Metabolic syndrome and ischemic heart disease in elderly men and women

Asthma and high-intensity interval training have no effect on clustered cardiometabolic risk or arterial stiffness in adolescents

PURPOSE

Cardiometabolic risk, including arterial stiffness, is increasing in youth. Those with asthma are suggested to be particularly at risk of cardiovascular disease. Efficient and effective strategies are required to prevent the atherosclerotic process in youth. The purpose of this study was to investigate the effect of 6 months high-intensity interval training (HIIT) on cardiometabolic risk in youth with and without asthma.

METHODS

65 adolescents (31 mild asthma; 34 non-asthma) were recruited, 32 (16 asthma) of whom were randomly allocated to receive HIIT three times per week for 6 months. At baseline, mid-intervention, post-intervention and at a 3-month follow-up, anthropometric, metabolic and vascular determinants of cardiometabolic risk were assessed. Following principal component analysis (PCA), linear mixed models were used to assess the influence of asthma, HIIT and their interaction.

RESULTS

Seven factors were identified which explained 88% of the common variance shared among the parameters. Those with asthma demonstrated lower arterial stiffness factor scores mid-intervention (P = 0.047) and lower cholesterol factor scores post-intervention (P = 0.022) but there was no effect of the intervention, or interaction effects, on any PCA-identified factor, at any time-point. HIIT was associated with a lower low-density lipoprotein and diastolic blood pressure at mid-intervention.

DISCUSSION

Neither arterial stiffness nor clustered cardiometabolic risk are influenced by HIIT in adolescents with or without asthma, despite important changes in blood lipid and pressure profiles. Blood pressure, augmentation and pulse wave velocity should be considered physiologically distinct constructs and as potential markers of cardiovascular health.

Executive functioning and the metabolic syndrome: a project FRONTIER study

Decrements in cognitive functioning have been linked to the metabolic syndrome (MetS), a risk factor for cardiovascular disease defined by the presence of three of the following: elevated blood pressure, increased waist circumference, elevated blood glucose, elevated triglycerides, and low high-density lipoprotein cholesterol. We examined the relationship between four measures of executive functioning (EF) and MetS as diagnosed by National Heart, Lung, and Blood Institute-American Heart Association criteria. MetS was examined in a rural population of 395 persons with a mean age of 61.3 years, 71.4% women, 37.0% Hispanic, 53.7% White non-Hispanic. There was a 61.0% prevalence of MetS. We derived a factor score from the four executive function measures which was used to compare those with and without the syndrome, as well as any additive effects of components of the syndrome. Those with MetS exhibited significantly poorer performance than those without the syndrome. However, there was no additive effect, having more components of the syndrome was not related to lower performance. The presence of MetS was associated with poorer EF in this rural cohort of community dwelling volunteers.

Clusters of AMI risk factors and their association with left ventricular hypertrophy: a population-based study within the Skaraborg Project, Sweden

OBJECTIVES

Risk factors for acute myocardial infarction (AMI) are known to cluster and to be differently distributed in men and women. The aim of this study was to sex-specifically explore clusters of acknowledged AMI risk factors by factor analysis, and to study whether such clusters are associated with left ventricular hypertrophy (LVH), used as a subclinical measure of CHD.

METHODS

In 2001-2005, 2328 subjects (30-74 years) were randomly selected from two municipalities in Sweden (participation-rate 76%) and were assessed with regard to cardiovascular risk factors; 852 participants also had an echocardiographic examination performed.

RESULTS

Factor analysis identified three identical factors in men and women. WHR, HOMA-ir, systolic blood pressure, and ApoB/ApoA1 loaded significantly on the principal "metabolic factor", leisure-time physical activity and self-rated health loaded significantly on the "vitality factor", and smoking and alcohol consumption loaded significantly on the "addiction factor". The metabolic factor was associated with LVH in both men (P<0.001) and women (P<0.001), whereas the addiction factor was associated with LVH solely in men (P=0.002).

CONCLUSIONS

The consistent pattern in the clustering of acknowledged AMI risk factors suggests common underlying mechanisms in both men and women. However, whereas the metabolic factor was paramount in both men and women in the association with LVH, the addiction factor had an impact solely in men. As LVH often precedes AMI, a deeper understanding of risk factors for LVH, including consideration of the supposed sex differences, can be useful in order to explore prevention strategies for AMI.

Ethnic variation in the impact of metabolic syndrome components and chronic kidney disease

OBJECTIVE

To examine the ethnic differences in the association between metabolic syndrome components and CKD in Asian populations.

METHODS

We analyzed data from three independent populations in Singapore representing the three major Asian ethnic groups (n=3167 Chinese, 3082 Malays and 3228 Indians) aged 40-80 years. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m(2). Factor analysis of metabolic syndrome components was conducted and factor scores were used as independent variables in multivariable logistic regression models.

RESULTS

The prevalence of CKD was highest among Malays (21.0% vs. 7.4%, 5.9% in Indians and Chinese). Factor analysis identified three factors among Chinese (glycemia, blood pressure [BP], and obesity/lipid) and Malays (glycemia, BP, and lipids) accounting for 70% of the variance and four factors (glycemia, BP, lipids, and obesity) among Indians accounting for 82% of the variance. Glycemia was positively associated with CKD in all three ethnic groups. BP was positively associated with CKD among Malays (OR [95% CI] of 1.16 [1.06-1.28]), whereas it showed an inverse association among Chinese (0.84 [0.71-0.99]) and Indians (0.84 [0.73-0.97]). However, this inverse association lost significance after adjusting for antihypertensive medication use in Chinese and Indians. Obesity/lipids among Chinese and obesity among Indians showed a positive association; lipids showed an inverse association among Malays.

CONCLUSIONS

These data suggest that while hyperglycemia was associated with CKD in all three ethnic groups, the impact of BP, lipids, obesity on CKD varies across ethnic groups. Understanding the specific associations may allow greater understanding of how CKD develops in different racial/ethnic groups.

Factor structure underlying components of allostatic load

Allostatic load is a commonly used metric of health risk based on the hypothesis that recurrent exposure to environmental demands (e.g., stress) engenders a progressive dysregulation of multiple physiological systems. Prominent indicators of response to environmental challenges, such as stress-related hormones, sympatho-vagal balance, or inflammatory cytokines, comprise primary allostatic mediators. Secondary mediators reflect ensuing biological alterations that accumulate over time and confer risk for clinical disease but overlap substantially with a second metric of health risk, the metabolic syndrome. Whether allostatic load mediators covary and thus warrant treatment as a unitary construct remains to be established and, in particular, the relation of allostatic load parameters to the metabolic syndrome requires elucidation. Here, we employ confirmatory factor analysis to test: 1) whether a single common factor underlies variation in physiological systems associated with allostatic load; and 2) whether allostatic load parameters continue to load on a single common factor if a second factor representing the metabolic syndrome is also modeled. Participants were 645 adults from Allegheny County, PA (30–54 years old, 82% non-Hispanic white, 52% female) who were free of confounding medications. Model fitting supported a single, second-order factor underlying variance in the allostatic load components available in this study (metabolic, inflammatory and vagal measures). Further, this common factor reflecting covariation among allostatic load components persisted when a latent factor representing metabolic syndrome facets was conjointly modeled. Overall, this study provides novel evidence that the modeled allostatic load components do share common variance as hypothesized. Moreover, the common variance suggests the existence of statistical coherence above and beyond that attributable to the metabolic syndrome.

