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Biomedical subjects

S Julius

Publications and source records attributed to S Julius.

At least 37 records · Page 2Linked to original sources

Trials of antihypertensive treatment--new agenda for the millennium.

In 1968 a group of investigators from the US Veterans Association study reported that, compared to placebo, antihypertensive medication dramatically reduces morbidity and mortality in patients whose diastolic blood pressure was 115 mm Hg or higher. Three years later a reduction of morbidity had also been demonstrated in subjects whose diastolic pressure ranged from 95 to 114 mm Hg. In the following decades these findings were confirmed in numerous investigations of various populations. We now know that antihypertensive treatment is beneficial in mild hypertension, in isolated systolic hypertension, and in hypertension of the elderly. When it comes to the treatment of mild hypertension we will have to practice evidenceless medicine and act on the internal logic of the issue. The logic suggests that many present-day antihypertensive agents are harmless, that over the long term they may prevent target organ damage, that early intervention may be more beneficial than late treatment, and, finally, that treating mild hypertension may have a major positive impact on public health.

Antihypertensive Agents↗

Relative influence of insulin resistance versus blood pressure on vascular changes in longstanding hypertension. ICARUS, a LIFE sub study. Insulin Carotids US Scandinavia.

BACKGROUND: Insulin resistance is associated with hypertension. The relative influences of hyperinsulinaemia and high blood pressure on vascular hypertrophy and carotid distensibility is unclear in patients with longstanding hypertension. METHODS: In 88 unmedicated patients with stage II-III hypertension and left ventricular hypertrophy on electrocardiogram we measured blood pressure, minimal forearm vascular resistance (MFVR) using plethysmography, intima-media thickness (IMT) and the wall distensibility of the common carotid arteries using ultrasound, and insulin sensitivity using a 2-h isoglycaemic hyperinsulinaemic clamp. RESULTS: IMT was positively correlated to systolic blood pressure (r= 0.26, P < 0.05), whole body glucose uptake index (M/IG; r= 0.22, P< 0.05), age (r= 0.24, P< 0.05) and negatively correlated to body mass index (r= -0.24, P < 0.05); IMT did not correlate to fasting serum insulin (r= -0.14, NS). In men (n = 64) MFVR was positively correlated to systolic blood pressure (r = 0.30, P < 0.05), but was unrelated to M/G and serum insulin. The distensibility of the common carotid arteries was negatively correlated to systolic blood pressure (r = -0.40, P< 0.001) and in untreated patients (n = 22) positively correlated to M/IG (r = 0.47, P < 0.05). CONCLUSIONS: High systolic blood pressure was related to vascular hypertrophy, whereas hyperinsulinaemia and insulin resistance were not, suggesting that longstanding high blood pressure is a far more important determinant for structural vascular changes than insulin resistance at this stage of the hypertensive disease. However, hyperinsulinaemia and insulin resistance were associated with low distensibility of the common carotid arteries in the subgroup of never treated hypertensive patients.

Aged↗

Determinants of left ventricular structure and mass in young subjects with sympathetic over-activity. The Tecumseh Offspring Study.

