Ten-year risk of cardiovascular incidence related to diabetes, prediabetes, and the metabolic syndrome

Impact of metabolic syndrome, diabetes and prediabetes on cardiovascular events: Tehran lipid and glucose study

AIMS

To compare the cardiovascular disease (CVD) risk associated with the metabolic syndrome (MetS) and dysglycemia, independent of each other during a median follow-up of 6.7 years.

METHODS

Study population included 4018 Iranian subjects >or=40 years, free of CVD or coronary heart disease (CHD) at baseline. Incidence rates and hazard ratio (HR) were estimated by the presence or absence of MetS and dysglycemia. Considering the glycemic status, the ability of MetS in prediction of CVD after adjustment for age, sex and CVD risk factors was assessed.

RESULTS

The prevalence of MetS, impaired fasting glucose or impaired glucose tolerance (IFG/IGT) and diabetes were 51.4%, 27.3%, and 18.7%, respectively. The addition of MetS to diabetes did not change the CVD risk compared to diabetic subjects without MetS (reference group) after adjustment for age and sex [HR: 1.62 (95% CI 0.93-2.81)] and CVD risk factors [HR: 1.49 (95% CI 0.86-2.60)]. However, addition of MetS to IFG/IGT increased the risk of CVD by 2.5 times compared to those with IFG/IGT without MetS (the risk factor adjusted HR: 2.45 (95% CI 1.32-4.55)).

CONCLUSIONS

In Iranian population, MetS did not add to diabetes to predict incident CVD however, IFG/IGT was a significant predictor only in the presence of MetS.

Antihypertensive medications: benefits of blood pressure lowering and hazards of metabolic effects

Blood pressure reduction is associated with significant reduction in adverse cardiovascular outcomes. Certain blood pressure-lowering drugs have adverse effects on glucose homeostasis, and have been associated with the development of both prediabetes and diabetes during use. There is controversy over the significance of diabetes that develops during treatment with antihypertensives and whether the benefits of blood pressure reduction offset the hazards of dysglycemia that can lead to diabetes. Many treatment guidelines have recently undergone revisions to include consideration for the metabolic effects of antihypertensive drugs, particularly in high-risk populations. This review summarizes the data related to the benefits of blood pressure reduction as well as the adverse metabolic effects and new-onset diabetes associated with some medications.

Components of metabolic syndrome and their combinations as predictors of cardiovascular disease in Japanese patients with type 2 diabetes. Implications for improved definition. Analysis from Japan Diabetes Complications Study (JDCS)

AIM

The prognostic power of metabolic syndrome (MetS) in patients with diabetes has been studied with inconsistent results depending on the definition of MetS. To clarify the best combination of MetS components to predict future cardiovascular disease (CVD) events, we estimated CVD risk in Japanese patients with type 2 diabetes according to MetS components.

METHODS

Patients were categorized according to the presence three MetS components in addition to hyperglycemia. hypertension, dyslipidemia and excess waist circumference (WC) (according to either Japanese or Asian cut-off values). Hazard ratios for CVD events were compared in patients with various categories of MetS components.

RESULTS

At least two components of MetS were required for a significantly elevated risk for CVD; however, component combinations with significantly increased risk differed depending on gender or the WC cut-off value. Any two among 1) excess WC (men > or =90 cm, women > or =80 cm); 2) hypertension (systolic blood pressure > or =130 mmHg or diastolic blood pressure > or =85 mmHg or use of an antihypertensive agent); and 3) dyslipidemia (triglycerides > or =150 mg/dL or HDL-cholesterol <40 mg/dL or use of drug treatment) could be used to identify significantly higher risk (approximately twice) for CVD regardless of gender.

CONCLUSIONS

The results suggest that the current MetS criteria should be modified when applied to patients with type 2 diabetes.

Dairy foods and risk of stroke

BACKGROUND

Consumption of milk and other dairy foods has been associated with reduced risk of stroke, although not all studies have shown this consistently.

METHODS

We examined the association between dairy food intake and risk of stroke subtypes within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Between 1985 and 1988, 26,556 Finnish male smokers aged 50-69 years who had no history of stroke completed a food frequency questionnaire. We used Cox proportional hazards models to estimate relative risks (RRs) and 95% confidence intervals (CIs), adjusted for potential confounders.

