Insulin resistance syndrome predicts coronary heart disease events in elderly type 2 diabetic men

Associations of Insulin Resistance and High-Sensitivity C-Reactive Protein with Metabolic Abnormalities in Korean Patients with Type 2 Diabetes Mellitus: A Preliminary Study

We conducted this single-center, retrospective, cohort study to examine whether insulin resistance (IR) and high-sensitivity C-reactive protein (hsCRP) have a relationship with metabolic abnormalities in patients with type 2 diabetes mellitus (T2DM). In a total of 3758 patients (n = 3758) with T2DM, we analyzed medical records and thereby evaluated their baseline characteristics such as age, sex, duration of T2DM, systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference, body mass index (BMI), visceral fat thickness (VFT), fasting plasma insulin levels, C-peptide levels, glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), homeostatic model assessment of insulin resistance (HOMA-IR), homeostatic model assessment of β-cell function (HOMA-β), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), albuminuria, intima-media thickness (IMT) and hsCRP. The patients were stratified according to the tertile of the K index of the insulin tolerance test (KITT) or hsCRP. Thus, they were divided into the lowest (≥2.37), middle (1.54-2.36) and highest tertile (0-1.53) of KITT and the lowest (0.00-0.49), middle (0.50-1.21) and highest tertile (≥1.22) of hsCRP. Moreover, associations of KITT and hsCRP with metabolic abnormalities, such as steatotic liver disease (SLD), metabolic syndrome (MetS), albuminuria, diabetic retinopathy and carotid atherosclerosis, were also analyzed. There was a significant positive correlation between the prevalence of SLD, MetS, albuminuria and diabetic retinopathy and KITT (p < 0.001). Moreover, there was a significant positive association between the prevalence of SLD, MetS and albuminuria and hsCRP (p < 0.001). In conclusion, our results indicate that clinicians should consider the relationships of IR and hsCRP with metabolic abnormalities in the management of patients with T2DM. However, further large-scale, prospective, multi-center studies are warranted to confirm our results.

Precision subclassification of type 2 diabetes: a systematic review

BACKGROUND

Heterogeneity in type 2 diabetes presentation and progression suggests that precision medicine interventions could improve clinical outcomes. We undertook a systematic review to determine whether strategies to subclassify type 2 diabetes were associated with high quality evidence, reproducible results and improved outcomes for patients.

METHODS

We searched PubMed and Embase for publications that used 'simple subclassification' approaches using simple categorisation of clinical characteristics, or 'complex subclassification' approaches which used machine learning or 'omics approaches in people with established type 2 diabetes. We excluded other diabetes subtypes and those predicting incident type 2 diabetes. We assessed quality, reproducibility and clinical relevance of extracted full-text articles and qualitatively synthesised a summary of subclassification approaches.

RESULTS

Here we show data from 51 studies that demonstrate many simple stratification approaches, but none have been replicated and many are not associated with meaningful clinical outcomes. Complex stratification was reviewed in 62 studies and produced reproducible subtypes of type 2 diabetes that are associated with outcomes. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into clinically meaningful subtypes.

CONCLUSION

Critical next steps toward clinical implementation are to test whether subtypes exist in more diverse ancestries and whether tailoring interventions to subtypes will improve outcomes.

Systematic review of precision subclassification of type 2 diabetes

Heterogeneity in type 2 diabetes presentation, progression and treatment has the potential for precision medicine interventions that can enhance care and outcomes for affected individuals. We undertook a systematic review to ascertain whether strategies to subclassify type 2 diabetes are associated with improved clinical outcomes, show reproducibility and have high quality evidence. We reviewed publications that deployed 'simple subclassification' using clinical features, biomarkers, imaging or other routinely available parameters or 'complex subclassification' approaches that used machine learning and/or genomic data. We found that simple stratification approaches, for example, stratification based on age, body mass index or lipid profiles, had been widely used, but no strategy had been replicated and many lacked association with meaningful outcomes. Complex stratification using clustering of simple clinical data with and without genetic data did show reproducible subtypes of diabetes that had been associated with outcomes such as cardiovascular disease and/or mortality. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into meaningful groups. More studies are needed to test these subclassifications in more diverse ancestries and prove that they are amenable to interventions.

InsuTAG: A novel physiologically relevant predictor for insulin resistance and metabolic syndrome

The aim of this study was to investigate whether a novel physiologically relevant marker, InsuTAG (fasting insulin × fasting triglycerides) can predict insulin resistance (IR) and metabolic syndrome (MetS). Data of 618 participants from the Retirement Health and Lifestyle Study (RHLS) were evaluated for the current study. IR was defined by homeostatic model assessment (HOMA-IR) scores. Pearson correlations were used to examine the associations of InsuTAG with HOMA-IR and other markers. Predictions of IR from InsuTAG were evaluated using multiple regression models. Receiver operating characteristic curves (ROC) were constructed to measure the sensitivity and specificity of InsuTAG values and to determine the optimum cut-off point for prediction of IR. InsuTAG was positively correlated with HOMA-IR (r = 0.86; p < 0.0001). InsuTAG is a strong predictor of IR accounting for 65.0% of the variation in HOMA-IR values after adjusting for potential confounders. Areas under the ROC curve showed that InsuTAG (0.93) has higher value than other known lipid markers for predicting IR, with a sensitivity and specificity of 84.15% and 86.88%. Prevalence of MetS was significantly (p < 0.0001) higher in subjects with InsuTAG values greater than optimal cut-off value of 11.2. Thus, InsuTAG appears to be a potential feasible marker of IR and metabolic syndrome.

Inflammatory Biomarkers of Cardiometabolic Risk in Obese Egyptian Type 2 Diabetics

Inflammatory biomarkers provide a minimally invasive means for early detection and specific treatment of metabolic syndrome and related disorders. The objective of this work was to search for inflammatory biomarkers of cardiometabolic risk in obese type 2 diabetics. The study was performed on 165 persons attending the medical outpatient clinic of Ismailia General Hospital. Their mean age was (50.69 ± 10.15) years. They were divided into three groups. The control group was composed of 55 non-obese, non-diabetic healthy volunteers, 32 males and 23 females. Two study groups were included in this study: group 2 was composed of 55 obese, non-diabetic subjects, 25 males and 30 females matched for age and gender. All patients including the control were subjected to clinical history taking, a clinical examination for the measurement of body mass index (BMI). Investigations were carried out for fasting blood glucose, fasting serum insulin, insulin resistance (IR), the lipid profile, lipoprotein band lipoprotein phospholipase A2, and non-high-density lipoprotein cholesterol (non-HDL-C). Urea, albumin and creatinine analysis and liver function tests were performed, and a complete blood count (CBC) was taken. Hemoglobin A1C (HbA1C), serum high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were tested. There were statistically significant differences among the studied groups in terms of total cholesterol, non-HDL-C, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), lipoprotein-associated phospholipase A2 and apolipoprotein B. The inflammatory biomarkers hs-CRP, IL-6 and TNF-α were significantly statistically increased in the study groups by (1.62 ± 0.99, 2.32 ± 1.11), (1.73 ± 1.14, 2.53 ± 1.34), and (1.87 ± 1.09, 2.17 ± 0.89) respectively, where p < 0.01. Significant positive correlation was found between Homeostatic Model Assessment (HOMA)-IR, hs-CRP and IL-6. There was a significant positive correlation between non-HDL and hs-CRP, IL-6 and TNF-α and triglycerides and hs-CRP. In conclusion, in this study, CRP, IL-6, and TNF-α were significantly elevated in obese Egyptian type 2 diabetics and were positively correlated with insulin resistance, non-HDL and triglycerides. These inflammatory biomarkers could help in the premature identification of obese type 2 diabetic patients at high cardiometabolic risk. Additionally, these biomarkers are critical for providing prognostics and the validity of future potential anti-inflammatory therapeutic modalities.