Ambulatory blood pressure and the metabolic syndrome in normotensive and untreated hypertensive men

BACKGROUND

Components of the metabolic syndrome are typically intercorrelated in epidemiologic studies and, when combined, predict type 2 diabetes and cardiovascular diseases. However, it remains unclear whether a single construct underlies the various components and which of the components are most closely associated with the underlying syndrome. Here, we use our confirmatory factor analytic model of the metabolic syndrome to examine the extent to which measures of ambulatory blood pressure, reflecting blood pressure variability throughout the day and night, may strengthen the association between blood pressure and the other components of the syndrome.

METHODS

Participants were a community sample of 358 men (248 with hypertension), ages 40-70, not receiving antihypertensive medications. Confirmatory factor analysis was employed to examine model fit and the strength of association between clinic and ambulatory blood pressure and the metabolic syndrome.

RESULTS

The blood pressure factor loaded significantly on the underlying metabolic syndrome but the strength of association was not as great (loading = 0.34, p < 0.01) as those observed for the obesity, insulin resistance and lipid factors. The factor loadings for the ambulatory measures (awake loading = 0.19; sleep loading = 0.16, p values < 0.01) were significant but smaller in magnitude than the loadings for clinic blood pressure.

CONCLUSIONS

Both clinic and ambulatory measures of blood pressure are significantly associated with the underlying metabolic syndrome using confirmatory factor analytic methods. However, the strength of association appears greater for the clinic measures relative to the ambulatory measures in this study.

Validating metabolic syndrome through principal component analysis in a medically diverse, realistic cohort

BACKGROUND

The concept of metabolic syndrome has been subject to etiological and clinical controversies in recent years. Associations among the five risk factors (obesity, hypertension, hyperglycemia, high triglyceride levels, and low high-density lipoprotein cholesterol) may help establish the validity of the concept, especially in a cohort representative of an actual population.

METHODS

We used principal component analysis (PCA) to analyze the structure of the physiological components of metabolic syndrome in 7213 patients contained in an administrative database for the Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Quebec, a realistic cohort with diverse medical histories. We validated the results by repeating the analysis on stratified and random subgroups of patients, and on different combinations of risk factors. The first axis of the PCA was used to predict coronary heart disease (CHD) and diabetes.

RESULTS

The two first axes explained 53% of the variance. The first axis (33%) was associated in the expected direction with all five predictor variables, consistent with its interpretation as metabolic syndrome. The first axis was more predictive of subsequent CHD and diabetes than the formal definition of metabolic syndrome.

CONCLUSIONS

These results suggest that the concept of metabolic syndrome accurately captures an existing underlying physiological process. A continuous indicator could be constructed to identify metabolic syndrome more accurately, thus improving risk assessment for CHD and diabetes mellitus. Metabolic syndrome can be measured well even without all five predictors. However, discrepancies with other studies suggest that our results may not be generalizable, perhaps because our cohort tends to be sicker.

Alterations in the QRS complex in the offspring of patients with metabolic syndrome and diabetes mellitus: early evidence of cardiovascular pathology

OBJECTIVE

This study was undertaken to evaluate the nature and onset of changes in the QRS complex in the offspring of patients with diabetes mellitus (DM) and metabolic syndrome (MetS).

METHODS AND METHODS

A total of 529 subjects, divided into 5 groups, were included in the study: (i) group DM (n = 92), patients with DM; (ii) group MetS (n = 125), patients with MetS; (iii) group O-DM (n = 109), offspring of patients with DM; (iv) group O-MetS (n = 122), offspring of patients with MetS; and (v) group HO (n = 81), offspring of healthy subjects. QRS parameters analyzed included amplitude, maximum QRS spatial vector magnitude, electrical axis (EA), and 3 electrocardiogram (ECG) criteria for left ventricular hypertrophy based on amplitude criteria: Sokolow-Lyon index, Cornell voltage, and Gubner criterion.

RESULTS

Patients with DM and MetS showed a significant leftward shift of the EA when compared with the control group. A modest but significant leftward shift of EA was also observed in both offspring groups. These EA and maximum QRS spatial vector magnitude changes were reflected in the individual leads of the 12-lead ECG. The prevalence of a positive diagnosis by accepted electrocardiographic criteria (ECG left ventricular hypertrophy) was low.

CONCLUSION

Patients with DM and MetS displayed significant changes in QRS complex that suggest depolarization sequence deterioration. Similar changes were observed also in the offspring of patients with DM and MetS, which suggests early subclinical cardiovascular damage. These findings have implications for prevention, early diagnosis, and treatment in the offspring of patients with DM and MetS.

Leisure time and occupational physical activity in relation to obesity and insulin resistance: a population-based study from the Skaraborg Project in Sweden

The objective was to study obesity and insulin resistance in relation to leisure time physical activity (LTPA) and occupational physical activity (OPA) in a Swedish population, with particular focus on sex differences. Using a cross-sectional design, waist circumference, body mass index (BMI), glucose/insulin metabolism, blood pressure, heart rate, self-reported education, smoking, alcohol consumption, LTPA, and OPA were assessed in 1745 men and women (30-74 years) randomly chosen from 2 municipalities in southwestern Sweden. In both men and women, LTPA was inversely associated with BMI, waist circumference, and the homeostasis model assessment of insulin resistance (HOMA-IR), respectively. These associations remained statistically significant after adjustments for age, OPA, education, alcohol consumption, smoking, and study area, and also for BMI in the analyses concerning waist circumference and HOMA-IR. A statistically significant interaction term (P = .030), adjusted for multiple confounders, revealed a stronger association between LTPA and HOMA-IR in women compared with men. Occupational physical activity was positively associated with BMI (P < .001), waist circumference (P < .001), and HOMA-IR (P = .001), however, only in women. These associations remained when adjusting for multiple confounders. The sex differences were confirmed by statistically significant interaction terms between sex and OPA in association with BMI, waist circumference, and HOMA-IR, respectively. The observed sex differences regarding the strength of the association between LTPA and insulin resistance, and the positive association between OPA and obesity and insulin resistance found solely in women, warrant further investigation. Although exploration of the metabolic effects of OPA appears to be needed, thorough measurement of potential confounders is also vital to understand contextual effects.

ELECTROCARDIOGRAPHIC ABNORMALITIES AMONG MEXICAN AMERICANS: CORRELATIONS WITH DIABETES, OBESITY, AND THE METABOLIC SYNDROME

BACKGROUND

Resting ischemic electrocardiographic abnormalities have been associated with cardiovascular mortality. Simple markers of abnormal autonomic tone have also been associated with diabetes, obesity, and the metabolic syndrome in some populations. Data on these electrocardiographic abnormalities and correlations with coronary risk factors are lacking among Mexican Americans wherein these conditions are prevalent.

OBJECTIVE

This study aimed to evaluate the prevalent resting electrocardiographic abnormalities among community-dwelling Mexican Americans, and correlate these findings with coronary risk factors, particularly diabetes, obesity, and the metabolic syndrome.

METHODS

Study subjects (n=1280) were drawn from the Cameron County Hispanic Cohort comprised of community-dwelling Mexican Americans living in Brownsville, Texas at the United States-Mexico border. Ischemic electrocardiographic abnormalities were defined as presence of ST/T wave abnormalities suggestive of ischemia, abnormal Q waves, and left bundle branch block. Parameters that reflect autonomic tone, such as heart rate-corrected QT interval and resting heart rate, were also measured.

RESULTS

Ischemic electrocardiographic abnormalities were more prevalent among older persons and those with hypertension, diabetes, obesity, and the metabolic syndrome. Subjects in the highest quartiles of QTc interval and resting heart rate were also more likely to be diabetic, hypertensive, obese, or have the metabolic syndrome.

CONCLUSIONS

Among Mexican Americans, persons with diabetes, obesity, and the metabolic syndrome were more likely to have ischemic electrocardiographic abnormalities, longer QTc intervals, and higher resting heart rates. A resting electrocardiogram can play a complementary role in the comprehensive evaluation of cardiovascular risk in this minority population.

