Clustering of procoagulation, inflammation, and fibrinolysis variables with metabolic factors in insulin resistance syndrome

The Metabolic Syndrome: A Concept Hard to Define

The metabolic syndrome integrates, in a single diagnosis, the manifestations of insulin resistance that may lead to increased cardiovascular morbidity and precedes type 2 diabetes. Here we discuss the strengths and limitations of the definitions of the metabolic syndrome and the epidemiology of the syndrome including information from non-Caucasian populations. The definitions proposed by the World Health Organization (WHO) and the National Cholesterol Education Program (NCEP) are the most frequently used. The relative risk of having long-term complications is greater for the WHO definition; this is explained by the inclusion of the insulin resistance criteria. The cut-off points used in these definitions should be, but are not, adjusted for ethnicity; as a result, in non-Caucasian subjects, there is lack of agreement among these criteria. In a Mexican population-based survey the prevalence was 13.61% using the WHO definition and 26.6% using the NCEP-III criteria. Cases identified by the WHO criteria had a more severe form of the disease. We propose that the metabolic syndrome should be viewed as a progressive long-term process that leads to major complications. Its definition should reflect the continuous nature of the disease; the categorical approach of the current criteria oversimplifies the complexity of the syndrome. The threshold for defining abnormality should be based on the associated risk of the identified phenotype. Refinement of the definition of both affected and nonaffected subjects is required. The available definitions include, in each of these categories, heterogeneous groups with a broad range of risk of future complications.

Association of Metabolic Syndrome and C-reactive Protein Levels with Intracranial Atherosclerotic Stroke

Background

The risk factors for intracranial atherosclerosis are unclear but may differ from those for other stroke subtypes. Here, we investigated whether metabolic syndrome, an emerging risk factor for cardiovascular disease, is associated with intracranial atherosclerotic stroke.

Methods

Using the Adults Treatment Panel III criteria, we evaluated the components of metabolic syndrome in 439 patients with ischemic stroke or transient ischemic attacks. The prevalence of metabolic syndrome within each stroke subtype was determined, and the association between intracranial atherosclerosis and metabolic syndrome was evaluated.

Results

Metabolic syndrome was observed more frequently in patients with intracranial atherosclerosis than in those with other types of stroke (P=0.003). In a multiple regression analysis, metabolic syndrome, but not conventional risk factors, was independently associated with intracranial atherosclerosis (P=0.016). By contrast, the serum level of C-reactive protein was correlated negatively with the presence of intracranial atherosclerosis. Intracranial atherosclerosis was most prevalent in patients with metabolic syndrome and low levels of C-reactive protein (P=0.024).

Conclusions

Our results indicate that metabolic syndrome is a strong independent risk factor for intracranial atherosclerotic stroke. Therefore, treatment of metabolic abnormalities may be an important prevention strategy for intracranial atherosclerotic stroke.

Factor Analysis of Clustered Cardiovascular Risks in Adolescence

Background— Clustering of cardiovascular (CV) risks begins in childhood, yet studies of the factor structure underlying this clustering have focused on adults. The increasing rates of obesity and type 2 diabetes and the growing importance of metabolic syndrome among adolescents make assessment of CV risk clustering even more urgent in this age group.

Methods and Results— Exploratory factor analysis (principal components analysis) was performed with data from 1578 healthy seventh to 12th graders from the Princeton School District Study, a school-based study in Cincinnati, Ohio. Measured CV risks included cholesterol, triglycerides, fasting insulin and glucose, body mass index (BMI), waist circumference, fibrinogen, and blood pressure. Factor analysis yielded 4 uncorrelated factors (adiposity [BMI, waist, fibrinogen, insulin], cholesterol [LDL and total cholesterol], carbohydrate-metabolic [glucose, insulin, HDL cholesterol, triglycerides], and blood pressure [systolic and diastolic blood pressure]). These factors explained approximately 67% of the total variance. A summary cumulative risk scale was derived from factor scores, and high risk was defined as scoring in the top 5%. Although insulin loaded onto both the adiposity and carbohydrate-metabolic factors, obesity was a much stronger correlate of high cumulative risk (odds ratio=19.2; 95% CI, 7.6 to 48.5) than hyperinsulinemia (odds ratio=3.5; 95% CI, 1.8 to 6.8). A sizable proportion (18.5%; n=12) of those who were at high cumulative risk were not at high risk for any of the individual factors.

Conclusions— The patterning of CV risk clustering seen among adults is present in healthy adolescents. Among youth, obesity is the predominant correlate of cumulative risk.

Elevated interleukin-18 levels are associated with the metabolic syndrome independent of obesity and insulin resistance

OBJECTIVE

Activated innate immunity is thought to be involved in the pathogenesis of metabolic syndrome and type 2 diabetes. Interleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine with important regulatory functions in the innate immune response. We sought to determine whether an elevated IL-18 concentration was a risk predictor for metabolic syndrome in a community population independent of obesity and hyperinsulinemia.

METHODS AND RESULTS

A representative general population, aged 27 to 77 years, without clinical diabetes was studied for clinical and biochemical risk factors for metabolic syndrome. Serum IL-18 concentration measured in 955 subjects correlated with metabolic syndrome traits including body mass index (BMI), waist circumference, triglyceride, high-density lipoprotein (inversely), and fasting glucose and insulin levels (all P<0.001). Mean IL-18 levels rose progressively with the increasing number of metabolic risk factors (ANOVA P<0.001). After adjusting for age, gender, BMI, and insulin levels, increasing IL-18 tertiles were associated with an odds ratio for metabolic syndrome of 1.0, 1.42, and 2.28, respectively (P trend=0.007). The graded risk relation was even stronger in nonobese subjects and not attenuated when adjusted for C-reactive protein and IL-6 levels.

CONCLUSIONS

Our findings support the hypothesis that activation of IL-18 is involved in the pathogenesis of the metabolic syndrome.

Presence of the metabolic syndrome does not impair coronary collateral vessel formation in patients with documented coronary artery disease

OBJECTIVE

The metabolic syndrome confers an increased risk for cardiovascular morbidity and mortality. The presence of coronary collaterals may have beneficial effects during myocardial ischemia and may improve cardiovascular outcome in patients with coronary artery disease. Impaired collateral formation could be one of the reasons for the increased cardiovascular risk in patients with the metabolic syndrome. The aim of the present study was to determine the influence of the metabolic syndrome and insulin resistance on the presence of coronary collaterals.

RESEARCH DESIGNS AND METHODS

We conducted a cross-sectional study in 227 patients referred for elective percutaneous transluminal coronary angioplasty to the University Medical Centre Utrecht. The metabolic syndrome was diagnosed according to Adult Treatment Panel III, and homeostasis model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were used to quantify insulin resistance. Coronary collaterals were graded with Rentrop's classification. Rentrop grade >/=1 indicated the presence of collaterals. Results were adjusted for age, sex, and severity of coronary artery disease.

RESULTS

A total of 103 patients (45%) were diagnosed with the metabolic syndrome. There was no association between the metabolic syndrome and the presence of coronary collateral formation (odds ratio [OR] 1.2 [95% CI 0.7-2.0]). Also, the degree of insulin resistance was not related to the presence of coronary collaterals. The OR for HOMA-IR (highest versus lowest tertile) was 0.7 (0.3-1.5) and for QUICKI (lowest versus highest tertile) 0.8 (0.4-1.6).

CONCLUSIONS

The metabolic syndrome and insulin resistance are not related to the presence of coronary collaterals in patients with documented coronary artery disease.

