Troglitazone-Induced Changes in Adiponectin Do Not Affect Endothelial Function in Diabetes

OBJECTIVE

Adiponectin has been proposed to be related to endothelial function. We have examined the relationship between the increase in adiponectin levels that is associated with troglitazone treatment and endothelium-dependent vasodilation in type 2 diabetic patients.

RESEARCH METHODS AND PROCEDURES

Seventy-two patients participated in this randomized, placebo-controlled, double-blinded study. High-resolution ultrasound images were used to measure the flow-mediated dilation (endothelium-dependent) and nitroglycerin-induced dilation (endothelium-independent) of the brachial artery. Laser Doppler perfusion imaging was employed to measure the vascular reactivity in the forearm skin.

RESULTS

Troglitazone treatment resulted in an average 75% increase in the adiponectin levels, but no changes were observed in the endothelium-dependent vasodilation, any other measurement of vascular reactivity, or any other markers of endothelial activation. Also, no changes were observed in the expression of the receptor for advanced glycation end-products in skin biopsies taken from the forearm. Significant correlations were observed during troglitazone treatment between the changes in the adiponectin levels and the changes in fasting plasma glucose (r = -0.29, p < 0.05), hemoglobin A(1c) (r = -0.30, p < 0.05), total cholesterol (r = 0.25, p < 0.05), and low-density lipoprotein-cholesterol (r = 0.34, p < 0.01).

DISCUSSION

The increase in adiponectin levels after troglitazone treatment is not associated with an improvement in the endothelium-dependent vasodilation, indicating that adiponectin is not a major determinant of endothelial function. In addition, receptor for advanced glycation end-products expression in the skin microcirculation is not affected by troglitazone treatment.

Lifestyle intervention improves heart rate recovery from exercise in adults with type 2 diabetes: results from the Look AHEAD study

The primary aims of this paper were (1) to evaluate the influence of intensive lifestyle weight loss and exercise intervention (ILI) compared with diabetes support and education (DSE) upon Heart Rate Recovery (HRR) from graded exercise testing (GXT) and (2) to determine the independent and combined effects of weight loss and fitness changes upon HRR. In 4503 participants (45-76 years) who completed 1 year of intervention, HRR was measured after a submaximal GXT to compare the influence of (ILI) with (DSE) upon HRR. Participants assigned to ILI lost an average 8.6% of their initial weight versus 0.7% in DSE group (P < 0.001) while mean fitness increased in ILI by 20.9% versus 5.8% in DSE (P < 0.001). At Year 1, all exercise and HRR variables in ILI improved (P < 0.0001) versus DSE: heart rate (HR) at rest was lower (72.8 ± 11.4 versus 77.7 ± 11.7 b/min), HR range was greater (57.7 ± 12.1 versus 53.1 ± 12.4 b/min), HR at 2 minutes was lower (89.3 ± 21.8 versus 93.0 ± 12.1 b/min), and HRR was greater (41.25 ± 22.0 versus 37.8 ± 12.5 b/min). Weight loss and fitness gain produced significant separate and independent improvements in HRR.

Effects of N-acetyl-cysteine on endothelial function and inflammation in patients with type 2 diabetes mellitus

Endothelial dysfunction has been associated with premature vascular disease. There is increasing data that N-acetyl-cysteine (NAC) may prevent or improve endothelial dysfunction. The aim of this study was to assess the effects of NAC on endothelial function in patients with type 2 diabetes mellitus, a population at high risk for endothelial dysfunction. Twenty-four patients with diabetes mellitus were assigned randomly to initial therapy with either 900 mg NAC or placebo twice daily in a double-blind, cross-over study design. Flowmediated vasodilation (FMD) of the brachial artery was assessed at baseline, after four weeks of therapy, after a four-week wash-out period, and after another four weeks on the opposite treatment. Plasma and red blood cell glutathione levels and high-sensitivity C-reactive protein (CRP) were measured at all four visits. At baseline, FMD was moderately impaired (3.7±2.9%). There was no significant change in FMD after four weeks of NAC therapy as compared to placebo (0.1±3.6% vs. 1.2±4.2%). Similarly, there was no significant change in glutathione levels. However, median CRP decreased from 2.35 to 2.14 mg/L during NAC therapy (p=0.04), while it increased from 2.24 to 2.65 mg/L with placebo. No side effects were noted during the treatment period. In this double-blind, randomized cross-over study, four weeks of oral NAC therapy failed to improve endothelial dysfunction in patients with diabetes mellitus. However, NAC therapy decreased CRP levels, suggesting that this compound may have some efficacy in reducing systemic inflammation.