OBJECTIVE: In this study, we tested the hypothesis that sympathetic over-activity may cause metabolic abnormalities and affect left ventricular (LV) structure and mass early in life. SUBJECTS AND SETTING: The study population consisted of 111 healthy adolescents and young adults living in Tecumseh, Michigan (USA). MAIN OUTCOME MEASURES: Correlations of LV mass and structure with several clinical variables in relation to the activity of the sympathetic nervous system. METHODS: Power spectrum density estimates of heart rate variability were calculated with an auto-regressive method, and subjects were divided by cluster analysis into two groups according to low-frequency and high-frequency components. LV data were obtained by echocardiographic assessment RESULTS: Subjects with signs of sympathetic over-activity (n = 38, group 1) had higher heart rate, blood pressure (BP), waist/hip ratio and cholesterol levels than the rest of the group (n = 73, group 2). In group 1 subjects, insulin emerged as the strongest univariate correlate of interventricular septum and posterior wall thicknesses (P< 0.001 for both) and of LV mass (P= 0.009). These relationships remained significant when body mass index was accounted for. By contrast, the marginal univariate relationship with diastolic BP did not remain significant in multivariate analysis. In group 2 subjects, BP was strongly correlated with LV wall thickness and mass both in univariate (P values from 0.03 to < 0.001) and multivariate analyses, while insulin was not. The interactive effect of sympathetic activity and insulin on echocardiographic data was confirmed by multivariate analyses performed in the subjects grouped together (P values from 0.02 to 0.001 for the sympathetic activity x insulin interaction term). CONCLUSIONS: In young subjects with heightened sympathetic activity and initial metabolic abnormalities, insulin is a strong determinant of LV wall thickness and geometry, while in subjects with normal autonomic nervous system activity, the main determinant of left ventricular size is the haemodynamic load.

Adolescent↗

Overweight and hypertension : a 2-way street?

Cross-sectionally, higher weight is associated with higher blood pressure levels; prospectively, baseline weight and weight gain predict higher blood pressure. The loss of weight is frequently associated with a decrease in blood pressure. These findings suggest that weight gain may pathophysiologically contribute to blood pressure elevation. In this review, we present data to indicate that the reverse is also true; persons of equal weight who had higher initial blood pressures gain more weight in the future. We also propose a plausible hypothesis to explain this reverse relationship. Both the blood pressure elevation and the gain of weight may reflect a primary increase in sympathetic tone. It is well known that in a milieu of increased sympathetic tone, the beta-adrenergic responsiveness decreases. Sympathetic overactivity and decreased cardiovascular beta-adrenergic responsiveness have been described in hypertension. beta-Adrenergic receptors mediate increases in energy expenditure. If these metabolic receptors were downregulated in hypertension, the ability of hypertensive patients to dissipate calories would decrease and they would gain more weight. The possible relationship of decreased beta-adrenergic responsiveness to weight in hypertension can be experimentally tested. Such research may contribute to an explanation of why patients with hypertension can rarely lose weight. An understanding of this pathophysiological relationship may open new avenues for therapeutic interventions.

Adult↗

Baseline characteristics in relation to electrocardiographic left ventricular hypertrophy in hypertensive patients: the Losartan intervention for endpoint reduction (LIFE) in hypertension study. The Life Study Investigators.

The Losartan Intervention For Endpoint (LIFE) reduction in hypertension study is a double-blind, prospective, parallel group study designed to compare the effects of losartan with those of atenolol on the reduction of cardiovascular morbidity and mortality. A total of 9194 patients with hypertension and ECG left ventricular hypertrophy (LVH) by Cornell voltage-duration product and/or Sokolow-Lyon voltage criteria were enrolled in the study, with baseline clinical and ECG data available in 8785 patients (54% women; mean age, 67+/-7 years). ECG LVH by Cornell voltage-duration product criteria was present in 5791 patients (65.9%) and by Sokolow-Lyon voltage in 2025 patients (23.1%). Compared with patients without ECG LVH by Cornell voltage-duration product criteria, patients with ECG LVH by this method were older; more obese; more likely to be female, white, and to have never smoked; more likely to be diabetic and have angina; and had slightly higher systolic, diastolic, and pulse blood pressures. In contrast, patients with ECG LVH by Sokolow-Lyon criteria were slightly younger; less obese; more likely to be male, black, and current smokers; less likely to have diabetes; more likely to have angina and a history of cerebrovascular disease; and had higher systolic and pulse blood pressure but slightly lower diastolic blood pressure than patients without ECG LVH by this method. By use of multivariate logistic regression analyses, presence of ECG LVH by Cornell voltage-duration product criteria was predominantly associated with higher body mass index, increased age, and female gender, whereas presence of ECG LVH by Sokolow-Lyon voltage criteria was predominantly related to lower body mass index, male gender, and black race. Thus, hypertensive patients who meet Cornell product and Sokolow-Lyon voltage criteria are associated with different, but potentially equally adverse, risk factor profiles.