Insulin resistance and cardiovascular disease

Insulin resistance is characterised by a decreased rate of insulin-mediated glucose uptake and is associated with adverse changes in cardiovascular risk factors, such as high triglyceride levels, low levels of high-density lipoprotein cholesterol, raised blood pressure, obesity and increased levels of plasminogen activator inhibitor 1. The term `insulin resistance syndrome' (IRS) is used to describe the complex of factors associated with insulin resistance that is found in patients both with and without type 2 diabetes. Although the presence of insulin resistance syndrome is generally considered to be a risk factor for cardiovascular disease, there is a lack of definitive evidence for a causal link. Recently, however, a statistical method known as factor analysis has been applied to the cluster of cardiovascular risk factors associated with IRS. This has been able to show that the `insulin resistance factor' (high plasma insulin and glucose levels, body mass index, waist-to-hip ratio and triglyceride levels) predicted coronary heart disease events in elderly non-diabetic men as well as in patients with type 2 diabetes. Therefore, treatment of insulin resistance whether by pharmacological (eg. thiazolidinediones) or nonpharmacological means has the potential to offer both improvements in glycaemic control and in cardiovascular events.

Insulin Resistance as a Predictor of the Late Catch-up Phenomenon After Drug-Eluting Stent Implantation

BACKGROUND

Percutaneous coronary intervention (PCI) is an effective treatment for patients with ischemic heart disease. In particular, restenosis is suppressed after drug-eluting stent (DES) implantation. However, several problems remain. Previously, we reported neointimal proliferation after DES implantation, which was associated with insulin resistance (IR). The aim of the present study was to clarify whether IR is associated with mortality and major adverse cardiac and cerebrovascular events (MACCE) after 1st-generation DES implantation.

METHODS AND RESULTS

We researched the clinical records of 109 patients who had undergone elective PCI and DES implantation between May 2007 and December 2010. We segregated these patients according to the value of the homeostasis model assessment of IR (HOMA-IR) into Group P (n=63; HOMA-IR ≥2.5, positive) and Group N (n=46; HOMA-IR <2.5, negative), and examined the relationship between HOMA-IR and MACCE. The observation period was 7.4±1.6 years. There were no differences between the 2 groups in the occurrence of all-cause death, cardiac death, restenosis, myocardial infarction, stroke, heart failure, or stent thrombosis. However, the late catch-up phenomenon was significantly more common in Group P than in Group N (12.7% vs. 2.2% P=0.048).

CONCLUSIONS

IR is a useful predictor of the late catch-up phenomenon after DES implantation, and improvement of IR may help to prevent the phenomenon. (Circ J 2016; 80: 657-662).

Is Insulin Resistance a Feature of or a Primary Risk Factor for Cardiovascular Disease?

The two major pathophysiological abnormalities in type 2 diabetes are insulin resistance and impaired insulin secretion. Insulin resistance is a general term meaning that insulin does not exert its normal effects in insulin-sensitive target tissues, such as skeletal muscle, adipose tissue, and liver, the major target tissues for insulin action in glucose metabolism. Insulin resistance (IR) promotes cardiovascular disease via multiple mechanisms, including changes in classic cardiovascular risk factors and downregulation of the insulin signaling pathways in different tissues. This review presents evidence for the association of insulin resistance with cardiovascular disease from clinical and population-based studies. The causality of the association of insulin resistance with cardiovascular disease is discussed on the basis of recent findings from the Mendelian randomization studies.

Association of IL-6 polymorphism -174G/C and metabolic syndrome in hypertensive patients

Introduction. Visceral obesity, the central core of metabolic syndrome (MetS), is conceived as the pathogenic basis of an increased cardiovascular burden and is related with changes in cytokines. We investigated whether IL-6-174G/C gene polymorphism is associated with MetS prevalence in hypertensive patients. Method. A population of hypertensive patients was included and stratified by the presence of MetS according to IDF criteria and evaluated by Framingham risk score. The IL-6-174G/C genotyping was performed by polymerase chain reaction and the prevalence of MetS was compared between “C” carrier and “non-C” carrier groups. Results. From an original sample of 664 patients, 612 (34.2% men, age 57.3 ± 10.1, 30.4% diabetics) were included. MetS was diagnosed in 51.3% of total population and “C” carriers demonstrated high prevalence of MetS (P < 0.05) and each of its components. On binary logistic regression, it was observed that the IL-6 polymorphism was independently associated with occurrence of MetS, even after adjusting for covariates (OR 1.13–2.37, 95% CI, P < 0.05). Conclusion. The C allele at the -174 locus of IL-6 gene is independently associated with the occurrence of metabolic syndrome, emphasizing the importance of inflammatory genetic background in the pathogenesis of visceral obesity and related cardiovascular burden.

Markers of tissue-specific insulin resistance predict the worsening of hyperglycemia, incident type 2 diabetes and cardiovascular disease

We investigated the ability of surrogate markers of tissue-specific insulin resistance (IR, Matsuda IR, Adipocyte IR, Liver IR) to predict deterioration of hyperglycemia, incident type 2 diabetes and cardiovascular events in the Metabolic Syndrome in Men (METSIM) Study. The METSIM Study includes 10,197 Finnish men, aged 45-73 years, and examined in 2005-2010. A total of 558 of 8,749 non-diabetic participants at baseline were diagnosed with new-onset diabetes and 239 with a new CVD event during a 5.9-year follow-up of this cohort (2010-2013). Compared to fasting plasma insulin level, Matsuda IR (IR in skeletal muscle) and Adipocyte IR were significantly better predictors of 2-hour plasma glucose and glucose area under the curve after adjustment for confounding factors. Liver IR was the strongest predictor of both incident type 2 diabetes (hazard ratio = 1.83, 95% confidence interval: 1.68-1.98) and cardiovascular events (hazard ratio = 1.31, 95% confidence interval: 1.15-1.48). Hazard ratios for fasting insulin were 1.37 (95% confidence interval: 1.32-1.42) and 1.11 (95% confidence interval: 1.00-1.24), respectively. Tissue-specific markers of IR, Matsuda IR and Adipocyte IR, were superior to fasting plasma insulin level in predicting worsening of hyperglycemia, and Liver IR was superior to fasting insulin level in predicting incident type 2 diabetes and cardiovascular events.