Protein content in diabetes nutrition plan

Medical nutrition therapy plays a major role in diabetes management. Macronutrient composition has been debated for a long time. However, there is increasing evidence that a modest increase in dietary protein intake above the current recommendation is a valid option toward better diabetes control, weight reduction, and improvement in blood pressure, lipid profile, and markers of inflammation. Increasing the absolute protein intake to 1.5-2 g/kg (or 20-30% of total caloric intake) during weight reduction has been suggested for overweight and obese patients with type 2 diabetes and normal kidney function. Increased protein intake does not increase plasma glucose, but increases the insulin response and results in a significant reduction in hemoglobin A(1c). In addition, a higher dietary protein intake reduces hunger, improves satiety, increases thermogenesis, and limits lean muscle mass loss during weight reduction using a reduced calorie diet and increased physical activity. It is preferable to calculate protein intake for patients with diabetes as grams per kilogram of body weight and not as a fixed percentage of total energy intake to avoid protein malnutrition when a hypocaloric diet is used. The relationship between protein intake as grams per kilogram of body weight and albumin excretion rate is very weak, except in hypertensive patients and particularly in those with uncontrolled diabetes. A protein intake of 0.8-1 g/kg should be recommended only for patients with diabetes and chronic kidney disease. Other patients with diabetes should not reduce protein intake to less than 1 g/kg of body weight. This review discusses the effects of different amounts of protein intake in a diabetes meal plan. It particular, it discusses the effects of protein intake on renal function, the effects of protein content on diabetes control, and the effects of increased dietary protein on body weight.

Weight loss, glycemic control, and changes in cardiovascular biomarkers in patients with type 2 diabetes receiving incretin therapies or insulin in a large cohort database

OBJECTIVE

Weight loss in patients with type 2 diabetes can improve glycemic control, lower blood pressure, and improve dyslipidemia. Glucagon-like peptide (GLP-1) receptor agonists are associated with weight loss and have potentially beneficial effects on cardiovascular risk biomarkers; however, there is limited information to indicate whether these effects remain outside of clinical trials.

RESEARCH DESIGN AND METHODS

Medical records from the General Electric Centricity research database were analyzed retrospectively to evaluate the relationship between weight loss and glycemic control and changes in blood pressure and lipids in patients with type 2 diabetes initiating therapy with exenatide, sitagliptin, or insulin. Baseline and follow-up (90-365 days after the index date) for weight, A1C, fasting blood glucose (FBG), blood pressure, triglycerides, and LDL, HDL, and total cholesterol were assessed.

RESULTS

A total of 6,280, 5,861, and 32,398 patients receiving exenatide, sitagliptin, or insulin, respectively, were included in the analysis. Exenatide-treated patients lost a mean +/- SD of 3.0 +/- 7.33 kg, sitagliptin-treated patients lost 1.1 +/- 5.39 kg, and insulin-treated patients gained 0.6 +/- 9.49 kg. There was a significant association between weight loss and a reduction in A1C and FBG with exenatide only and a reduction in blood pressure for all therapies. Weight loss was associated with some improvements in lipids, primarily in the GLP-1 receptor agonist group, with little association in the insulin group.

CONCLUSIONS

Weight reduction with GLP-1 receptor agonists was associated with a shift toward a more favorable cardiovascular risk profile. Outcome trials are needed to determine whether improvement in biomarkers translates into a reduction in cardiovascular events in patients with type 2 diabetes.