Diabetes in the elderly and in women: cardiovascular risks

The prevalence of diabetes in the United States is on the rise because of changing characteristics of our population. Ours is an aging population; women who are older than 75 years constitute the fastest growing segment of our population. Our population is increasingly more overweight and sedentary and the numbers of minority persons who have a higher prevalence of obesity and diabetes are on the rise. Currently, at least 17 million persons have known diabetes; another 4 million have the disease but have not been diagnosed. There also is a much larger population-perhaps up to 60 million per-sons-who has the metabolic syndrome. Up to 60% of persons who have essential hypertension have impaired insulin resistance and other characteristics of this syndrome. This article focuses on the metabolic syndrome and diabetes in women and the elderly.

An evaluation of the metabolic syndrome in the HyperGEN study

BACKGROUND: In 2001 the National Cholesterol Education Program (NCEP) provided a categorical definition for metabolic syndrome (c-MetS). We studied the extent to which two ethnic groups, Blacks and Whites were affected by c-MetS. The groups were members of the Hypertension Genetic Epidemiology Network (HyperGEN), a part of the Family Blood Pressure Program, supported by the NHLBI. Although the c-MetS definition is of special interest in particular to the clinicians, the quantitative latent traits of the metabolic syndrome (MetS) are also important in order to gain further understanding of its etiology. In this study, quantitative evaluation of the MetS latent traits (q-MetS) was based on the statistical multivariate method factor analysis (FA). RESULTS: The prevalence of the c-MetS was 34% in Blacks and 39% in Whites. c-MetS showed predominance of obesity, hypertension, and dyslipidemia. Three and four factor domains were identified through FA, classified as "Obesity," "Blood pressure," "Lipids," and "Central obesity." They explained approximately 60% of the variance in the 11 original variables. Two factors classified as "Obesity" and "Central Obesity" overlapped when FA was performed without rotation. All four factors in FA with Varimax rotation were consistent between Blacks and Whites, between genders and also after excluding type 2 diabetes (T2D) participants. Fasting insulin (INS) associated mainly with obesity and lipids factors. CONCLUSIONS: MetS in the HyperGEN study has a compound phenotype with separate domains for obesity, blood pressure, and lipids. Obesity and its relationship to lipids and insulin is clearly the dominant factor in MetS. Linkage analysis on factor scores for components of MetS, in familial studies such as HyperGEN, can assist in understanding the genetic pathways for MetS and their interactions with the environment, as a first step in identifying the underlying pathophysiological causes of this syndrome.

The metabolic syndrome in Chinese, Malays and Asian Indians. Factor analysis of data from the 1998 Singapore National Health Survey

We used factor analysis to define and compare the manner in which the various features of the metabolic syndrome are linked or clustered in Chinese, Malays and Asian Indians. One thousand nine hundred and fifty seven men (1324 Chinese, 391 Malays and 261 Asian Indians) and 2308 women (1622 Chinese, 391 Malays and 296 Asian Indians) were examined. Anthropometry, blood pressure, serum glucose, lipid concentrations, and serum insulin were measured for all subjects. These data were then subjected to factor analysis which reduced the variables examined to three factors in all ethnic groups and both genders. The first (dyslipidemia) factor was positively loaded for obesity, insulin resistance (IR), fasting triglyceride and negatively loaded for HDL-cholesterol. The second (hyperglycemia) factor was positively loaded for IR and blood glucose. The third (hypertension) factor was positively loaded for obesity and blood pressure. IR was positively loaded in the hypertension factor in Malay women but not in others. Rather than a single entity causally associated with insulin resistance (IR), our findings support a concept in which the metabolic syndrome represents several distinct entities (dyslipidemia, hypertension and hyperglycemia). It appears that Malay females may be more prone to develop hypertension in association with IR.

Hemostatic risk factors and insulin sensitivity, regional body fat distribution, and the metabolic syndrome

Disturbances in the thrombotic and fibrinolytic systems are a feature of insulin resistance, obesity, and the metabolic syndrome. However, there are few studies in which these relationships have been explored in mainly asymptomatic individuals using sophisticated measures of insulin sensitivity and regional adiposity. Variables of the hemostatic system were measured in 106 men (aged 32-68 yr; body mass index, 20-34 kg/m(2)). Insulin sensitivity was measured by minimal model analysis and regional adiposity by dual energy x-ray absorptiometry. Clustering of intercorrelated variables was assessed by the statistical technique of factor analysis. Plasma levels of procoagulant factors VII and X, anticoagulant proteins C and S, and plasminogen activator inhibitor-1 correlated positively with total and percent central body fat (r = 0.25-0.38; P < 0.05) and negatively with insulin sensitivity (except protein S; r = -0.24 to -0.35; P < 0.05). On factor analysis, procoagulant factors VII and X, proteins C and S, and plasminogen activator inhibitor-1 were components of the cluster of variables that explained the greatest proportion of the variance in the data (39.2%). Other variables included in this cluster were those typical of the metabolic syndrome and also serum gamma-glutamyl transferase activity. These results suggest that factors VII and X and proteins C and S are features of the intercorrelated disturbances of the metabolic syndrome. Associations with adiposity and liver enzyme activity suggest the involvement of hepatic fat deposition.

An update on alcohol and atherosclerosis

PURPOSE OF REVIEW

Epidemiological studies consistently link moderate alcohol use with a lower risk of cardiovascular disease, but a number of important issues remain controversial. These include the putative impact of non-alcoholic constituents of some alcoholic beverages, the role of genetic factors, potential mechanisms for this association, and confirmation of the relationship in experimental models.

RECENT FINDINGS

Although high-density lipoprotein cholesterol (HDL-C) is considered the primary mediator of the cardiovascular effects of moderate drinking, recent evidence has shown the alcohol-HDL-C relation is not linear beyond the range of moderate drinking. Moderate alcohol use also has important inverse relations with inflammatory factors. Some, but not all, animal models confirm the anti-atherogenic effects of ethanol and highlight inflammatory factors as one possible mechanism. The non-alcoholic constituents of red wine also have anti-atherogenic and perhaps even life-extending properties in vitro, but their relevance to humans remains uncertain. Genetic variants of the apolipoprotein E and interleukin 6 genes in humans may modify how alcohol influences atherosclerosis, further emphasizing the importance of HDL-C and inflammatory factors as mediators.

SUMMARY

The robust relationship between moderate drinking and lower risk of cardiovascular disease remains an intriguing area of investigation. Clarifying potential gene-environment interactions and translational research into uses for non-alcoholic components will be important areas for future investigation.

Apolipoprotein B determines risk for recurrent coronary events in postinfarction patients with metabolic syndrome

The adult treatment panel III (ATP III) of the National Cholesterol Education Program recognizes metabolic syndrome (MS) as a secondary target for risk-reduction therapy given the well-known increase in risk of cardiovascular disease (CVD) by all MS components. We investigated potential CVD risk arising from 17 laboratory variables in postinfarction patients with MS by identifying such patients from the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study using slightly modified ATP III criteria for MS. This gave 272 patients with MS out of a total of 766 postinfarction patients without history of diabetes. Comparison between non-MS and MS patients using Kaplan-Meier analysis revealed no difference in outcome between groups. Additionally, a proportional hazards model applied to dichotomized laboratory parameters demonstrated only apoB as a significant predictor of risk for recurrent coronary events in MS patients with hazard ratio, 1.97 (95% CI; 1.08, 3.60; P < 0.05). We conclude that there is no difference in outcomes between non-MS and MS postinfarction patients; that apoB is significantly associated with risk for recurrent coronary events in postinfarction patients with MS; that further studies would be needed to recommend the routine determination of apoB in these patient groups.

Visceral obesity and hemostatic profile in patients with type 2 diabetes: the effect of gender and metabolic compensation

BACKGROUND

Type 2 diabetes (T2DM) patients are characterized by a very high risk of cardiovascular diseases. Among the factors that are responsible for this phenomenon are abdominal obesity and hemostatic abnormalities.

AIM OF THE STUDY

To examine the association of the markers of coagulation and fibrinolysis with the parameters of abdominal obesity and metabolic compensation in T2DM patients.