Early adversity and adult health outcomes

Adversity in childhood has effects on mental and physical health, not only in childhood but across the lifespan. A chief task of our research has been to define the pathways by which childhood experience has these surprising health outcomes, often decades later. The concept of allostatic load, which refers to dysregulations across major biological regulatory systems that have cumulative interacting adverse effects over time, provides a mechanism for understanding these relations and defining specific pathways. To chart these pathways, we examine early childhood socioeconomic status, family environment, and genetic predispositions as antecedents to socioemotional functioning/psychological distress; and neural responses to threat that have downstream effects on major stress regulatory systems, ultimately culminating in risks to mental and physical health outcomes. This integrative approach to investigating the impact of childhood experience on adult health outcomes illustrates the significance of multilevel integrative approaches to understanding developmental psychopathology more generally.

Association of metabolic syndrome and diabetes with subclinical coronary stenosis and plaque subtypes in middle-aged individuals

AIMS

  The presence of subclinical stenosed coronary segments and plaque subtypes has not been compared among those with metabolic syndrome, diabetes, or neither condition in middle-aged individuals. In select, intermediate-risk subjects, it may be reasonable to directly measure atherosclerosis burden by low-dose, multidetector-row computed tomographic coronary angiography.

METHODS

  We performed a cross-sectional analysis of 1024 consecutive, newly self-referred subjects (692 men, 332 women; mean age 53.0±9.7 years) who underwent health evaluation at the China Medical University Hospital. Participants had at least one cardiac risk factor, but no known coronary heart disease.

RESULTS

  Among our 1024 subjects, 135 had diabetes, 334 had metabolic syndrome and 555 had neither condition. The subjects with diabetes and those with metabolic syndrome had a higher prevalence of non-calcified, calcified and mixed-type plaques and stenosed coronary segments than the subjects with neither condition (P<0.05). The odds ratios for diabetes and the presence of any plaque, mixed plaque, calcified plaque and stenosed segment compared with neither metabolic syndrome nor diabetes were 2.893, 3.629, 2.099 and 2.036, respectively, all of which were significant (P<0.05). The odds ratio for metabolic syndrome and the presence of any plaque compared with neither metabolic syndrome nor diabetes was 1.606 (95% CI 1.063-2.426; P<0.05).

CONCLUSION

  In middle-aged subjects, diabetes was related to an increased risk of the presence of mixed plaques, calcified plaques and stenosed coronary segments. However, metabolic syndrome was related to an increased risk of the presence of any coronary plaque, but not related to stenosed coronary segments.

The role of estrogen deficiency in skin ageing and wound healing

The links between hormonal signalling and lifespan have been well documented in a range of model organisms. For example, in C. elegans or D. melanogaster, lifespan can be modulated by ablating germline cells, or manipulating reproductive history or pregnenolone signalling. In mammalian systems, however, hormonal contribution to longevity is less well understood. With increasing age human steroid hormone profiles change substantially, particularly following menopause in women. This article reviews recent links between steroid sex hormones and ageing, with special emphasis on the skin and wound repair. Estrogen, which substantially decreases with advancing age in both males and females, protects against multiple aspects of cellular ageing in rodent models, including oxidative damage, telomere shortening and cellular senescence. Estrogen's effects are particularly pronounced in the skin where cutaneous changes post-menopause are well documented, and can be partially reversed by classical Hormone Replacement Therapy (HRT). Our research shows that while chronological ageing has clear effects on skin wound healing, falling estrogen levels are the principle mediator of these effects. Thus, both HRT and topical estrogen replacement substantially accelerate healing in elderly humans, but are associated with unwanted deleterious effects, particularly cancer promotion. In fact, much current research effort is being invested in exploring the therapeutic potential of estrogen signalling manipulation to reverse age-associated pathology in peripheral tissues. In the case of the skin the differential targeting of estrogen receptors to promote healing in aged subjects is a real therapeutic possibility.

Management of dyslipidemia in the elderly population

The elderly population is increasing worldwide. Despite a major decrease in deaths from coronary heart disease (CHD), this malady remains the major cause of death in elderly men and women. In this paper, we review the role of dyslipidemia as a major known risk factor in the pathogenesis of CHD, age-related changes in lipoprotein metabolism, and differences in changes in lipids that occur in men and women during aging. Next we provide an overview of the available studies and recommendations from ATP III. Finally, we comment on the screening and management, cost and side effects of therapy as it applies to an aging population.

Stability of the factor structure of the metabolic syndrome across pubertal development: confirmatory factor analyses of three alternative models

OBJECTIVE

To test the fit and stability of 3 alternative models of the metabolic syndrome's factor structure across 3 developmental stages.

STUDY DESIGN

With data from the Fels Longitudinal Study, confirmatory factor analyses tested 3 alternative models of the factor structure underlying relationships among 8 metabolic syndrome-associated risks. Models tested were a 1-factor model (A), a 4-factor model (B), and a second-order latent factor model (C). Developmental stages assessed were prepuberty (ages 8-10), puberty (ages 11-15), and postpuberty (ages 16-20).

RESULTS

Convergence was achieved for all developmental stages for model A, but the fit was poor throughout (root mean square error of approximation > 0.1). Standardized factor loadings for waist circumference and body mass index were much stronger than those for fasting insulin at all 3 time points. Although prepuberty and postpuberty models converged for models B and C, each model had problems with Heywood cases. The puberty model did not converge for either model B or C.

CONCLUSIONS

The hypothetical structures commonly used to support the metabolic syndrome concept do not provide adequate fit in a pediatric sample and may be variable by maturation stage. A components-based approach to cardiovascular risk reduction, with emphasis on obesity prevention and control, may be a more appropriate clinical strategy for children and youth than a syndromic approach.

Lung function impairment and metabolic syndrome: the critical role of abdominal obesity

RATIONALE

Increased risk for cardiovascular morbidity and mortality has been related to both lung function impairment and metabolic syndrome. Data on the relationship between lung function and metabolic syndrome are sparse.

OBJECTIVES

To investigate risk for lung function impairment according to metabolic syndrome traits.

METHODS

This cross-sectional population-based study included 121,965 men and women examined at the Paris Investigations Préventives et Cliniques Center between 1999 and 2006. The lower limit of normal was used to define lung function impairment (FEV(1) or FVC < lower limit of normal). Metabolic syndrome was assessed according to the American Heart Association/National Heart, Lung, and Blood Institute statement.

MEASUREMENTS AND MAIN RESULTS

We used a logistic regression model and principal component analysis to investigate the differential associations between lung function impairment and specific components of metabolic syndrome. Lung function impairment was associated with metabolic syndrome (prevalence = 15.0%) independently of age, sex, smoking status, alcohol consumption, educational level, body mass index, leisure-time physical activity, and cardiovascular disease history (odds ratio [OR] [95% confidence interval], 1.28 [1.20-1.37] and OR, 1.41 [1.31-1.51] for FEV(1) and FVC, respectively). Three factors were identified from factor analysis: "lipids" (low high-density lipoprotein cholesterol, high triglycerides), "glucose-blood pressure" (high fasting glycemia, high blood pressure), and "abdominal obesity" (large waist circumference). All factors were inversely related to lung function, but abdominal obesity was the strongest predictor of lung function impairment (OR, 1.94 [1.80-2.09] and OR, 2.11 [1.95-2.29], for FEV(1) and FVC, respectively). Similar results were obtained for women and men.

CONCLUSIONS

We found a positive independent relationship between lung function impairment and metabolic syndrome in both sexes, predominantly due to abdominal obesity. Further studies are required to clarify the underlying mechanisms.