RESULTS

During a mean follow-up of 13.6 years, 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were ascertained. We observed positive associations between whole milk intake and risk of intracerebral hemorrhage (RR = 1.41 for the highest vs. lowest quintile of intake; 95% CI = 1.02-1.96) and between yogurt intake and subarachnoid hemorrhage (RR = 1.83 for the highest vs. lowest quintile of intake; 95% CI = 1.20-2.80). Men in the highest quintile of cream intake had a moderate decreased risk of cerebral infarction (0.81; 0.72-0.92) and intracerebral hemorrhage (0.72; 0.52-1.00). There were no strong associations between intakes of total dairy, low-fat milk, sour milk, cheese, ice cream, or butter and risk of any stroke subtype.

CONCLUSIONS

These findings suggest that intake of certain dairy foods may be associated with risk of stroke.

Metabolic syndrome increases the risk of stroke: a 5-year follow-up study in a Chinese population

Limited information is available on the relationship between metabolic syndrome and stroke in the Chinese population. The aim of this study was to establish the prevalence of metabolic syndrome in the Chinese population and the relationship between stroke and metabolic syndrome in that population. 2,173 subjects aged 45 years and above without a history of stroke were recruited from six communities in Chongqing city, China. The participants were followed for incident stroke events (ischemic stroke and hemorrhagic stroke) for 5 years. Incidence rates and hazard ratios (HRs) for both subtypes of stroke were stratified by the presence or absence of metabolic syndrome and by each component. Among the subjects, women had a higher prevalence rate of metabolic syndrome than men (26 vs. 19%). As the number of metabolic syndrome components increased, HRs increased significantly, up to 5.1 (95% CI, 1.9-7.4) for ischemic stroke and 3.3 (95% CI, 1.7-5.7) for hemorrhagic stroke. We found that abdominal obesity had the highest HR (2.12, P < 0.001) for ischemic stroke, followed by metabolic syndrome (HR 1.65, P < 0.001). For hemorrhagic stroke, high blood pressure had the highest HR (2.17, P < 0.001), followed by abdominal obesity (HR 1.83, P < 0.001). After 5-year follow-up, the survival rates of stroke events were 94.2% among those with metabolic syndrome and 96.9% among those without. As the number of metabolic syndrome components increased, survival rates decreased progressively, from 99.6% for individuals with none of the components to 90.1% for those with four to five components. The results showed that metabolic syndrome is highly prevalent among the Chinese adult population and is associated with an increased risk for both ischemic stroke and hemorrhagic stroke.

Short-term treatment with metformin improves the cardiovascular risk profile in first-degree relatives of subjects with type 2 diabetes mellitus who have a metabolic syndrome and normal glucose tolerance without changes in C-reactive protein or fibrinogen

OBJECTIVE

To study if metformin, when administered to first-degree relatives of type 2 diabetes mellitus subjects who have metabolic syndrome and normal glucose tolerance, could improve the cardiovascular risk profile and reduce the levels of both C-reactive protein and fibrinogen.

INTRODUCTION

Metabolic syndrome is associated with higher cardiovascular morbidity and mortality. Metformin has vasculo-protective effects even in normoglycemic subjects, and C-reactive protein and fibrinogen are considered markers of endothelial injury and inflammation.

METHODS

Thirty-one non-diabetic first-degree relatives of type 2 diabetes mellitus subjects with metabolic syndrome were randomized (1:1) and double-blinded for placement in the placebo and metformin groups (850 mg bid/+/-90 days); 16 subjects were administered metformin (mean age 40.0 [33.5-50] years; 13 females) and 15 subjects were in the placebo group (mean age 37.0 [32-42] years; 9 females). Blood samples were collected at baseline and at the end of treatment for biochemical analyses, including an assessment of C-reactive protein and fibrinogen levels.

RESULTS

Metformin improved the lipid profile and decreased fasting plasma glucose, systolic blood pressure, weight and body mass index without changing body composition. For those in the placebo we identified no changes in fibrinogen (282.2 [220.4-323.7] mg/L vs. 286.7 [249.6-295.1] mg/L; NS) or in C-reactive protein levels (0.68 [0.3-1.2] vs. 0.64 [0.3-1.0] mg/L; NS). The same was also observed for the levels of fibrinogen (303.9 [217.6-347.6] mg/L vs. 290.9 [251.5-301.9] mg/L; NS) and C-reactive proteins (0.78 [0.3-1.1] vs. 0.80 [0.4-0.9] mg/L; NS) in the metformin group.