METHODS

46 T2DM patients participated in the study: 24 men (mean age 61.1 +/- 7.9 years) and 22 postmenopausal women (mean age 62.6 +/- 8.7 years). In each patient the content and distribution of fatty tissue was measured by a dual energy X-ray absorptiometry method (DEXA). The central abdominal fat/gynoid hip fat (CAF/GF) ratio was calculated. The following hemostatic parameters were measured: fibrinogen (Fb), factor VII (fVII), antithrombin III (ATIII), C protein (pC), tissue plasminogen activator inhibitor (PAI-1) and alpha 2 antiplasmin (alpha2 AP). In addition, the biochemical indices of metabolic compensation were measured: HbA1c, glucose levels and lipids.

RESULTS

Patients of both genders were divided according to median CAF/GF ratio. The activity of PAI-1 was significantly higher in women with CAF/GF ratio >or= 0.88 as compared to those with CAF/GF < 0.88 (2.64 +/- 1.28 vs. 1.61 +/- 0.27 U/ml, p < 0.05). The activity of ATIII was significantly lower in men with CAF/GF ratio >or= 1.17, as compared to those with CAF/GF < 1.17 (105.10 +/- 10.02 vs. 113.42 +/- 10.72 %, p < 0.05). There was a significant correlation between the CAF/GF ratio and the activity of PAI-1 in women (r = 0.30, p < 0.05). In addition, in men the CAF/GF ratio was negatively correlated with ATIII activity (r = -0.44, p < 0.05). Multiple stepwise regression analysis demonstrated independent association between the CAF/ GF ratio and the activity of PAI-1 (p < 0.001), and between the CAF/GF ratio and the activity of alpha2 AP (p < 0.01). There was an independent association between the concentration of HbA1c and the concentration of Fb (p < 0.001) and between triglycerides and the activity of fVII (p < 0.01).

CONCLUSIONS

The results of our study show that the patients with T2DM and with higher markers of abdominal obesity measured by DEXA show fibrinolysis impairment and thrombinogenesis elevation compared to those with lower abdominal obesity markers. Independent factors determining hypercoagulation also include metabolic control and lipids. Hemostatic disorders place subjects with diabetes and abdominal obesity at risk of developing vascular complications.

High prevalence of metabolic syndrome in Mexico

BACKGROUND

Our objective was to describe the prevalence of the metabolic syndrome using World Health Organization (WHO) and National Cholesterol Education Program (NCEP-III) definitions in a population-based survey.

METHODS

We performed an analysis of data from a Mexican nationwide, population-based study. The population was composed of 2,158 men and women aged 20-69 years sampled after a 9-12 h fasting period. Prevalence of the metabolic syndrome as defined by the NCEP-III definition and WHO criteria was estimated and case characteristics were assessed.

RESULTS

Age-adjusted prevalence was 13.61% for WHO criteria and 26.6% for the NCEP-III definition. Prevalence was 9.2 and 21.4%, respectively, in subjects without diabetes. Thirty five percent of affected cases were <40 years of age. In addition to criteria used for diagnosis, ca. 90% were either overweight or obese. In cases detected using WHO criteria, antihypertensive treatment or blood pressure reading >140/90 was found in 61.8%. The proportion of subjects who qualified for hypolipemiant treatment was lower: lifestyle modifications were needed in 42.1% and drug therapy was required in 18.9%. The same trends were found for cases detected using the NCEP definition.

CONCLUSIONS

Prevalence of the metabolic syndrome in Mexico is high. A large proportion of affected cases qualify for preventive actions for complications of the metabolic syndrome (i.e., weight loss, antihypertensive or hypolipemiant treatment). These results provide data for planning therapeutic programs for Mexican patients with the metabolic syndrome.

The metabolic syndrome defined by factor analysis and incident type 2 diabetes in a chinese population with high postprandial glucose

OBJECTIVE

The aim of this study was to examine how the major components of the metabolic syndrome relate to each other and to the development of diabetes using factor analysis.

RESEARCH DESIGN AND METHODS

The screening survey for type 2 diabetes was conducted in 1994, and a follow-up study of nondiabetic individuals at baseline was carried out in 1999 in the Beijing area. Among 934 nondiabetic and 305 diabetic subjects at baseline, factor analysis was performed using the principle components analysis with varimax orthogonal rotation of continuously distributed variables considered to represent the components of the metabolic syndrome. Fasting insulin was used as a marker for insulin resistance. Of the 559 subjects without diabetes at baseline, 129 developed diabetes during the 5-year follow-up. Factors identified at baseline were used as independent variables in univariate and multivariate logistic regression models to determine risk factor clusters predicting the development of diabetes.

RESULTS

Four factors were identified in nondiabetic and diabetic subjects. Fasting insulin levels, BMI, and waist-to-hip ratio were associated with one factor. Systolic and diastolic blood pressures were associated with the second factor. Two-hour postload plasma glucose (2-h PG) and serum insulin and fasting plasma glucose were associated with the third factor. Serum total cholesterol and triglycerides were associated with the fourth factor. The first and the third factors predicted the development of diabetes. In diabetic patients at baseline, the combination of systolic and diastolic blood pressure was the most important factor, and urinary albumin excretion rate clustered with fasting and 2-h PG levels.

CONCLUSIONS

Insulin resistance alone does not underlie all features of the metabolic syndrome. Different physiological processes associated with various components of the metabolic syndrome contain unique information about diabetes risk. Microalbunuria is more likely to be a complication of type 2 diabetes or hypertension than a marker for the metabolic syndrome.

Metabolic syndrome is associated with impaired long-term renal allograft function; not all component criteria contribute equally

Chronic renal transplant dysfunction (CRTD) remains a leading cause of renal allograft loss. Evidence suggests that immunological and ischemic insults are mainly associated with CRTD occurring within the first year after transplantation, whereas nonimmunological insults are predominantly associated with CRTD beyond the first year. Several cardiovascular risk factors, such as obesity, dyslipidemia, hypertension, and diabetes mellitus have been identified as important nonimmunological risk factors for CRTD. These risk factors constitute the metabolic syndrome (MS). As renal allograft function is a surrogate marker of renal allograft loss, we investigated the association of MS with impairment of renal allograft function beyond the first year after transplantation in a cross-sectional study of 606 renal transplant outpatients. Metabolic syndrome was defined using the definition of the National Cholesterol Education Program. Renal allograft function was assessed as the 24-h urinary creatinine clearance. A total of 383 out of 606 patients (63%) suffered from MS at a median time of 6 years (2.6-11.4) post-transplant. Presence of MS was associated with impaired renal allograft function beyond 1 year post-transplant [-4.1 mL/min, 95%CI (-7.1, -1.1)]. The impact of MS did not change appreciably after adjustment for established risk factors for CRTD [-3.1 mL/min, 95%CI (-6.0, -0.2)]. However, not all component criteria of MS contributed equally. Only systolic blood pressure and hypertriglyceridemia were independently associated with impaired renal allograft function beyond 1 year post-transplant in multivariate analyses.