Aged↗

The changing face of sympathetic overactivity in hypertension.

There is a lot of evidence showing that sympathetic activity is increased in a large proportion of patients with hypertension. However, the clinical impact of this state is frequently underestimated. Several factors seem to be misunderstood, such as whether sympathetic overactivity is reproducibly present, whether it lasts throughout 24 h, and what is the significance of its association with tachycardia. In this review, we present data to indicate that several haemodynamic changes in hypertension such as elevated cardiac output and heart rate and alteration in vascular resistance are neurogenic. The relationship between the increased sympathetic tone and decreased parasympathetic tone in hypertension is reciprocal, which strongly suggests that the abnormality emanates from the brain. The increase in sympathetic drive in hypertension is widespread across many organs. Beside the heart it is seen in the kidney and skeletal muscle, and even in platelets. We also discuss the possible mechanisms of the haemodynamic transition from this hyperkinetic state to established hypertension. We propose a hypothesis where down-regulation of beta-adrenergic responsiveness plays a major role in explaining the haemodynamic changes as well as metabolic alterations, such as hyperinsulinaemia and even the gain of weight in hypertension. Thus, the increased sympathetic tone may be involved in the genesis of multiple, pressure-independent coronary risk factors in hypertension.

Adolescent↗

Five decades of antihypertensive treatment: the unresolved issues.

The first effective antihypertensive treatment became available in the 1950s but the early drugs caused intolerable side effects. Drugs with a better side-effect profile became available in the 1960s, and their utility was soon subjected to rigorous clinical trials. In the 1970s, the availability of these drugs opened the door for outcome studies. Most of the results reported in the 1970s and 1980s were rather impressive. Antihypertensive treatment reduced mortality in severe and mild hypertension, in hypertension of the elderly, and in patients with advanced complications of hypertension. A large number of 'hard end point' (mortality and morbidity) trials were organized in the last decade of the 20th century. Most compare the merits of new antihypertensive agents (angiotensin-converting enzyme inhibitor, calcium channel blocker, angiotensin II receptor blocker) versus an older (beta-blocker or diuretic) drug. These trials are rooted in the fact that blood pressure lowering does not equally affect all complications of hypertension. Particularly bothersome is the fact that treatment decreases stroke but fails to substantially reduce coronary events. These variations in treatment outcomes may reflect the multifactorial pathophysiology of hypertension: essential hypertension is frequently associated with pressure-independent coronary risk factors, and the target organ status of a patient (left ventricular hypertrophy, renal dysfunction) greatly affects their prognosis. These new trials investigate whether the mechanism by which a drug decreases the pressure and how it affects various risk factors are of clinical relevance. The practice of medicine in hypertension is evidence bound. Historically, only when the superiority of the treatment had been convincingly shown did physicians alter practice patterns. The effects of systolic blood pressure lowering and of treating mild diastolic hypertension in younger patients have not been sufficiently investigated. Lowering of the systolic blood pressure and treating patients with mild hypertension might have major beneficial effects on public health. We need new studies in this area in order to improve clinical practice in hypertension.

Animals↗

High heart rate: a risk factor for cardiovascular death in elderly men.

