Associations between insulin resistance and thrombotic risk factors in high-risk South Asian subjects

Association between triglyceride glucose index and all-cause mortality in patients with cerebrovascular disease: a retrospective study

BACKGROUND

Triglyceride glucose (TyG) is associated with stroke, atherosclerosis, and adverse clinical outcomes. However, its correlation with cerebrovascular disease (CVD) mortality remains unclear. This study aimed to investigate the relationship between TyG index and mortality in patients with CVD.

METHODS

Patient data sourced from the Medical Information Mart for Intensive Care -IV database were categorized based on TyG quartiles. Kaplan-Meier survival analysis was used to estimate survival disparities among the TyG subgroups. Cox proportional risk modeling was used to examine the association between the TyG index and mortality. Generalized summation models were applied to fit the smoothed curves. log-likelihood ratio test were used to analyze the non-linear relationship.

RESULTS

The study comprised 1,965 patients (50.18% were male). The 28-day and 90-day mortality rates were 20.10% and 24.48%, respectively. The TyG index exhibited a linear relationship with the 28-day mortality (Hazards ratio (HR), 1.16; 95% confidence interval (CI), 0.99-1.36) and the 90-day mortality (HR, 1.18; 95% CI, 1.02-1.37). In the TyG Q4 group, each 1 mg/dl increase was linked to a 35% rise in the risk of 28-day mortality and a 38% increase in the risk of 90-day mortality. Subgroup analyses highlighted a more substantial association between TyG index and 90-day mortality in the diabetic group.

CONCLUSION

Our findings underscore the positive association between TyG and the 28- and 90-day mortality rates in patients with CVD. This insight may prove pivotal for identifying at-risk populations and enhancing risk prediction in the clinical management of CVD.

Magnitude and time course of insulin resistance accumulation with the risk of cardiovascular disease: an 11-years cohort study

BACKGROUND

The risk of cardiovascular disease (CVD) depended on the magnitude and exposure duration of insulin resistance (IR). This study aimed to investigate the associations of cumulative metabolic score for IR (cumMETS-IR) with incident CVD, and to further explore the modulated effects of time course of METS-IR accumulation.

METHODS

We enrolled 47,270 participants without CVD and underwent three examinations during 2006-2010 from the Kailuan study. CumMETS-IR from 2006 to 2010 were calculated as the mean values of METS-IR between consecutive examinations multiplying by time intervals between visits. Time course of METS-IR accumulation was calculated as the slope of METS-IR versus time. Hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD risk were calculated with multivariable-adjusted Cox regressions.

RESULTS

During a median follow-up of 10.99 years, we identified 3184 cases of incident CVD. The risk of incident CVD increased with increasing cumMETS-IR (HR, 1.77; 95% CI 1.58-1.98 for the Q4 versus Q1 group), exposure duration (HR, 1.60; 95% CI 1.45-1.77 for 6 years versus 0 years), and cumulative burden (HR, 1.49; 95% CI 1.37-1.61 for burden ≥ 0 versus < 0). A positive slope was associated with 14% higher risk of CVD (HR, 1.14; 95% CI 1.07-1.22). When combining cumMETS-IR and slope, those with cumMETS-IR ≥ median (142.78) and slope ≥ 0 had the highest risk of CVD (HR,1.38; 95% CI 1.25-1.53).

CONCLUSIONS

The risk of CVD increased with elevated cumMETS-IR and an increasing trend over time, emphasizing the importance of maintaining optimal METS-IR levels across life span.

Disparities in the Prevalence of Childhood Obesity-Related Comorbidities: A Systematic Review

Background

Non-communicable diseases among children are serious consequences of childhood obesity. However, less is known about the disparities in childhood obesity comorbidities burden. This review describes the salient pattern of disparities in the prevalence of childhood obesity-related non-communicable diseases and relevant inequalities in both high- and low/medium-income countries.

Method

A systematic literature search was performed in MEDLINE, Embase, CINAHL, PsycInfo, Scopus, and Web of Science databases by two independent reviewers. Inclusion criteria were as follows: age 2–18 years; the prevalence or incidence of childhood obesity comorbidities reported; and studies published in English from January 2010 to date. No restrictions on the setting. The prevalence data were analyzed using range and median for subgroups based on the country's development status, gender, and geographical region.