Factor analysis of the metabolic syndrome in spinal cord-injured men

Disturbances of carbohydrate and lipid metabolism in men with spinal cord injury are common, but poorly defined. Clustering of recognized risk factors for obesity and disorders of carbohydrate and lipid metabolism are characteristic of the metabolic syndrome. The purpose of this study was to investigate the presence of metabolic syndrome using modifications of the World Health Organization (WHO) definition and including total physical activity levels (minutes/week), in a group of active males with spinal cord injury who were carefully matched for age, height, and weight with active able-bodied males. Factor analysis is used widely to explore factors of the metabolic syndrome. This technique was used in this study of 20 spinal cord-injured (SCI) men and 20 able-bodied controls, matched for age, height, and weight. Three-factor models, each reflecting a different aspect of the metabolic syndrome, were identified for both study groups. The average communality score for the SCI group was 0.8 and 0.7 for the control group. For the SCI group, factor 1 reflected an interaction between adiposity measures, physical activity, and postload insulin and glucose, factor 2 was reflective of dyslipidemia, while factor 3 revealed an interaction between fasting levels of insulin and glucose. In the control group, factor 1 reflected an association between the adiposity measures and physical activity, factor 2 was reflective of postload glycemic control, with factor 3 reflecting an interaction between fasting insulin and dyslipidemia. By summation of the total variance of each factor, the 3-factor models explained 80% and 69% of the variance in the original 9 variables examined in the SCI and control groups, respectively. In summary, while the WHO definition for the metabolic syndrome appears suitable for use in identifying the incidence of this syndrome in SCI men, some modification of anthropometric and lipid measures may be required.

Intra-abdominal fat is a major determinant of the National Cholesterol Education Program Adult Treatment Panel III criteria for the metabolic syndrome

The underlying pathophysiology of the metabolic syndrome is the subject of debate, with both insulin resistance and obesity considered as important factors. We evaluated the differential effects of insulin resistance and central body fat distribution in determining the metabolic syndrome as defined by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III. In addition, we determined which NCEP criteria were associated with insulin resistance and central adiposity. The subjects, 218 healthy men (n = 89) and women (n = 129) with a broad range of age (26-75 years) and BMI (18.4-46.8 kg/m2), underwent quantification of the insulin sensitivity index (Si) and intra-abdominal fat (IAF) and subcutaneous fat (SCF) areas. The metabolic syndrome was present in 34 (15.6%) of subjects who had a lower Si [median: 3.13 vs. 6.09 x 10(-5) min(-1)/(pmol/l)] and higher IAF (166.3 vs. 79.1 cm2) and SCF (285.1 vs. 179.8 cm2) areas compared with subjects without the syndrome (P < 0.001). Multivariate models including Si, IAF, and SCF demonstrated that each parameter was associated with the syndrome. However, IAF was independently associated with all five of the metabolic syndrome criteria. In multivariable models containing the criteria as covariates, waist circumference and triglyceride levels were independently associated with Si and IAF and SCF areas (P < 0.001). Although insulin resistance and central body fat are both associated with the metabolic syndrome, IAF is independently associated with all of the criteria, suggesting that it may have a pathophysiological role. Of the NCEP criteria, waist circumference and triglycerides may best identify insulin resistance and visceral adiposity in individuals with a fasting plasma glucose <6.4 mmol/l.

Measures of insulin resistance add incremental value to the clinical diagnosis of metabolic syndrome in association with coronary atherosclerosis

BACKGROUND

Whether measures of insulin resistance provide incremental information regarding atherosclerotic cardiovascular disease beyond current National Cholesterol Education Program (NCEP) Adult Treatment Panel III metabolic syndrome (MetSyn) criteria or inflammatory markers is uncertain.

METHODS AND RESULTS

We examined the association of insulin resistance and MetSyn with coronary artery calcification (CAC) in 840 asymptomatic nondiabetic subjects. Both NCEP and World Health Organization-defined MetSyn were associated (ordinal regression odds ratio [OR] and 95% confidence intervals for NCEP-defined MetSyn) with CAC after controlling for age, non-MetSyn risk factors, and plasma CRP levels (OR, 1.93 [1.43 to 2.60], P<0.001) and after further controlling for homeostasis model assessment index (HOMA) (OR, 1.56 [1.14 to 2.15], P=0.006). Conversely, HOMA was significantly associated with CAC after adjusting for age, non-MetSyn risk factors, and CRP levels (OR, 1.62 [1.31 to 2.01], P<0.001) and after further adjusting for NCEP-defined MetSyn (OR, 1.45 [1.16 to 1.82], P=0.007). Addition of HOMA to the NCEP MetSyn significantly improved the association with CAC, but addition of CRP data to MetSyn or HOMA did not.

CONCLUSIONS

Both MetSyn and HOMA index were associated with coronary atherosclerosis independent of established risk factors, including CRP. These findings support the use of biomarkers of insulin resistance in addition to NCEP MetSyn criteria in assessing cardiovascular disease risk.

Prevalence and factor analysis of metabolic syndrome in an urban Korean population

OBJECTIVE

The aim of this study was to explore the prevalence and pattern of the metabolic syndrome and its association with hyperinsulinemia in an urban Korean population of 269 men and 505 women.

RESEARCH DESIGN AND METHODS

The National Cholesterol Education Program Adult Treatment Panel (ATP) III guidelines were used to calculate the sex-specific prevalence of the metabolic syndrome. After excluding individuals taking medication for hypertension, diabetes, or dyslipidemia, we used factor analysis to examine the pattern of the metabolic syndrome in 206 men and 449 women.

RESULTS

The prevalence of metabolic syndrome was 16.0% in men and 10.7% in women aged 30-80 years. However, ATP III criteria for central obesity are not optimal for an Asian-Pacific population; when waist circumference is reduced from 102 to 90 cm in men and 88 to 80 cm in women, the prevalence of the metabolic syndrome increased to 29.0 and 16.8%, respectively. Sex-specific factor analysis showed four factors in men (obesity, glucose intolerance, hypertension, and dyslipidemia) and three in women (obesity-hypertension, glucose intolerance, and obesity-dyslipidemia). Insulin resistance estimated from fasting insulin levels clustered with three of the four factors in men and two of the three factors in women. By ATP III or Asian-Pacific waist circumference criteria, the prevalence of the metabolic syndrome increased with increasing tertiles of insulin resistance, which was estimated by a homeostasis model assessment.

CONCLUSIONS

The metabolic syndrome is common in an urban Korean population when using Asian-Pacific waist criteria. The prevalence of the metabolic syndrome increased with increasing tertiles of insulin resistance.

Alcohol consumption and inflammatory markers in older adults: the Cardiovascular Health Study

OBJECTIVE

We sought to determine the relation of alcohol intake and systemic inflammation in a population-based sample of older adults.

METHODS AND RESULTS

As part of the Cardiovascular Health Study (CHS), 5865 adults aged 65 years and older reported their intake of beer, wine, and liquor. We determined white blood cell count (WBC), factor VIII coagulant activity (factor VIIIc), and levels of C-reactive protein (CRP), fibrinogen, and albumin as markers of systemic inflammation. Among participants without confirmed cardiovascular disease, alcohol consumption was inversely associated with WBC, factor VIIIc, and fibrinogen level, and positively associated with albumin concentration in multivariate analyses. We found no consistent modification of these results by sex, obesity, or beverage type. The relation of alcohol use and CRP levels was significantly modified by apoE genotype (P interaction 0.03), with a positive association among participants with an apoE4 allele (P = 0.05), but a trend toward an inverse association among those without an apoE4 allele (P = 0.15).

CONCLUSIONS

Alcohol intake is associated with lower levels of inflammatory markers in older adults free of cardiovascular disease.

Low-grade inflammation may play a role in the etiology of the metabolic syndrome in patients with coronary heart disease: the HIFMECH study

Risk of coronary heart disease has been related to insulin resistance, but the mechanism for this is incompletely understood. Variables attributed to insulin resistance are associated with low-grade inflammation. A case-control study was performed of 469 male myocardial infarction (MI) survivors aged < 60 years and 575 control subjects recruited from centers in northern and southern Europe. Principal factor analysis was used to explore correlations between insulin resistance and inflammatory variables. Three factors resulted: (a) "Metabolic Syndrome" (insulin/proinsulin/ triglyceride/body mass index [BMI]); (b) "Inflammation" (fibrinogen/C-reactive protein [CRP]/interleukin-6 [IL-6]); and (c) "Blood Pressure" (systolic and diastolic blood pressure). The "Metabolic Syndrome" factor was related to the "Inflammation" factor (largely independently of obesity), the "Blood Pressure" factor, smoking, and south location (all P < or = .0002). There were significant relationships between all 3 factors and case status (P < or = .0002). Markers of low-grade inflammation are strongly related to metabolic syndrome variables independently of obesity. This raises the possibility that links between insulin resistance and cardiovascular disease could, in part, represent common consequences of low-grade inflammation.

