Epidemiology of hypertension and insulin resistance syndrome

The Interaction of a Diabetes Gene Risk Score With 3 Different Antihypertensive Medications for Incident Glucose-level Elevation

BACKGROUND

Elevations of fasting glucose (FG) levels are frequently encountered in people treated with thiazide diuretics. The risk is lower in people treated with ACE inhibitors (ACEi). To determine if genetic factors play a role in FG elevation, we examined the interaction of a diabetes gene risk score (GRS) with the use of 3 different antihypertensive medications.

METHODS

We examined 376 nondiabetic hypertensive individuals with baseline FG <100 mg/dl who were genotyped for 24 genes associated with risk of elevated glucose levels. All participants had ≥1 follow-up FG level over 6 years of follow-up. Participants were randomized to treatment with a thiazide-like diuretic (chlorthalidone), a calcium channel blocker (CCB; amlodipine), or an ACEi (lisinopril). Outcomes were an FG increase of ≥13 or ≥27 mg/dl, the upper 75% and 90% FG increase in the parent cohort from which the present cohort was obtained. Odds ratios were adjusted for factors that increase FG levels.

RESULTS

For every 1 allele increase in GRS, the adjusted odds ratios (ORs) were 1.06 (95% confidence interval (CI): 0.99, 1.14; P = 0.06) and 1.09 (95% CI: 0.99, 1.20; P = 0.08). When results were examined by randomized medications, participants randomized to amlodipine had statistically significant odds for either outcome (OR: 1.23; 95% CI: 1.03, 1.48; P = 0.01 and OR: 1.31; 95% CI: 1.06, 1.62; P = 0.01). No such risk increase was found in participants randomized to the other 2 medications.

CONCLUSIONS

A diabetes GRS predicts FG elevation in people treated with a CCB, but not with an ACEi or diuretic. These findings require confirmation.

CLINICAL TRIALS REGISTRATION

Trial number NCT00000542.

Pathophysiology and Long-Term Management of the Metabolic Syndrome

The metabolic syndrome has been characterized by a cluster of abnormalities that include obesity, hyperglycemia, dyslipidemia, and hypertension. Other conditions associated with this syndrome include microalbuminuria, inflammation, a prothrombotic state, and a fatty liver. Together, these abnormalities lead to an environment where the risk of developing both type 2 diabetes and atherosclerotic cardiovascular disease are greatly enhanced. Recognition of this syndrome by practitioners, early treatment, and long-term management are crucial for disease prevention. Successful treatment requires the introduction of lifestyle changes initially and pharmacotherapy subsequently if lifestyle changes are not sufficient.

The effects of the renin-angiotensin-aldosterone system gene polymorphisms on insulin resistance in hypertensive families

INTRODUCTION

The hereditability of insulin resistance has been demonstrated in both familial and twin studies. The effects of renin-angiotensin-aldosterone system gene polymorphisms on insulin resistance remain inconclusive.

METHODS

This is a sibling-based association study. Polymorphisms of renin-angiotensin-aldosterone system genes were examined in 1113 hypertension and 676 normotension siblings from Chinese and Japanese hypertensive families. The generalized estimation equations method was used to compare the differences in metabolic variables between hypertension and normotensive siblings.

RESULTS

For the G-6A polymorphism of AGT, GG siblings had lower 2-h insulin than siblings carrying the A allele (p=0.006). Siblings with different variants of the angiotensin II type 1 receptor A1166C had no difference in metabolic variables. Siblings carrying the D allele of the angiotensin converting enzyme gene had higher levels of fasting glucose, fasting insulin, area under the curve of insulin levels and the homeostasis model assessment of insulin resistance than II siblings (all p<0.05). Lower levels of fasting glucose and 2-h glucose were observed in siblings with the T allele than their CC homozygotes for the C-344T polymorphism of CYP11B2 (p<0.05). Siblings carrying three high-risk genotypes of the angiotensin converting enzyme, angiotensinogen and CYP11B2 had higher fasting glucose level than siblings carrying no high-risk genotypes (p=0.011).

