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Biomedical subjects

J Staessen

Publications and source records attributed to J Staessen.

At least 91 records · Page 5Linked to original sources
PubMed1991

Pulse rate and sodium intake interact to determine blood pressure. A population study.

It has been suggested that certain factors need to be present for the pressor effect of sodium to become apparent. The present population study investigated whether pulse rate (PR) and salt intake interact to determine blood pressure (BP). Twenty-four hour urinary sodium (UNaV) was used as a measure of salt intake. A random population sample, including 2081 subjects with a minimum age of 18 years, was stratified on tertiles of PR. In subjects with a slow PR(less than 68 beats/min) and in those with a fast PR (greater than 78 beats/min), a significant curvilinear relationship between BP and UNaV was found, while in subjects with an intermediate PR the BP-UNaV correlation was not significant. There was also a significant interaction between PR and UNaV, indicating that when UNaV increased from 160 to 300 mmol/24 h, systolic/diastolic BP rose by 2/1 mm Hg in the fast PR third, but declined by 1/1 mm Hg in the slow PR third. These divergent trends could not be explained by smoking habits or alcohol consumption and were still present after cumulative adjustment for other important correlates of BP, ie, gender, age, body weight, urinary potassium, and contraceptive pill intake in women. In conclusion, the present data suggest that in subjects with a pulse rate greater than 78 beats/min a high salt intake may be associated with blood pressure elevation, whereas the opposite tendency is observed in individuals with a pulse rate less than 68 beats/min.

Adolescent↗
PubMed1991

Twenty-four-hour ambulatory blood pressure in men and women aged 17 to 80 years: the Allied Irish Bank Study.

In order to determine reference values for ambulatory blood pressure, a sample of 815 healthy bank employees (399 men and 416 women), aged 17-79 years, were investigated. Ambulatory blood pressure was recorded over 24 h, taking measurements at 30-min intervals. Blood pressure was also measured by trained observers in the clinic. Ambulatory blood pressure in the 815 subjects averaged 118/72 mmHg over 24 h, 124/78 mmHg during the day (1000-2259 h) and 106/61 mmHg at night (0100-0659 h). Office blood pressure, measured by an observer, was 4/2 mmHg lower (p less than 0.0001) than daytime ambulatory pressure. The 95th centiles for the daytime ambulatory pressure in men were: 114/88 mmHg for the age group 17-29 years (n = 107); 143/91 mmHg from 30-39 years (n = 123); 150/98 mmHg from 40-49 years (n = 109); and 155/103 mmHg in 50-79 year old men (n = 60); for the corresponding age groups in women, the 95th centiles of the daytime pressure were: 131/83 mmHg (n = 174); 132/85 mmHg (n = 149); 150/94 mmHg (n = 55); and 177/97 mmHg (n = 38).

Adult↗
PubMed1991

The assessment of the relationship between blood pressure and sodium intake using whole-day, daytime and overnight urine collections.

The usefulness of whole-day, daytime (waking to retiring time) and overnight urine samples for assessing the relationship between blood pressure and sodium intake was examined in 301 male London civil servants, aged from 37 to 58 years old. Systolic blood pressure (SBP)/diastolic blood pressure (DBP) averaged 126/78 mmHg and the 24-h urinary excretion of sodium and potassium was 174 and 73 mmol, respectively. There was poor consistency between day- and night-time urine samples with respect to both sodium and potassium content. The urinary excretion of sodium and potassium was lower (P less than 0.001) in overnight than in daytime samples. After standardization for creatinine, the night: day ratio was 0.79 for sodium output and 0.55 for potassium excretion. Blood pressure, adjusted for age and body mass index, was significantly and positively correlated with overnight sodium excretion (SBP/DBP: slope = 0.061/0.046 mmHg/mmol) whereas the correlations with sodium excretion in daytime (0.010/0.004 mmHg/mmol) and whole-day (0.024/0.016 mmHg/mmol) urine samples were not significant. Blood pressure was significantly correlated with the sodium:potassium ratio in whole-day urine (1.941/1.968 mmHg/unit). As the agreement between daytime and overnight urine samples was low with respect to both sodium and potassium content, and due to the fact that the relationship between blood pressure and sodium in overnight samples may at least partially reflect pressure diuresis, overnight urinary sodium, even if related to sodium intake, cannot be employed to assess the association between salt in the diet and blood pressure.