Prevalence and anthropometric risk of metabolic syndrome in taiwanese adolescents

Background. To evaluate the prevalence and the importance of anthropometric indexes on metabolic syndrome (MetS) among young adolescents in Taiwan. Methods. We conducted a cross sectional survey to obtain a representative sampling among Taipei adolescents in 2003, totally enrolled of 1,562 adolescents (764 boys and 798 girls) from age 11 to 15. We used modified NCEP-ATP III criteria to diagnose metabolic syndrome in young adolescents including: blood pressure ≧90th percentile, fasting glucose ≧90th, TG ≧ 90th, HDL-C ≦ 10th, and BMI or WC ≧ 90th according to age and gender specific recommendations. Results. The overall prevalence of MetS was 4.8% for boys and 3.9% for girls. BMI and WC were significantly associated with MetS for both boys and girls, even after adjusting for age, cigarette smoking, alcohol drinking and pubertal status. However, after further adjusting for BMI or WC, WC for boys (OR = 1.14, 95% CI = 1.05–1.24) and BMI for girls (OR = 1.36, 95% CI = 1.13–1.64) were significantly associated with MetS. Conclusions. Adolescents with abnormal BMI or waist circumference had 10 to 20 times higher odds of MetS when compared to normal subjects. Obesity, either general or central adiposity, may play an important role in the development of MetS among adolescents.

A systematic evaluation of the insulin resistance syndrome as an independent risk factor for cardiovascular disease mortality and derivation of a clinical index

Insulin resistance-related risk factor clustering (the insulin resistance syndrome or IRS) may be a cardiovascular disease (CVD) risk factor, but a convincing demonstration of this requires a rigorously derived reference measure and a systematic evaluation of measures and indices that derive from that measure. Using established IRS characteristics, factor analysis in 832 white men, generally healthy at baseline, generated a priori an IRS reference measure. An IRS diagnostic was chosen by evaluating CVD mortality risk in percentiles of the reference measure. An IRS clinical index was derived by (1) identification of readily measured, independent predictors of the IRS reference measure by multiple linear regression; (2) assignment to each predictor of a cut point optimal for discrimination of participants diagnosed with IRS; and (3) selection of a combination of the dichotomized predictors that further optimized IRS discrimination. The reference IRS diagnostic was defined by the top 16.7% of the IRS reference measure and predicted CVD mortality in Cox proportional hazards modeling (hazard ratio, 2.7; 95% confidence interval, 1.5-5.2; P = .002). An optimized IRS index was defined by triglycerides of at least 1.6 mmol/L and uric acid of at least 400 μmol/L plus any one of fasting plasma glucose of at least 5.4 mmol/L, diastolic blood pressure of at least 90 mm Hg, or body mass index of at least 27.0 kg/m(2) and predicted CVD mortality (hazard ratio, 2.14 [1.08-4.24]; P = .02). Prediction was independent of hypertension, hypercholesterolemia, and smoking. Conventionally derived glucoregulatory insulin resistance and metabolic syndrome were not predictive. The IRS is an independent risk factor for CVD mortality; and an effective, clinically usable index can be derived from readily measured variables.

The effects of lipoic acid and α-tocopherol supplementation on the lipid profile and insulin sensitivity of patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial

Antioxidants probably play an important role in the etiology of type 2 diabetes (DM2). This study evaluated the effects of supplementation with lipoic acid (LA) and α-tocopherol on the lipid profile and insulin sensitivity of DM2 patients. A randomized, double-blind, placebo-controlled trial involving 102 DM2 patients divided into four groups to receive daily supplementation for 4 months with: 600 mg LA (n = 26); 800 mg α-tocopherol (n = 25); 800 mg α-tocopherol + 600 mg LA (n = 25); placebo (n = 26). Plasma α-tocopherol, lipid profile, glucose, insulin, and the HOMA index were determined before and after supplementation. Differences within and between groups were compared by ANOVA using Bonferroni correction. Student's t-test was used to compare means of two independent variables. The vitamin E/total cholesterol ratio improved significantly in patients supplemented with vitamin E+LA and vitamin E alone (p ≤ 0.001). There were improvements of the lipid fractions in the groups receiving LA and vitamin E alone or in combination, and on the HOMA index in the LA group, but not significant. The results suggest that LA and vitamin E supplementation alone or in combination did not affect the lipid profile or insulin sensitivity of DM2 patients.

Serum levels of FGF-21 are increased in coronary heart disease patients and are independently associated with adverse lipid profile

Background

Fibroblast growth factor 21 (FGF-21) is a metabolic regulator with multiple beneficial effects on glucose homeostasis and lipid metabolism in animal models. The relationship between plasma levels of FGF-21 and coronary heart disease (CHD) in unknown.

Methodology/Principal Findings

This study aimed to investigate the correlation of serum FGF-21 levels and lipid metabolism in the patients with coronary heart disease. We performed a logistic regression analysis of the relation between serum levels of FGF-21 and CHD patients with and without diabetes and hypertension. This study was conducted in the Departments of Endocrinology and Cardiovascular Diseases at two University Hospitals. Participants consisted of one hundred and thirty-five patients who have been diagnosed to have CHD and sixty-one control subjects. Serum FGF-21 level and levels of fasting blood glucose; triglyceride; apolipoprotein B100; HOMA-IR; insulin; total cholesterol; HDL-cholesterol; LDL-cholesterol; and C-reactive protein were measured. We found that median serum FGF-21 levels were significantly higher in CHD than that of control subjects (P<0.0001). Serum FGF-21 levels in CHD patients with diabetes, hypertension, or both were higher than that of patients without these comorbidities. Serum FGF-21 levels correlated positively with triglycerides, fasting blood glucose, apolipoprotein B100, insulin and HOMA-IR but negatively with HDL-C and apolipoprotein A1 after adjusting for BMI, diabetes and hypertension. Logistic regression analysis demonstrated that FGF-21 showed an independent association with triglyceride and apolipoprotein A1.

Conclusions/Significance

High levels of FGF-21 are associated with adverse lipid profiles in CHD patients. The paradoxical increase of serum FGF-21 in CHD patients may indicate a compensatory response or resistance to FGF-21.

Interrelationship between exposure to PCDD/Fs and hypertension in metabolic syndrome in Taiwanese living near a highly contaminated area

Metabolic syndrome (MetS) consists of a constellation of metabolic abnormalities that confer increased risk of cardiovascular disease. There is a positive correlation between exposure to persistent organic pollutants and MetS. We examine the association between PCDD/Fs and MetS components in 1490 non-diabetic persons living near a highly dioxin-contaminated area. We used factor analysis, with a set of core variables considered central features of MetS and PCDD/Fs, to group similar risk factors. Serum PCDD/Fs were positively and significantly correlated with the number of MetS components. Four risk factors-lipidemia, blood pressure, body size, and glycemia-accounted for 72.6% of the variance in the 10 core factors, and PCDD/Fs were linked to MetS through shared correlations with high blood pressure. After adjusting for confounding factors, we found that diastolic blood pressure (β=0.018; p=0.006), glucose (β=0.013; p=0.046), and waist circumference (β=0.721; p=0.042) significantly increased with increasing serum PCDD/F levels. We found significant trends for associations between metabolic syndrome and serum low-chlorinated PCDD/Fs. The highest quintiles of 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF and 2,3,7,8-TCDD had the top three adjusted ORs (95% CI) of 3.5 (1.9-6.3), 2.9 (1.7-4.9) and 2.8 (1.6-4.9), respectively. We also found a slight monotonic relationship between serum PCDD/Fs and the prevalence of MetS, especially when the serum dioxin level was higher than 25.4pg WHO(98)-TEQ(DF)g(-1) lipid (the fourth Quintile). We hypothesize that high-dose exposure to PCDD/Fs is a blood pressure-related factor that raises MetS risk.