Results

Our search identified 6,837 articles, out of which we examined 145 full-text articles and included 54 articles in the analysis. The median prevalence of childhood obesity-related hypertension was 35.6 vs. 12.7% among middle- and low-income countries compared with high-income countries; 37.7 vs. 32.9% among boys compared with girls; and 38.6, 25.3, and 20.1% in Asia, South America, and Europe, respectively. For metabolic syndrome, the median prevalence was 26.9 vs. 5.5% among middle- and low-income countries compared with high-income countries; 55.2 vs. 12.0% among boys compared with girls; and 40.3, 25.8, and 7.7% in South America, Asia, and Europe, respectively. The prevalence of childhood obesity-related non-alcoholic fatty liver disease was 47.5 vs. 23% among middle- and low-income countries compared with high-income countries; and 52.1, 39.7, and 23.0% in Asia, South America, and Europe, respectively. The median prevalence of dyslipidemia was 43.5 vs. 63% among middle- and low-income countries compared with high-income countries; 55.2 vs. 12.0% among boys compared to girls; and 73.7 and 49.2% in Australia and Europe, respectively.

Conclusion

There are disparities in the prevalence of childhood obesity-related hypertension, metabolic syndrome, and non-alcoholic fatty liver disease, with middle- and low-income countries, boys, and Asian region having higher prevalence. Implementing targeted interventions for childhood obesity comorbidities should consider socioeconomic disparities and strengthening of research surveillance methods for a better understanding of non-communicable disease burden in the pediatric population.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO, identifier: CRD42021288607.

Relationship of cumulative exposure to the triglyceride-glucose index with ischemic stroke: a 9-year prospective study in the Kailuan cohort

BACKGROUND

A single measurement of the triglyceride-glucose (TyG) index, a simple and reliable surrogate marker of insulin resistance, is associated with ischemic stroke. However, evidence for an effect of a long-term elevation in TyG index on ischemic stroke is limited. Therefore, we evaluated the relationship between cumulative TyG index exposure and the risk of ischemic stroke.

METHODS

A total of 54,098 participants in the Kailuan study who had not experienced ischemic stroke underwent three measurements of fasting blood glucose and triglycerides during 2006-2007, 2008-2009, and 2010-2011. Cumulative exposure to TyG index was calculated as the weighted sum of the mean TyG index value for each time interval (value × time). Participants were placed into four groups according to the quartile of the weighted mean: Q1 group, < 32.01; Q2 group, 32.01-34.45; Q3 group, 34.45-37.47; and Q4 group, ≥ 37.47. Cox proportional hazard models were used to assess the relationships of the cumulative TyG index with incident ischemic stroke by calculating hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

There were 2083 incident ischemic stroke events over the 9 years of follow-up. The risk of ischemic stroke increased with the quartile of cumulative TyG index. After adjustment for multiple potential confounders, participants in groups Q4, Q3, and Q2 had significantly higher risks of ischemic stroke, with HRs (95% CIs) of 1.30 (1.12-1.52), 1.26 (1.09-1.45), and 1.09 (0.94-1.27), respectively (P_trend < 0.05), compared with the Q1 group. The longer duration of high TyG index exposure was significantly associated with increased ischemic stroke.

CONCLUSIONS

High cumulative TyG index is associated with a higher risk of ischemic stroke. This finding implies that monitoring and the maintenance of an appropriate TyG index may be useful for the prevention of ischemic stroke.

Relationship Between the Triglyceride Glucose Index and the Risk of First Stroke in Elderly Hypertensive Patients

Background

Several recent studies have shown the relationship between the triglyceride glucose (TyG) index and the risk of stroke in the general population and in a few patient cohorts; however, the role of the TyG index on stroke risk in elderly hypertensive patients has not been determined. Thus, we aimed to investigate the association of the TyG index with first stroke and first ischemic stroke in elderly individuals with hypertension.

Methods

We included 8487 elderly subjects with hypertension from the China H-type Hypertension Registry Study for the current analysis. The TyG index was calculated as ln (fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2). Outcomes were the first stroke and first ischemic stroke.

Results

During a median follow-up of 1.72 years, the first stroke was diagnosed in 82 patients (0.97%), and the first ischemic stroke was diagnosed in 48 patients (0.57%). Multivariable Cox proportional hazards models revealed that the TyG index was positively associated with the risk of first stroke (per 1-unit increment; HR: 1.72; 95% CI: 1.07, 2.76) and first ischemic stroke (HR: 2.31; 95% CI: 1.32, 4.05). When the TyG index was assessed as quartiles, significantly higher risks of first stroke (HR: 1.90; 95% CI: 1.04, 3.45) and first ischemic stroke (HR: 2.45; 95% CI: 1.16, 5.20) were found in participants in quartile 4 compared with those in quartiles 1–3.

Conclusion

The TyG index is potentially useful in the early identification of elderly hypertensive patients at high risk of experiencing a first stroke.