CONCLUSION

Our comprehensive analysis of renin-angiotensin-aldosterone system gene polymorphisms demonstrates that the angiotensin converting enzyme and CYP11B2 gene polymorphisms are associated with insulin resistance in hypertensive families.

Regulatory function of a malleable protein matrix as a novel fermented whey product on features defining the metabolic syndrome

Previously, we reported that a malleable protein matrix (MPM), composed of whey fermented by a proprietary Lactobacillus kefiranofaciens strain, has immunomodulatory and anti-inflammatory properties. MPM consumption leads to a considerable reduction in the cytokine and chemokine production (tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6), thus lowering chronic inflammation or metaflammation. Inhibition of metaflammation should provide positive impact, particularly in the context of dyslipidemia, insulin resistance, and hypertension. In this study, we investigated whether short-term MPM supplementation ameliorates those features of metabolic syndrome (MetS). The ability of MPM to potentially regulate triglyceride level, cholesterol level, blood glucose level, and hypertension was evaluated in different animal models. MPM lowers triglyceride level by 37% (P < .05) in a poloxamer 407 dyslipidemia-induced rat model. It also reduces total cholesterol by 18% (P < .05) and low-density lipoprotein-cholesterol level by 32% (P < .05) and raises high-density lipoprotein-cholesterol level by 17% (P < .01) in Syrian Golden hamsters fed a high fat/high cholesterol diet for 2 weeks. MPM reestablishes the fasting glucose insulin ratio index to normal levels (P = .07) in this latter model and lowers the plasma glucose level area under the curve (-10%, P = .09) in fructose-fed rats after 2 weeks of treatment. In spontaneously hypertensive rats, MPM-treated animals showed a reduction of SBP by at least 13% (P < .05) for 4 weeks. Results from this study suggest that MPM is a functional ingredient with beneficial effects on lipid metabolism, blood glucose control, and hypertension that might contribute to the management of MetS and thus reducing the risk of cardiovascular diseases.

Effects of thiazolidinediones on blood pressure

Peroxisome-proliferator-activated receptor-gamma (PPAR-gamma) agonists (known as thiazolidinediones; TDZs) activate nuclear receptors that regulate gene expression; they were developed as insulin-sensitizing drugs to treat type 2 diabetes mellitus. Although the prototypic TZD troglitazone was withdrawn from the market due to hepatic toxicity, rosiglitazone and pioglitazone are mainstays in managing type 2 diabetes mellitus. TZDs exert their hypoglycemic effect by reducing insulin resistance, hence improving insulin sensitivity. However, TZDs also exhibit a broad range of cardiovascular actions, with the clinical consequence of reduction in blood pressure (BP), observed in animal models and human diabetic subjects. The magnitude of reduction appears to be about 4 to 5 mm Hg in systolic and 2 to 4 mm Hg in diastolic BP--sufficient to significantly reduce subsequent cardiovascular event rates. But these BP-reducing properties, which are not present with metformin or sulfonylureas, are particularly important when viewed in conjunction with hypoglycemic effects. A significant proportion of patients with type 2 diabetes mellitus and BP mildly above target range might be successfully treated for both processes with a single drug.