Adult↗
PubMed1991

The effect of antihypertensive treatment on electrocardiogram voltages in the EWPHE trial.

Long-term effects of antihypertensive treatment on various electrocardiogram (ECG) voltages and the association between ECG findings at randomization and subsequent mortality were evaluated in the double-blind, placebo-controlled trial of elderly hypertensive patients, conducted by the European Working Party on High Blood Pressure in the Elderly (EWPHE). Patients were treated with a combination of hydrochlorothiazide and triamterene or matching placebo; methyldopa or placebo was added if blood pressures remained high. RaVL and SV1 + RV5 at randomization were related to systolic blood pressure (SBP) and RaVL was also related to diastolic blood pressure (DBP), after adjustment for age, gender, and body mass index (BMI). When adjusted for age and body mass index, the decreases in RaVL and SV1 + RV5 were not correlated with the changes in SBP after 1 year of active treatment but the decreases in SV1 + RV5 were positively related to the fall in DBP. After 4 years of active treatment, the fall in SBP was associated with decreases in RaVL and in SV1 + RV5, after adjustment for age and changes in BMI.

Aged↗
PubMed1991

Effects of exposure to cadmium on calcium metabolism: a population study.

The objective was to investigate the hypothesis that environmental exposure to cadmium may affect calcium metabolism in the population at large. The 1987 participants (965 men and 1022 women), from 20 to 80 years old, constituted a random sample of the population of four Belgian districts. The urinary excretion of cadmium, a measure of lifetime exposure, averaged 9.3 nmol/24 h in men (range 0.4-324 nmol/24 h) and 7.1 nmol/24 h (range 0.1-71 nmol/24 h) in women. Serum alkaline phosphatase activity and the urinary excretion of calcium correlated significantly and positively with urinary cadmium excretion in both men and women, and serum total calcium concentration negatively with urinary cadmium excretion in men only. The regression coefficients obtained after adjustment for significant covariates indicated that when urinary cadmium excretion increased twofold, serum alkaline phosphatase activity and urinary calcium excretion rose by 3-4% and 0.25 mmol/24 h respectively, whereas in men serum total calcium concentration fell by 6 mumol/l. After adjustment for significant covariates the relation between serum total calcium concentration and urinary cadmium excretion was not significant in women. The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body. The morbidity associated with this phenomenon in industrialised countries remains presently unknown and requires further investigation.

Adult↗
PubMed1991

Effect of cadmium on transmembrane Na+ and K+ transport systems in human erythrocytes.

The effects of cadmium (Cd2+) on Na+,K(+)-ATPase in disrupted human erythrocyte membranes and on various transmembrane Na+ and K+ transport systems in intact erythrocyte suspensions were studied. Cadmium2+ inhibited the erythrocyte Na+,K(+)-ATPase enzyme with a 50% inhibition at a Cd2+ concentration of 6.25 microM. The Cd2+ inhibition in the human erythrocyte was non-competitive with respect to Na+,K+, and ATP. Cadmium2+ exerted no acute effect, however, on the Na+,K(+)-ATPase pump activity as measured by the ouabain sensitive 86Rb uptake or Na+ efflux in intact red blood cells. Cadmium2+ also inhibited the Ca2+ dependent K+ channels in human red blood cells, whereas it had no effect on Na+,K+ cotransport, Na+,Li+ countertransport, anion carrier, and the number of active Na+ pump units. The data indicate that in human erythrocytes under acute conditions Cd2+ exerts an inhibitory effect on Na+,K(+)-ATPase enzyme in disrupted erythrocytes and the Ca2+ stimulated K+ efflux in intact red blood cells without affecting the Na+ pump, Na+,K+ cotransport, and Na+,Li+ countertransport activity.