Diagnostic criteria for metabolic syndrome: a comparative analysis in an unselected sample of adult male population

This analysis compares the performance of 7 different diagnostic criteria of metabolic syndrome (MS) with regard to the prevalence of the syndrome, the characteristics of subjects with a positive diagnosis, and the ability to correctly identify individuals at high calculated cardiovascular (CV) risk or with signs of systemic inflammation or early organ damage. The diagnostic criteria proposed by the World Health Organization (1998); European Group for the Study of Insulin Resistance (EGIR) (1999); Adult Treatment Panel III (ATP III) (2001); American Association of Clinical Endocrinologists (AACE) (2003); ATP III (2004); International Diabetes Federation (IDF) (2005); and American Heart Association/National Heart, Lung, and Blood Institute (2005) were applied to the population of 933 men aged 59.5 years (range, 33-81 years) attending the 2002-2004 examination of the Olivetti Heart Study. Standardized measurements were available for body mass index, waist circumference, blood pressure, fasting serum total and high-density lipoprotein cholesterol, triglyceride, glucose, insulin, high-sensitivity C-reactive protein, and microalbuminuria. Insulin resistance was estimated by the homeostasis model assessment index; and CV risk, by the Prospective Cardiovascular Munster algorithm. The MS prevalence ranged from 8.6% (AACE) to 44.5% (IDF). Among MS-positive subjects, insulin resistance ranged from 94.8% (EGIR) to 49.2% (IDF), whereas type 2 diabetes mellitus (excluded by EGIR and AACE criteria) rated 59.9% by World Health Organization and 22% to 24% by ATP III, IDF, or American Heart Association/National Heart, Lung, and Blood Institute. By most criteria, MS-positive subjects had greater calculated CV risk than MS-negative subjects; but in general, the ability to correctly identify individuals at high CV risk was dampened by limited sensitivity (maximum 60%). Lowering the cutoff for abdominal adiposity (waist circumference <94 cm by IDF) did not improve the performance in this regard but identified a larger number of individuals with microalbuminuria (56%) and elevated C-reactive protein (53%).

The metabolic syndrome: how to approach differing definitions

Metabolic syndrome (MetS) is a useful tool for identifying individuals at risk for type 2 diabetes and coronary heart disease (CHD). The syndrome has confused practitioners because of differences in definition, though definitions have come closer together over the years; however, the principles are clear: persons who have glucose intolerance, blood pressure elevation, dyslipidemia, and central obesity are at increased risk for type 2 diabetes mellitus and CHD. Identifying the presence in a given patient of the items in the cluster serves as a warning that risk of disease is increased, and should stimulate the practitioner to institute preventive measures early, with lifestyle change initially, and pharmacotherapy subsequently, as indicated by any continued risk factor presence.

Metabolic characterization of nondiabetic severely obese patients undergoing Roux-en-Y gastric bypass: preoperative classification predicts the effects of gastric bypass on insulin-glucose homeostasis

INTRODUCTION

Obese individuals may have normal insulin-glucose homeostasis, insulin resistance, or diabetes mellitus. Whereas gastric bypass cures insulin resistance and diabetes mellitus, its effects on normal physiology have not been described. We studied insulin resistance and beta-cell function for patients undergoing gastric bypass.

METHODS

One hundred thirty-eight patients undergoing gastric bypass had fasting insulin and glucose levels drawn on days 0, 12, 40, 180, and 365. Thirty-one (22%) patients with diabetes mellitus were excluded from this analysis. Homeostatic model of assessment was used to estimate insulin resistance, insulin sensitivity, and beta-cell function. Based on this model, patients were categorized as high insulin resistance if their insulin resistance was >2.3.

RESULTS

Body mass index did not correlate with insulin resistance. Forty-seven (34%) patients were categorized as high insulin resistance. Correction of insulin resistance for this group occurred by 12 days postoperatively. Sixty (43%) patients were categorized as low insulin resistance. They demonstrated an increase of beta-cell function by 12 days postoperatively, which returned to baseline by 6 months. At 1 year postoperatively, the low insulin resistance group had significantly higher beta-cell function per degree of insulin sensitivity.

CONCLUSIONS

Adipose mass alone cannot explain insulin resistance. Severely obese individuals can be categorized by degree of insulin resistance, and the effect of gastric bypass depends upon this preoperative physiology.

Small dense low-density lipoprotein cholesterol is a useful marker of metabolic syndrome in patients with coronary artery disease

AIM

An evaluation of the relation between small dense low-density lipoprotein cholesterol (sd-LDL-C) levels measured by the heparin-magnesium precipitation method and metabolic syndrome (MetS).

METHODS

We have prospectively measured sd-LDL-C levels by the heparin-magnesium precipitation method in 112 Japanese patients (male/female=80/32) with coronary artery disease (CAD) who received percutaneous coronary intervention (PCI). Patients were diagnosed with MetS according to modified Japanese criteria.

RESULTS

A total of 36 patients (32%) met the criteria for MetS. Sd-LDL-C levels were significantly higher in the MetS group than non-MetS group (20.7 +/- 1.5 mg/dL vs. 17.1 +/- 1.0 mg/dL, p=0.042), especially among patients without lipid-lowering therapy (26.4 +/- 2.6 mg/dL vs. 17.5 +/- 1.5 mg/dL, p= 0.0034). Sd-LDL-C levels gradually increased with the number of components used to define MetS (0; 14.5 +/- 1.8 mg/dL, 1; 16.5 +/- 1.8 mg/dL, 2; 16.7 +/- 1.3 mg/dL, 3; 19.3 +/- 1.7 mg/dL, 4; 23.1 +/- 2.1 mg/dL, 5; 40.0 mg/dL, p=0.0071). High-sensitivity C-reactive protein (hs-CRP) levels were significantly higher in the patients with MetS (1.09 +/- 0.17 mg/L vs. 0.67 +/- 0.09 mg/L, p=0.0204).

CONCLUSION

The sd-LDL-C level measured by the heparin-magnesium precipitation method is a useful marker of MetS in Japanese patients with CAD.