OBJECTIVE: To examine the association between heart rate and 12-year incidence rates of total and cardiovascular death in a cohort of elderly subjects stratified by sex. SUBJECTS AND METHODS: The study was carried out in 763 white men and 1175 women aged 65 years or older who were participating in the Cardiovascular Study in the Elderly. Subjects were divided into quintiles of heart rate; the top quintile comprised those with a heart rate of greater than 80/min and the bottom quintile, those with a heart rate of less than 64/min. RESULTS: In the men, the number of deaths from cardiovascular causes was significantly increased in those in the top quintile of heart rate (crude relative risk, 1.55) but decreased in those in the bottom quintile (crude relative risk, 0.65). Similar relationships were found in the women, but the associations did not reach statistical significance (all-cause, P = .11; cardiovascular, P = .15). After adjustment for baseline age, body mass index, hypertension, diabetes mellitus, angina or previous myocardial infarction (coronary heart disease), regular medication, lipid levels, smoking, alcohol intake, forced expiratory volume in 1 second, and other confounders, the relative risk for cardiovascular death in the men was 1.38 (95% confidence interval, 0.94-2.03) for the subjects in the top quintile of heart rate and 0.82 (95% confidence interval, 0.52-1.28) for those in the bottom quintile. In the Cox analysis, predictors of time to cardiovascular death were heart rate (P < .001), age (P < .001), coronary heart disease (P < .001), clinical heart failure (P = .001), diabetes mellitus (P = .001), hypertension (P = .02), and triglyceride levels (P = .04), whereas total (P = .20) and high-density lipoprotein-cholesterol (P = .21) levels and smoking (P = .74) were found to be nonsignificant by the model. The heart rate-cardiovascular death association held true when subjects who died in 2 years after enrollment were excluded (P = .008). CONCLUSIONS: An elevated heart rate may be a strong predictor of cardiovascular death in elderly men. Conversely, a low heart rate is related to a better outcome in these subjects.

Aged↗

Relevance of heart rate as a risk factor in hypertension.

Numerous studies have shown that resting heart rate is closely correlated with blood pressure and that it is prospectively related to the development of hypertension. Moreover, there is mounting evidence to indicate that a high heart rate is associated with increased cardiovascular morbidity and mortality. In this respect, heart rate can be considered both as a marker of risk and as an independent factor in the induction of risk. Sympathetic overactivity seems to be responsible for the increase in blood pressure and hematocrit, and for the metabolic abnormalities often observed in subjects with tachycardia. Experimental studies in monkeys have shown that heart rate can also exert a direct atherogenic action on the arteries through increased wall stress. Furthermore, tachycardia can favor the occurrence of ventricular arrhythmias and sudden death. Reduction of heart rate appears to be a reasonable additional goal of antihypertensive therapy, especially in subjects with increased sympathetic tone. Nondihydropyridine calcium antagonists and drugs with agonistic properties at the I1-imidazoline receptors of the rostral ventrolateral medulla may be drugs of choice for this purpose, but whether they offer a significant morbidity-mortality advantage must be proven in prospective trials.

Animals↗

Long-term potential of angiotensin receptor blockade for cardiovascular protection in hypertension: the VALUE trial. Valsartan Antihypertensive Long-term Use Evaluation.

The recent decrease of cardiovascular mortality in the USA is less pronounced than it has been in the preceding three decades. Elsewhere, cardiovascular mortality decreased and in some countries it increased. Cerebrovascular disease and ischemic heart disease were responsible for 21% of deaths recorded by the World Health Organization in 1990 and 1997, of which hypertension was estimated to be directly responsible for half of these deaths. Apart from blood pressure (BP) elevation, essential hypertension is frequently associated with factors that increase the risk of poor cardiovascular outcomes: insulin resistance/dyslipidemia, elevated angiotensin and norepinephrine, a tendency for hypercoagulability, platelet overactivity, tachycardia, vulnerability to arrhythmias, vascular hypertrophy, endothelial dysfunction, and left ventricular hypertrophy. Excess activation of the renin-angiotensin system, independent of BP elevation, contributes to these abnormalities. To achieve better results in the future, focus must be shifted from BP lowering to recognition of specific effects of drugs on these diverse pathophysiologic aspects of hypertension. The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial, which is evaluating the effect of valsartan (Diovan((R))) vs. amlodipine, is a milestone in the effort to test whether newer compounds offer a better reduction of the cardiovascular consequences of hypertension, as well as good BP control. The hypothesis is that valsartan by antagonizing the negative effects of angiotensin on smooth muscle cell growth, endothelial function, sympathetic overactivity, and coagulation, may have for the same degree of BP lowering, better protective effects than the leading calcium antagonist amlodipine.