Genome-wide linkage scan for the metabolic syndrome: the GENNID study

In the United States, the metabolic syndrome (MetS) constitutes a major public health problem with over 47 million persons meeting clinical criteria for MetS. Numerous studies have suggested genetic susceptibility to MetS. The goals of this study were (i) to identify susceptibility loci for MetS in well-characterized families with type 2 diabetes (T2D) in four ethnic groups and (ii) to determine whether evidence for linkage varies across the four groups. The GENNID study (Genetics of NIDDM) is a multicenter study established by the American Diabetes Association in 1993 and comprises a comprehensive, well-characterized resource of T2D families from four ethnic groups (whites, Mexican Americans, African Americans, and Japanese Americans). Principal component factor analysis (PCFA) was used to define quantitative phenotypes of the MetS. Variance components linkage analysis was conducted using microsatellite markers from a 10-cM genome-wide linkage scan, separately in each of the four ethnic groups. Three quantitative MetS factors were identified by PCFA and used as phenotypes for MetS: (i) a weight/waist factor, (ii) a blood pressure factor, and (iii) a lipid factor. Evidence for linkage to each of these factors was observed. For each ethnic group, our results suggest that several regions harbor susceptibility genes for the MetS. The strongest evidence for linkage for MetS phenotypes was observed on chromosome 2 (2q12.1-2q13) in the white sample and on chromosome 3 (3q26.1-3q29) in the Mexican-American sample. In conclusion, the results suggest that several regions harbor MetS susceptibility genes and that heterogeneity may exist across groups.

Association between circulating oxidized low-density lipoprotein and incidence of the metabolic syndrome

CONTEXT

Experimental data support the hypothesis that oxidized low-density lipoprotein (LDL) is associated with the metabolic syndrome. However, this hypothesis has not been tested in humans.

OBJECTIVE

To establish the relation of oxidized LDL with metabolic syndrome in the general community.

DESIGN, SETTING, AND PARTICIPANTS

The Coronary Artery Risk Development in Young Adults (CARDIA) study is a population-based, prospective, observational study. We studied 1889 participants who were between the ages of 18 and 30 years at the time of recruitment in 1985 and 1986 and living in 1 of 4 US metropolitan areas (41% African American; 56% women) and were seen both at year 15 (2000-2001, ages 33-45 years) and year 20 examinations (2005-2006).

MAIN OUTCOME MEASURE

The longitudinal association of oxidized LDL and incident metabolic syndrome. Oxidized LDL was measured with a monoclonal antibody-based enzyme-linked immunosorbent assay. The metabolic syndrome was defined according to the Adult Treatment Panel III of the National Cholesterol Education Program.

RESULTS

Incident metabolic syndrome was diagnosed at the year 20 follow-up in 12.9% (243 of 1889) of participants who did not have metabolic syndrome at the 15-year follow-up. The odds ratios (ORs) for incident metabolic syndrome after 5 years' follow-up and adjusted for age, sex, race, study center, cigarette smoking, body mass index, physical activity, and LDL cholesterol levels by quintiles of oxidized LDL were 2.1 (95% confidence interval [CI], 1.1-3.8) for the second quintile (55.4-69.1 U/L); 2.4 (95% CI, 1.3-4.3) for the third quintile (69.2-81.2 U/L); 2.8 (95% CI, 1.5-5.1) for the fourth quintile (81.3-97.3 U/L); and 3.5 (95% CI, 1.9-6.6) for the fifth quintile (> or =97.4 U/L). The adjusted ORs for incidence of dichotomous components of metabolic syndrome in the highest vs the lowest quintile of oxidized LDL were 2.1 (95% CI, 1.2-3.6) for abdominal obesity, 2.4 (95% CI, 1.5-3.8) for high fasting glucose, and 2.1 (95% CI, 1.1-4.0) for high triglycerides. Low-density lipoprotein cholesterol was not associated with incident metabolic syndrome or with any of its components in the fully adjusted model containing oxidized LDL.

CONCLUSION

Higher concentration of oxidized LDL was associated with increased incidence of metabolic syndrome overall, as well as its components of abdominal obesity, hyperglycemia, and hypertriglyceridemia.

Biomarkers related to aging in human populations

Biomarkers are increasingly employed in empirical studies of human populations to understand physiological processes that change with age, diseases whose onset appears linked to age, and the aging process itself. In this chapter, we describe some of the most commonly used biomarkers in population aging research, including their collection, associations with other markers, and relationships to health outcomes. We discuss biomarkers of the cardiovascular system, metabolic processes, inflammation, activity in the hypothalamic-pituitary axis (HPA) and sympathetic nervous system (SNS), and organ functioning (including kidney, lung, and heart). In addition, we note that markers of functioning of the central nervous system and genetic markers are now becoming part of population measurement. Where possible, we detail interrelationships between these markers by providing correlations between high risk levels of each marker from three population-based surveys: the National Health and Nutrition Examination Survey (NHANES) III, NHANES 1999-2002, and the MacArthur Study of Successful Aging. NHANES III is used instead of NHANES 1999-2002 when specific markers of interest are available only in NHANES III and when we examine the relationship of biomarkers to mortality which is only known for NHANES III. We also describe summary measures combining biomarkers across systems. Finally, we examine associations between individual markers and mortality and provide information about biomarkers of growing interest for future research in population aging and health.

Metabolic syndrome as a risk factor for coronary heart disease and stroke: An 11-year prospective cohort in Taiwan community

OBJECTIVE

Patterns of metabolic syndrome among populations in the Asia-Pacific region remain unknown. This study sought to establish the prevalence of metabolic syndrome in Taiwan and the risk of cardiovascular disease imparted by this syndrome.

METHODS AND RESULTS

A cohort of 3602 individuals aged 35 years and above from one Taiwan community in 1990-1991 was followed up for a median of 9.0 years (inter-quartile range: 7.9-10.0 years). Women had a higher prevalence rates of age-standardized metabolic syndrome than men (28.9% versus 16.6%) by original NCEP-ATP III criteria, and the rates increased progressively. As numbers of metabolic syndrome increased, the hazard risk (HR) increased significantly, up to 5.5 (95% confidence interval [CI], 2.2-13.7) for coronary heart disease and 3.5 (95% CI, 1.9-6.5) for stroke. We found that low HDL cholesterol and high BMI had the highest risk for coronary heart disease (HR, 2.3), followed by metabolic syndrome (HR, 1.8). For stroke events, high blood pressure had the highest risk (HR, 3.0), also followed by metabolic syndrome (HR, 2.1). The highest attributable risk for the general population was low HDL cholesterol for coronary heart disease event and high blood pressure for stroke.

CONCLUSIONS

Metabolic syndrome was highly prevalent among the adult population and associated with an increased risk for coronary heart disease and stroke.

In addition to obesity and insulin resistance, microalbuminuria and diminished insulin secretion are linked with the metabolic syndrome in community-dwelling nondiabetic Taiwanese subjects

Although insulin resistance and obesity are currently considered primary factors underlying development of the metabolic syndrome, microalbuminuria and inadequate insulin secretion may also be involved. The present study is the first to examine intercorrelations among these factors in a community-based Taiwanese population. An epidemiological survey of chronic diseases conducted in 1996 was utilized to evaluate 1340 community-dwelling, nondiabetic adults. Principal component factor analyses involving varimax orthogonal rotation of transformed continuously distributed variables were performed. Sex-specific factor analyses yielded four separate factors in women (obesity/insulin resistance, lipid, blood pressure and insulin resistance/secretion factors) and three in men (obesity/insulin resistance/secretion, lipid and blood pressure factors). For men the corrected insulin response clustered with obesity, and insulin resistance loaded on the same factor, explaining 31% of variance; however, microalbuminuria was closely linked with blood pressure variables, and the corrected insulin response loaded on the same factor, explaining 13.2% of variance. Obesity and insulin resistance were confirmed as central anomalies of all features of the metabolic syndrome. The observed linkage of impaired beta-cell function and microalbuminuria with the metabolic syndrome should facilitate prediction of the onset of cardio-vasculo-metabolic disorders. Inadequate beta-cell function and microalbuminuria are plausible components of the metabolic syndrome in Taiwanese subjects.