Metabolic and inflammation variable clusters and prediction of type 2 diabetes: factor analysis using directly measured insulin sensitivity

Factor analysis, a multivariate correlation technique, has been used to provide insight into the underlying structure of the metabolic syndrome. The majority of previous factor analyses, however, have used only surrogate measures of insulin sensitivity; very few have included nontraditional cardiovascular disease (CVD) risk factors such as plasminogen activator inhibitor (PAI)-1, fibrinogen, and C-reactive protein (CRP); and only a limited number have assessed the ability of factors to predict type 2 diabetes. The objective of this study was to investigate, using factor analysis, the clustering of metabolic and inflammation variables using data from 1,087 nondiabetic participants in the Insulin Resistance Atherosclerosis Study (IRAS) and to determine the association of these clusters with risk of type 2 diabetes at follow-up. This study includes information on directly measured insulin sensitivity (S(i)) from the frequently sampled intravenous glucose tolerance test among African-American, Hispanic, and non-Hispanic white subjects aged 40-69 years. Principal factor analysis of data from nondiabetic subjects at baseline (1992-1994) identified three factors, which explained 28.4, 7.4, and 6% of the total variance in the dataset, respectively. Based on factor loadings of >or= 0.40, these factors were interpreted as 1) a "metabolic" factor, with positive loadings of BMI, waist circumference, 2-h glucose, log triglyceride, and log PAI-1 and inverse loadings of log S(i) + 1 and HDL; 2) an "inflammation" factor, with positive loadings of BMI, waist circumference, fibrinogen, and log CRP and an inverse loading of log S(i) + 1; and 3) a "blood pressure" factor, with positive loadings of systolic and diastolic blood pressure. The results were similar within strata of ethnicity, and there were only subtle differences in sex-specific analyses. In a prospective analysis, each of the factors was a significant predictor of diabetes after a median follow-up period of 5.2 years, and each factor remained significant in a multivariate model that included all three factors, although this three-factor model was not significantly more predictive than models using either impaired glucose tolerance or conventional CVD risk factors. Factor analysis identified three underlying factors among a group of inflammation and metabolic syndrome variables, with insulin sensitivity loading on both the metabolic and inflammation variable clusters. Each factor significantly predicted diabetes in multivariate analysis. The findings support the emerging hypothesis that chronic subclinical inflammation is associated with insulin resistance and comprises a component of the metabolic syndrome.

Metabolic syndrome: an appraisal of the pro-inflammatory and procoagulant status

Inflammation and hypercoagulability predispose to atherothrombosis and seem to be important features of the metabolic syndrome. The most convincing evidence is the association with increased levels of C-reactive protein. The hemostatic abnormality that has been most consistently associated with insulin resistance is an elevated plasminogen activator inhibitor-1 level. In contrast, markers of hypercoagulability have been associated inconsistently with hyperinsulinemia and glucose intolerance. Fibrinogen clusters with inflammatory factors, which suggests involvement of adipose tissue-generated inflammatory cytokines. Elevated von Willebrand's factor and factor VIII levels aggregate with indicators of endothelial injury,whereas vitamin K-dependent coagulation proteins correlate with triglyceride levels.

The metabolic syndrome in treatment-seeking obese persons

Obesity is a major risk factor for several metabolic diseases, frequently clustering to form the metabolic syndrome, carrying a high risk of cardiovascular mortality. We aimed to assess the prevalence of the metabolic syndrome in treatment-seeking obese subjects and the potential protective effect of physical activity. A cross-sectional analysis of data from a large Italian database of treatment-seeking obese subjects was performed. The metabolic syndrome was defined according to the criteria provisionally set by the National Cholesterol Education Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults, based on waist circumference, fasting glucose, triglyceride (TG) and high-density lipoprotein-cholesterol (HDL-C) levels, and arterial pressure. Data were available in 1,889 Caucasian subjects, 78% females, from 25 obesity centers. Minimum criteria for the metabolic syndrome were fulfilled in 53% of cases. The prevalence increased with age and obesity class and was negatively associated with participation in a structured program of physical activity (odds ratio, 0.76; 0.58 to 0.99; P =.041), after correction for age, sex, and body mass. The prevalence of cardiovascular disease was higher in subjects with the metabolic syndrome. A subset of 12.8% of cases had no metabolic abnormalities. They had a lower prevalence of abdominal obesity and cardiovascular disease. Isolated obesity was significantly associated with physical activity (odds ratio, 1.86; 1.33 to 2.60; P =.0003). Multiple metabolic disorders are present in most obese patients, and their prevalence is lower in physically active subjects. It is time to move towards a more integrated approach and to reconsider resource allocation to improve lifestyle changes for large-scale control of obesity.

Primary prevention in rheumatology: the importance of hyperuricemia

Hyperuricemia (HU) is present in 5-30% of the general population, although the prevalence is higher among some ethnic groups and seems to be increasing worldwide. Classically, chronic HU has been considered a risk factor for gout or lithiasis and is associated with alcoholism, obesity, hypertension, dyslipidemia, hyperglycemia/diabetes mellitus, renal failure and intake of certain drugs. HU is also associated with cardiovascular diseases such as hypertension, vascular disease, pre-eclampsia, pulmonary arterial hypertension, stroke, heart failure, ischemic heart disease and also metabolic syndrome, renal disease and increased mortality. It is uncertain if these associations are dependent or not, especially cardiovascular and renal diseases. Patients with chronic HU and also those with gout require both medical investigation for associated diseases or drugs as well as nutritional counseling and life-style changes. HU should alert physicians to possible complications.

Heritability of multivariate factors of the metabolic syndrome in nondiabetic Japanese americans

A rapidly growing body of evidence demonstrates important associations between the metabolic syndrome, characterized by a cluster of risk factors or phenotypes that include dyslipidemia, central obesity, hypertension, and hyperinsulinemia, and both cardiovascular disease and type 2 diabetes. The purpose of the present study was to characterize the metabolic syndrome in a sample of 432 individuals from 68 Japanese-American families, using factor analysis of quantitative phenotypes, and to estimate the heritability of these independent factors. Using nine characteristic phenotypes that included LDL particle size and C-reactive protein (CRP), factor analysis identified three multivariate factors interpreted as lipids, body fat/insulin/glucose/CRP, and blood pressure, explaining 65% of the variance. Heritability analysis revealed significant genetic effects on all of the factors: lipids (h(2) = 0.52, P < 0.001), body fat/insulin/glucose/CRP (h(2) = 0.27, P = 0.016), and blood pressure (h(2) = 0.25, P = 0.026). This analysis shows that independent, multivariate factors of the metabolic syndrome are heritable, demonstrating genetic influences on the underlying pathophysiological mechanisms of the syndrome.

Prevalence of the metabolic syndrome in patients with coronary heart disease, cerebrovascular disease, peripheral arterial disease or abdominal aortic aneurysm

Metabolic syndrome patients are at increased risk for developing cardiovascular morbidity and mortality. The increasing prevalence of the metabolic syndrome in various asymptomatic populations has been well documented, however, limited information is available about the prevalence in manifest atherosclerotic vascular disease patients. The aim of this study is to determine the overall and gender-specific prevalence of the metabolic syndrome and its components in these patients. This cross-sectional survey of 1117 patients, aged 18-80 years, mean age 60+/-10 years, comprised patients with coronary heart disease (n=527), cerebrovascular disease (n=258), peripheral arterial disease (n=232) or abdominal aortic aneurysm (n=100). Metabolic syndrome was defined by Adult Treatment Panel III. The prevalence of the metabolic syndrome in the study population was 46%: 58% in PAD patients, 41% in CHD patients, 43% in CVD patients and 47% in AAA patients. Overall, women had a higher prevalence than men (56% versus 43%). Age did not influence the metabolic syndrome prevalence; crude odds ratios (crude OR) 1.00 (95% CI: 0.99-1.02). Our results demonstrate a high prevalence of the metabolic syndrome in patients with manifest atherosclerotic vascular disease. Screening for metabolic syndrome in patients with high risk for new vascular incidents may identify patients with even higher vascular risk and may direct anti-atherosclerotic treatment in order to prevent new vascular incidents in the same or another vascular bed.