Metabolic syndrome: treatment of hypertensive patients

Metabolic syndrome (MetSyndr), a constellation of abnormalities [obesity, glucose intolerance, insulin resistance (IR), dyslipidemia (low HDL-cholesterol, high LDL-cholesterol and triglycerides (TG)], and elevated blood pressure (BP)], increases the risk of cardiovascular (CV) disease and premature death. From 10% to 30% of the adult population in industrialized countries has MetSyndr, which effectively predicts the development of type 2 diabetes mellitus (T2D) and CV disease. Because of the complex etiology of MetSyndr, a multi-targeted, integrated therapeutic approach is required to simultaneously treat high BP, obesity, lipid disorders and T2D (if present), to fully protect CV, cerebrovascular and renal systems. If lifestyle modification (weight control, diet, exercise, smoking cessation, moderation of alcohol intake) is ineffective, pharmaco-theraphy should be added to treat simultaneously the lipid- and non-lipid CV risk factors. Patients with HTN and MetSyndr should be started on angiotensin-converting enzyme (ACE) inhibitors, unless contraindicated. The ACE inhibitors and angiotensin receptor blockers (ARBs) reduce the odds of developing new onset T2D and also decrease albuminuria. The ACE inhibitors provide cardioprotective and renoprotective benefits beyond their effect on BP; they also improve IR. The ARBs are renoprotective in addition to being cardioprotective. Long-acting calcium channel blockers are also recommended in hypertensive patients with MetSyndr; these drugs also improve IR. Thiazides (at low doses) and selected ss-blockers can be given to patients with HTN and MetSyndr. Celiprolol in combination with diuretics has a favorable effect on glucose tolerance and IR in patients with HTN and MetSyndr, and spironolactone added to ACE inhibitor or ARB therapy provides additional reno- and CV protective benefits in patients with diabetic nephropathy. Carvedilol, a ss-blocker with vasodilating properties, added to ACE inhibitor or ARB therapy, is effective in preventing worsening of microalbuminuria in patients with HTN and MetSyndr; it also improves IR and glycemic control. Most patients eventually require two or more antihypertensive drugs to reach BP goal. It is recommended that therapy in patients whose BP is more than 20/10 mm Hg above target at diagnosis be initiated with a combination of antihypertensive drugs, administered either as individual drugs or as fixed-dose formulations. Treatment with fixed-dose combinations, such as irbesartan + hydrochlorothiazide provides good BP control in more than two-thirds of hypertensive patients with MetSyndr. Lipid and BP targets are reached in a high percent of patients with HTN and CV disease treated with a combination of amlodipine + atorvastatin. In conclusion, hypertensive patients with the MetSyndr be treated aggressively for each component of the syndrome to provide CV, cerebrovascular and renal protection.

Metabolic effects of antihypertensive agents: role of sympathoadrenal and renin-angiotensin systems

Reports of beneficial, neutral and adverse impacts of antihypertensive drug classes on glucose and lipid metabolism can be found in human data. Furthermore, mechanisms for these diverse effects are often speculative and controversial. Clinical trial data on the metabolic effects of antihypertensive agents are highly contradictory. Comparisons of clinical trials involving different agents are complicated by differences in the spectrum of metabolic disturbances that accompany hypertension in different groups of patients. Two physiological systems are predominant at the interface between metabolic and cardiovascular regulation: the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS). These two systems are major targets of antihypertensive drug actions, and also mediate many of the beneficial and adverse effects of antihypertensive agents on glucose and lipid metabolism. Thiazides and beta-adrenergic antagonists can adversely affect glucose and lipid metabolism, which are frequently compromised in human essential hypertension, and increase the incidence of new cases of diabetes. Laboratory studies confirm these effects, and suggest that compensatory activation of the SNS and RAS may be one mechanism. Other antihypertensives directly targeting the SNS and RAS may have beneficial effects on glucose and lipid metabolism, and may prevent diabetes. Resolution of the controversies surrounding the metabolic effects of antihypertensive agents can only be resolved by further laboratory studies, in addition to controlled clinical trials.

A meta-analysis of the effect of thiazolidinediones on blood pressure

In epidemiologic studies, insulin resistance is associated with hypertension. Thiazolidinediones (TZDs) are antidiabetic agents that decrease insulin resistance. Multiple clinical trials have evaluated the effect of TZDs on blood pressure (BP) with inconsistent results. The aim of this study was to estimate the effect of TZDs on BP. The authors searched PubMed for clinical trials published in English. A total of 37 clinical trials that reported a change in BP were included in the analysis. Trials with independent-group design and trials with pre-post design were evaluated separately. When compared with baseline, TZDs lowered systolic BP by 4.70 mm Hg (95% confidence interval, -6.13 to -3.27) and diastolic BP by 3.79 mm Hg (95% confidence interval, -5.82 to -1.77). When compared with placebo, TZDs lowered systolic BP by 3.47 mm Hg (95% confidence interval, -4.91 to -2.02) and diastolic BP by 1.84 mm Hg (95% confidence interval, -3.43 to -0.25). Thus, TZDs lower both systolic and diastolic BP, albeit the BP-lowering effect is small and may not be of clinical significance.