The Metabolic Syndrome and the Carotid Artery Structure in Noninstitutionalized Elderly Subjects

Background and Purpose— In contrast to the young adult population, limited data are presently available regarding the epidemiology of the metabolic syndrome (MetS) and its relationship with cardiovascular disease risk in the elderly. We have investigated the frequency of the MetS and its association with the carotid artery structure in an elderly free-living population.

Methods— The study population consists of 5585 French noninstitutionalized elderly men and women aged 65 to 85 years, free of diabetes, who participated in the multicenter Three City Study and who underwent ultrasound examination of the carotid arteries at baseline examination between March 1999 and March 2001. The MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

Results— The MetS was present in 12.1% of the study participants, with slightly higher rates in men. Subjects with the MetS had higher frequency of carotid plaques (odds ratio, 1.30; 95% CI, 1.09 to 1.55), higher intima-media thickness of the common carotid artery (odds ratio, 1.81; 95% CI, 1.37 to 2.41), and higher lumen diameter (odds ratio, 2.17; 95% CI, 1.61 to 2.94) (upper quintiles) after adjustment for other cardiovascular risk factors. This association was observed in both genders and in subjects without prevalent cardiovascular disease. Elevated blood pressure as defined in the MetS was the main determinant of the relations between the MetS and the carotid parameters, especially the lumen diameter.

Conclusions— The present data suggest that noninstitutionalized elderly subjects with the MetS have altered structure of the carotid arteries.

Abdominal obesity and insulin resistance in patients with type 2 diabetes in a Swedish community. Skaraborg hypertension and diabetes project

OBJECTIVE

To explore the association between abdominal obesity and insulin resistance in patients with type 2 diabetes.

DESIGN

A cross-sectional observational study.

SETTING

Primary care in Skara, Sweden.

SUBJECTS

A total of 198 men and 186 women with type 2 diabetes who consecutively completed an annual check-up in 1992-1993.

MAIN OUTCOME MEASURES

Abdominal obesity was defined according to criteria for the metabolic syndrome using the waist circumference (WC): > 102 cm for men and > 88 cm for women. Insulin resistance was estimated using the Homeostasis Model Assessment (HOMA), and was dichotomized by the 75th percentile (IR).

RESULTS

Abdominal obesity was found in 66 men (33%), and in 106 women (57%). Pearson's correlation coefficients between components of the metabolic syndrome and IR were statistically significant for WC, waist-hip ratio, serum triglycerides, and HDL cholesterol, and were higher for WC (0.40) than for waist-hip ratio (0.23) in both genders (p < 0.001). The association between WC and IR was challenged by successively entering other components of the metabolic syndrome into the model in a logistic regression. In the final model, adjusting for differences in age, systolic blood pressure, HbA1c, serum triglycerides, HDL cholesterol, and microalbuminuria, the association remained statistically significant both in men (OR 8.6, 95% CI 3.0-25.2, p < 0.001), and in women (OR 5.6, 95% CI 1.7-18.1, p = 0.004).

CONCLUSIONS

WC provides a feasible measure for insulin resistance in the vast majority of subjects with type 2 diabetes. It is convenient and less expensive than direct means and could be used as a proxy for insulin resistance in population studies.

The metabolic syndrome and nonfatal ischemic heart disease; a population-based study

OBJECTIVES

Metabolic syndrome comprises insulin resistance, abdominal fat distribution, dyslipidemia and hypertension. The metabolic syndrome is expected to be diagnosed in millions of subjects in the near future worldwide. There are very few data in literature clearly documenting that subjects with metabolic syndrome have an increased cardiovascular risk.

DESIGN

Cross-sectional, population-based study.

MATERIALS AND METHODS

We used National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP)-III criteria and Minnesota Code of a 12-lead resting electrocardiogram (EKG) to assess the association of metabolic syndrome and nonfatal ischemic heart disease in 3723 subjects, aged 25 years and over, selected by cluster random sampling in three Iranian ports in the northern Persian Gulf. Electrocardiogram with evidence of IHD (IHD EKG) was defined as myocardial infarction (codes 1.1 and 1.2) and ischemia (codes 1.3, 4.1-4.4, 5.1-5.3 and 7.1) together.

RESULTS

An estimated 49.08% (52.04% of males and 46.34% of females) were identified as fulfilling NCEP-ATP III criteria for diagnosing the metabolic syndrome. Prevalence of EKG with evidence of ischemic heart disease (IHD EKG) was 12.7% (10.4% for men and 14.7% for women, p<0.0001). In multiple logistic regression analysis, metabolic syndrome was found to have a significant association with IHD EKG [OR=1.35, CI (1.09-1.66), p=0.005] after adjusting for sex and age. Of the metabolic syndrome components, elevated blood sugar (OR=2.69, p<0.001), high blood pressure (OR=1.79, p=0.001) and low HDL-C (OR=1.27, p=0.02) had significant independent association with IHD EKG.

CONCLUSION

The metabolic syndrome, which occurs very frequently in the general population, has a significant association with nonfatal ischemic heart disease by electrocardiogram criteria.

Clinical Outcomes in Metabolic Syndrome

Metabolic syndrome is a clustering of cardiovascular risk factors. Its definition is the presence of any 3 of the following: obesity, hypertriglyceridemia, low high-density lipoprotein, hypertension, and impaired fasting glucose. The development of coronary artery disease is the most dreaded complication of this disease. In the United States, Mexican Americans and African American women are the most affected. Management of this syndrome includes physical exercise, weight loss, and effective drug treatment of dyslipidemia, high blood pressure, and impaired fasting blood glucose. Because of the increasing prevalence of obesity and diabetes, there is a rise in fatal and nonfatal cardiovascular events. With the development of effective antiplatelet medication and newer drug-eluting stents, percutaneous coronary intervention has become an effective revascularization strategy for those with coronary artery disease. Rates of stent restenosis and target-lesion revascularization have been reduced. Oral hypoglycemic drugs like thiazolidinediones improve insulin resistance and may have a favorable effect in those with metabolic syndrome. Diagnosis and appropriate management of metabolic syndrome are challenges as the presence of risk factors predates the coronary event.

Is the factor structure of the metabolic syndrome comparable between men and women and across three ethnic groups: the Miami Community Health Study

PURPOSE

The metabolic syndrome (MS) is conceived as a cluster of disorders that increase risk for coronary heart disease and type 2 diabetes. Studies examining its structure primarily have used an exploratory factor analytic technique, but yielded discrepant results. There also is a lack of research that investigates whether the clustering pattern is similar across sex and ethnic groups. This study uses confirmatory factor analysis to evaluate the factor structure of the MS and examines its similarity between men and women and across three ethnic groups (Caucasian, African, and Cuban Americans).

METHOD

A hierarchical four-factor model with an overarching MS factor uniting insulin resistance, obesity, lipid, and blood pressure factors was tested with 517 individuals from the Miami Community Health Study.

RESULTS

Findings show that the proposed structure was well supported (comparative fit index=0.97) and similar between men and women and across ethnic groups. The MS was represented strongly by insulin resistance, followed by obesity, lipid factors, and, to a lesser extent, a blood pressure factor.