Obesity as the core of the metabolic syndrome and the management of coronary heart disease

The global burden of coronary heart disease (CHD) has led to the introduction of international guidelines to minimize the morbidity and mortality that result from this condition. These guidelines recognize the contribution of multiple risk factors to the development of CHD and advocate a multifaceted approach to treatment. Obesity, particularly visceral adiposity, contributes to the clustering of many other risk factors, such as hypertension, insulin resistance/type 2 diabetes and dyslipidemia, within individual patients. The molecular mechanisms underlying the metabolic abnormalities induced by visceral adiposity have yet to be fully elucidated; however, adipocytokines such as adiponectin, tumor necrosis factor-alpha and resistin seem to play an important role in this process. Obesity is a major modifiable CHD risk factor, and the benefits of weight loss are numerous, leading to improvements in several co-morbidities. Guidelines advocate lifestyle changes to correct excess bodyweight and improve the CHD risk factor profile. In addition, pharmacologic therapy is recommended for the management of other risk factors, such as hypertension and dyslipidemia, which may not be adequately controlled by lifestyle changes alone. Lowering low-density lipoprotein cholesterol (LDL-C) levels is the primary target for drug therapy for CHD prevention, and statins are first-line lipid-modifying therapy. The introduction of more efficacious statins with favorable effects on the lipid profile will optimize the control of dyslipidemia. Combining these new treatments with lifestyle changes and drug therapies for managing other CHD risk factors, as part of a multifaceted approach to treatment, will have benefits for CHD prevention.

Traditional and Novel Risk Factors in Older Adults: Cardiovascular Risk Assessment Late in Life

As a population-based, longitudinal study of nearly 6000 older American adults, the Cardiovascular Health Study provides an excellent opportunity to assess the roles of traditional and novel cardiovascular risk factors in the development of coronary heart disease. Cardiovascular Health Study investigators have analyzed both traditional risk factors, such as diabetes, hypertension, and smoking, and new risk factors, such as hemostatic factors, inflammatory markers, exposure to infectious agents, and genetic determinants. These analyses have led to several important conclusions. First, older adults without previous cardiovascular events have a tremendous burden of subclinical vascular disease, which may change how physicians view risk factor modification in this age group. Second, some traditional cardiovascular risk factors lose importance as predictors of cardiovascular disease among older adults. Third, even modest elevations in fasting blood glucose or systolic blood pressure-below the levels used to define diabetes or hypertension-may have prognostic implications. Fourth, novel cardiovascular risk factors may add further information about cardiovascular disease risk in older adults. Promising potential candidates identified in the Cardiovascular Health Study include markers of hemostatic activation, fibrinogen, factor VIII coagulant activity, C-reactive protein, and exposure to herpes simplex virus-1 and possibly chlamydia. Future Cardiovascular Health Study investigations will help to clarify which combination of traditional and newer risk factors provides the best estimate of cardiovascular risk for older adults.

Inflammation and activated innate immunity in the pathogenesis of type 2 diabetes

There is increasing evidence that an ongoing cytokine-induced acute-phase response (sometimes called low-grade inflammation, but part of a widespread activation of the innate immune system) is closely involved in the pathogenesis of type 2 diabetes and associated complications such as dyslipidemia and atherosclerosis. Elevated circulating inflammatory markers such as C-reactive protein and interleukin-6 predict the development of type 2 diabetes, and several drugs with anti-inflammatory properties lower both acute-phase reactants and glycemia (aspirin and thiazolidinediones) and possibly decrease the risk of developing type 2 diabetes (statins). Among the risk factors for type 2 diabetes, which are also known to be associated with activated innate immunity, are age, inactivity, certain dietary components, smoking, psychological stress, and low birth weight. Activated immunity may be the common antecedent of both type 2 diabetes and atherosclerosis, which probably develop in parallel. Other features of type 2 diabetes, such as fatigue, sleep disturbance, and depression, are likely to be at least partly due to hypercytokinemia and activated innate immunity. Further research is needed to confirm and clarify the role of innate immunity in type 2 diabetes, particularly the extent to which inflammation in type 2 diabetes is a primary abnormality or partly secondary to hyperglycemia, obesity, atherosclerosis, or other common features of the disease.

Obesity and the Metabolic Syndrome: implications for dietetics practitioners

The Metabolic Syndrome encompasses a set of laboratory and physical findings, including central adiposity, insulin resistance, hypertension, high triglycerides, and low HDL-cholesterol and several abnormalities in clotting and inflammatory markers. Using the definition provided by the Adult Treatment Panel III of the National Cholesterol Education Program, 24% of adult Americans have the Metabolic Syndrome. Central location of fat and release of fatty acids and cytokines from enlarged fat cells located in the intra-abdominal fat tissue provide the major agents that incite this syndrome. From a practical point of view, identifying dietary and lifestyle factors, including low levels of physical activity, are important in designing a diet and exercise program that can help individuals with the Metabolic Syndrome to reduce the associated detrimental health consequences.

Systemic hypertension, diabetes mellitus, and dyslipidemia in relation to body mass index: evaluation of a Brazilian population

OBJECTIVE: To determine the prevalence of systemic hypertension, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia in a Brazilian population in relation to body mass index. METHOD: Retrospective evaluation of 1213 adults (mean age: 45.2 ± 12.8; 80.6% females) divided into groups according to body mass index [normal (18.5 - 24.4 kg/m²); overweight (25 - 29.9 kg/m²); grade 1 obesity (30 - 34.9 kg/m²); grade 2 obesity (35 - 39.9 kg/m²), and grade 3 obesity (> 40 kg/m²)]. The prevalence of hypertension, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia were analyzed in each group. The severity of cardiovascular risk was determined. High-risk patients were considered those reporting 2 or more of the following factors: systemic hypertension, HDL < 35 mg/dL, total cholesterol > 240 mg/dL, triglycerides > 200 mg/dL when HDL < 35 mg/dL, and glycemia > 126 mg/dL. Moderate-risk patients were those reporting 2 or more of the following factors: systemic hypertension, HDL < 45, triglycerides > 200 mg/dL, and total cholesterol > 200 mg/dL. RESULTS: The prevalence of systemic hypertension, diabetes mellitus, hypertriglyceridemia, and low HDL-cholesterol levels increased along with weight, but the prevalence of hypercholesterolemia did not. The odds ratio adjusted for gender and age, according to grade of obesity compared with patients with normal weight were respectively 5.9, 8.6, and 14.8 for systemic hypertension, 3.8, 5.8, and 9.2 for diabetes mellitus and 1.2, 1.3, and 2.6 for hypertriglyceridemia. We also verified that body mass index was positively related to cardiovascular high risk (P < .001) CONCLUSION: In our population, cardiovascular risk increased along with body mass index.