Gamma-glutamyltransferase: an effect modifier in the association between age and hypertension in a 4-year follow-up study

We performed a prospective study to assess whether the relationship of age with hypertension was stronger in men with high normal serum gamma glutamyltransferase (GGT) than in those with lower GGT levels. The study population included 8170 healthy male workers in a steel manufacturing company who had undergone health examinations in both 1994 and 1998. The higher the baseline GGT level, the effect of age on the development of hypertension was stronger. The incidence of hypertension among those aged 25-34, 35-44 and 45-50 years was 0.9, 2.2, 3.8% in those with GGT<20 U/l; 1.0, 4.1, 12.5% in those with GGT between 20 and 39 U/l; and 1.9, 6.3, 17.2% in those with GGT> or =40 U/l, respectively. All relationships persisted after adjusting for baseline values of body mass index, alcohol intake, smoking, exercise, family history of hypertension, systolic and diastolic blood pressure, and changes of body mass index during 4 years (P for interaction=0.03). Our data supported the hypothesis that the effect of age on the development of hypertension differed by baseline GGT level, although the underlying mechanism for this interaction is unclear.

Gamma-glutamyltransferase is a predictor of incident diabetes and hypertension: the Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Gamma-glutamyltransferase (GGT), which maintains cellular concentrations of glutathione, may be a marker of oxidative stress, and GGT itself may produce oxidative stress. We performed a prospective study to examine whether serum GGT predicts diabetes and hypertension.

METHODS

Study participants were 4844 black and white men and women 18-30 years of age in 1985-1986; they were reexamined 2, 5, 7, 10, and 15 years later. Year 0 GGT cutpoints were 12, 17, 25, and 36 U/L (overall 25th, 50th, 75th, and 90th percentiles; the laboratory cutpoints for abnormal are 40 U/L in women and 50 U/L in men). We deleted 32 participants with prevalent diabetes and 140 participants with prevalent hypertension from the respective incidence analyses.

RESULTS

After adjustment for study center, race, sex, and age in proportional hazards regression, the hazard ratios across year 0 GGT categories were 1.0, 1.6, 1.7, 4.0 (95% confidence interval, 2.0-8.1), and 5.5 (2.7-11.1) for 15-year incident diabetes and 1.0, 1.2, 1.7 (1.2-2.2), 2.3 (1.7-3.2), and 2.3 (1.7-3.2) for hypertension. Additional adjustment for year 0 alcohol consumption, body mass index, cigarette smoking, and physical activity attenuated this relationship, but GGT remained a significant predictor.

CONCLUSIONS

Serum GGT within a range regarded as physiologically normal is associated with incident diabetes and hypertension. Considering known functionality of GGT, these associations are consistent with a role for oxidative stress in risk for diabetes and hypertension.

Insulin sensitivity and the risk of incident hypertension: insights from the Insulin Resistance Atherosclerosis Study

OBJECTIVE

The insulin resistance syndrome has been described as including hypertension. Previous studies have documented cross-sectional associations between insulin sensitivity (S(I)) and blood pressure or prevalent hypertension. Prospective data have been sparse.

RESEARCH DESIGN AND METHODS

The Insulin Resistance Atherosclerosis Study (IRAS) is a prospective study of the associations of S(I) with atherosclerosis and other risk factors for cardiovascular disease. We examined the association between S(I), measured using the frequently sampled intravenous glucose tolerance test with minimal model analysis, and incident hypertension (defined as per the Joint National Committee), at the 5-year examination in 840 IRAS participants who were free of hypertension at the baseline examination.