CONCLUSIONS

This study provides empirical support for identifying and diagnosing the MS by its component factors in a diverse population.

Relation of childhood socioeconomic status and family environment to adult metabolic functioning in the CARDIA study

OBJECTIVE

Low SES and a conflict-ridden, neglectful, or harsh family environment in childhood have been linked to a high rate of physical health disorders in adulthood. The objective of the present investigation was to evaluate a model of the pathways that may help to explain these links and to relate them to metabolic functioning (MF) in the Coronary Artery Risk Development In Young Adults (CARDIA) dataset.

METHODS

Participants (n = 3225) in the year 15 assessment of CARDIA, age 33 to 45 years, completed measures of childhood socioeconomic status (SES), risky early family environment (RF), adult psychosocial functioning (PsyF, a latent factor measured by depression, hostility, positive and negative social contacts), and adult SES. Indicators of the latent factor MF were assessed, specifically, cholesterol, insulin, glucose, triglycerides, and waist circumference.

RESULTS

The overall prevalence of metabolic syndrome was 9.7%. Structural equation modeling indicated that childhood SES and RF are associated with MF via their association with PsyF (standardized path coefficients: childhood SES to RF -0.13, RF to PsyF 0.44, PsyF to MF 0.09, all p < .05), but also directly (coefficient from childhood SES to MF -0.12, p < .05), with good overall model fit. When this model was tested separately for race-sex subgroups, it fit best for white women, fit well for African-American women and white men, but did not fit well for African-American men.

CONCLUSIONS

These results indicate that childhood SES and early family environment contribute to metabolic functioning through pathways of depression, hostility, and poor quality of social contacts.

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.

The metabolic syndrome in older individuals: prevalence and prediction of cardiovascular events: the Cardiovascular Health Study

OBJECTIVE

The prevalence of the metabolic syndrome, a potent risk factor for cardiovascular diseases (CVDs), has not been adequately explored in older individuals. Moreover, two sets of criteria have been proposed for the definition of metabolic syndrome, one by the World Health Organization (WHO) and one by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII). We therefore investigated the prevalence of this syndrome in a subgroup of older participants from the Cardiovascular Health Study (CHS) who were free of CVD at baseline. We also compared the prognostic significance of the two definitions of the metabolic syndrome.

RESEARCH DESIGN AND METHODS

A total of 2,175 subjects from the CHS who were free of CVD at baseline and not taking antihypertensive or lipid-lowering medications were studied. Prevalence of the metabolic syndrome was assessed with both the WHO and ATPIII criteria. The incidence of coronary or cerebrovascular disease was ascertained during a median follow-up time of 4.1 years.

RESULTS

Prevalence of the metabolic syndrome was 28.1% by ATPIII criteria and 21.0% by WHO criteria. The two sets of criteria provided concordant classification for 80.6% of participants. Multivariate Cox propotional hazard models showed that the metabolic syndrome defined with the ATPIII criteria, but not with the WHO criteria, was an independent predictor of coronary or cerebrovascular events and was associated with a 38% increased risk (hazard ratio 1.38 [95% CI 1.06-1.79], P < 0.01).

CONCLUSIONS

Prevalence of the metabolic syndrome in older individuals is approximately 21-28% (depending on the definition used). The two sets of criteria have 80% concordance in classifying subjects. As defined by the ATPIII criteria, the metabolic syndrome yields independent prognostic information, even after adjusting for traditional cardiovascular risk factors and the individual domains of the metabolic syndrome.

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.

Factor analysis of metabolic syndrome among the middle-aged Bengalee Hindu men of Calcutta, India

BACKGROUND

The prevalence of coronary heart disease (CHD) is known to be very high in the people of Indian origin. In India, rates are rising and CHD has been predicted to rank first among the causes of death in the Indian population by 2015. The reasons for the increased susceptibility of Indians to CHD are yet to be understood completely. However, studies hinted that clustering of risk variables of the metabolic syndrome (MS) could be responsible for the increasing incidence of CHD in the Indians. Therefore, identification of the components of the MS could be one aspect in the way to curb the increasing incidence of CHD among the Asian Indians.

METHODS

Principal component factor analysis (PCFA) was undertaken to identify the components or factors of the metabolic syndrome (MS) among the middle-aged Bengalee Hindu men of Calcutta, India, and was compared with the findings from other studies. The present cross-sectional study consisted of 212 Bengalee Hindu men aged 30 years and above. Besides anthropometric measures, lipid profile, blood pressure, and fasting plasma glucose (FPG) were collected from each participant. Waist-hip ratio (WHR), trunk-extremity ratio (TER), and central fat skinfold ratio (CFSR) were computed accordingly. The lipid profile measures that were included were total cholesterol (TC), fasting triglyceride (FTG), high (HDL-C), low (LDL-C), and very low density lipoprotein cholesterol (VLDL-C).

RESULTS

Principal components factor analysis revealed four uncorrelated factors that cumulatively explained 72.37% of the observed variance of the metabolic syndrome by measured variables. These four factors could be identified as central obesity (factor 1), centralized subcutaneous fat (factor 2), lipid profile blood glucose (factor 3), and blood pressure (factor 4). The present factor analysis confirms the general finding from other factor analyses of the metabolic syndrome on different ethnic groups that have identified three to four factors. Furthermore, the first two factors, that is, central obesity and centralized subcutaneous fat cumulatively explained 47% of the observed variance of metabolic syndrome in this population.

CONCLUSION

Since more than one factor was identified for the metabolic syndrome and as no observed variable loaded on all four factors, therefore, more than one physiological mechanism could be accounted for the clustering of risk variables of the metabolic syndrome among the Bengalee Hindu men.

Identification of Women's Coronary Heart Disease and Risk Factors Prior to First Myocardial Infarction

PURPOSE

To understand when women's coronary heart disease (CHD) and CHD risk factors are recognized prior to first myocardial infarction (MI).

METHODS

Medical record review of the 10 years prior to incident MI among women with a confirmed incident MI between January 1, 1996, and December 31, 2001, to determine the timing of CHD diagnosis as well as assessment and treatment for risk factors.

RESULTS

One hundred fifty women had incident MIs during the study period. They made 8732 ambulatory visits and had 457 hospitalizations during the period of review (mean 9.1 years, range 6.2-10 years). Average age at incident MI was 74.7 years (SD 12.6, range 38.9-99.8 years). A CHD diagnosis prior to first MI was present in 52% (n = 78) of the women but was less common in those <70 years (p = 0.001). All but 3 women had one or more modifiable risk factors identified prior to their first MI. Treatment of recognized risk factors varied from 81% (antihypertension medications) to only 28% (drug therapy for abnormal lipid levels). Having a diagnosis of CHD was associated with an increased likelihood of having identified risk factors and receiving drug treatment for identified risk factors.

CONCLUSIONS

Women with undiagnosed CHD (48%) and those with unrecognized or untreated risk factors for CHD, especially younger women, represent missed opportunities for prevention of cardiac events.

Characteristics of US adults with the metabolic syndrome and therapeutic implications

BACKGROUND

The third Adult Treatment Panel (ATP III) of the National Cholesterol Education Program defines clinical criteria for diagnosis of the metabolic syndrome, which increases cardiovascular risk and is a target for therapy.

AIM

We analysed the third National Health and Nutrition Examination Survey (NHANES III; 1988-94) to determine how many US adults meet these criteria and are recommended for lipid-modifying drug therapy by ATP III.

METHODS

NHANES III data were used to estimate the number of individuals with the metabolic syndrome and the number recommended for treatment by ATP III, based on 1990 census data.