Relationship between metabolic syndrome components and vascular properties in Japanese type 2 diabetic patients without cardiovascular disease or nephropathy

To investigate the effect of metabolic syndrome (MS) components on early atherosclerosis markers, i.e., urinary albumin excretion rate (UAE), pulse wave velocity (PWV), and carotid intima-media thickness (IMT), we studied 536 Japanese patients with type 2 diabetes without cardiovascular disease or nephropathy. The MS definition by ATP III was employed. UAE, PWV, and IMT increased significantly with increasing the number of components even before fulfilling the diagnosis of MS. UAE was significantly influenced by high blood pressure, high triglycerides, and low HDL cholesterol. PWV was significantly increased by high blood pressure. IMT was significantly increased by high blood pressure and abdominal obesity. Multiple regression analysis, including MS components and putative risk factors, indicated that the number of MS components, age and glycosylated HbA1C were independent determinants of UAE, PWV, and IMT. LDL cholesterol and male gender were independent determinants of IMT. In conclusion, UAE, PWV, and IMT increased according to increasing the number of MS in type 2 diabetic patients without cardiovascular disease or diabetic nephropathy. The current observation considering the modifiable factors may help to identify patients who are at high risk of experiencing cardiovascular disease.

Common familial influences on clustering of metabolic syndrome traits with central obesity and insulin resistance: the Kiel obesity prevention study

OBJECTIVE

The phenotypic heterogeneity of metabolic syndrome (MSX) suggests heterogeneity of the underlying genotype. The aim of the present study was to examine the common genetic background that contributes to the clustering between the two main features (insulin resistance, central obesity) and different MSX component traits.

METHODS

In all, 492 individuals from 90 families were investigated in a three-generation family path study as part of the Kiel Obesity Prevention Study (KOPS, 162 grandparents, 66.1+/-6.7 years, 173 parents, 41.3+/-5.4 years and 157 children, 10.8+/-3.4 years). Overall heritability was estimated and common familial (genetic and environmental) influences on insulin resistance (HOMA-IR) or central obesity (elevated waist circumference, WC), respectively, and different MSX traits were compared in a bivariate cross-trait correlation model.

RESULTS

Prevalence of MSX (according to NCEP criteria) was 27.2% (f) and 27.8% (m) in adults and 3.5% (f) and 8.5% (m) in children and adolescents, respectively. MSX phenotype was found to be highly variable, comprising 16 subtypes of component trait combinations. Within-trait heritability was 38.5% for HOMA-IR and 53.5% for WC, cross-trait heritability was 53.4%. As much as 6-18% and 3-10% of the shared variance between different MSX component traits (lipid profile, blood pressure) and WC or HOMA-IR, respectively, may be genetic. With the exception of HDL-C, the shared genetic variance between MSX component traits and WC was higher than the genetic variance shared with HOMA-IR.

CONCLUSION

A common genetic background contributes to the clustering of different MSX component traits and central obesity or insulin resistance. Common genetic influences favour central obesity as a major characteristic linking these traits.

A community-based epidemiologic study of gender differences in the relationship between insulin resistance/beta-cell dysfunction and diabetic retinopathy among type 2 diabetic patients in Kinmen, Taiwan

PURPOSE

The purpose of this study was to explore whether there were gender differences in the relation of insulin resistance and beta-cell dysfunction to diabetic retinopathy among type 2 diabetic patients.

METHODS

From 1999 to 2002, a screening regimen for diabetic retinopathy was performed by a panel of ophthalmologists using ophthalmoscopy and 45-degree color fundus photography to examine the fundus in a total of 971 type 2 diabetic patients examined between 1991 and 1993 in Kinmen, Taiwan. Seven hundred and twenty-five type 2 diabetic patients (301 males and 424 females) attended ophthalmological fundus checkup.

RESULTS

The response rate in males and females was 71.3 and 77.2%. The proportion of diabetic retinopathy at the first eye screening was 16.3% in males and 20.1% in females. From the multiple logistic regression, the type of diabetes (known cases vs. new cases) was a significant factor of diabetic retinopathy in both males (OR = 3.65, 95% CI: 1.59-8.37) and females (OR = 3.66, 95% CI: 2.01-6.70). Diabetic retinopathy was also strongly affected by the homeostasis model assessment of insulin resistance (HOMA IR) and homeostasis model assessment of beta-cell dysfunction (HOMA beta-cell) (p < 0.0001 for trend test). In males, those who were in the 2nd quartile, 3rd quartile, and 4th quartile of HOMA IR had 4.87 times (95% CI: 1.18-20.11), 6.83 times (95% CI: 1.91-24.46), and 10.15 times (95% CI: 2.42-42.56) the risk for diabetic retinopathy as compared to those in the 1st quartile. There was a reduced risk for diabetic retinopathy in relation to HOMA beta-cell for the 2nd quartile, 3rd quartile, and 4th quartile of 86% (95% CI: 37-97%), 95% (95% CI: 77-99%), and 96% (95% CI: 78-99%) as compared to that in the 1st quartile. Only the 4th quartile had a significant risk (OR = 2.62, 95% CI: 1.17-5.86) for diabetic retinopathy as compared to that in the 1st quartile in females. The reduced risk for diabetic retinopathy found in relation to HOMA beta-cell for the 3rd and 4th quartiles were 66% (95% CI: 6-88%) and 66% (95% CI: 10-87%) as compared to that in the 1st quartile.

CONCLUSIONS

Gender differences in the relationship between insulin resistance/beta-cell dysfunction and diabetic retinopathy were demonstrated in type 2 diabetic patients.

Metabolic syndrome and progression of atherosclerosis among middle-aged US adults

Metabolic syndrome, indicated by insulin resistance/hyperinsulinemia, obesity, central obesity, atherogenic dyslipidemia, and hypertension, contributes to atherosclerotic cardiovascular disease. However, it is controversial whether the indicators of metabolic syndrome are related to subclinical atherosclerosis collectively or individually. Whether there is any gender-based difference in the mechanisms of metabolic syndrome-induced atherosclerosis progression is also unknown. Two models were compared in this study. Model 1 assumes that a latent factor, metabolic syndrome per se, impacts subclinical atherosclerosis (collective effects model); Model 2 assumes the effect of the syndrome is mediated through its indicators (individual effects model). Data were obtained from the Los Angeles Atherosclerosis Study. The cohort consists of 573 adults (age, 40-60 years) who were asymptomatic for cardiovascular disease. Subclinical atherosclerosis was assessed by measuring common carotid artery intima-media thickness (CCA-IMT) using B-mode ultrasound. Three examinations were completed at 1.5-year intervals from 1995-1999. The analyses were performed with SAS 8.2 and AMOS 4.0. The results showed that atherogenic effects of metabolic syndrome were mediated through its indicators; there were gender-based differences in the mechanisms of metabolic syndrome-induced atherosclerosis. Central obesity was significantly associated with the baseline IMT for men only, whereas triglycerides were significantly associated with the progression of IMT for women only. Systolic blood pressure was significantly associated with the baseline and progression for both men and women. However, fasting insulin was not found to be significantly associated with the baseline and progression of IMT in the multivariate model, although it was significantly associated with other components of metabolic syndrome.