Genetic determinants of arterial thrombosis

Arterial thrombosis is a complex disorder that involves multiple genetic and environmental factors interacting to produce the characteristic phenotype. In the past decades, investigators have focused on the molecular genetics of arterial vascular disorders and have identified numerous polymorphisms and mutations in genes related to the hemostatic system and to enzymes involved in the synthesis and bioavailability of nitric oxide (NO); however, the relation between most polymorphisms and the risk of coronary artery disease, ischemic stroke, and peripheral vascular disease remains highly controversial. In this review, we describe the most common genetic variations involved in the pathogenesis of arterial thrombosis, their functional implications, and their association with disease risk. Specifically, we consider polymorphisms in coagulation factors (fibrinogen, prothrombin, FV Leiden, FVII, and FXIII); fibrinolytic factors (tissue-type plasminogen activator, plasminogen activator inhibitor-1, and thrombin-activatable fibrinolysis inhibitor); platelet surface receptors; methylenetetrahydrofolate reductase; endothelial NO synthase; and the antioxidant enzymes paraoxonase and plasma glutathione peroxidase. Overall, there seems to be a modest contribution of individual genetic variants in the hemostatic and antioxidant systems to the risk of arterial thrombosis. Thus, future research ought to focus on identifying novel genetic determinants and on the interaction of these genetic risk factors with each other and the environment to understand better the pathobiology and susceptibility to arterial thrombotic disease.

Linkage analysis of a composite factor for the multiple metabolic syndrome: the National Heart, Lung, and Blood Institute Family Heart Study

Recent studies have demonstrated significant genetic and phenotypic correlation underlying the clustering of traits involved in the multiple metabolic syndrome (MMS). The aim of this study was to identify chromosomal regions contributing to MMS-related traits represented by composite factors derived from factor analysis. Data from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study were subjected to a maximum likelihood-based factor analysis. These analyses generated an MMS factor that was loaded by BMI, waist-to-hip ratio, subscapular skinfold, triglycerides, HDL, homeostasis model assessment index, plasminogen activator inhibitor-1 antigen, and serum uric acid. Genetic data were obtained for 2,467 subjects from 387 three-generation families (402 markers, the NHLBI Mammalian Genotyping Service) and 1,082 subjects from 256 sibships (243 markers, the Utah Molecular Genetics Laboratory). Multipoint variance components linkage analysis (GENEHUNTER version 2.1) of the MMS factor was conducted in the combined marker set sample. The greatest evidence for linkage was found on chromosome 2, with a peak LOD of 3.34 at 240 cM. Suggestive linkage was also observed for regions on chromosomes 7, 12, 14, and 15. In summary, a genomic region on chromosome 2 may contain a pleiotropic locus contributing to the clustering of MMS-related phenotypes.

A major health hazard: the metabolic syndrome

The clustering of several metabolic and cardiovascular disease risk factors has been termed the metabolic syndrome. The metabolic syndrome seems to result from a collision between susceptible "thrifty genes" and a society characterized by an increased prevalence of obesity and a sedentary lifestyle. The typical patient is characterized by abdominal obesity, a varying degree of glucose intolerance, dyslipidemia and often hypertension. The components of the metabolic syndrome are associated with insulin resistance, disturbances of coagulation and fibrinolysis, endothelial dysfunction and elevated markers of sub-clinical inflammation. The current review focuses mainly on the new definitions of the syndrome, the results of recent epidemiological studies and the consequences of the metabolic syndrome as an important risk factor for cardiovascular disease, premature death and diabetes. The metabolic syndrome constitutes a major challenge for public health professionals in the field of preventive medicine since more than 40 million U.S. adults seem to be affected by the syndrome. Lifestyle changes could have a profound influence on the syndrome and its development.

Thrombin, inflammation, and cardiovascular disease: an epidemiologic perspective

The exploration of coagulation led to identifying inflammation as a major factor in arterial disease throughout life. "Integrative molecular physiology" reflects our emerging understanding of how coagulation and inflammation integrate with one another, in both normal physiology and in pathophysiology. Our own responses to environmental challenge provide much of the damage that cumulatively results in chronic cardiovascular disease. Only by intervening in exquisitely precise ways can we hope to effectively and safely modify the course of lifelong chronic diseases, such as atherosclerosis.

Genotype, obesity and cardiovascular disease--has technical and social advancement outstripped evolution?

Teleologically, our ancestors were highly adapted hunter-gatherers. In recent history, the environment in which Homo sapiens exists has altered drastically and humans are exposed to environments for which the hunter-gatherer genotype is ill-suited. The adoption of a sedentary Western lifestyle, and the case of obtaining food of a high calorific content imposed upon a thrifty genotype, have resulted in the current global epidemic of obesity, Type 2 diabetes and the Metabolic Syndrome. The ramification of this epidemic is that cardiovascular disease is becoming a global healthcare problem, which will have its greatest impact on the developing nations. A global strategy is required to reduce the impact of the Western lifestyle on the health of developing nations and prevent obesity and Type 2 diabetes. Such an approach needs to be culturally sensitive, integrated, and multidisciplinary and involve a range of interventions that work at the individual and community levels. If lifestyle measures fail, then pharmacological intervention may be necessary. For this, novel agents such as dual PPARalpha/gamma agonists may be the therapy of the future.

Relationship of metabolic syndrome and fibrinolytic dysfunction to cardiovascular disease

BACKGROUND

The clustering of impaired glucose metabolism, elevated triglycerides, low HDL cholesterol, and abdominal obesity is known as the metabolic syndrome. Individuals with this syndrome suffer an excess of cardiovascular disease (CVD) for reasons that are unclear.

METHODS AND RESULTS

We randomly sampled 1276 adults of South Asian, Chinese, European, and Native Indian ancestry from 4 communities in Canada. Participants provided fasting blood samples for glucose, lipids, and fibrinolytic measurements; had an oral glucose tolerance test; and underwent a B-mode carotid ultrasound examination. CVD was determined by history and ECG. The prevalence of the metabolic syndrome was 25.8% (95% CI, 23.5 to 28.2) and varied substantially by ethnic group: 41.6% among Native Indians, 25.9% among South Asians, and 22.0% among Europeans, compared with 11.0% among the Chinese (overall, P=0.0001). People with the metabolic syndrome had more atherosclerosis (maximum intimal medial thickness, 0.78+/-0.18 versus 0.74+/-0.18 mm; P=0.0005), CVD (17.2% versus 7.0%; P=0.0001), and elevated plasminogen activator inhibitor-1 (24.2 versus 14.6 U/mL; P=0.001) compared with levels among people without the metabolic syndrome. For the same amount of atherosclerosis, people with the metabolic syndrome had a greater prevalence of CVD, even among nondiabetic individuals. This difference in CVD prevalence among the groups was attenuated after adjustment for plasminogen activator inhibitor-1 levels, suggesting that fibrinolytic dysfunction mediates the increased risk of CVD in individuals with the metabolic syndrome.

CONCLUSIONS

CVD among people with the metabolic syndrome is explained by their excess of atherosclerosis and impaired fibrinolysis. Interventions to prevent atherosclerosis progression and improve fibrinolytic function require evaluation in this high-risk group.

The metabolic syndrome and C-reactive protein, fibrinogen, and leukocyte count: findings from the Third National Health and Nutrition Examination Survey

To examine the association between the metabolic syndrome and C-reactive protein, fibrinogen, and leukocyte count, the author did a cross-sectional analysis of data from 8570 participants aged >/=20 years from the Third National Health and Nutrition Examination Survey (1988-1994). The metabolic syndrome was defined using criteria established by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. The age-adjusted prevalence of having an elevated C-reactive protein concentration was 29.0% (S.E.: 1.6%) for participants with the metabolic syndrome and 12.1% (S.E.: 0.6%) for participants without the metabolic syndrome (adjusted odds ratio (OR), 2.80; 95% confidence interval (CI): 2.36, 3.33). Compared with participants who had no abnormalities, the corresponding adjusted ORs were 1.91 (95% CI: 1.27, 2.87), 3.00 (95% CI: 1.96, 4.60), 5.01 (95% CI: 3.39, 7.41), 5.97 (95% CI: 3.83, 9.31), and 6.79 (95% CI: 3.55, 12.99) for participants with 1, 2, 3, 4, and 5 metabolic abnormalities, respectively. Participants with the metabolic syndrome had higher fibrinogen concentrations and white blood cell counts than those without this syndrome. Many people with the metabolic syndrome have a low-grade inflammation, which may increase their risk for future adverse events. A better understanding of the potential consequences of the high prevalence of low-grade inflammation among people with the metabolic syndrome is needed.