CONCLUSIONS

Metformin treatment in first-degree relatives of type 2 diabetes mellitus sufferers who have metabolic syndrome and normal glucose tolerance improved the cardiovascular risk profile without changing the levels of C-reactive protein and fibrinogen.

Insulin increases reendothelialization and inhibits cell migration and neointimal growth after arterial injury

OBJECTIVE

Insulin has both growth-promoting and protective vascular effects in vitro, however the predominant effect in vivo is unclear. We investigated the effects of insulin in vivo on neointimal growth after arterial injury.

METHODS AND RESULTS

Rats were given subcutaneous control (C) or insulin implants (3U/d;I) 3 days before arterial (carotid or aortic) balloon catheter injury. Normoglycemia was maintained by oral glucose and, after surgery, by intraperitoneal glucose infusion (saline in C). Insulin decreased intimal area (P<0.01) but did not change intimal cell proliferation or apoptosis. However, insulin inhibited cell migration into the intima (P<0.01) and increased expression of smooth muscle cell (SMC) differentiation markers (P<0.05). Insulin also increased reendothelialization (P<0.01) and the number of circulating progenitor cells (P<0.05).

CONCLUSIONS

These results are the first demonstration that insulin has a protective effect on both SMC and endothelium in vivo, resulting in inhibition of neointimal growth after vessel injury.

A gluco-metabolic risk index with cardiovascular risk stratification potential in patients with coronary artery disease

The primary objective of this study was to classify patients with CAD as regards their gluco-metabolic state by easily available clinical variables. A secondary objective was to explore if it was possible to identify CAD patients at a high cardiovascular risk due to metabolic perturbations. The 1,867 patients with CAD were gluco-metabolically classified by an OGTT. Among these, 990 patients had complete data regarding all components of the metabolic syndrome, BMI, HbA1c and medical history. Only FPG and HDL-c adjusting for age significantly impacted OGTT classification. Based on these variables, a neural network reached a cross-validated misclassification rate of 37.8% compared with OGTT. By this criterion, 1,283 patients with complete one-year follow-up concerning all-cause mortality, myocardial infarction and stroke (CVE) were divided into low- and high-risk groups within which CVE were, respectively, 5.1 and 9.4% (p=0.016).Adjusting for confounding variables the relative risk for a CVE based on the neural network was 2.06 (95% CI: 1.18-3.58) compared with 1.37 (95% CI: 0.79-2.36) for OGTT.

CONCLUSIONS

The neural network, based on FPG, HDL-c and age, showed useful risk stratification capacities; it may, therefore, be of help when stratifying further risk of CVE in CAD patients.

Should we treat all patients with coronary heart disease or the equivalent with statins?

Statins have proven benefit in preventing cardiovascular events and should be prescribed for almost all patients with coronary heart disease (CHD) or equivalent. However, evidence is lacking to support treating all such individuals. Potential exceptions include those in the initial days of acute coronary syndrome, those with symptomatic systolic heart failure, those with very low low-density lipoprotein cholesterol, diabetic patients without associated metabolic syndrome, and those with high CHD risk calculated mainly on the basis of advanced age. In these cases, the decision to prescribe statins depends on clinical judgment, and surrogate tests for CHD may be useful.

Cardiovascular therapies and associated glucose homeostasis: implications across the dysglycemia continuum

Certain cardiovascular drugs have adverse effects on glucose homeostasis, which may lead to important long-term implications for increased risks of adverse outcomes. Thiazide diuretics, niacin, and beta-adrenergic blockers impair glucose homeostasis. However, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have demonstrated beneficial metabolic effects. The newer vasodilating beta-blocking agents and calcium antagonists appear to be metabolically neutral. These considerations, in addition to meticulous attention to blood pressure control and lifestyle changes, have the potential to beneficially modify glycemia and long-term risks. These considerations have particular importance in younger patients who may also have pre-diabetes or the metabolic syndrome and who are likely to require therapy over the course of decades.

Fasting blood glucose and the risk of stroke and myocardial infarction

BACKGROUND

Although diabetes is a well-known risk factor of atherosclerotic cardiovascular diseases, the cardiovascular disease risk of glycemia below the current diabetic threshold remains uncertain.