Biological Transport, Active↗
PubMed1991

Effect of prostaglandin inhibition by indomethacin on plasma active and inactive renin concentration in men.

The effect of inhibition of prostaglandin synthesis by indomethacin on active renin and on acid-activable inactive renin was studied in nine healthy, sodium-replete men, both at rest and exercise. These volunteers were investigated after pretreatment with placebo or indomethacin, 150 mg daily for 3 days. Indomethacin induced a decrease in active (p = 0.004), total (p less than 0.001), and inactive (p = 0.02) renin at rest recumbent on average by 42, 19, and 8%, respectively, and at rest sitting on average by 45, 15, and 3%, respectively. Inhibition of prostaglandins with indomethacin reduced (p less than 0.001) active and total renin at each level of work load but not (p = 0.32) inactive renin. However, the exercise-induced stimulation (p less than 0.05) of active and total renin still occur during indomethacin. Indomethacin reduced (p less than 0.001) at rest sitting and at maximal exercise the plasma concentrations of immunoreactive prostaglandins E2 by 50 and 54%, respectively, prostaglandin F2 alpha by 36 and 39%, respectively, and 13,14-dihydro-15-keto-prostaglandin F alpha by 38 and 60%, respectively. The urinary excretion of immunoreactive prostaglandin E2 and F2 alpha was also reduced.

Adult↗
PubMed1991

Prognostic significance of exercise versus resting blood pressure in hypertensive men.

The outcome of 143 male hypertensive patients, investigated in the period 1972-1982, was ascertained in 1989 to determine if brachial artery pressure measured during a progressive graded exercise test on the bicycle ergometer is a better predictor of mortality and cardiovascular events than pressure at rest. During the total follow-up time of 1,573 patient years, 27 patients suffered at least one fatal or nonfatal cardiovascular event and 13 patients died. Using the Cox regression model, the age-adjusted relative hazard rates of systolic pressure at supine rest, at 50 W, at peak work load, and at 50% of peak exercise capacity were significant for total mortality (p less than or equal to 0.01) and for cardiovascular events (p less than or equal to 0.03). Pressure during exercise, however, did not significantly (p = 0.11-0.97) predict the outcome of the patients when age and pressure at rest were taken into account. The results were similar for diastolic pressure. In conclusion, intra-arterial pressures at rest and during submaximal and peak exercise significantly predict mortality and the incidence of cardiovascular events in hypertensive men, independent of age. However, there is no additional prognostic precision of the exercise pressures when age and the rest pressure are taken into account.

Adolescent↗
PubMed1991

Treatment of isolated systolic hypertension in the elderly.

Isolated systolic hypertension affects between 10 and 20% of the elderly population and carries a substantial risk of cardiovascular complications. As no prospective, randomized trials have produced scientific evidence of a treatment benefit in elderly patients with isolated systolic hypertension, opinion on when and how to treat this condition differs among expert committees as well as among individual doctors. This article reviews the present treatment policies in patients with isolated systolic hypertension. It describes the ongoing intervention studies that have been designed to examine the hypothesis that antihypertensive treatment confers a benefit to elderly patients with isolated systolic hypertension in terms of a reduced morbidity and mortality. The Syst-Eur trial, which was recently initiated by the European Working Party on High Blood Pressure in the Elderly, is described in greater detail.

Aged↗
PubMed1991

Reference values for the ambulatory blood pressure and the blood pressure measured at home: a population study.