Amlodipine↗

Parental hyperdynamic circulation predicts insulin resistance in offspring: The Tecumseh Offspring Study.

Controversy surrounds the pathogenetic mechanisms of the relationship between hyperdynamic circulation and insulin resistance. Two hundred eight children and young adults (mean age, 17.2+/-3.0 years; range, 11 to 26 years) from the Tecumseh Offspring Study whose parents had been assessed with Doppler echocardiography at the age of 34 years during the previous Tecumseh Blood Pressure Study were considered for this analysis. Offspring data were stratified according to tertiles of parental cardiac index. Parents in the top cardiac index tertile had increased heart rate (P=0.001), stroke volume (P=0.0001), left ventricular fractional shortening (P=0.02), and plasma epinephrine (P=0.02) compared with parents in the other tertiles. Body mass index (BMI) and blood pressure were similar in all groups. Offspring of parents with a high cardiac index had greater BMI (P=0.001), skinfold thickness (P=0.008), and waist/hip ratio (P=0.02), higher diastolic blood pressure (P=0.02) and plasma insulin level (P=0.001), and higher heart rate during Stroop's color test (P=0.02) than offspring of parents with a lower cardiac index. In a multivariate regression analysis, offspring BMI was predicted by parental BMI and cardiac index (P=0.0001 and 0.003, respectively). The mother-child relationship explained most of the cardiac index-BMI association. In summary, parental hyperdynamic circulation was an important predictor of overweight, abnormal fat distribution, increased blood pressure, and hyperinsulinemia in offspring. Our results illustrate the complexity of interaction between a genetic tendency and its phenotypic expression. We speculate that the degree of beta-adrenergic responsiveness may be a major determinant of the phenotypic differences between the parents and offspring found in this study.

Adolescent↗

The physiological determinants and risk correlations of elevated heart rate.

A number of studies have shown that fast heart rate is associated with high blood pressure and metabolic disturbances, and that it is a strong precursor of hypertension, atherosclerosis, and cardiovascular events. Subjects with tachycardia often also exhibit increased plasma insulin, overweight, and higher hematocrit. These relationships have been observed also in the elderly and among hypertensive individuals and have held true after controlling for smoking, alcohol intake, and physical activity habits. In three different populations studied with a mixture analysis we demonstrated that the heart rate-blood pressure association was mostly explained by a subpopulation of subjects with high heart rates who had higher levels of blood pressure, total cholesterol, triglycerides, postload glucose, and plasma insulin. The clustering of these risk factors may explain why cardiovascular morbidity is higher in individuals with fast heart rates. Sympathetic overactivity seems to be responsible for both the increase in heart rate and blood pressure, and for the metabolic abnormalities. In addition to being a marker of sympathetic overactivity, tachycardia seems to have a direct action in the induction of risk. Studies in cholesterol-fed monkeys have shown that the reduction of heart rate could retard the development of coronary atherosclerosis. Furthermore, fast heart rate increases the pulsatile nature of the arterial blood flow and increases arterial wall stress. Antihypertensive drugs that lower the heart rate seem to have a good potential for prolonging life expectancy in humans.

Blood Pressure↗

The international database of self-recorded blood pressures in normotensive and untreated hypertensive subjects.