Importance of diagnosing and treating the metabolic syndrome in reducing cardiovascular risk

Applying the criteria for the metabolic syndrome serves as a simple and inexpensive tool for identifying patients at high risk for diabetes and coronary heart disease, particularly those who do not fall into traditional risk categories. Several independent physiological processes underlie the non-random risk-factor clustering that defines the metabolic syndrome, including insulin resistance, central obesity, dyslipidemia, impaired glucose tolerance, and hypertension. Other non-classic risk factors, such as abnormal oxidized low-density lipoprotein-cholesterol, adiponectin, and C-reactive protein levels, are highly correlated with the metabolic syndrome. Use of the metabolic syndrome criteria for assessment is comparable with other risk-scoring systems in accurately predicting cardiovascular disease risk and is simpler to implement in the clinic. Further research is needed to define the etiology of the metabolic syndrome.

Clustering of insulin resistance with vascular dysfunction and low-grade inflammation in type 2 diabetes

Vascular dysfunction, low-grade inflammation, insulin resistance, and impaired fibrinolysis have each been reported to be present in type 2 diabetes, but their relationships, and the role of obesity, have not been investigated. We measured insulin sensitivity (euglycemic clamp), forearm blood flow responses to graded local acetylcholine (Ach) and sodium nitroprusside (SNP) infusions, plasma concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, von Willebrand factor (vWF), plasminogen activator inhibitor (PAI)-1, tissue plasminogen activator (tPA), and high-sensitivity C-reactive protein (hs-CRP) in 81 diabetic patients. When patients were stratified by insulin resistance, more severe insulin resistance was associated (P < 0.05) with overweight, central fat distribution, hypertension, and dyslipidemia (with similar sex distribution, age, fasting plasma glucose, and HbA1c). With regard to vascular function, both endothelium-dependent (Ach) (-22, -40, and -52%; P < 0.0001) and -independent (SNP) (-3, -7, and -27%; P < 0.02) vasodilatation were progressively reduced across insulin resistance tertiles. In multivariate analysis, inflammatory markers (IL-6, hs-CRP, and TNF-alpha) were independently associated with insulin resistance and fasting glycemia, fibrinolytic markers PAI-1 and tPA with insulin resistance and central fat distribution, and vascular indexes (vWF, Ach, and SNP vasodilation) with insulin resistance and obesity or cytokines (TNF-alpha or IL-6). In type 2 diabetes, insulin resistance is associated with vascular dysfunction/damage, impaired fibrinolysis, and low-grade inflammation independently of obesity and poor glycemic control.

Meta-analysis of the relationship between alcohol consumption and coronary heart disease and mortality in type 2 diabetic patients

AIMS/HYPOTHESIS

This systematic review examines the relationship between alcohol consumption and long-term complications of type 2 diabetes. Meta-analyses could only be performed for total mortality, mortality from CHD, and CHD incidence, because the availability of articles on other complications was too limited.

MATERIALS AND METHODS

A PubMed search through to September 2005 was performed and the reference lists of relevant articles examined. Among the relevant articles there were six cohort studies reporting on the risk of total mortality and/or fatal and/or incident CHD in alcohol non-consumers and in at least two groups of alcohol consumers.

RESULTS

Statistical pooling showed lower risks in alcohol consumers than in non-consumers (the reference category). The relative risk (RR) of total mortality was 0.64 (95% CI 0.49-0.82) in the <6 g/day category. In the higher alcohol consumption categories (6 to <18, and > or =18 g/day), the RRs of total mortality were not significant. Risks of fatal and total CHD were significantly lower in all three categories of alcohol consumers (<6, 6 to <18 and > or =18 g/day) than in non-consumers, with RRs ranging from 0.34 to 0.75.

CONCLUSIONS/INTERPRETATION

This meta-analysis shows that, as with findings in the general population, moderate alcohol consumption is associated with a lower risk of mortality and CHD in type 2 diabetic populations.

The metabolic syndrome and cardiovascular disease

The metabolic syndrome, which is very common in the general population, is defined by the clustering of several classic cardiovascular risk factors, such as type 2 diabetes, hypertension, high triglycerides and low high-density lipoprotein cholesterol (HDL). Central obesity and insulin resistance, which are the two underlying disorders of the syndrome, are further risk factors for cardiovascular disease. Moreover, a panel of novel (non-traditional) risk factors are ancillary features of the metabolic syndrome. They include biomarkers of chronic mild inflammation (e.g. C-reactive protein, CRP), increased oxidant stress (e.g. oxidized low density lipoprotein, LDL), thrombophilia (e.g. plasminogen activator inhibitor-1, PAI-1) and endothelial dysfunction (e.g. E-selectin). Therefore, subjects with the metabolic syndrome are potentially at high risk of developing atherosclerosis and clinical cardiovascular events.In recent years several longitudinal studies have confirmed that subjects with the metabolic syndrome present with atherosclerosis and suffer from myocardial infarction and stroke at rates higher than subjects without the syndrome. The risk of cardiovascular disease (CVD) is particularly high in women with the syndrome and in subjects with pre-existing diabetes, CVD and/or high CRP. However, an increased risk is already present in subjects with a cluster of multiple mild abnormalities. The risk related to the metabolic syndrome is definitely higher when subjects affected are compared to subjects free of any metabolic abnormality.

Die Bedeutung der Rehabilitation beim herzkranken Diabetiker nach chirurgischen Eingriffen

Patients with diabetes nowadays are not directly endangered by dysglycemia, but they suffer vascular complications. The diabetic patient with existing cardiovascular (CV) disease has a particularly high risk for further CV complications and, therefore, requires specific attention. These patients need an intense and multimodal therapeutic approach which includes a strong interdisciplinary cooperation between the cardiologist and the diabetologist. Cardiac rehabilitation can effectively improve prognosis of CV patients with numbers needed to treat (NNT) comparable to standard pharmacological treatment. In diabetics, after coronary surgery, metabolism frequently and markedly deteriorates, and this requires strict metabolic monitoring and close cooperation between the diabetes team and the other professionals (cardiologist, nurses, physiotherapists, psychologists . . .) to reduce complications arising from hyperglycemia and also hypoglycemia and to improve the CV risk factors by lifestyle changes. Frequently, diabetes is only diagnosed during the hospital stay for CV complication; therefore, in these patients, specific attention is required for teaching and inauguration of therapy. Due to the high risk of these patients and the need of qualified metabolic co-treatment, following CV surgery, diabetic patients should be treated preferentially in rehabilitation centres specialised in both cardiac and metabolic care. Recent studies indicate that a multimodal and aggressive approach in CV diabetic patients can markedly improve their prognosis.

Five-year risk of developing clinical diabetes after first myocardial infarction; the FINAMI study

AIM

To investigate the incidence of clinical diabetes as determined by the incidence of diabetes drug reimbursements within a 5-year period after the first myocardial infarction (MI) in patients who were non-diabetic at the time of their first MI.

RESEARCH DESIGN AND METHODS

A population-based MI register, FINMONICA/FINAMI, recorded all coronary events in persons of 35-64 years of age between 1988 and 2002 in four study areas in Finland. These records were used to identify subjects sustaining their first MI (n = 2632). Participants of the population-based risk factor survey FINRISK (surveys 1987, 1992, 1997 and 2002), who did not have diabetes or a history of MI, served as the control group (n = 7774). The FINMONICA/FINAMI study records were linked with the National Social Security Institute's drug reimbursement records, which include diabetes medications, using personal identification codes. The records were used to identify subjects who developed diabetes during the 5-year follow-up period (n = 98 in the MI group and n = 79 in the control group).