METHODS AND RESULTS

A total of 652,901 Korean men aged 30 to 64 years from the Korean National Health Insurance System were categorized into 8 groups by fasting blood glucose (FBG) level at baseline and were followed up for cardiovascular diseases occurrence during 1992-2001. Over the follow-up period of 8.8 years, 10,954 stroke and 3766 myocardial infarction events occurred. In age-adjusted analyses, there was evidence of linear associations between FBG and myocardial infarction, ischemic stroke, and intracerebral hemorrhagic stroke. However, with additional adjustment for socioeconomic position, behaviors, and other cardiovascular disease risk factors, the associations with myocardial infarction and intracerebral hemorrhagic stroke were markedly attenuated with increased risk only at the highest FBG levels (> or =7.5 mmol/L). With full adjustment, the association with ischemic stroke persisted; a linear increase in the risk of ischemic stroke was observed from FBG level of 5.6 mmol/L. When the analyses were repeated with those persons who had been diagnosed with diabetes removed, there was no evidence of associations of FBG with intracerebral hemorrhagic stroke, but the association with ischemic stroke persisted.

CONCLUSIONS

In this Korean male population, the association with high FBG differed between ischemic stroke, intracerebral hemorrhagic stroke, and myocardial infarction. The linear increase in the risk of ischemic stroke, independently of other cardiovascular risk factors, was observed at a level below the current FBG criteria for impaired fasting glucose (> or =5.6 mmol/L). However, for other cardiovascular diseases, the current cutoff for diagnosing diabetes appropriately identified Korean men at risk.

Comparison of Definitions of Metabolic Syndrome in Relation to the Risk of Developing Stroke and Coronary Heart Disease in Finnish and Swedish Cohorts

Background and Purpose— The purpose of this study was to compare definitions of metabolic syndrome with regard to their prediction of stroke and coronary heart disease incidence.

Methods— The study comprises 4041 men and 3812 women of 6 Finnish and Swedish cohorts aged 25 to 74 years at baseline. Hazard ratio was estimated applying Cox regression analyses adjusting for cohort, cholesterol, and smoking and using age as a time scale. A paired homogeneity test was performed to compare the differences.

Results— A total of 113 (47) ischemic and 43 (15) hemorrhagic stroke and 235 (50) coronary heart disease events were accumulated in men (women). Hazard ratios (95% CIs) for ischemic stroke in men were 1.59 (1.09 to 2.32), 1.52 (1.01 to 2.28), 1.16 (0.77 to 1.74), and 1.27 (0.87 to 1.86), respectively, for the World Health Organization, National Cholesterol Education Program, National Cholesterol Education Program revised, and the International Diabetes Federation definitions of metabolic syndrome, and in women 2.20 (1.15 to 4.19), 2.68 (1.47 to 4.87), 2.31 (1.27 to 4.20), and 1.91 (1.05 to 3.49), respectively. The corresponding hazard ratios (95% CIs) for coronary heart disease were 1.57 (1.21 to 2.04), 1.51 (1.15 to 1.99), 1.63 (1.25 to 2.13), and 1.46 (1.12 to 1.89) in men and 1.32 (0.69 to 2.51), 1.54 (0.85 to 2.79), 1.81 (1.02 to 3.21), and 2.47 (1.37 to 4.45) in women. None of the definitions of metabolic syndrome predicted hemorrhagic stroke. There was no difference between definitions of metabolic syndrome and between a full definition and its individual components.

Conclusions— Metabolic syndrome as well as its individual components predicted the incidence of the ischemic stroke and the coronary heart disease equally well and should be treated equally as well.

Central adiposity and associated lifestyle factors in Cree children

Aboriginal children are prone to central adiposity (CA), a component of the metabolic syndrome. The objective of this study was to determine if lifestyle factors were associated with CA in Canadian Cree children. Children aged 9-12 years were classified as having CA if their waist circumference met or exceeded the 85th percentile of the NHANES III reference. Weight status was determined using the CDC growth reference, dietary intake using three 24 h dietary recalls, physical activity using pedometers, and fitness by completion of the 20 m shuttle run test. Of the 178 children (79% participation rate), 32.6% were normal weight, 23.6% were overweight, and 43.8% were obese. Half (52.2%) of the children had CA (97.4% of obese children, 35.7% of overweight children, and 2.2% of normal weight children). Waist circumference was negatively correlated with pedometer step counts (r = -0.187, p = 0.012) and shuttle run time (r = -0.508, p < 0.001). In children with CA, waist circumference was positively correlated with sweetened beverage intake (r = 0.250, p = 0.016). The odds ratio (adjusted for age and sex) for CA for children consuming 3 or more fruits and vegetables per day was 0.43 (95% CI 0.18 - 0.98), for meeting step recommendations for a healthy body weight was 0.45 (95% CI 0.24 - 0.84), and for relative fitness was 0.12 (95% CI 0.04 - 0.33). CA was prevalent in children who were overweight and obese. Preventive strategies might include promoting a healthy diet, physical activity, and fitness.