Effects of adiposity and 30 days of caloric restriction upon protein metabolism in moderately vs. severely obese women

Protein metabolism adapts during caloric restriction (CR) to minimize protein loss, and it is unclear whether greater fat stores favorably affect this response. We sought to determine whether protein metabolism is related to degree of obesity and whether the response to CR is impacted by pre-CR adiposity level. Whole body protein metabolism was studied in 12 obese women over a wide range of BMI (30-53 kg/m(2)) as inpatients using [1-(13)C]leucine as a tracer following 5 days of a weight-maintaining diet and then after 30 days of CR (1,400 kcal deficit with maintained protein intake). When expressed as total rates, per body weight (BW) or per fat-free mass (FFM), leucine rate of appearance (Ra), and nonoxidative leucine disposal (NOLD) were significantly higher in the individuals with a greater degree of obesity (P < 0.05). Leucine oxidation (Rox) was also higher in more highly obese women when expressed as a total rate (P < 0.05) but not if expressed per BW or FFM. CR reduced BW, FFM, and fat mass (P < 0.001), and declines were relatively similar between individuals. CR reduced Ra (P < 0.001), NOLD (P < 0.01), and Rox (P < 0.05), and the relative decline was not affected by differences in fat mass. CR-induced declines were significant even when Ra and NOLD were normalized to BW or FFM. We conclude that fat mass, like FFM, is a key determinant of protein turnover. However, during CR, higher fat mass does not favorably alter the response of protein metabolism and does not mitigate the loss of FFM.

Prevalence and predictors of abnormal cardiovascular responses to exercise testing among individuals with type 2 diabetes: the Look AHEAD (Action for Health in Diabetes) study

OBJECTIVE

We examined maximal graded exercise test (GXT) results in 5,783 overweight/obese men and women, aged 45-76 years, with type 2 diabetes, who were entering the Look AHEAD (Action for Health in Diabetes) study, to determine the prevalence and correlates of exercise-induced cardiac abnormalities.

RESEARCH DESIGN AND METHODS

Participants underwent symptom-limited maximal GXTs. Questionnaires and physical examinations were used to determine demographic, anthropometric, metabolic, and health status predictors of abnormal GXT results, which were defined as an ST segment depression > or =1.0 mm, ventricular arrhythmia, angina pectoris, poor postexercise heart rate recovery (<22 bpm reduction 2 min after exercise), or maximal exercise capacity less than 5.0 METs. Systolic blood pressure response to exercise was examined as a continuous variable, without a threshold to define abnormality.

RESULTS

Exercise-induced abnormalities were present in 1,303 (22.5%) participants, of which 693 (12.0%) consisted of impaired exercise capacity. ST segment depression occurred in 440 (7.6%), abnormal heart rate recovery in 206 (5.0%), angina in 63 (1.1%), and arrhythmia in 41 (0.7%). Of potential predictors, only greater age was associated with increased prevalence of all abnormalities. Other predictors were associated with some, but not all, abnormalities. Systolic blood pressure response decreased with greater age, duration of diabetes, and history of cardiovascular disease.

CONCLUSIONS

We found a high rate of abnormal GXT results despite careful screening for cardiovascular disease symptoms. In this cohort of overweight and obese individuals with type 2 diabetes, greater age most consistently predicted abnormal GXT. Long-term follow-up of these participants will show whether these abnormalities are clinically significant.

STAR 3 randomized controlled trial to compare sensor-augmented insulin pump therapy with multiple daily injections in the treatment of type 1 diabetes: research design, methods, and baseline characteristics of enrolled subjects

BACKGROUND

Sensor-augmented pump therapy (SAPT) integrates real-time continuous glucose monitoring (RT-CGM) with continuous subcutaneous insulin infusion (CSII) and offers an alternative to multiple daily injections (MDI). Previous studies provide evidence that SAPT may improve clinical outcomes among people with type 1 diabetes. Sensor-Augmented Pump Therapy for A1c Reduction (STAR) 3 is a multicenter randomized controlled trial comparing the efficacy of SAPT to that of MDI in subjects with type 1 diabetes.

METHODS

Subjects were randomized to either continue with MDI or transition to SAPT for 1 year. Subjects in the MDI cohort were allowed to transition to SAPT for 6 months after completion of the study. SAPT subjects who completed the study were also allowed to continue for 6 months. The primary end point was the difference between treatment groups in change in hemoglobin A1c (HbA1c) percentage from baseline to 1 year of treatment. Secondary end points included percentage of subjects with HbA1c < or =7% and without severe hypoglycemia, as well as area under the curve of time spent in normal glycemic ranges. Tertiary end points include percentage of subjects with HbA1c < or =7%, key safety end points, user satisfaction, and responses on standardized assessments.