Triglyceride glucose index influences platelet reactivity in acute ischemic stroke patients

Aim

Insulin resistance was reported to increase the risk of ischemic stroke, which can be assessed by the triglyceride glucose (TyG) index. However, it remains unclear whether the TyG index influences the platelet reactivity during the treatment of ischemic patients.

Methods

Ischemic stroke patients receiving dual antiplatelet therapy (DAPT) within 48 h onset were consecutively included. The TyG index was calculated as ln (fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2). The top quartile of TyG index was defined as insulin resistance. The platelet reactivity was assessed by thromboelastography. The platelet inhibition rate induced by arachidonic acid (AA) or adenosine diphosphate (ADP) was used to confirm the high residual on-treatment platelet reactivity (HRPR) to aspirin or clopidogrel, respectively. The association between TyG index and platelet reactivity was assessed by Kruskal–Wallis test. The independent risk factors of HRPR were determined by multivariate logistic regression analysis.

Results

A total of 1002 patients were included and divided into 4 groups by quartiles of the TyG index (< 2.02; 2.02–2.27; 2.27–2.52; ≥2.52). The findings demonstrated that the maximum intensity of the clot increased, but the AA-induced platelet inhibition rate decreased, depending on the TyG index quartiles. No significant difference was found in the ADP-induced platelet inhibition rate among groups. The prevalence of aspirin HRPR increased depending on the TyG index quartile. Unlike the non-insulin resistance group, the insulin resistance group was independently associated with aspirin HRPR (OR = 1.689, 95% CI 1.14 to 2.51, P = 0.009).

Conclusions

In acute ischemic stroke patients taking DAPT, the elevation of the TyG index is associated with enhanced platelet reactivity and higher prevalence of aspirin HRPR. Insulin resistance assessed by the TyG index could be an independent risk factor for aspirin HRPR.

Triglyceride Glucose Index and Prognosis of Patients With Ischemic Stroke

Background: The triglyceride glucose index (TyG index) has been proposed as a simple and credible surrogate marker of insulin resistance. However, it is unclear whether TyG index correlates with adverse clinical outcomes in patients with ischemic stroke. Accordingly, this study aimed to explore the relationship between baseline TyG index and clinical outcomes of ischemic stroke individuals. Methods: We included eligible subjects with ischemic stroke from the China National Stroke Registry II for the current analysis. TyG index was calculated and divided into quartiles to explore the relationship with the outcomes of ischemic stroke. Outcomes included stroke recurrence, all-cause mortality, poor functional outcome at 12 months, and neurologic worsening at discharge. Multivariable Cox regression and logistic regression models were performed to explore the correlation of baseline TyG index with the outcomes. Results: Among the 16,310 patients enrolled in the study, the average age was 64.83 ± 11.9 years, and 63.48% were men. The median TyG index was 8.73 (interquartile range, 8.33-9.21). After adjustment for multiple potential covariates, the fourth quartile of TyG index was associated with an increased risk of stroke recurrence (adjusted HR, 1.32; 95% CI, 1.11-1.57; P = 0.002), all-cause mortality (adjusted HR, 1.25; 95%CI, 1.06-1.47; P = 0.01) at 12-month follow-up, and neurological worsening (adjusted OR, 1.26; 95% CI, 1.02-1.55; P = 0.03) at discharge, but not poor functional outcome compared with the first quartile. Conclusion: TyG index representing insulin resistance was associated with an increased risk of stroke recurrence, all-cause mortality, and neurologic worsening in patients with ischemic stroke.

Value of triglyceride-glucose index for the estimation of ischemic stroke risk: Insights from a general population

BACKGROUND AND AIMS

Recent studies have recognized triglyceride-glucose index (TyG) as a practical surrogate of insulin resistance. Previous studies have demonstrated that insulin resistance contributes to ischemic stroke via multiple mechanisms. Our study aimed to investigate the association between TyG and prevalent ischemic stroke, exploring the value of TyG to optimize the risk stratification of ischemic stroke.

METHODS AND RESULTS

This cross-sectional study included 10,900 subjects (mean age: 59.95 years, 59.8% females) from rural areas of northeast China between September 2017 to May 2018. TyG was calculated as ln[fasting triglyceride (mg/dl) × fasting plasma glucose (mg/dl)/2]. The prevalence of ischemic stroke was 5.49%. After adjusting for all covariates, each SD increment of TyG caused 22.8% additional risk for ischemic stroke. When dividing TyG into quartiles, the top quartile had a 1.776 times risk for ischemic stroke against the bottom category. Furthermore, smoothing curve fitting demonstrated this association was linear in the whole range of TyG. Finally, AUC revealed an improvement when introducing TyG into clinical risk factors (0.746 vs 0.751, p = 0.029). Consistently, category-free net reclassification index (0.195, 95% CI: 0.112-0.277, P < 0.001) and integrated discrimination index (0.003, 95% CI: 0.001-0.004, P < 0.001) confirmed the improvement by TyG to stratify ischemic stroke risk.