Recent advances in metabolic syndrome and cardiovascular disease

Metabolic syndrome is defined as an association of central obesity and several other cardiometabolic risk factors. Dysfunctional visceral adipose tissue and inflammatory status appear to be involved in its genesis. New definitions have decreased the threshold for glycaemia and one has lowered the threshold for waist circumference, leading to an increase in the prevalence of metabolic syndrome. However, the impact on mortality with these new definitions is lower than with the National Cholesterol Education Program-Adult Treatment Panel III 2001 definition. An increase in waist circumference, along with increased glycaemia, triglycerides and/or blood pressure is more highly associated with an increased risk of mortality than are other associations, while a decrease in high density lipoprotein cholesterol increases risk of coronary heart disease. The risk of sudden death and stroke is particularly notable with metabolic syndrome. Metabolic syndrome is associated with an increase in heart rate, pulse pressure, arterial stiffness and left ventricular hypertrophy, impairment of diastolic function, enlargement of the left atrium and atrial fibrillation. In the 2007 European recommendations for the management of high blood pressure, metabolic syndrome is now taken into consideration for both risk stratification and in selecting the optimal therapeutic strategy for arterial hypertension.

Independent associations between metabolic syndrome, diabetes mellitus and atherosclerosis: observations from the Dallas Heart Study

Diabetes mellitus (DM) has been termed a "coronary disease equivalent", yet data suggest that only those DM subjects with metabolic syndrome (MetS) are at increased coronary risk. Using data from the Dallas Heart Study, a large, probability-based population study, we assessed the individual and joint associations between MetS, DM and atherosclerosis, defined as coronary artery calcium (CAC) detected by electron-beam computerised tomography (EBCT) and abdominal aortic plaque (AAP) detected by magnetic resonance imaging. Among 2,735 participants, the median age was 44 years; 1,863 (68%) were non-white; 1,509 (55%) were women; 697 (25.5%) had MetS without DM; 53 (1.9%) had DM without MetS; and 246 (9.0%) had both DM and MetS. The prevalence of CAC increased from those with neither MetS nor DM (16.6%) to MetS only (24.0%) to DM only (30.2%) to both MetS and DM (44.7%) (ptrend <0.0001). The prevalence of CAC was higher in those with both DM and MetS versus either alone (p<0.0001). After adjustment, MetS and DM were each independently associated with CAC (odds ratio [OR] 1.4, 95% confidence intervals [CI] 1.1-1.8; OR 1.8, 95% CI 1.3-2.5, respectively). Compared with the group without DM or MetS, those with both MetS and DM had the most CAC (adjusted OR 2.3; 95% CI 1.6-3.2). All analyses of AAP yielded qualitatively similar results. In conclusion, both MetS and DM are independently associated with an increased prevalence of atherosclerosis, with the highest observed prevalence in subjects with both DM and MetS.

Clinician's Corner: The Metabolic Syndrome: A Lifestyle Medicine Foe Worthy of a Seek and Destroy Mission

The Metabolic syndrome (MetS) is comprised of dyslipidemia, elevated blood pressure, elevated plasma glucose, abdominal obesity and associated prothrombotic and proinflammatory states. It is accompanied by a life long twofold increased risk of cardiovascular disease and a fivefold increase risk for diabetes. Since cardiovascular disease and diabetes are predictable by modifiable risk factors, metabolic syndrome is a prime candidate for lifestyle modification utilizing the tools of Lifestyle Medicine (LM), (exercise, nutritional therapy and behavior modification). Such approaches can prevent the development of full blown Type II diabetes (5) and dramatically modify all of the components of the metabolic syndrome. This article discusses the definition and importance of MetS and how to screen for it and manage it using LM principles.