RESULTS

Adjusted for age, sex, ethnicity, and smoking status, for each unit greater S(I), the risk of hypertension was 10% lower (95% CI 2-19, P < 0.05).

CONCLUSIONS

These findings, from a prospective study, support the presence of a modest protective association between greater S(I) and lower risk of hypertension. These findings support the contention that interventions that improve S(I) may be beneficial with respect to the development of hypertension and cardiovascular disease. This contention should be tested in randomized clinical trials.

Insulin resistance syndrome revisited: application of self-organizing maps

BACKGROUND

Most common chronic diseases have a multifaceted aetiological background. Because currently used statistical methods have severe limitations in describing complex non-linear processes, the authors evaluated the usefulness of a multivariate method which is able to describe non-linear phenomena, the self-organizing map (SOM).

METHODS

The study subjects were the 1650 participants of the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD). The SOM model was constructed using 25 continuous biochemical and physiological variables. The aim of the SOM algorithm, together with Sammon's mapping, is to group the data into reduced but representative format and divide the study population into homogeneous subgroups.

RESULTS

The study population consisted of four groups (clusters) according to the method used. In the clusters C1 to C4 were 637, 445, 275 and 121 men, respectively. There were eight neurons (n = 172) which were not included to the four main clusters. The mean values of the variables related to insulin resistance syndrome in the identified SOM map were 32.1 (kg/m(2)) for body mass index (BMI), 1.01 for waist-to-hip ratio (WHR), 158.7 mmHg and 103.8 mmHg for systolic (SBP) and diastolic blood pressure (DBP), 2.8 mmol/l for triglycerides, 6.2 mmol/l for blood glucose and 22.4 mU/l for serum insulin. There was a statistically significant difference in the mean values of BMI, WHR, SBP, DBP, HDL, triglycerides and blood glucose between the cluster representing the insulin resistance syndrome and the normal cluster.

CONCLUSIONS

This study shows that the multidimensional structures of insulin resistance syndrome can be visualized and identified at qualitative and quantitative level using the SOM algorithm.

The association between leptin and proinsulin is lost with central obesity

OBJECTIVE

Hyperproinsulinaemia and hyperleptinaemia are interrelated features of the insulin resistance syndrome that are linked to the prospective risk of cardiovascular diseases. Whether the association between leptin and proinsulin is different between groups displaying different degrees of risk for cardiovascular diseases is not known. We therefore examined this association in men versus women and in pre- versus postmenopausal women from a population-based sample.

DESIGN AND SUBJECTS

Healthy subjects (n = 158; 85 men and 73 pre- and postmenopausal women) from the Northern Sweden Monitoring of Trends and Determinants in Cardiovascular Disease population were studied with a cross-sectional design.

METHODS

Anthropometric measurements (body mass index and waist circumference) and oral glucose tolerance tests were performed. Enzyme-linked immunosorbent assays were used for the analyses of specific insulin and proinsulin, and radioimmunoassay for leptin. Insulin resistance and beta-cell function were calculated according to the homeostasis assessment model. Partial correlation coefficients adjusted for age and measures of adiposity were calculated and multiple linear regression analyses were performed with leptin as dependent variable.

RESULTS

In nonobese men and premenopausal women and in obese postmenopausal women, leptin was significantly associated with proinsulin after stratification for waist circumference. Furthermore, a multivariate analyses taking age and measures of adiposity into account, showed that high fasting proinsulin was a significant predictor of high leptin in these groups. In contrast, this association was lost with increasing central obesity in men and premenopausal women.

CONCLUSIONS

This study shows that both the degree of adiposity and the hormonal milieu influence the association between circulating leptin and proinsulin in a normal population. Therefore, the insulin resistance syndrome seems to be characterized by lost association between leptin and proinsulin, which may be explained by dysfunction in the adipoinsular axis.