CONCLUSION

The prevent ischemic stroke correlated proportionally with the increment of TyG, implicating the linearity of TyG as an indicator of ischemic stroke. Our findings suggest the potential value of TyG to optimize the risk stratification of ischemic stroke in a general population.

Insulin resistance in ischemic stroke

Insulin resistance often refers to a pathological condition in which cells fail to respond to the normal actions of insulin. Increasing literature has noted a critical role of insulin resistance in the pathogenesis of ischemic stroke. Insulin resistance plays an important role in the pathogenesis of ischemic stroke via enhancing advanced changes of atherosclerosis. A variety of literature indicates that insulin resistance enhances platelet adhesion, activation and aggregation which are conducive to the occurrence of ischemic stroke. Insulin resistance also induces hemodynamic disturbances and contributes to the onset of ischemic stroke. In addition, insulin resistance may augment the role of the modifiable risk factors in ischemic stroke and induce the occurrence of ischemic stroke. Preclinical and clinical studies have supported that improving insulin resistance may be an effective measure to prevent or delay ischemic stroke.

Review: Diabetes and cardiac disease in South Asians

South Asians have a higher prevalence of diabetes, coronary heart disease and cardiovascular death. Their predisposition to insulin resistance partly explains this excess risk. After immigration, the adoption of a western diet allied to increased sedentary behaviour leads to weight gain, hypertension and hyperlipidaemia, factors which in turn combine to amplify the chances of getting heart disease. Further contributory factors are increased sub-clinical inflammation, increased thrombogenic tendency and higher serum homocysteine levels. South Asians with diabetes might do as well as White people with respect to intensive glycaemic and blood pressure control. However, there is little evidence for measures to reduce cardiovascular risk as South Asians have not been included as a subgroup in most large trials. Future prospective studies, including studies on the prevention of diabetes and cardiovascular disease in this high-risk population, are therefore urgently required.

The Relationship of Metabolic Syndrome Traits with Beta-Cell Function and Insulin Sensitivity by Oral Minimal Model Assessment in South Asian and European Families Residing in the Netherlands

Background. There are different metabolic syndrome traits among patients with different ethnicities. Methods. We investigated this by studying 44 South Asians and 54 Europeans and classified them in three groups according to the occurrence of metabolic syndrome (MetS) and Type 2 Diabetes (T2D). Insulin sensitivity index (ISI), static, dynamic, and total beta-cell responsivity indices (Φ), and disposition indices (DIs) were calculated with the use of oral minimal model (OMM). Results. In both ethnicities, ISI was lower in the subgroup with MetS and T2D as compared to the subgroup without MetS nor T2D (P < 0.004). South Asians without MetS were more insulin resistant than Europeans without MetS (P = 0.033). In the South Asians, ISI, dynamic DI, and static DI were associated significantly (P < 0.006) with high-density lipoprotein cholesterol and triglycerides. In the Europeans, ISI was associated with waist-to-hip ratio (P = 0.005) and systolic and diastolic blood pressure (P < 0.005), while static DI was related to the systolic blood pressure (P = 0.005). Conclusions. MetS was linked with insulin resistance and reduced capacity to handle glucose regardless of ethnicity. ISI and DIs were associated with lipid traits in South Asians and with blood pressure in Europeans suggesting that insulin resistance enhances different metabolic syndrome traits among different ethnicities.

Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes-related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. 'Westernization', acculturation, socio-economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic-specific cut-off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries.

mtDNA lineages reveal coronary artery disease-associated structures in the Lebanese population

Population origins and ancestry have previously been found to be important determinants of coronary artery disease (CAD). This study investigates associations of Lebanese mitochondrial DNA lineages with CAD and studies their correlation with other populations, exploring population structures that may infer mitochondria functional associations and reveal population movements and origins. Sequencing the mitochondrial hypervariable sequence 1 (HVS-1) of 363 controls and 448 cases revealed that haplogroup W was more frequent (P = 0.013) in cases compared to controls, and was associated with increased risk of CAD (OR = 5.50, 95% CI = 1.50-35.30, P = 0.026) among Lebanese samples. Haplogroup A was only found in controls (P = 0.029). We have detected stronger geographic correlation between haplogroup W and CAD (Pearson's r = 0.316, P < 0.001) than between haplogroup A and CAD (r = 0.149, P < 0.001). HVS-1 phylogenetic network of haplogroup W shows controls are restricted to European clusters while cases belong mostly to Middle Eastern natives. The network of haplogroup A shows that the controls belong to a cluster dominated by Central Asians. Our results show evidence of a gene flow into Lebanon, creating CAD-associated population structures that are similar to those in the source populations, maintained by limited admixture, and probably encompassing variations on the nuclear and/or the mitochondrial genome that are correlated with the disease.

