant (3.6 mm Hg) and nonsignificant (1.9 mm Hg) decreases in systolic and diastolic blood pressure, respectively, were observed. The method of Hills and Armitage was used, reducing ethanol in daily alcohol consumption by 28 ml. The lowering effect of reduced alcohol consumption on blood pressure was independent of changes in salt consumption, which were estimated by 24-hour urine collection and body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulse pressure, mean blood pressure and impaired glucose tolerance--a study in middle-aged subjects

In a study of 695 middle-aged subjects, without antihypertensive agents, and without more pronounced obesity, both pulse pressure (PP) and mean blood pressure (MBP) were strongly related to 2-h blood glucose in 75 g OGTTs (p < 0.001). All hypertensives (DBP > or = 90 mm Hg) were separated into 39 with higher PP (> or = 60 mm Hg) and 137 with lower PP (< 60 mm Hg). The high PP hypertensives, compared with the low PP hypertensives and all 519 normotensives, had higher frequency of impaired glucose tolerance (IGT; WHO-criteria), 33%, 6%, and 4%, respectively (p < 0.001), and also higher mean 2-h blood glucose, 5.9, 4.5, and 4.2 mmol.l-1, respectively (p < 0.001). These differences were independent of MBP levels. Similarly, all 54 hypertensives with higher MBP (> or = 110 mm Hg) had more IGT and higher 2-h glucose than the 122 hypertensives with lower MBP (< 110 mm Hg) or the normotensives, 30%, 5% and 4%, respectively (p < 0.001), and 5.8, 4.4, 4.2 mmol.l-1, respectively (p < 0.001), independently of PP. Thus, both high PP and high MBP were related to IGT, independently of each other.

Pulsatile versus steady component of blood pressure: a cross-sectional analysis and a prospective analysis on cardiovascular mortality

Studies on the prognostic significance of blood pressure on cardiovascular disease have essentially investigated the levels of diastolic or systolic blood pressure. However, blood pressure may also be divided into two other components: steady (mean arterial pressure) and pulsatile (pulse arterial pressure). The relations of these two components with cardiovascular risk factors and cardiovascular mortality were investigated in 18,336 men and 9,351 women aged 40-69 years, who were followed up for a mean period of 9.5 years. However, the interpretation of the relations is complicated by the strong correlation existing between these two components. A principal component analysis was performed to obtain two independent parameters: a steady and a pulsatile component index, strongly correlated with mean and pulse arterial pressure, respectively. In the cross-sectional analysis, relations were stronger with the steady component index than with the pulsatile component index; an association was found between left ventricular hypertrophy and the pulsatile component index in both sexes. The survival analysis was not performed in women under 55 as only 11 cardiovascular deaths occurred in this group. The steady component index was a strong prognostic factor of all types of cardiovascular death in both sexes. In women, the pulsatile component index was positively correlated to death from coronary artery disease and inversely correlated to stroke. In conclusion, the steady component of blood pressure is a strong risk factor for cardiovascular death in both sexes; the pulsatile component could be a risk factor independent of the steady component in women older than 55 years.

Obesity and hypertension in a longitudinal study of black physicians: the Meharry Cohort Study

Obesity has been considered a risk factor among the precursors of essential hypertension for many years. Most related studies were general population surveys or predominantly white, male cohorts. This paper reports results of a longitudinal study of former black medical students, now practicing physicians for an average of 22.5 years. A remarkably high 43.8% were found to have developed hypertension. Fifty nine per cent of those who became obese during the study were hypertensive compared with 40% of the non-obese, 36% of those initially obese only, and 45% of those obese on both examinations. The risk ratio was 1.7 for the most obese (greater than or equal to 130% relative body weight) compared with 1.0 for the leanest group Dynamic weight change together with baseline diastolic blood pressure, were more prominent precursors than the other variables studied. Weight control would appear to be a potentially important nonpharmacologic hypertension risk reduction measure.

Dietary variability and its impact on nutritional epidemiology

Dietary intakes are subject to measurement errors and to day-to-day variation, which have contributed to obscuring the suspected relation between dietary lipids and ischemic heart disease. The effect of measurement error on the correlation between dietary intakes and serum cholesterol levels has been studied by others. In this paper we study the effects of errors on the categorization of subjects according to the quantities of their intakes, and the effects of this misclassification on the observed relation between observed dietary intakes and disease. Our model is based on a bivariate normal joint distribution of true and observed intakes, from which various conditional probabilities can be calculated. Tables are given to simplify many of these computations. We conclude that the usual period of collection of dietary records, 1 week, is usually adequate. The model developed is applicable to any measurement recorded with error, and two examples of its application to the classification of subjects as normotensive or hypertensive are given. The model does depend on a large number of assumptions, some of which are clearly not met. Hence the actual numerical values obtained should be treated with some scepticism. If, however, the assumptions are approximately met, then the results should be reasonable approximations to the truth.

Pulse pressure-II. Factors associated with follow-up values in three Chicago epidemiologic studies

This report, the second in a series on pulse pressure and pure systolic hypertension, examined in prospective analyses the associations between both the initial values of five variables and the changes in these variables and pulse pressure, utilizing data from three Chicago epidemiologic studies, in order to determine whether variables known to be related to blood pressure and hypertension are related to pure systolic hypertension or 'classical' hypertension. In these analyses follow-up pulse pressure, which was measured from 2-5 years after the initial measurement of the other variables, was redefined so that the association between the initial value or change and pulse pressure indicated whether the initial value or change was more strongly related to follow-up systolic or diastolic blood pressure. In these three studies, only the initial value for cigarette use had a consistent positive association with follow-up pulse pressure. Change in heart rate was generally positively related to follow-up pulse pressure, while the initial value was not. For relative weight and serum cholesterol, both the change and the initial tended to be negatively related. For glucose, the association was not consistent for either the initial value or the change. The results from these prospective analyses thus suggest that cigarette use is related to pure systolic hypertension, rather than 'classical' hypertension.

Pulse pressure-III. Prognostic significance in four Chicago epidemiologic studies

This report, the third in a series on pulse pressure and pure systolic hypertension, examines the associations between blood pressure and the cardiovascular diseases and coronary heart disease, both cross-sectionally and prospectively, utilizing data from four Chicago epidemiologic studies, in an effort to determine whether or not a widened pulse pressure, or pure systolic hypertension, is an independent risk factor. In these analyses, blood pressure is divided into two components, one related to level and the other to pulse pressure, with pulse pressure redefined so that the association between pulse pressure and the prevalence of ECG abnormalities or mortality, indicates whether the endpoint is more strongly related to systolic or diastolic blood pressure. In these studies, blood pressure level is significantly related to both ECG abnormalities and mortality. In the cross-sectional analyses, pulse pressure is generally positively related to the prevalence of ECG abnormalities, indicating a stronger association for systolic blood pressure, and thus a possible association with pure systolic hypertension. However, in the prospective analyses, pulse pressure is generally not related to mortality, indicating an equal association with mortality for systolic and diastolic blood pressure in these studies. Thus, although the cross-sectional analyses generally support the hypothesis that a widened pulse pressure, or pure systolic hypertension, is an independent risk factor for the cardiovascular diseases and coronary heart disease, the prospective analyses do not.