Significance of exaggerated natriuresis after angiotensin AT1 receptor blockade or angiotensin- converting enzyme inhibition in obese Zucker rats

1. Obese Zucker rats (OZR) were shown to be salt-sensitive in that they develop hypertension when placed on a high-salt diet. Because angiotensin (Ang) II is a major antinatriuretic factor, the present studies were undertaken to determine whether the characteristic of salt-sensitivity of OZR is associated with an enhanced antinatriuretic function of endogenous AngII. 2. The extent of AngII-mediated antinatriuresis was investigated in OZR and lean Zucker rats (LZR) using candesartan (100 microg/kg, i.v.), a selective angiotensin AT1 receptor antagonist, and ramipril (1 mg/kg, i.v.), an angiotensin-converting enzyme (ACE) inhibitor. The total number of AngII binding sites and their affinity were also assessed in renal cortical tubular membrane preparations of OZR and LZR using a specific radioligand-binding assay. Plasma renin activity was determined using a standard radioimmunoassay. 3. Both candesartan and ramipril produced substantially greater increases in urinary sodium excretion and urine flow in OZR and these effects were significantly greater than those observed in LZR. These observations suggest that basal antinatriuretic function of endogenous AngII is exaggerated in OZR. 4. The functional overexpression of AngII was not due to any alterations in the affinity or the total number of AngII binding sites in renal cortical tubular membranes. Higher plasma renin values in the OZR could have contributed to the phenomenon. 5. In conclusion, marked diuresis and natriuresis after AT1 receptor blockade and/or ACE inhibition suggest that the extent of endogenous AngII-mediated sodium transport under basal conditions is greatly augmented in OZR. It is proposed this phenomenon may be a contributing factor for the salt- sensitivity in the OZR.

Clinical value of microalbuminuria in hypertension

Microalbuminuria (MA) is a well recognized marker of cardiovascular complications in hypertension, but whether MA can predict adverse outcome in this clinical condition is still a subject for debate. The fact that in hypertensive cohorts those patients who showed an increase in albumin excretion rate also manifested an increased incidence of morbid events indicates that the presence of MA in hypertension may carry an increased cardiovascular risk. However, the prognostic significance of MA remains controversial because no results of prospective studies performed in hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of MA in hypertension, including severity of the disease, selection procedures, concomitant risk factors, degree of obesity, age, and sex distribution. This accounts for the large differences in the prevalence of MA that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 40%. There is still conflict over whether MA in hypertension is due to increased intraglomerular pressure or to glomerular damage. The data from the literature suggest that in subjects with mild hypertension the main determinant of albumin excretion rate is the haemodynamic load. In subjects with more severe hypertension and hypertensive complications, the augmented urinary albumin leak is probably the consequence of a systemic microvascular disturbance which involves the glomeruli. In this respect, the insulin resistance state often associated to high blood pressure appears as one of the main pathogenetic factors. Whether management of hypertensive populations may be improved by monitoring of albumin excretion rate and whether antihypertensive drugs which are more effective in decreasing urinary albumin can be more beneficial in patients with MA remains to be determined.

Leptin is associated with increased risk of myocardial infarction

OBJECTIVES AND DESIGN

Leptin is involved in the regulation of bodyweight and metabolism in man and might also be involved in the pathophysiology of the insulin resistance syndrome, which is associated with the development of cardiovascular diseases. We tested whether leptin is a risk factor for acute myocardial infarction (AMI) in a nested case-referent study.

SUBJECTS AND METHODS

Sixty-two men with first-ever AMI were identified who, prior to AMI, had participated in population-based health surveys in Northern Sweden. Referents were matched for sex, age, date and type of health survey, and geographical region. Blood pressure, body mass index (BMI) and the presence of smoking, diabetes and hypertension were recorded. Total cholesterol, apolipoprotein A-1 (apo A-1), apolipoprotein B (apo B), plasminogen activator inhibitor (PAI-1), insulin, and leptin were analysed in stored samples. Their influences on first-ever AMI were analysed by conditional logistic regression analysis.