Inflammation and thrombosis in diabetes

Patients with diabetes mellitus are at increased risk of cardiovascular morbidity and mortality. Atherothrombosis, defined as atherosclerotic lesion disruption with superimposed thrombus formation, is the most common cause of death among these patients. Following plaque rupture, adherence of platelets is followed by local activation of coagulation, the formation of a cross-linked fibrin clot and the development of an occlusive platelet rich fibrin mesh. Patients with diabetes exhibit a thrombotic risk clustering which is composed of hyper-reactive platelets, up regulation of pro-thrombotic markers and suppression of fibrinolysis. These changes are mainly mediated by the presence of insulin resistance and dysglycaemia and an increased inflammatory state which directly affects platelet function, coagulation factors and clot structure. This prothrombotic state is related to increased cardiovascular risk and may account for the reduced response to antithrombotic therapeutic approaches, underpinning the need for adequate antithrombotic therapy in patients with diabetes to reduce their cardiovascular mortality.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Interrelationships of Factor VII activity and plasma leptin with insulin resistance in coronary heart disease

OBJECTIVE

An increase of FVII activity (FVIIc) has been proposed to be an independent cardiovascular risk factor. Whether FVII is associated with insulin resistance in coronary heart disease (CHD) is still unknown. We tested the hypothesis that plasma FVII activity and leptin are associated with insulin resistance independently.

METHODS

We studied 130 subjects, of which 65 were CHD subjects and 65 were non-CHD control subjects. Fasting plasma levels of leptin, insulin, glucose, FVIIc activity, fibrinogen, lipid parameters were estimated for all the subjects. Body mass index (BMI), waist circumference (WC) and blood pressure levels were also determined.

RESULTS

We observed significantly raised plasma levels of FVIIc activity, leptin and insulin resistance among the CHD subjects compared to the non-CHD subjects. Raised FVIIc activity levels in CHD were significantly positively correlated with insulin resistance. Raised plasma leptin levels in CHD were correlated with insulin resistance, BMI and WC. Multivariate regression analysis showed that elevated levels of FVII activity in CHD was significantly associated with insulin resistance, independent of dyslipidemia, leptin, blood pressure levels, BMI, WC, gender and age. Furthermore, raised leptin levels in CHD subjects were significantly associated with insulin resistance and BMI, independently of each other and of dyslipidemia, FVIIc, blood pressure levels, WC, gender and age.

CONCLUSION

Raised FVII and leptin levels in CHD patients were independently associated with insulin resistance, this was not observed among the non-CHD subjects.

Alanine aminotransferase is associated with atherothrombotic risk factors in a British South Asian population

BACKGROUND

Alanine aminotransferase (ALT) predicts the development of Type 2 diabetes mellitus and cardiovascular disease in Caucasian subjects.

OBJECTIVES

This study aimed to determine the incidence of an elevated ALT and its relationship to metabolic and atherothrombotic risk factors in a healthy British South Asian population.

PATIENTS/METHODS

One hundred and forty-three participants from the West Yorkshire community were recruited randomly from general practice registers and were grouped according to whether their ALT was above or within the normal range (cut-off 35 IU L(-1)) and examined for differences in metabolic and atherothrombotic risk factors. All participants were originally from South Asia, with their grandparents being born in India, Pakistan, or Bangladesh.

RESULTS

The incidence of a raised ALT was 24%. Those with a raised ALT had a more adverse metabolic profile, with significantly higher body mass index, waist/hip ratio, fasting insulin, glucose, homeostasis model assessment homeostasis model assessment insulin resistance (HOMA-IR), and triglycerides, and lower high-density lipoprotein (HDL) cholesterol. Fifty per cent had the metabolic syndrome [International Diabetes Federation (IDF) criteria]. They also had a more adverse atherothrombotic profile, with higher tissue-type plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) antigen. In accordance, the group as a whole showed a positive correlation of ALT (age-adjusted) with waist/hip ratio, insulin, glucose, triglycerides, PAI-1 antigen, factor XIII B subunit, and FXII, and a negative correlation with HDL cholesterol.

CONCLUSION

Raised ALT is common in apparently healthy British South Asians, and is significantly associated with an adverse metabolic and atherothrombotic risk profile.