RESULTS

A total of 495 subjects were enrolled, and the baseline characteristics similar between the SAPT and MDI groups. Study completion is anticipated in June 2010.

CONCLUSIONS

Results of this randomized controlled trial should help establish whether an integrated RT-CGM and CSII system benefits patients with type 1 diabetes more than MDI.

Statement by an American Association of Clinical Endocrinologists/American College of Endocrinology consensus panel on type 2 diabetes mellitus: an algorithm for glycemic control

This report presents an algorithm to assist primary care physicians, endocrinologists, and others in the management of adult, nonpregnant patients with type 2 diabetes mellitus. In order to minimize the risk of diabetes-related complications, the goal of therapy is to achieve a hemoglobin A1c (A1C) of 6.5% or less, with recognition of the need for individualization to minimize the risks of hypoglycemia. We provide therapeutic pathways stratified on the basis of current levels of A1C, whether the patient is receiving treatment or is drug naïve. We consider monotherapy, dual therapy, and triple therapy, including 8 major classes of medications (biguanides, dipeptidyl-peptidase-4 inhibitors, incretin mimetics, thiazolidinediones, alpha-glucosidase inhibitors, sulfonylureas, meglitinides, and bile acid sequestrants) and insulin therapy (basal, premixed, and multiple daily injections), with or without orally administered medications. We prioritize choices of medications according to safety, risk of hypoglycemia, efficacy, simplicity, anticipated degree of patient adherence, and cost of medications. We recommend only combinations of medications approved by the US Food and Drug Administration that provide complementary mechanisms of action. It is essential to monitor therapy with A1C and self-monitoring of blood glucose and to adjust or advance therapy frequently (every 2 to 3 months) if the appropriate goal for each patient has not been achieved. We provide a flow-chart and table summarizing the major considerations. This algorithm represents a consensus of 14 highly experienced clinicians, clinical researchers, practitioners, and academicians and is based on the American Association of Clinical Endocrinologists/American College of Endocrinology Diabetes Guidelines and the recent medical literature.

Effects of lifestyle changes to reduce risks of diabetes and associated cardiovascular risks: results from large scale efficacy trials

The increasing prevalence of type 2 diabetes throughout the world is now recognized as a major health problem. A growing segment of the population has impaired glucose tolerance (IGT), which is a strong predictor of progression to type 2 diabetes. Further, 24% of Americans now meet the criteria for the metabolic syndrome, a risk factor for both type 2 diabetes and cardiovascular disease (CVD). The diabetes epidemic is associated with changes in lifestyle-most notably increased energy intake, changes in diet composition and decreased levels of physical activity-and the development of overweight and obesity. This review examines the effects of several intensive lifestyle intervention trials on the risk of diabetes and CVD among high-risk populations. Common features of these lifestyle interventions are dietary modification, weight loss and increased physical activity. These trials indicate that lifestyle modification is effective in decreasing the progression from IGT to type 2 diabetes and reducing CVD risk factors. However, the effectiveness of lifestyle interventions for reductions in CVD events has yet to be determined.

Value of urinary albumin-to-creatinine ratio as a predictor of type 2 diabetes in pre-diabetic individuals

OBJECTIVE

The albumin-to-creatinine ratio (ACR) reflects urinary albumin excretion and is increasingly being accepted as an important clinical outcome predictor. Because of the great public health need for a simple and inexpensive test to identify individuals at high risk for developing type 2 diabetes, it has been suggested that the ACR might serve this purpose. We therefore determined whether the ACR could predict incident diabetes in a well-characterized cohort of pre-diabetic Americans.

RESEARCH DESIGN AND METHODS

A total of 3,188 Diabetes Prevention Program (DPP) participants with a mean BMI of 34 kg/m(2) and elevated fasting glucose, impaired glucose tolerance, and baseline urinary albumin excretion measurements were followed for incident diabetes over a mean of 3.2 years.