RESULTS

Men with first-ever AMI had higher BMI, plasma insulin and leptin, and diastolic blood pressure than the referents. Furthermore, they had lower plasma apo A-1 and were more often smokers. Smoking, high leptin, PAI-1 and cholesterol, and low apo A-1 levels were significant risk factors for first-ever AMI in univariate analysis. High leptin (OR 8.97; 95% CI: 1.73-46.5) and cholesterol (OR 5.18; 95% CI: 1.34-20.0) levels remained significant risk factors for AMI in a multivariate model. High apo A-1 was protective (OR = 0.13; 95% CI: 0.03-0.55). The combination of high leptin and low apo A-1 was associated with a particularly pronounced increased risk for AMI.

CONCLUSION

Plasma leptin strongly predicts first-ever AMI. Our data support the hypothesis that leptin is an important link in the development of cardiovascular disease in obesity.

Leptin is a risk marker for first-ever hemorrhagic stroke in a population-based cohort

BACKGROUND AND PURPOSE

Leptin, important for body weight regulation, may be involved in the pathogenesis of the insulin resistance syndrome, associated with cardiovascular disease. We tested to determine whether leptin is a risk marker for first-ever stroke in a nested case-referent study.

METHODS

We identified 113 patients with first-ever stroke (94 with ischemic and 19 with hemorrhagic stroke) who, before the stroke, had participated in population-based health surveys in northern Sweden. Referents were matched for sex, age, date and type of health survey, and geographic region. Blood pressure (BP), body mass index (BMI), and presence of smoking, diabetes, and hypertension were recorded. Total cholesterol, insulin, and leptin were analyzed in stored samples. Risk markers for first-ever stroke were analyzed by conditional logistic regression analysis.

RESULTS

Patients with hemorrhagic stroke had higher levels of BMI and systolic and diastolic BPs. Leptin levels were 72% and 59% higher in males and females, respectively, with hemorrhagic stroke versus referents. Patients with ischemic stroke more often had hypertension, diabetes mellitus, and higher fasting glucose and insulin levels. A diagnosis of hypertension and elevated systolic and diastolic BPs were significant risk markers for first-ever hemorrhagic stroke in univariate analysis. High leptin (OR=20.55; 95% CI, 1.12 to 376.7) levels together with hypertension (OR=16.28; 95% CI, 1.49 to 177.3) remained as significant risk markers in a multivariate model. The combination of high leptin and high systolic or diastolic BP were associated with a profoundly increased risk for hemorrhagic stroke (OR=22.11; 95% CI, 1.57 to 310.9). Diabetes, hypertension, and obesity (BMI >/=27), together with high levels of insulin, glucose, systolic and diastolic BP, were significant risk markers for first-ever ischemic stroke in univariate analysis. Hypertension (OR=2.10; 95% CI, 1.14 to 3.86) remained as an independent risk marker in a multivariate model.

CONCLUSIONS

Plasma leptin is strongly associated with an increased risk for first-ever hemorrhagic stroke, independent of other risk markers for cardiovascular disease. Leptin may be an important link in the development of cardiovascular disease in obesity.

Increased fibrinogen levels and acquired hypofibrinolysis in young adults with ischemic stroke

BACKGROUND AND PURPOSE

Elevated fibrinogen levels and abnormalities in the fibrinolytic system are related to the occurrence of cardiovascular events. However, the role of these factors in the evolution of cerebrovascular disease has received less attention, in particular in young stroke patients. The aim of this study was to evaluate possible abnormalities in plasma fibrinogen levels and the state of the fibrinolytic system in young adults with a first-ever ischemic stroke.

METHODS

This study is based on 102 consecutive patients aged 18 to 44 years admitted between January 1991 and May 1996 as a result of a first ischemic stroke. Forty-one healthy controls were recruited. Evaluations of anthropometric/metabolic variables, plasma fibrinogen levels, and the fibrinolytic system were undertaken >/=3 months (mean, 5.4+/-2.0 months) after admission.