Increased 5-year mortality in the migrant South Asian stroke patients with diabetes mellitus in the United Kingdom: the West Birmingham Stroke Project

BACKGROUND

Stroke is a major cause of premature mortality in Britain, but its burden is markedly greater amongst South Asians. Because of the paucity of data in this area, we investigated the magnitude and impact of risk from cardiovascular comorbidities on survival amongst South Asian stroke patients.

METHODS

We reviewed hospital case records of consecutive first in life time ischaemic stroke patients [self reported ethnicity and International Classification of Disease (ICD) 10th revision, codes 430-438] admitted to an inner city hospital in the UK between 1997 and 2001. In-hospital mortality data and CVD risk factors were analysed. Five-year mortality data was obtained from the National Health Tracing Services.

RESULTS

Of 1474 ischaemic stroke patients, 242 (16%) were South Asian of whom, 143 (59.1%) were male. The prevalence of hypertension was 70.2%, followed by diabetes 56.2%, hyperlipidaemia 7% and myocardial infarction 10.3%. At 5 years follow-up, 40.5% had died. Cumulative event-free survival at 5 years was significantly poorer in patients with diabetes (log-rank test, p=0.009). On Cox regression analysis, incorporating age, gender and other CVD risk factors, diabetes mellitus was an independent predictor of mortality odds ratio=1.65 (1.02-2.6, p=0.039). Hypertension and dyslipidaemia did not discriminate survival amongst South Asian patients.

CONCLUSION

Stroke mortality in South Asians is associated with presence of diabetes mellitus. This highlights the significance of early and intensive CVD risk modification strategies in ethnic minorities particularly in patients with diabetes. Further research is warranted in South Asians to examine the underlying basis and related pathophysiological abnormalities.

Diabetes mellitus as a prothrombotic condition

Diabetes mellitus (DM) is characterized by fasting hyperglycaemia and a high risk of atherothrombotic disorders affecting the coronary, cerebral and peripheral arterial trees. The risk of myocardial infarction (MI) is 3-5 fold higher in Type 2 DM and a DM subject with no history of MI has the same risk as a non-DM subject with a past history of MI. In total around 70% of deaths are vascular with poorer outcomes to both acute events and cardiological interventions. It was proposed that clustering of vascular risk factors (hyperinsulinaemia, dysglycaemia, dyslipidaemia and hypertension) around insulin resistance (IR) accounted for the increase in risk with Type 2 DM. The importance of this became apparent with the recognition that risk clustering occurs in normoglycaemic and impaired glucose tolerance (IGT) subjects with IR, in total around 25% of the population in addition to long-standing Type 1 subjects with renal disease. Evidence indicates that thrombotic risk clustering also occurs in association with IR, suppression of fibrinolysis due to elevated concentrations of the fibrinolytic inhibitor, plasminogen activator inhibitor-1 (PAI-1) is invariable with IR and there is evidence that this is regulated by the effects of triglyceride on the PAI-1 gene promoter. Other studies indicated that prothrombotic risk (coagulation factors VII, XII and fibrinogen) also associates with the IR syndrome. The development of endothelial cell dysfunction with suppression of nitric oxide and prostacyclin synthesis, combined with platelet resistance to the anti-aggregatory effects of these hormones leads to loss of control over platelet activation. In addition, hyperglycaemia and glycation have marked effects on fibrin structure function, generating a clot which has a denser structure, resistant to fibrinolysis. The combination of increased circulating coagulation zymogens, inhibition of fibrinolysis, changes in fibrin structure/function and alterations in platelet reactivity creates a thrombotic risk clustering which underpins the development of cardiovascular disease.

High prevalence of the metabolic syndrome among Northern Jordanians

BACKGROUND

The prevalence of the metabolic syndrome is rapidly increasing with a considerable ethnic variation within and across populations. This study was conducted to estimate the prevalence of the metabolic syndrome and its individual components using Adult Treatment Panel III (ATP III) criteria among Northern Jordanians.

METHODS

Data were analyzed from a cross-sectional study that included a random sample of 1121 northern Jordanians aged 25 years and above. The metabolic syndrome was defined by ATP III criteria.

RESULTS

The age-adjusted prevalence of the metabolic syndrome was 36.3% (95% CI 33.6-39.0%) (28.7% among men and 40.9% among women). The prevalence increased significantly with age in men and women. The prevalence of the metabolic syndrome was significantly higher in women than in men in age groups of 40-49 and 60 years and above. Low HDL cholesterol was the most common abnormality in men (62.7%), and abdominal obesity was the most common abnormality in women (69.1%).

CONCLUSIONS

Prevalence of the metabolic syndrome in North Jordan is considerably higher than in developed countries and other Arab populations. An integrated approach is needed for the prevention and treatment of the metabolic syndrome.