In order to determine reference values for the ambulatory blood pressure, a population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated. The ambulatory blood pressure was recorded over 24 h, taking measurements at 20 min intervals from 8 am to 10 pm, and at 45 min intervals from 10 pm to 8 am. Blood pressure was also measured by trained observers on each of two separate home visits (5 readings per visit). The ambulatory blood pressure in the 328 subjects averaged 118/71 mmHg over 24 h, 124/76 mmHg during the day (10 am-8 pm), and 108/62 mmHg at night (0 am-6 am). Blood pressure measured by an observer at the occasion of the second home visit was 4/5 mmHg lower (P less than 0.001) than the daytime ambulatory blood pressure. The 95th centiles for the daytime ambulatory pressures were 144/95 mmHg in 85 men below age 50; 154/90 mmHg in 74 men aged greater than or equal to 50 years; 132/85 mmHg in 96 women below age 50; and 151/91 mmHg in 73 women aged greater than or equal to 50 years. The 95th centiles for the nighttime pressures in these four sex-age groups were 124/79, 140/83, 121/70, and 132/72 mmHg, respectively.

Adult↗
PubMed1991

Isolated systolic hypertension in the elderly: implications of Systolic Hypertension in the Elderly Program (SHEP) for clinical practice and for the ongoing trials.

The Systolic Hypertension in the Elderly Program (SHEP) was a double-blind placebo-controlled outcome trial on the treatment of isolated systolic hypertension (systolic pressure: 160-219 mmHg and diastolic pressure less than 90 mmHg). From 447, 921 screenes (age greater than or equal to 60 years) 4,736 patients were randomised. A significant reduction of non-fatal stroke (37%), non-fatal myocardial infarction (33%) and left ventricular failure (54%) was observed in the active treatment group. By contrast, the reduction in transient ischaemic attacks (25%), and in total (13%), cardiovascular (20%), cerebrovascular (29%) and coronary (20%) mortality did not reach a level of statistical significance. SHEP is a landmark trial on the treatment of isolated systolic hypertension (ISH) in the elderly. However, the question to what extent the SHEP results can be extrapolated to clinical practice remains open for debate. Indeed, it is possible that due to selection, the SHEP patients were not entirely representative of the elderly with ISH in the population at large. By contrast with previous intervention studies in elderly patients with combined systolic and diastolic hypertension, the SHEP trail did not demonstrate a significant beneficial effect of antihypertensive treatment on any of the cardiovascular mortality endpoints. Confirmation or rejection of the SHEP results in other trials, including the Syst-Eur study, conducted by the rejection of the SHEP results in other trials, including the Syst-Eur study, conducted by the European Working Party on High Blood Pressure in the Elderly and the Chinese trial in elderly ISH patients, is now awaited.

Aged↗
PubMed1991

The association between blood pressure, calcium and other divalent cations: a population study.

This report investigated the associations between blood pressure and the levels of various divalent cations in blood and urine in the population at large. The 1,982 participants (963 men and 1019 women; mean age 48 years) constituted a stratified random sample of the population of 4 Belgian districts. Systolic/diastolic pressure averaged 133/78 mmHg in men, and 128/76 mmHg in women. Serum total calcium (2.37 mmol/l), serum magnesium (1.00 mmol/l) and blood cadmium (10.0 nmol/l) were on average similar in the two sexes. By contrast, serum zinc (13.1 and 12.6 mumol/l, respectively), blood lead (0.56 and 0.36 mumol/l) and the urinary excretions of calcium (4.86 and 3.95 mmol/24h), copper (0.16 and 0.13 mumol/24h), and cadmium (9.4 and 7.2 nmol/24h) were significantly higher in men than in women. After adjustment for significant blood pressure covariates (age, body mass index, pulse rate, log gamma-glutamyltranspeptidase, smoking habits, and in women the contraceptive pill), serum total calcium was independently and positively correlated with systolic pressure in both sexes, and with diastolic pressure in women. After similar adjustments systolic pressure was positively correlated with urinary copper in men and women. In addition, systolic pressure and blood lead, and diastolic pressure and urinary cadmium were negatively correlated in men. In conclusion, this population study demonstrated a positive relationship between systolic blood pressure and both serum total calcium and urinary copper.