RESULTS

An estimated 36.3 million (23%) US adults have the metabolic syndrome. Of these, 84% met the criterion for obesity, 76% for blood pressure, 75% for HDL-C, 74% for triglycerides and 41% for glucose. Most (54%) are in the higher risk categories of ATP III, yet only 39% overall are recommended for drug therapy by ATP III cutpoints; of these, most will achieve LDL-C targets with reductions of 35-40%. Of the 15.3 million individuals with the metabolic syndrome and triglycerides > or = 2.26 mmol/l (200 mg/dl), non-HDL-C is above ATP III recommendations in 11.6 million.

CONCLUSIONS

Of the large number of Americans with the metabolic syndrome, ATP III recommends drug therapy for only a minority, because LDL-C typically is not substantially elevated. Instead, high triglycerides and low HDL-C are more common; clinical trial data are needed to determine whether optimal therapy should focus on reductions in LDL-C or on comprehensive improvements to the lipid profile.

The metabolic syndrome and coronary heart disease in older women: findings from the British Women's Heart and Health Study

AIMS

To compare two proposed definitions of the metabolic syndrome and to determine the clinical importance of the syndrome with respect to its association with coronary heart disease (CHD).

METHODS

Cross-sectional study of 3770 women aged 60-79 years randomly selected from 23 British towns.

RESULTS

The prevalence of the metabolic syndrome was high in this population and similar with both definitions: 28.2% (95% confidence interval 26.8, 29.7%) of the women had metabolic syndrome according to a modified version of the WHO definition, and 29.2% (27.7, 30.7%) had the ATP III-defined syndrome. There was reasonable agreement between the two definitions, with 79% of the participants being similarly classified by both definitions. The syndrome was associated with prevalent CHD, with the magnitude of the association with CHD being similar for both definitions. The odds ratio (95% confidence interval) for the age, smoking, physical activity, adult and childhood social class adjusted association of the WHO defined syndrome with prevalent CHD was 1.45 (1.19, 1.75) and for the ATP III-defined syndrome was 1.53 (1.27, 1.85). Insulin resistance alone, hypertension alone and dyslipidaemia alone were all associated with CHD, with the magnitudes of these associations being similar to those for the WHO and ATP III-defined syndrome with CHD.

CONCLUSIONS

The prevalence of the metabolic syndrome is high in older British women and is associated with CHD. There is reasonable agreement between a modified version of the WHO definition and the ATP III definition of the syndrome, and both are similarly associated with CHD. Single components of the syndrome are associated with CHD to a similar magnitude as the syndrome.

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 modifies the cardiovascular risk associated with angiographic coronary artery disease in women: a report from the Women's Ischemia Syndrome Evaluation

BACKGROUND

The metabolic syndrome, which is characterized by a constellation of fasting hyperglycemia, hypertriglyceridemia, low HDL cholesterol, hypertension, and/or abdominal obesity, is a risk factor for the development of coronary artery disease (CAD) and cardiovascular events. The interrelationship between metabolic status and CAD on cardiovascular risk in women is not known.

METHODS AND RESULTS

We evaluated interrelationships between angiographic CAD, the metabolic syndrome, and incident cardiovascular events among 755 women from the Women's Ischemia Syndrome Evaluation (WISE) study who were referred for coronary angiography to evaluate suspected myocardial ischemia; 25% of the cohort had the metabolic syndrome at study entry. Compared with women with normal metabolic status, women with the metabolic syndrome had a significantly lower 4-year survival rate (94.3% versus 97.8%, P=0.03) and event-free survival from major adverse cardiovascular events (death, nonfatal myocardial infarction, stroke, or congestive heart failure; 87.8% versus 93.5%, P=0.003). When the subjects were stratified by the presence or absence of angiographically significant CAD at study entry, in women with angiographically significant CAD, the metabolic syndrome resulted in significantly higher risk of cardiovascular events than in women with normal metabolic status (hazard ratio 4.93, 95% CI 1.02 to 23.76; P=0.05), whereas it did not result in increased 4-year cardiovascular risk in women without angiographically significant CAD (hazard ratio 1.41, 95% CI 0.32 to 6.32; P=0.65).

CONCLUSIONS

These data suggest that in women with suspected myocardial ischemia, the metabolic syndrome modifies the cardiovascular risk associated with angiographic CAD. Specifically, the metabolic syndrome was found to be a predictor of 4-year cardiovascular risk only when associated with significant angiographic CAD.

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.

The metabolic syndrome, circulating oxidized LDL, and risk of myocardial infarction in well-functioning elderly people in the health, aging, and body composition cohort

The object of this study was to establish the association between the metabolic syndrome and oxidized LDL (oxLDL) and to determine the risk for coronary heart disease (CHD) in relation to the metabolic syndrome and levels of oxLDL. OxLDL was measured in plasma from 3,033 elderly participants in the Health, Aging, and Body Composition study. The metabolic syndrome was defined according to criteria established in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. We observed that the metabolic syndrome was associated with higher levels of oxLDL due to a higher fraction of oxLDL, not to higher levels of LDL cholesterol. Individuals with the metabolic syndrome had twice the odds of having high oxLDL (>1.90 mg/dl) compared with those not having the metabolic syndrome, after adjusting for age, sex, ethnicity, smoking status, and LDL cholesterol. Among those participants who had the metabolic syndrome at study entry, incidence rates of future CHD events were 1.6-fold higher, after adjusting for age, sex, ethnicity, and smoking status. OxLDL was not an independent predictor of total CHD risk. However, those with high oxLDL showed a greater disposition to myocardial infarction (relative risk 2.25, 95% confidence interval 1.22-4.15). We concluded that the metabolic syndrome, a risk factor for CHD, is associated with higher levels of circulating oxLDL that are associated with a greater disposition to atherothrombotic coronary disease.

Current concepts of cardiovascular diseases in diabetes mellitus

The incidence of diabetes has reached epidemic proportions across the world. In patients with diabetes, there is a two to four times increased risk of developing coronary artery disease (CAD). Diabetes seems to eliminate the protective benefits of hormones in women against CAD. Patients with type II diabetes also have hypertension, dyslipidemia, obesity, endothelial dysfunction and prothrombotic factors, called 'the metabolic syndrome'. Not only the incidence of CAD is higher in diabetes, the mortality of the diabetic patients after a cardiac event is significantly increased as compared to non-diabetics, including sudden death. Although in the past 35 years there has been a decline in the rate of death due to CAD in the general population, this has not been seen among patients with diabetes. Primary prevention can play an important role in decreasing the incidence of CAD in diabetic patients. Aggressive treatment of hyperlipidemia and hypertension is essential. Recent knowledge about the protective effects of aspirin, statins, angiotension converting enzyme inhibitors, and glitazones in the diabetic patients, if used appropriately will go a long way in primary and secondary prevention of CAD in patients with diabetes.

The metabolic syndrome, diabetes, and subclinical atherosclerosis assessed by coronary calcium

OBJECTIVES

We compared the prevalence and extent of coronary artery calcium (CAC) among persons with the metabolic syndrome (MetS), diabetes, and neither condition.

BACKGROUND

The prevalence and extent of CAC has not been compared among those with MetS, diabetes, or neither condition.

METHODS

Of 1,823 persons (36% female) age 20 to 79 years who had screening for CAC by computed tomography, 279 had MetS, 150 had diabetes, and the remainder (n = 1,394) had neither condition. Metabolic syndrome was defined with >or=3 of the following: body mass index >or=30 kg/m(2); high-density lipoprotein cholesterol <40 mg/dl if male or <50 mg/dl if female; triglycerides >or=150 mg/dl; blood pressure >or=130/85 mm Hg or on treatment; or fasting glucose 110 to 125 mg/dl. The prevalence and odds of any and significant (>or=75th percentile) CAC among these groups and by number of MetS risk factors were determined.