RESULTS

Of the participants, 94% manifested ACR levels below the microalbuminuria range and 21% ultimately developed diabetes during follow-up. Quartiles of ACR (median [range] within quartiles: 1, 3.0 [0.7-3.7]; 2, 4.6 [3.7-5.5]; 3, 7.1 [5.5-9.7]; and 4, 16.5 [9.7-1,578]) were positively associated with age, markers of adiposity and insulin secretion and resistance, blood pressure, and use of antihypertensive agents with antiproteinuric effects and inversely related to male sex and serum creatinine. An elevated hazard rate for developing diabetes with doubling of ACR disappeared after adjustment for covariates. Within the DPP intervention groups (placebo, lifestyle, and metformin), we found no consistent trend in incident diabetes by quartile or decile of ACR.

CONCLUSIONS

An ACR at levels below the microalbuminuria range does not independently predict incident diabetes in adults at high risk of developing type 2 diabetes.

Primary prevention of cardiovascular disease and type 2 diabetes in patients at metabolic risk: an endocrine society clinical practice guideline

OBJECTIVE

The objective was to develop clinical practice guidelines for the primary prevention of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) in patients at metabolic risk.

CONCLUSIONS

Healthcare providers should incorporate into their practice concrete measures to reduce the risk of developing CVD and T2DM. These include the regular screening and identification of patients at metabolic risk (at higher risk for both CVD and T2DM) with measurement of blood pressure, waist circumference, fasting lipid profile, and fasting glucose. All patients identified as having metabolic risk should undergo 10-yr global risk assessment for either CVD or coronary heart disease. This scoring will determine the targets of therapy for reduction of apolipoprotein B-containing lipoproteins. Careful attention should be given to the treatment of elevated blood pressure to the targets outlined in this guideline. The prothrombotic state associated with metabolic risk should be treated with lifestyle modification measures and in appropriate individuals with low-dose aspirin prophylaxis. Patients with prediabetes (impaired glucose tolerance or impaired fasting glucose) should be screened at 1- to 2-yr intervals for the development of diabetes with either measurement of fasting plasma glucose or a 2-h oral glucose tolerance test. For the prevention of CVD and T2DM, we recommend that priority be given to lifestyle management. This includes antiatherogenic dietary modification, a program of increased physical activity, and weight reduction. Efforts to promote lifestyle modification should be considered an important component of the medical management of patients to reduce the risk of both CVD and T2DM.

The peroxisome proliferator-activated receptor-gamma agonist pioglitazone represses inflammation in a peroxisome proliferator-activated receptor-alpha-dependent manner in vitro and in vivo in mice

OBJECTIVES

Our aim was to investigate if the peroxisome proliferator-activated receptor (PPAR)-gamma agonist pioglitazone modulates inflammation through PPARalpha mechanisms.

BACKGROUND

The thiazolidinediones (TZDs) pioglitazone and rosiglitazone are insulin-sensitizing PPARgamma agonists used to treat type 2 diabetes (T2DM). Despite evidence for TZDs limiting inflammation and atherosclerosis, questions exist regarding differential responses to TZDs. In a double-blinded, placebo-controlled 16-week trial among recently diagnosed T2DM subjects (n = 34), pioglitazone-treated subjects manifested lower triglycerides and lacked the increase in soluble vascular cell adhesion molecules (sVCAM)-1 evident in the placebo group. Previously we reported PPARalpha but not PPARgamma agonists could repress VCAM-1 expression. Since both triglyceride-lowering and VCAM-1 repression characterize PPARalpha activation, we studied pioglitazone's effects via PPARalpha.

METHODS

Pioglitazone effects on known PPARalpha responses--ligand binding domain activation and PPARalpha target gene expression--were tested in vitro and in vivo, including in wild-type and PPARalpha-deficient cells and mice, and compared with the effects of other PPARgamma (rosiglitazone) and PPARalpha (WY14643) agonists.

RESULTS

Pioglitazone repressed endothelial TNFalpha-induced VCAM-1 messenger ribonucleic acid expression and promoter activity, and induced hepatic IkappaBalpha in a manner dependent on both pioglitazone exposure and PPARalpha expression. Pioglitazone also activated the PPARalpha ligand binding domain and induced PPARalpha target gene expression, with in vitro effects that were most pronounced in endothelial cells. In vivo, pioglitazone administration modulated sVCAM-1 levels and IkappaBalpha expression in wild-type but not PPARalpha-deficient mice.