RESULTS

Sixteen per cent of men and 20% of women sustaining their first MI were known to have diabetes and thus were excluded from this analysis. Non-diabetic men having a first MI were at more than twofold {hazard ratio (HR) 2.3 [95% confidence interval (CI) 1.6-3.4]}, and women fourfold [HR 4.3 (95% CI 2.4-7.5)], risk of developing diabetes mellitus during the next 5 years compared with the control population without MI.

CONCLUSIONS

Many patients who do not have diabetes at the time of their first MI develop diabetes in the following 5 years.

The metabolic syndrome: time for a critical appraisal: joint statement from the American Diabetes Association and the European Association for the Study of Diabetes

The term "metabolic syndrome" refers to a clustering of specific cardiovascular disease (CVD) risk factors whose underlying pathophysiology is thought to be related to insulin resistance. Since the term is widely used in research and clinical practice, we undertook an extensive review of the literature in relation to the syndrome's definition, underlying pathogenesis, and association with CVD and to the goals and impact of treatment. While there is no question that certain CVD risk factors are prone to cluster, we found that the metabolic syndrome has been imprecisely defined, there is a lack of certainty regarding its pathogenesis, and there is considerable doubt regarding its value as a CVD risk marker. Our analysis indicates that too much critically important information is missing to warrant its designation as a "syndrome." Until much needed research is completed, clinicians should evaluate and treat all CVD risk factors without regard to whether a patient meets the criteria for diagnosis of the "metabolic syndrome."

The metabolic syndrome: time for a critical appraisal. Joint statement from the American Diabetes Association and the European Association for the Study of Diabetes

BACKGROUND

The term 'metabolic syndrome' refers to a clustering of specific cardiovascular disease (CVD) risk factors whose underlying pathophysiology is thought to be related to insulin resistance.

METHODS

Since the term is widely used in research and clinical practice, we undertook an extensive review of the literature in relation to the syndrome's definition, underlying pathogenesis, association with cardiovascular disease and to the goals and impact of treatment.

DISCUSSION

While there is no question that certain CVD risk factors are prone to cluster, we found that the metabolic syndrome has been imprecisely defined, there is a lack of certainty regarding its pathogenesis, and there is considerable doubt regarding its value as a CVD risk marker. Our analysis indicates that too much critically important information is missing to warrant its designation as a 'syndrome'.

CONCLUSION

Until much-needed research is completed, clinicians should evaluate and treat all CVD risk factors without regard to whether a patient meets the criteria for diagnosis of the 'metabolic syndrome'.

Inflammation markers and erythrocyte sedimentation rate but not metabolic syndrome factor score predict coronary heart disease in high socioeconomic class males: the HDDRISC study

OBJECTIVE

To evaluate prediction of coronary heart disease (CHD) by quantitative measures of the metabolic syndrome and inflammation in a cohort of high socio-economic status males.

METHODS

Incident CHD was identified in a cohort of 649 male participants in a company health programme during a mean follow-up of 10.6 years. Using factor analysis, metabolic syndrome and sub-clinical inflammation scores were derived from baseline measurements, which included an oral glucose tolerance test-derived measure of insulin resistance. Factor scores were then included as predictor variables in a Cox regression analysis of incident CHD.

RESULTS

Forty-two cases of definite CHD were identified on follow-up. The conventional risk factors, cigarette smoking, blood pressure, total cholesterol and low HDL cholesterol were clearly distinguished as significant predictors of incident CHD. Erythrocyte sedimentation rate was also an independent predictor (coefficient 0.0480, z score 2.39, p=0.017). The metabolic syndrome factor included insulin resistance, body mass index, serum triglycerides, glucose tolerance, serum uric acid and fasting plasma glucose. The inflammation factor included serum globulin, blood leukocyte count, low albumin, haemoglobin and cholesterol, but not erythrocyte sedimentation rate. The inflammation factor score was a significant predictor of CHD (coefficient 0.4601, z score 2.43, p=0.015) but the metabolic syndrome factor was not (coefficient 0.2488, z score 1.24, p=0.2).

CONCLUSIONS

Erythrocyte sedimentation rate and a factor analysis-derived measure of sub-clinical inflammation were important in the development of CHD in this relatively low-risk group, but neither metabolic syndrome factor score nor its individual components predicted CHD.

What is the relationship between exercise and metabolic abnormalities? A review of the metabolic syndrome

Prevention of the metabolic syndrome and treatment of its main characteristics are now considered of utmost importance in order to combat the epidemic of type 2 diabetes mellitus and to reduce the increased risk of cardiovascular disease and all-cause mortality. Insulin resistance/hyperinsulinaemia are consistently linked with a clustering of multiple clinical and subclinical metabolic risk factors. It is now widely recognised that obesity (especially abdominal fat accumulation), hyperglycaemia, dyslipidaemia and hypertension are common metabolic traits that, concurrently, constitute the distinctive insulin resistance or metabolic syndrome. Cross-sectional and prospective data provide an emerging picture of associations of both physical activity habits and cardiorespiratory fitness with the metabolic syndrome. The metabolic syndrome, is a disorder that requires aggressive multi-factorial intervention. Recent treatment guidelines have emphasised the clinical utility of diagnosis and an important treatment role for 'therapeutic lifestyle change', incorporating moderate physical activity. Several previous narrative reviews have considered exercise training as an effective treatment for insulin resistance and other components of the syndrome. However, the evidence cited has been less consistent for exercise training effects on several metabolic syndrome variables, unless combined with appropriate dietary modifications to achieve weight loss. Recently published randomised controlled trial data concerning the effects of exercise training on separate metabolic syndrome traits are evaluated within this review. Novel systematic review and meta-analysis evidence is presented indicating that supervised, long-term, moderate to moderately vigorous intensity exercise training, in the absence of therapeutic weight loss, improves the dyslipidaemic profile by raising high density lipoprotein-cholesterol and lowering triglycerides in overweight and obese adults with characteristics of the metabolic syndrome. Lifestyle interventions, including exercise and dietary-induced weight loss may improve insulin resistance and glucose tolerance in obesity states and are highly effective in preventing or delaying the onset of type 2 diabetes in individuals with impaired glucose regulation. Randomised controlled trial evidence also indicates that exercise training decreases blood pressure in overweight/obese individuals with high normal blood pressure and hypertension. These evidence-based findings continue to support recommendations that supervised or partially supervised exercise training is an important initial adjunctive step in the treatment of individuals with the metabolic syndrome. Exercise training should be considered an essential part of 'therapeutic lifestyle change' and may concurrently improve insulin resistance and the entire cluster of metabolic risk factors.

Metabolic syndrome amplifies the age-associated increases in vascular thickness and stiffness

OBJECTIVES

We sought to evaluate whether the clustering of multiple components of the metabolic syndrome (MS) has a greater impact on these vascular parameters than individual components of MS.