Adult↗
PubMed1991

Methods for describing the diurnal blood pressure curve.

Ambulatory blood pressure recordings supply information on the blood pressure variation during habitual daily activities and sleep. Whether the circadian blood pressure curve is modulated by an endogenous clock or whether the diurnal fluctuations in blood pressure are mainly or exclusively determined by the pattern of activity remains disputed. Whatever the underlying mechanism, most experts agree that it still remains to be ascertained whether the blood pressure profile can help in unraveling the pathophysiology of hypertension and determining a subject's cardiovascular risk. The methods for parametrizing the diurnal blood pressure curve in individual subjects, summarized in this article, may provide summary statistics for larger groups of individuals or for the population at large.

Activities of Daily Living↗
PubMed1991

An inventory of studies on ambulatory blood pressure in large groups of subjects.

We made an inventory of 19 studies that have been or are being undertaken to better characterize the distribution of ambulatory blood pressure in the population at large or in larger groups of individuals selected from the population. No study was without some degree of selection in the recruitment of its subjects, but none of the subjects was selected or excluded on the basis of ambulatory blood pressure. These studies could provide the data required to define more precise, age- and sex-specific, diagnostic criteria for ambulatory blood pressure measurement in day-to-day clinical practice.

Blood Pressure↗
PubMed1991

The determinants and prognostic significance of serum uric acid in elderly patients of the European Working Party on High Blood Pressure in the Elderly trial.

Determinants and risks associated with serum uric acid were investigated in 822 elderly hypertensive patients treated with hydrochlorothiazide and triamterene or placebo. Pretreatment serum uric acid levels were significantly higher in men than in women and had positive correlation with serum creatinine. After adjustment for serum creatinine, positive correlations of serum uric acid with body weight and fasting blood glucose in women and with serum cholesterol in men were significant. During follow-up, serum uric acid increased significantly in the treated patients, but remained unchanged in the placebo group. Total, cardiovascular, and noncardiovascular mortality were unrelated to initial serum uric acid levels. One placebo patient and seven treated patients developed gout. Of those seven, most were male patients and had significantly higher serum levels of uric acid and creatinine than the other patients. Gender and renal function were the major determinants of serum uric acid in elderly hypertensive patients.

Aged↗
PubMed1991

Ambulatory blood pressure monitoring in clinical trials.

Monitoring ambulatory blood pressure, instead of taking pressure readings in hospital, avoids the so-called white-coat effect and allows more readings to be obtained over a longer period of time. It improves the accuracy of the blood pressure estimate and increases the statistical power of therapeutic trials for hypertension. Subjects with white-coat or office hypertension can be detected by ambulatory blood pressure monitoring and excluded from clinical trials. In 23 studies, including a total of 3304 normotensive subjects, the 24-h ambulatory blood pressure averaged 118/72 mmHg; the daytime and night-time pressures were 123/76 mmHg and 106/64 mmHg, respectively. If the mean plus two standard deviation (s.d.) interval is considered the upper limit of normal, the meta-analysis suggested that hypertension may be suspected if the 24-h pressure exceeds 129/87 mmHg, or if the daytime or night-time pressures are higher than 146/91 mmHg or 127/79 mmHg, respectively. On balance, most studies suggest that placebo effects on blood pressure are not observed when blood pressure is measured with ambulatory recorders. If confirmed, this observation indicates that it is possible to simplify the design of trials in the field of hypertension. Ambulatory blood pressure readings should be obtained with properly validated monitors. If the recordings are of sufficient quality, editing does not increase the precision of the subsequent statistical analyses. The statistical analyses should account for diurnal rhythms, and subject and treatment effects.

Antihypertensive Agents↗