CONCLUSIONS

Pioglitazone regulates inflammatory target genes in hepatic (IkappaBalpha) and endothelial (VCAM-1) settings in a PPARalpha-dependent manner. These data offer novel mechanisms that may underlie distinct TZD responses.

Overweight Latino children and adolescents have marked endothelial dysfunction and subclinical vascular inflammation in association with excess body fat and insulin resistance

OBJECTIVE

We measured plasma markers of endothelial dysfunction, vascular inflammation, and pro-coagulation in obese Hispanic/Latino children and adolescents with normal glucose tolerance and determined their relationship to body composition and indexes of glucose and lipid metabolism.

RESEARCH DESIGN AND METHODS

A total of 38 lean or obese Hispanic children and adolescents (10-18 years of age) were selected. The overweight group (n = 21) had a BMI >85th percentile for their age and sex, and the lean group (n = 17) had a BMI between the 25th and 50th percentiles. Studies included an oral glucose tolerance test, measurements of plasma glucose and lipids, several markers of endothelial function and inflammation, and determination of body composition by dual X-ray absorptiometry.

RESULTS

The obese group had higher systolic blood pressure and plasma triglycerides and was more insulin resistant than the lean group. The obese group also had higher plasma soluble intercellular adhesion molecule (259.5 +/- 60.0 vs. 223.2 +/- 47.5 ng/ml, P = 0.047), tumor necrosis factor-alpha (2.57 +/- 1.1 vs. 1.74 +/- 0.6 pg/ml, P = 0.008), high-sensitivity C-reactive protein (2.0 vs. 0.13 mg/l, P < 0.0001), plasminogen-activated inhibitor-1 (47.0 +/- 35.7 vs. 12.0 +/- 5.2 ng/ml, P < 0.0001), tissue plasminogen activator (6.1 +/- 1.9 vs. 4.1 +/- 0.8 ng/ml, P = 0.001), and white blood cell count (6.9 vs. 5.3 x 10(3), P = 0.031) and lower levels of adiponectin (8.7 +/- 3.3 vs. 12.6 +/- 5.2 microg/ml, P = 0.022). No significant differences were observed for soluble vascular cell adhesion molecule or interleukin-6.

CONCLUSIONS

Overweight Hispanic children and adolescents with normal glucose tolerance exhibit increased plasma markers of endothelial dysfunction and subclinical inflammation in association with obesity and insulin resistance. These abnormalities may predispose them to the development of type 2 diabetes and cardiovascular disease.

Challenges in the Management of Type 2 Diabetes in the Elderly

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Differences in A1C by race and ethnicity among patients with impaired glucose tolerance in the Diabetes Prevention Program

OBJECTIVE

We sought to examine racial and ethnic differences in A1C in individuals with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

We studied 3,819 individuals aged > or = 25 years with IGT who were found to be eligible to participant in the Diabetes Prevention Program. A1C was compared among five racial and ethnic groups before and after adjustment for factors that differed among groups or might affect glycemia including age, sex, education, marital status, blood pressure, adiposity (BMI and waist circumference), hematocrit, fasting and post-glucose load glucose levels, glucose area under the curve (AUC), beta-cell function, and insulin resistance.

RESULTS

Mean +/- SD A1C was 5.91 +/- 0.50%. Among whites, A1C was 5.80 +/- 0.44%, among Hispanics 5.89 +/- 0.46%, among Asian 5.96 +/- 0.45%, among American Indians 5.96 +/- 0.46%, and among blacks 6.19 +/- 0.59%. Age, sex, systolic blood pressure, diastolic blood pressure, BMI, fasting glucose, glucose AUC, corrected insulin response, and insulin resistance were each independent predictors of A1C. Adjusting for these and other factors, mean A1C levels were 5.78% for whites, 5.93% for Hispanics, 6.00% for Asians, 6.12% for American Indians, and 6.18% for blacks (P < 0.001).