BACKGROUND

Intima-media thickness (IMT) and vascular stiffness have been shown to be independent predictors of adverse cardiovascular events. The MS is defined as the clustering of three or more of the cardiovascular risk factors of dysglycemia, hypertension, dyslipidemia, and obesity.

METHODS

Carotid IMT and stiffness were derived via B-mode ultrasonography in 471 participants from the Baltimore Longitudinal Study on Aging, who were without clinical cardiovascular disease and not receiving antihypertensive therapy.

RESULTS

The MS conferred a disproportionate increase in carotid IMT (+16%, p < 0.0001) and stiffness (+32%, p < 0.0001), compared with control subjects. Multiple regression models, which included age, gender, smoking, low-density lipoprotein, as well as each individual component of MS as continuous variables, showed that MS was an independent determinant of both IMT (p = 0.002) and stiffness (p = 0.012). The MS was associated with a greater prevalence of subjects whose values were in the highest quartiles of IMT, stiffness, or both.

CONCLUSIONS

Even after taking into account each individual component of MS, the clustering of at least three of these components is independently associated with increased IMT and stiffness. This suggests that the components of MS interact to synergistically impact vascular thickness and stiffness. Future studies should examine whether the excess cardiovascular risk associated with MS is partly mediated through the amplified alterations in these vascular properties.

Prevalence and risk factors for angina in elderly Taiwanese

BACKGROUND

Angina is a hallmark symptom of cardiovascular disease, which has become an important public health issue in Taiwan. The purpose of this study was to examine the prevalence of angina and its risk factors in elderly Taiwanese.

METHODS

The study was based on a government-sponsored health examination performed in Tao-Yuan, North Taiwan, from April to June 2001. A total of 2060 participants aged 65 years and older were enrolled. Data were collected through a physician-conducted Rose questionnaire, a biochemical blood test, and a physical examination. Multivariate logistic regression was used to evaluate the relationship between angina and risk factors.

RESULTS

Prevalence of angina was 15.0% in this study, 15.1% in men, and 14.4% in women. Women had a significantly higher body mass index (BMI), total serum cholesterol, and triglyceride. Participants with hypertension had a 1.6-fold 95% confidence interval (CI): 1.2-2.0 increased risk of having angina, 1.4-fold (95% CI: 1.0-1.9) increased risk for men and 2.1-fold (95% CI: 1.3-3.5) for women. Diabetes mellitus was associated with a 1.8-fold (95% CI: 1.2-2.6) increase in the risk for men. Conventional cardiovascular risk factors such as BMI, cholesterol, triglyceride, and smoking were not significantly associated with angina.

CONCLUSIONS

The findings of this study suggest the need to prioritize hypertension treatment for elderly Taiwanese in both genders, and to provide adequate diabetes mellitus treatment for men, as these conditions are associated with the development of angina, a clinical indicator of cardiovascular disease.

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.

Insulin resistance and other risk factors for coronary heart disease in elderly men. The Study of Men Born in 1913 and 1923

BACKGROUND

We have previously shown that insulin is not a major risk factor for CHD. Our data have been re-analysed with longer follow-up and the homeostasis model assessment (HOMA) method.

DESIGN

Prospective cohort study of 57- and 67-year-old men.

METHODS

Insulin resistance was estimated with the HOMA equation. Standard methods were used to measure risk factors. The endpoint (CHD) was the combination of non-fatal myocardial infarction and fatal CHD during 13 years of follow-up.

RESULTS

The risk of CHD increased 2.5-fold in known diabetics compared with those with normal glucose tolerance, 2.2-fold among those in the highest compared with the lowest quintile of insulin resistance, and 2.4-fold among those in the highest compared with the lowest quintile of fasting insulin. Increased physical activity decreased the risk of CHD by 65%. Cholesterol was also a significant risk factor for CHD but blood pressure, obesity and smoking were not related to the incidence of CHD.

CONCLUSION

Insulin resistance is a significant risk factor for CHD. Whether it is a causal risk factor remains to be proven. Regular physical activity protects against CHD.

Cardiovascular risk associated with the metabolic syndrome

The term metabolic syndrome refers to a clustering of cardiovascular risk factors, most of which also share insulin resistance as an additional feature. Scientific effort has concentrated on understanding why these diverse cardiovascular risks co-occur in individuals and in determining the presumed common environmental or genetic factors that might underpin this. Clinically important developments include publication of standard definitions of the metabolic syndrome and recommendations for the use of type 2 diabetes and the presence of the metabolic syndrome as critical "risk stratifiers" in cardiovascular disease prevention. The remarkable recent secular increases in the prevalence of type 2 diabetes and obesity in many populations mean that the importance of the metabolic syndrome as a determinant of cardiovascular disease is likely to increase until these trends can be reversed.

Effect of metformin treatment on multiple cardiovascular disease risk factors in patients with type 2 diabetes mellitus

In light of the conflicting results of the recent United Kingdom Prospective Study (UKPDS), where diabetic patients on metformin monotherapy had lower all-cause mortality and the addition of metformin in sulfonylurea-treated patients was associated with an increased risk of diabetes-related death, we sought to compare the effects on cardiovascular disease (CVD) risk factors of metformin monotherapy with metformin treatment when added to a sulfonylurea compound in patients with type 2 diabetes. Thirty-one volunteers with type 2 diabetes mellitus, 16 on dietary therapy and 15 on sulfonylurea monotherapy (SU), were treated with metformin for 12 weeks. Measurements were made of (1) fasting plasma glucose, hemoglobin A(1c) (HbA(1c)), lipid, remnant lipoprotein cholesterol (RLP-C) levels, and low-density lipoprotein (LDL) particle size; (2) daylong plasma glucose, insulin, free fatty acid (FFA), triglyceride (TG), and RLP-C concentrations; and (3) fasting levels of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-selectin). Fasting plasma glucose concentrations decreased to a similar degree after treatment with metformin in both the metformin monotherapy group (12.45 +/- 0.48 v 9.46 +/- 0.47 mmol/L, P <.001) and the combined SU and metformin therapy group (14.09 +/- 0.51 v 10.57 +/- 0.85 mmol/L, P =.001). Fasting plasma lipid concentrations and LDL particle size did not significantly change in either treatment group, whereas fasting RLP-C concentrations were significantly lower in the metformin monotherapy group (0.43 +/- 0.09 v 0.34 +/- 0.07 mmol/L, P =.02). Daylong concentrations of plasma glucose, FFA, TG, and RLP-C were lower to a similar degree in both treatment groups, whereas daylong plasma insulin concentrations were unchanged. Fasting plasma sVCAM-1 levels were significantly lower in both the metformin monotherapy group (484 +/- 19 v 446 +/- 18 ng/mL, P =.02) and the combined SU and metformin therapy group (496 +/- 29 v 456 +/- 31 ng/mL, P =.05), whereas fasting plasma sICAM-1 and sE-selectin levels were essentially unchanged. Administration of metformin, either as monotherapy or in combination with a sulfonylurea drug, improved glycemic control and led to a decrease in several CVD risk factors in patients with type 2 diabetes.