OBJECTIVES: To pool data from individual subjects in an attempt to determine an operational threshold for making clinical decisions based on the self-recorded blood pressure (SRBP) and to examine how many hypertensive subjects, diagnosed by conventional blood pressure (CBP) measurement, would have a self-recorded blood pressure within the normotensive range if the proposed thresholds were applied. DATA SOURCES: Thirteen research groups studied 4668 untreated subjects. RESULTS: In total 2401 subjects were normotensive, 494 were borderline hypertensive and 1773 were definitely hypertensive. Hypertension had been diagnosed from the mean of 1-6 (median 3) CBP measurements obtained during 1-3 (median 1) visits. The reference values for SRBP measurements determined from the 95th percentiles of the distributions for normotensive subjects were 137 mmHg systolic and 85 mmHg diastolic. Of the subjects with systolic hypertension, 16% had systolic SRBP </= 137 mmHg. Similarly, 25% of those with diastolic hypertension had diastolic SRBP </= 85 mmHg. The probability that hypertensive subjects had SRBP below these thresholds was 34% (diastolic) to 62% (systolic) greater for women than it was for men, was 2-3 times greater if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension, and increased by 50% (diastolic) to 126% (systolic) when SRBP had been measured on more than 3 days. In contrast, for each 10 mmHg increment in systolic CBP, this probability decreased by 35% for systolic SRBP and by 11% for diastolic SRBP; for each 5 mmHg increment in diastolic CBP it decreased by 36% for diastolic SRBP. In addition, for systolic blood pressure, the probability decreased by 31% for each 10-year increment in age. CONCLUSIONS: Until the relationship between SRBP and the incidence of cardiovascular morbidity and mortality has been clarified further by prospective studies, a mean self-recorded blood pressure above 137 mmHg systolic or 85 mmHg diastolic may be considered hypertensive. Among the hypertensive patients 16-31% had SRBP below these thresholds, but this proportion decreased if the hypertensive subjects had higher CBP.

Adolescent↗

Effects of intensive blood-pressure lowering and low-dose aspirin in patients with hypertension: principal results of the Hypertension Optimal Treatment (HOT) randomised trial. HOT Study Group.

BACKGROUND: Despite treatment, there is often a higher incidence of cardiovascular complications in patients with hypertension than in normotensive individuals. Inadequate reduction of their blood pressure is a likely cause, but the optimum target blood pressure is not known. The impact of acetylsalicylic acid (aspirin) has never been investigated in patients with hypertension. We aimed to assess the optimum target diastolic blood pressure and the potential benefit of a low dose of acetylsalicylic acid in the treatment of hypertension. METHODS: 18790 patients, from 26 countries, aged 50-80 years (mean 61.5 years) with hypertension and diastolic blood pressure between 100 mm Hg and 115 mm Hg (mean 105 mm Hg) were randomly assigned a target diastolic blood pressure. 6264 patients were allocated to the target pressure < or =90 mm Hg, 6264 to < or =85 mm Hg, and 6262 to < or =80 mm Hg. Felodipine was given as baseline therapy with the addition of other agents, according to a five-step regimen. In addition, 9399 patients were randomly assigned 75 mg/day acetylsalicylic acid (Bamycor, Astra) and 9391 patients were assigned placebo. FINDINGS: Diastolic blood pressure was reduced by 20.3 mm Hg, 22.3 mm Hg, and 24.3 mm Hg, in the < or =90 mm Hg, < or =85 mm Hg, and < or =80 mm Hg target groups, respectively. The lowest incidence of major cardiovascular events occurred at a mean achieved diastolic blood pressure of 82.6 mm Hg; the lowest risk of cardiovascular mortality occurred at 86.5 mm Hg. Further reduction below these blood pressures was safe. In patients with diabetes mellitus there was a 51% reduction in major cardiovascular events in target group < or =80 mm Hg compared with target group < or =90 mm Hg (p for trend=0.005). Acetylsalicylic acid reduced major cardiovascular events by 15% (p=0.03) and all myocardial infarction by 36% (p=0.002), with no effect on stroke. There were seven fatal bleeds in the acetylsalicylic acid group and eight in the placebo group, and 129 versus 70 non-fatal major bleeds in the two groups, respectively (p<0.001). INTERPRETATION: Intensive lowering of blood pressure in patients with hypertension was associated with a low rate of cardiovascular events. The HOT Study shows the benefits of lowering the diastolic blood pressure down to 82.6 mm Hg. Acetylsalicylic acid significantly reduced major cardiovascular events with the greatest benefit seen in all myocardial infarction. There was no effect on the incidence of stroke or fatal bleeds, but non-fatal major bleeds were twice as common.