CONCLUSIONS

A1C levels are higher among U.S. racial and ethnic minority groups with IGT after adjustment for factors likely to affect glycemia. Among patients with IGT, A1C may not be valid for assessing and comparing glycemic control across racial and ethnic groups or as an indicator of health care disparities.

Reduction in weight and cardiovascular disease risk factors in individuals with type 2 diabetes: one-year results of the look AHEAD trial

OBJECTIVE

The effectiveness of intentional weight loss in reducing cardiovascular disease (CVD) events in type 2 diabetes is unknown. This report describes 1-year changes in CVD risk factors in a trial designed to examine the long-term effects of an intensive lifestyle intervention on the incidence of major CVD events.

RESEARCH DESIGN AND METHODS

This study consisted of a multicentered, randomized, controlled trial of 5,145 individuals with type 2 diabetes, aged 45-74 years, with BMI >25 kg/m2 (>27 kg/m2 if taking insulin). An intensive lifestyle intervention (ILI) involving group and individual meetings to achieve and maintain weight loss through decreased caloric intake and increased physical activity was compared with a diabetes support and education (DSE) condition.

RESULTS

Participants assigned to ILI lost an average 8.6% of their initial weight vs. 0.7% in DSE group (P < 0.001). Mean fitness increased in ILI by 20.9 vs. 5.8% in DSE (P < 0.001). A greater proportion of ILI participants had reductions in diabetes, hypertension, and lipid-lowering medicines. Mean A1C dropped from 7.3 to 6.6% in ILI (P < 0.001) vs. from 7.3 to 7.2% in DSE. Systolic and diastolic pressure, triglycerides, HDL cholesterol, and urine albumin-to-creatinine ratio improved significantly more in ILI than DSE participants (all P < 0.01).

CONCLUSIONS

At 1 year, ILI resulted in clinically significant weight loss in people with type 2 diabetes. This was associated with improved diabetes control and CVD risk factors and reduced medicine use in ILI versus DSE. Continued intervention and follow-up will determine whether these changes are maintained and will reduce CVD risk.

The role of glucose as an independent cardiovascular risk factor

The role of hyperglycemia as an independent risk factor for the development of atherosclerosis and CVD is strongly suggested by data from large epidemiologic studies as well as by numerous clinical trials. However, the specific roles of elevated fasting plasma glucose, postprandial glucose levels, and average blood glucose as measured by glycosylated hemoglobin (HbA(1c)) are less clear. Population studies and clinical trials addressing these issues have been reviewed with the conclusion that HbA(1c) is an independent risk factor for CVD in both diabetic and nondiabetic subjects. There is also strong evidence that postchallenge plasma glucose levels independently predict CVD events, whereas the evidence that fasting plasma glucose levels are predictive is much weaker. The implications for treatment are that targets for HbA(1c) and postprandial glucose levels are important to achieve, not only to reduce the risk of microvascular complications, but also to reduce the risk of CVD morbidity and mortality in people with diabetes.

Air pollution and inflammation in type 2 diabetes: a mechanism for susceptibility

BACKGROUND

Particulate air pollution has been associated with several adverse cardiovascular health outcomes, and people with diabetes may be especially vulnerable. One potential pathway is inflammation and endothelial dysfunction-processes in which cell adhesion molecules and inflammatory markers play important roles.

AIM

To examine whether plasma levels of soluble intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and von Willebrand factor (vWF) were associated with particle exposure in 92 Boston area residents with type 2 diabetes.

METHODS

Daily average ambient levels of air pollution (fine particles (PM2.5), black carbon (BC) and sulphates) were measured approximately 500 m from the patient examination site and evaluated for associations with ICAM-1, VCAM-1 and vWF. Linear regressions were fit to plasma levels of ICAM-1, VCAM-1 and vWF, with the particulate pollutant index, apparent temperature, season, age, race, sex, glycosylated haemoglobin, cholesterol, smoking history and body mass index as predictors.

RESULTS

Air pollutant exposure measures showed consistently positive point estimates of association with the inflammatory markers. Among participants not taking statins and those with a history of smoking, associations between PM(2.5), BC and VCAM-1 were particularly strong.

CONCLUSIONS

These results corroborate evidence suggesting that inflammatory mechanisms may explain the increased risk of air pollution-associated cardiovascular events among those with diabetes.