RESULTS

Those with neither MetS nor diabetes, MetS, or diabetes had a prevalence of CAC of 53.5%, 58.8%, and 75.3% (p < 0.001), respectively, among men and 37.6%, 50.8%, and 52.6% (p < 0.001), respectively, among women. Coronary artery calcium increased by the number (0 to 5) of MetS risk factors (from 34.0% to 58.3%) (p < 0.001). Forty-one percent of subjects with MetS had either a >20% 10-year risk of CHD or CAC >or=75th percentile for age and gender. Risk factor-adjusted odds for the presence of CAC were 1.40 (95% confidence interval [CI] 1.05 to 1.87) among those with MetS and 1.67 (95% CI 1.12 to 2.50) among those with diabetes, versus those with neither condition.

CONCLUSIONS

Those with MetS or diabetes have an increased likelihood of CAC compared with those having neither condition.

Depressive symptoms and metabolic risk in adult male twins enrolled in the National Heart, Lung, and Blood Institute twin study

OBJECTIVE

To determine the extent to which depressive symptoms are associated with metabolic risk factors and whether genetic or environmental factors account for this association.

METHOD

Twin structural equation modeling was employed to estimate genetic and environmental contributions to the covariation of depressive symptoms, as indexed by the Centers for Epidemiological Studies-Depression Scale, and common variance among blood pressure, body mass index, waist-to-hip ratio, and serum triglycerides and glucose among 87 monozygotic and 86 dizygotic male twin pairs who participated in the NHLBI twin study.

RESULTS

Depressive symptoms were associated with individual components of the metabolic syndrome and common variance among the risk factors. Twin structural equation modeling indicated that the associations were attributable to environmental (nongenetic) factors.

CONCLUSIONS

These results support the hypothesis that depressive symptoms may increase risk for a pattern of physiological risk consistent with the metabolic syndrome.

Factor analysis of the metabolic syndrome among elderly Koreans--the South-west Seoul Study

AIMS

To examine the relationship between the components of the metabolic syndrome and to explore whether insulin resistance unifies the clustering of components of the metabolic syndrome among urban elderly Koreans using exploratory factor analysis.

METHODS

We included 1314 non-diabetic subjects over the age of 60 years, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. Factor analysis was carried out using the principle components analysis with Varimax orthogonal rotation of the components of the metabolic syndrome.

RESULTS

We found four major factors of cardiovascular disease risk variables in our study subjects. Impaired glucose tolerance, dyslipidaemia, hypertension and obesity aggregated as the major domain. Obesity and dyslipidaemia variables were closely related and loaded on the same factor. However, hypertension was not linked closely with other factors of the metabolic syndrome.

CONCLUSIONS

Insulin resistance is not the only contributor to the metabolic syndrome among urban elderly Koreans. Although the components of the metabolic syndrome were closely related, the finding of more than one factor suggests that more than one pathophysiological mechanism underlies full expression of the metabolic syndrome among elderly Koreans.

Metabolic syndrome: major impact on coronary risk in a population with low cholesterol levels--a prospective and cross-sectional evaluation

The prevalence and the excess coronary heart disease (CHD) risk of the metabolic syndrome (MS) and its components were investigated in the Turkish Adult Risk Factor Study in both a prospective and a cross-sectional manner. In a population sample, representative of Turkish adults who have low levels of high- and low-density lipoprotein-cholesterol (HDL-C and LDL-C), MS was identified in conformity with the definition used in the recent NCEP guidelines. Prospective analysis was based on 2398 men and women (mean age at baseline 49.1+/-13 years) who had a baseline examination in 1997/98 and were followed-up for a mean of 3 years. CHD was diagnosed based on clinical findings and Minnesota coding of resting electrocardiograms. Fatal and nonfatal CHD developed in 126 subjects. 27% of men and 38.6% of women were found to have MS at baseline examination. When adjusted for age, MS was an independent predictor of subsequent overall fatal and nonfatal CHD in both genders, displaying an RR of 1.71. At the final cross-sectional evaluation, coronary risk associated with MS in men was primarily accounted for by standard MS components (largely inherent in glucose intolerance, hypertension and in a surrogate of small, dense LDL particles), in addition to a minor independent contribution by C-reactive protein (CRP). In women with MS, a substantial residual coronary risk remained after controlling for five components, which was partly accounted for by levels of LDL-C and CRP. It was estimated that MS was the culprit in just over half the cases of CHD in Turkey.

CONCLUSION

MS was the major determinant of CHD risk in a population having generally low levels of HDL-C and LDL-C in middle-aged and elderly adults, extending to three out of every eight adults, and imposing an overall excess CHD risk of approximately 70%. In contrast to men, a substantial residual coronary risk is retained in Turkish women after controlling for five MS components.

Components of the "metabolic syndrome" and incidence of type 2 diabetes

The combination of insulin resistance, dyslipidemia, hypertension, and obesity has been described as a "metabolic syndrome" that is a strong determinant of type 2 diabetes. Factor analysis was used to identify components of this syndrome in 1,918 Pima Indians. Prospective analyses were conducted to evaluate associations of identified factors with incidence of diabetes. Factor analysis identified 4 factors that accounted for 79% of the variance in the original 10 variables. Each of these factors reflected a proposed component of the metabolic syndrome: insulinemia, body size, blood pressure, and lipid metabolism. Among 890 originally nondiabetic participants with follow-up data, 144 developed diabetes in a median follow-up of 4.1 years. The insulinemia factor was strongly associated with diabetes incidence (incidence rate ratio [IRR] for a 1-SD difference in factor scores = 1.81, P < 0.01). The body size and lipids factors also significantly predicted diabetes (IRR 1.52 and 1.37, respectively, P < 0.01 for both), whereas the blood pressure factor did not (IRR 1.11, P = 0.20). Identification of four unique factors with different associations with incidence of diabetes suggests that the correlations among these variables reflect distinct metabolic processes, about which substantial information may be lost in the attempt to combine them into a single entity.

Prevalence of insulin resistance syndrome in southwestern France and its relationship with inflammatory and hemostatic markers

OBJECTIVE

To assess the prevalence and relationships of insulin resistance syndrome (IRS) with inflammatory and hemostatic markers in a representative sample of the population of Southwestern France aged 35-64 years.

RESEARCH DESIGN AND METHODS

In this cross-sectional study, data were collected from 597 men and 556 women and were assessed regarding BMI, blood pressure, total and HDL cholesterol levels, triglyceride level, glucose level, plasma insulin level, white blood cell count, fibrinogen level, factor VII level, von Willebrand factor, C-reactive protein level, soluble intercellular adhesion molecule, soluble vascular cell adhesion molecule-1, and soluble CD(14). Insulin resistance was defined by homeostasis model assessment > or =3.8.

RESULTS

Prevalence of IRS was higher in men than in women (23 vs. 12%, respectively; P < 0.001) and increased with age in both sexes (9, 24, and 34% for age groups 35-44, 45-54, and 55-64 years, respectively, for men and 4, 10, and 21% for women). After adjusting for age, alcohol consumption, tobacco smoking, and also for menopause in women, subjects (men and women) with IRS had significantly higher white blood cell count, factor VII levels, coagulating factor VII levels, and C-reactive protein levels than the other subjects. In men, further increases in soluble intercellular adhesion molecule and soluble vascular cell adhesion molecule-1 were noted, whereas in women, the differences were borderline significant. Conversely, no differences were found in fibrinogen, von Willebrand factor, and soluble CD(14) in both sexes.

CONCLUSIONS

IRS is relatively common in residents of Southwestern France and is related to a deleterious increase in hemostatic and inflammatory parameters.