RESULTS

Patients had lower tissue plasminogen activator activity and increased plasminogen activator inhibitor type 1 activity at baseline, as well as increased tissue plasminogen activator mass concentration both at baseline and after a venous occlusion test. Overall, there were no significant differences between the main etiologic subgroups regarding plasma fibrinogen levels and fibrinolytic variables. Baseline fibrinolytic variables were strongly correlated with body mass index, serum triglycerides, and cholesterol levels. After adjustments in multivariate models, fibrinogen levels and tissue plasminogen activator mass concentration both at baseline and after venous occlusion test remained significantly increased in patients. Logistic multiple regression analyses indicated that plasma fibrinogen was a strong predictor of ischemic stroke (odds ratio, 11.25; 95% CI, 3.27 to 38. 69).

CONCLUSIONS

Increased fibrinogen levels and tissue plasminogen activator mass concentration are independently associated with ischemic stroke in young adults. Metabolic perturbations are closely interrelated with aberrations in tissue plasminogen activator and plasminogen activator inhibitor type 1 activity in these patients, findings consistent with an acquired hypofibrinolysis.

Hypertension and insulin resistance in a native unindustrialised rural population of India

A cross-sectional survey of 2964 individuals aged 16-70 years from a rural area of North India was carried out to test the hypothesis that a rural unindustrialised hypertensive population of North India has central obesity and hyperinsulinemia. Oral glucose tolerance test was carried out on 68 newly detected hypertensives, 82 age- and sex-matched community controls and 58 genetically related members of hypertensives (family controls). Fasting blood samples were examined for plasma glucose, serum insulin and lipids. Postglucose-load blood samples were examined for plasma glucose and serum insulin. Three blood pressure readings were recorded using Random Zero Sphygmomanometer. Anthropometric measurements (waist-hip ratio, subscapular and triceps skinfold thickness) of all three groups of individuals (hypertensives, community controls and family controls) were also recorded. The hypertensives had significantly higher fasting and postglucose-load serum insulin levels (P<0.05), body mass index (21.3 vs. 19 kg/m2: P<0.05), waist-hip ratio (0.89 vs. 0.85: P<0.001), subscapular (18.5 mm vs. 12.7 mm: P<0.001) and triceps fold thickness (17.6 mm vs. 12.9 mm: P<0.05) than community controls. The family controls had significantly higher systolic blood pressure than community controls (P<0.05). The lipids were not significantly different in all the three groups. Multiple logistic regression showed that both fasting and postglucose-load serum insulin were significantly associated with hypertension independent of waist-hip ratio and body mass index. The results of the present study suggest that hyperinsulinemia is related to hypertension in a rural unindustrialised population of North India.

Relation of fasting insulin to blood pressure and lipids in adolescents and parents

This study was intended to clarify the relation between fasting insulin, lipids, and blood pressure in adolescents before the onset of hypertension and to examine the association of these data with similar data obtained in their parents. The participants in this study were 183 adolescents 14 to 18 years old (96 girls) completing a 4-year intervention trial and their parents (164 mothers, 122 fathers). Blood pressure was measured twice on the right arm in a seated position using a random-zero sphygmomanometer. Fasting blood samples were obtained for lipid and insulin analyses. Fasting insulin was significantly correlated with systolic blood pressure in the adolescents and also in the parents before and after adjustment for body mass index. Fasting insulin was correlated significantly with levels of cholesterol, triglycerides, and HDL and LDL cholesterol in the adolescents. It was correlated only with triglycerides and HDL-cholesterol in mothers and fathers. After adjustment for body mass index, the correlations between fasting insulin and lipids in the children were not significant. A significant relation was shown between children's systolic blood pressure and mothers' fasting insulin and systolic blood pressure. Significant correlations were found between the children's and fathers' triglycerides and HDL-cholesterol, whereas significant correlations were found for fasting insulin and all lipids between mothers and children, and these remained significant after adjustment for body mass index. These results show (1) a significant relation between fasting insulin and both lipids and systolic blood pressure in adolescents and (2) a significant relation for these factors between adolescents and their parents. Although weight appears to play an important role in this relation during adolescence, genetic and environmental factors other than those mediated via weight may control insulin metabolism within families. The data support a role for studies during early biological development to address these issues.