Ethnic differences in cardiovascular risk factors in healthy Caucasian and South Asian individuals with the metabolic syndrome

BACKGROUND

The metabolic syndrome is a cluster of atherothrombotic risk factors that are commonly associated with insulin resistance.

OBJECTIVES

The aim of this study was to investigate ethnic differences in insulin resistance and non-traditional cardiovascular risk factors in relation to the International Diabetes Federation (IDF) definition of the metabolic syndrome.

PATIENTS AND METHODS

A total of 245 healthy South Asians and 245 age- and sex-matched Caucasians were studied. C-reactive protein (CRP), complement C3, plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA) were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated from fasting plasma glucose and insulin levels.

RESULTS

Fifty Caucasian (20%) and 95 (39%) South Asian subjects had the metabolic syndrome as defined by the IDF. In South Asian subjects, HOMA-IR, CRP, C3, PAI-1 and t-PA were significantly higher in subjects with the metabolic syndrome. In contrast, in Caucasian individuals there was no difference in HOMA-IR or C3 levels and only CRP, PAI-1 and t-PA were higher in subjects with the metabolic syndrome. In a logistic regression model, plasma levels of CRP and PAI-1 were independent predictors of the metabolic syndrome in Caucasians, whereas plasma levels of C3 and t-PA as well as HOMA-IR were independent predictors of the metabolic syndrome in South Asian subjects.

CONCLUSIONS

In the cohort of individuals studied, the IDF definition of the metabolic syndrome was associated with insulin resistance in the South Asian but not the Caucasian population. This work also showed ethnic differences in non-traditional cardiovascular risk factors in the presence of the metabolic syndrome.

Ethnic diversity: South Asian ethnicity is associated with increased coronary artery bypass grafting mortality

OBJECTIVE

South Asian ethnicity might result in a higher atherosclerotic vascular risk compared with white ethnicity. However, the effect of South Asian ethnicity on clinical outcomes after cardiac surgery is unknown. Thus, we determined whether South Asian ethnicity is a predictor of a poorer outcome after coronary artery bypass grafting.

METHODS

We examined data from 6177 South Asian and white patients who underwent coronary artery bypass grafting at the Toronto General Hospital from January 1994 through June 2003 and used propensity score matching techniques to analyze 917 patients from each group in more detail. Patients were matched for age, sex, body surface area, left ventricular ejection fraction, New York Heart Association class, previous cardiac surgery, number of diseased vessels, and other factors. Independent predictors of operative morbidity and mortality were determined by means of multivariate logistic regression.

RESULTS

Overall operative mortality was 1.8%. Mortality was higher in South Asian patients than in white patients (2.5% vs 1.1%, P = .02). Postoperative morbidity (eg, myocardial infarction, sepsis, sternal wound infection, postoperative hospital stay, and use of inotropes) also was higher in the South Asian group. In addition to the standard independent predictors of mortality, South Asian ethnicity was an independent predictor of mortality (odds ratio, 3.1; 95% confidence interval, 1.4-6.8).

CONCLUSIONS

These data indicate that South Asian ethnicity per se is an independent predictor of a poorer outcome after coronary artery bypass grafting and suggest that ethnicity is a cardiovascular risk factor that should be considered when assessing clinical outcomes preoperatively before coronary artery bypass grafting or other interventional revascularization procedures.

Roles of transglutaminases in cardiac and vascular diseases

All transglutaminases share the common enzymatic activity of transamidation, or the cross-linking of glutamine and lysine residues to form N epsilon (gamma-glutamyl) lysyl isopeptide bonds. The plasma proenzyme factor XIII is responsible for stabilizing the fibrin clot against physical and fibrinolytic disruption. Another member of the transglutaminase family, tissue transglutaminase or TG2 is abundantly expressed in cardiomyocytes, vascular cells and macrophages. The transglutaminases have a variety of functions independent of their transamidating activity. For example, TG2 binds and hydrolyzes GTP, thereby fostering signal transduction by several G protein coupled receptors. Accumulating evidence points to novel roles for factor XIII and TG2 in cardiovascular biology including: (a) modulating platelet activity, (b) regulating glucose control, (c) contributing to the development of hypertension, (d) influencing the progression of atherosclerosis, (e) regulating vascular permeability and angiogenesis (f) and contributing to myocardial signaling, contractile activity and ischemia/reperfusion injury. In this review, we summarize the cardiovascular biology of two members of the family of transglutaminases, Factor XIII and TG2.