Stroke: a vascular pathology with inadequate management

Stroke is a leading cause of death and disability in the world, and the worldwide burden from stroke will increase further during the 21st century. Major advances in the treatment and prevention of stroke have occurred but additional measures are needed. Much of the modern care of stroke mimics the modern treatment of heart disease, in part because of the success of thrombolytic therapy in improving outcomes. Nevertheless, the impact of thrombolytic therapy is limited because of the short therapeutic window. Additional measures are needed to limit the neurological consequences of stroke. Prevention remains a critical component of the management of patients with cerebrovascular disease. Although surgical therapies and antithrombotic medications (antiplatelet agents and anticoagulants) are effective in lessening the likelihood of stroke or recurrent stroke, new strategies are needed to lower the risk further. Measures aimed at stabilizing the vascular endothelium or preventing fracture of atherosclerotic plaques show great promise. Medications including cholesterol-lowering agents and antihypertensive medications, such as the angiotensin-converting enzyme inhibitors, appear effective in stroke prevention. These agents could be combined with antithrombotic agents and surgical interventions to lessen the risk of stroke.

Associations between inflammatory markers, traditional risk factors, and complications in patients with type 2 diabetes mellitus

OBJECTIVE

Inflammatory markers predict cardiovascular events in a wide range of patients. Two factors, fibrinogen (FIB) and high-sensitivity C reactive protein (CRP), are currently entering clinical practice as cardiovascular risk predictors. In patients with type 2 diabetes mellitus, we sought to examine the relationship between macrovascular disease, urinary albumin/creatinine ratio (ACR), and FIB or CRP, as well as the relationship of FIB and CRP with traditional risk predictors of these complications of diabetes.

METHODS

In 202 consecutive patients with type 2 diabetes mellitus from a diabetes clinic, clinical and biochemical data were obtained and a cross-sectional analysis was performed.

RESULTS

Patients with macrovascular disease had higher FIB (P=.02) but not higher CRP. They were older, more likely to have retinopathy or elevated serum creatinine, had higher ACR and lower HDL cholesterol. They were more likely to be treated with statins, beta-blockers, and ASA. Adjustment for statin therapy did not result in significant differences in CRP levels according to macrovascular disease status. Both FIB (P=.01) and CRP (P=.02) were significantly higher in patients with ACR whose values were in the proteinuria range. In multivariate analysis, both FIB (P=.001) and CRP (P=.03) were positively correlated with ACR, but no association was seen between CRP and ACR when FIB was entered in the model. Other factors positively associated with ACR were age, diastolic blood pressure, retinopathy, and hemoglobin A1c (HbA1c). FIB and CRP were strongly correlated (R=.49, P< or =.001) and this effect was independent of statin therapy. CRP was positively associated with body mass index (BMI), serum triglycerides, and sulfonylurea therapy and negatively associated with metformin therapy. Patients on statin therapy had significantly higher FIB and lower CRP. Women on hormone replacement therapy (HRT) had significantly lower FIB and higher CRP.

CONCLUSIONS

In patients with diabetes: (1) the two markers, FIB and CRP, are interrelated; (2) FIB is significantly associated with presence of microvascular disease, independent of CRP; (3) CRP is strongly associated with metabolic factors but not with complications of diabetes, independently of FIB; (4) statins and HRT were divergently associated with CRP and FIB as HRT was associated with lower FIB and higher CRP, while statins showed the reverse association; and (5) CRP and FIB provide different information about the characteristics and consequences of diabetes mellitus because of divergent associations with biological indicators and therapeutic agents.

It is never too late: change in physical activity fosters change in cardiovascular risk factors in middle-aged women

The purpose of the study was to determine the effect of physical activity, particularly change in physical activity over time, on cardiovascular risk factors in women. The 520 women in this analysis are part of an ongoing epidemiologic investigation of the effects of menopause on risk for cardiovascular disease; the investigation spans almost 20 years. The findings show that on average, physically active women have healthier risk factor profiles over time, and that as women change their activity level, their risk factor profiles change as well. Thus, for middle-aged women going through the menopausal transition, it is never too late to reduce their cardiovascular risk by increasing their activity level.

Skeletal muscle dictates the fibrinolytic state after exercise training in overweight men with characteristics of metabolic syndrome

While there is indisputable evidence supporting the beneficial role of aerobic exercise in reducing cardiovascular risk factors, there are few dose-response studies of this relationship. Increasingly, it is thought that the cardiovascular benefits of exercise are significantly influenced by adaptations within skeletal muscle and its vasculature. However, little is known about the molecular mechanisms underlying these adaptations. To address this need, we initiated a study utilizing longitudinal, microarray-based gene expression profiling of serial skeletal muscle biopsies obtained from the study of targeted risk reduction intervention through defined exercise (STRRIDE). STRRIDE participants were overweight and exhibited symptoms characteristic of the metabolic syndrome that typically precedes type II diabetes such as insulin resistance, abnormal lipids and glucose intolerance. Expression data were statistically filtered and sorted into exercise training-responsive clusters based on gene product knowledge. One such cluster included genes that promote the degradation of fibrin clots such as tissue plasminogen activator (t-PA), connective tissue activation peptide III (CTAP III) and tetranectin. The fibrinolytic activity and protein levels of tetranectin, and t-PA and its endogenous inhibitor PAI-1, were subsequently shown to change significantly in both skeletal muscle and serum in response to exercise training. Our data show that the rigors of exercise directly induce fibrinolytic genes and protein cascades, both within muscle, and in the systemic circulation. This finding is particularly significant given that the metabolic syndrome is an independent risk factor for peripheral vascular disease and thrombotic events within the heart and brain. We conclude that aerobic exercise training induces both local and systemic changes in fibrinolysis and vascular homeostasis that are probably protective against cardiovascular disease.

Weak and non-independent association between plasma TAFI antigen levels and the insulin resistance syndrome

Increased plasma thrombin-activatable fibrinolysis inhibitor (TAFI) levels were recently shown to be a part of the insulin resistance syndrome. We investigated the relationship between plasma TAFI antigen levels and insulin resistance markers and compared these results with those obtained for PAI-1 and fibrinogen which are known to be closely related to insulin resistance syndrome and fat mass, respectively. Eighty-nine obese females had 1.3-, 1.2-, and 3-fold higher circulating TAFI, fibrinogen and PAI-1, respectively, compared with 64 lean females. Univariate analysis showed that the significance level for association between TAFI or fibrinogen concentrations and insulin resistance markers was lower than the significance level for association between PAI-1 and insulin resistance markers. Nevertheless, TAFI, fibrinogen, and PAI-1 plasma levels were significantly associated to each other. In linear stepwise ascendant analysis, insulin resistance markers accounted for 50% of the interindividual variability of plasma PAI-1 and only for 10% of plasma TAFI and 13% of fibrinogen variability. The contribution of insulin resistance markers to plasma TAFI antigen levels variability disappeared when PAI-1 or fibrinogen was entered in the statistical model. TAFI mRNA was detected in the liver but not in adipose tissue and endothelial cells. No TAFI mRNA was detected in normal or atherosclerotic vessels either. These results suggest that elevated TAFI antigen levels found in obese subjects are not independently associated with the metabolic markers of the insulin resistance syndrome. Increased plasma TAFI antigen levels in obesity might reflect a specific pathway of regulation at the liver level.