Aged↗

Reference values for self-recorded blood pressure: a meta-analysis of summary data.

BACKGROUND: The widespread clinical use of self-recorded blood pressure measurement is limited by the lack of generally accepted reference values. The purpose of this study was therefore to perform a meta-analysis of summary data in an attempt to determine an operational threshold for self-recorded blood pressures. STUDIES AND METHODS: Seventeen studies, including a total of 5422 subjects, were reviewed. Eight of these 17 studies included both normotensive and untreated hypertensive subjects, while the other 9 reports included normotensive subjects only. Within each study an operational cutoff point between normotension and hypertension was derived by means of the mean+2 SDs and the 95th percentiles of the self-recorded blood pressure in normotensive subjects. These 2 methods were contrasted with 2 other techniques that have been applied in the literature to calculate (1) the self-recorded pressures equivalent to a conventional pressure of 140 mm Hg systolic and 90 mm Hg diastolic by means of regression analysis and (2) the self-recorded blood pressures at the percentiles corresponding to a conventional pressure of 140/90 mm Hg. The latter 2 methods were applied in untreated subjects not selected on the basis of their blood pressure. RESULTS: With weighting for the number of subjects included in the various studies, the self-recorded blood pressure averaged 115/71 mm Hg in normotensive persons and 119/74 mm Hg in untreated subjects not selected on the basis of their blood pressure. The reference values for self-recorded blood pressures determined by the mean+2 SDs (137/89 mm Hg) or the 95th percentile (135/86 mm Hg) of the distribution in normotensive subjects were concordant within 2/3 mm Hg, whereas the cutoff points derived with the regression and percentile methods were considerably lower, ie, 125/79 and 129/84 mm Hg, respectively. CONCLUSIONS: Until the relationship between self-recorded pressure and the incidence of cardiovascular morbidity and mortality is further clarified by prospective studies, a mean self-recorded blood pressure above 135 mm Hg systolic or 85 mm Hg diastolic may be considered hypertensive.

Blood Pressure Determination↗

Syndrome X: is it for real?

The term syndrome X has been applied to the association of hypertension, non-insulin-dependent diabetes mellitus (NIDDM), android obesity, insulin resistance, and dyslipidemia. In this paper, based on population samples from Tecumseh, Michigan, and Hiroshima, Japan, characterized by persons > or = 40 years of age, we examine the validity of regarding this constellation of traits as a true syndrome, i.e., an array of traits with a single, unifying pathophysiology underlying its components. Data were not available on insulin resistance and dyslipidemia, and obesity was expressed as body mass index (BMI) without the division into android and non-android types. The four ethnic-gender data sets were analyzed on the basis of two age classes, age > or = 40 years and age > or = 50 years, and two obesity classes, BMI > or = 27 and > or = 30. A simple chi 2 test of goodness-of-fit under a model of independence revealed non-random associations between hypertension, NIDDM, and BMI which were in part attributable to an excess of persons with all three traits. However, when the four data sets were subjected to separate log-linear analyses of the three-way association tables, none of the three-factor interaction terms (i.e., syndrome X) was significant. High significance was, however, observed in the two-factor interaction term for BMI*hypertension. It is concluded that the significant association between these three traits is driven by the BMI*hypertension interaction, and there is no evidence in these data sets of a significant role for a syndrome X. Genet.

Adult↗