Effect of pioglitazone on insulin sensitivity, vascular function and cardiovascular inflammatory markers in insulin-resistant non-diabetic Asian Indians

AIMS

To determine the effects of pioglitazone (30 mg once daily for 16 weeks) on insulin sensitivity, insulin-mediated vasodilation, vascular inflammatory markers, fat distribution and lipids in Asian Indians and Caucasians of European ancestry.

METHODS

Cross-sectional study. Eighteen non-diabetic Asian Indians and 17 Caucasians of comparable age (34 +/- 3 vs. 36 +/- 3 years) and body mass index (26.0 +/- 1.2 vs. 24.7 +/- 1.0 kg/m(2)) had measurements of insulin sensitivity (M, insulin clamp at 6 pmol/kg per min), abdominal fat (computed tomographic scan at L4-L5), endothelial-dependent (reactive hyperaemia, RH) and -independent (0.4 mg sublingual nitroglycerin, TNG) vasodilation using brachial artery ultrasound before and after the 2-h clamp at baseline and after pioglitazone therapy.

RESULTS

Asian Indians were insulin resistant compared with Causasians during the baseline clamp (M = 25.6 +/- 1.7 vs. 41.1 +/- 2.2 micromol/kg per min, P < 0.0001) and improved significantly after pioglitazone (to 33.9 +/- 1.7 micromol/kg per min, P < 0.001). Vasodilatory responses to RH and TNG were similar in Asian Indians and Caucasians at baseline and did not change. Insulin-mediated vasodilation improved after pioglitazone in Asian Indians, but not in Caucasians, and correlated with the change in insulin sensitivity (r = 0.52, P = 0.03). C-reactive protein (CRP) was higher in Asian Indians vs. Caucasians (1.6 +/- 0.4 vs. 0.9 +/- 0.2 mg/l) and was negatively correlated with insulin sensitivity (r = -0.53, P = 0.02). In the Asian Indian group, CRP and plasminogen activator inhibitor-1 decreased and adiponectin increased after pioglitazone, but there were no significant changes in total or visceral fat.

CONCLUSIONS

These results demonstrate that insulin-resistant Asian Indians respond favourably to an insulin sensitizer with improvements in insulin sensitivity, cardiovascular and inflammatory risk markers, and vascular responses to insulin. These agents may have a role in decreasing the risk of diabetes and cardiovascular disease in this high-risk population.

Meticillin-resistant Staphylococcus aureus infection in diabetic mice enhanced inflammation and coagulation

BALB/cA mice were used to study the interaction of diabetes and meticillin-resistant Staphylococcus aureus (MRSA) infection on pathogen distribution, cytokine profile and inflammatory and endothelial-injury markers, as well as coagulation and anticoagulation factors. Meticillin-susceptible S. aureus (MSSA) infection did not cause death within the experimental period. MRSA-infected nondiabetic and diabetic mice died on 19·1±1·4 and 10·6±0·7 days post-infection (p.i.), respectively. MRSA and MSSA infection in diabetic mice did not result in symptomatic bacteraemia; however, MRSA infection in diabetic mice significantly reduced glucose levels (P<0·05). Diabetic mice showed significantly higher levels of C-reactive protein, fibrinogen, fibronectin and von Willebrand factor than nondiabetic mice (P<0·05), and MRSA infection further elevated the plasma levels of these inflammatory and endothelial markers (P<0·05). Before infection, diabetic mice had significantly higher plasminogen activator inhibitor-1 (PAI-1) activity, lower antithrombin III (AT-III) and protein C activities (P<0·05), and MRSA infection significantly increased PAI-1 activity further and reduced the activity of AT-III and protein C (P<0·05). MRSA infection increased the production of three Th1 cytokines, interleukin 2 (IL-2), tumour necrosis factor alpha and gamma interferon, in diabetic mice (P<0·05); however, three Th2 cytokines, IL-4, IL-6, IL-10, were elevated at 2 and 4 days p.i., and then dropped gradually. MRSA infection in diabetic mice accelerated the inflammation process, endothelial injury and blood coagulation in diabetic mice. Therefore, the development of proper infection diagnosis and timely use of effective treatments for MRSA-infected diabetic individuals is important and necessary.

Abnormalities of coagulation, platelet function, and fibrinolysis associated with syndromes of insulin resistance

Insulin resistance that accompanies obesity, hypertension, polycystic ovary syndrome, and the early phases of type 2 diabetes is characterized by a prothrombotic state. The prothrombotic state is a reflection of the direct effects of hyperinsulinemia and associated metabolic abnormalities (postprandial hyperglycemia, increased free fatty acids, and hypertriglyceridemia) on platelets, coagulation, and fibrinolysis. Therapies that improve insulin sensitivity and thereby decrease insulin resistance, hyperinsulinemia, and metabolic abnormalities decrease the prothrombotic state.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

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

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