Navigating the choices for diabetes prevention

Matrix Metalloproteinase 9 Gene Promoter (rs 3918242) Mutation Reduces the Risk of Diabetic Microvascular Complications

BACKGROUND

Many studies have evaluated the association between matrix metalloproteinase 9 (MMP9) gene promoter polymorphism and diabetic microvascular complications. However, the results are conflicting and inconclusive. The aim of this meta-analysis was to evaluate the association more precisely.

MATERIALS AND METHODS

Studies were retrieved from the PubMed, Embase, Medline, China National Knowledge Infrastructure, Web of Science, and Cochrane databases. All statistical analyses were performed using Review Manager 5.2.

RESULTS

Data were abstracted from four case-control studies that included 446 patients with diabetic microvascular complications and 496 diabetic control subjects. The MMP9-1562 C/T genotype was significantly associated with the risk of diabetic nephropathy after stratification by specific type of microvascular complication (CT + TT vs. CC: OR = 0.42, 95% CI = 0.26-0.69, p = 0.0006; TT vs. CC + CT: OR = 0.37, 95% CI = 0.19-0.76, p = 0.006).

CONCLUSIONS

This study adds to the evidence that MMP9-1562 T gene mutation might reduce the risk of diabetic nephropathy.

Effects of Acute Ingestion of Native Banana Starch on Glycemic Response Evaluated by Continuous Glucose Monitoring in Obese and Lean Subjects

An abnormal glycemic profile, including postprandial glycemia and acute glucose spikes, precedes the onset of overt diabetes in obese subjects. Previous studies have shown the beneficial effects of chronic native banana starch (NBS) supplementation. In this study, we examined the effects of acute ingestion of NBS on glycemic profiles by means of continuous glucose monitoring in obese and lean subjects. In a crossover study, obese and lean subjects consumed beverages containing either 38.3 g of NBS or 38.3 g of digestible corn starch (DCS) twice daily during 4 days. On day 5, a 3-h meal tolerance test (MTT) was performed to evaluate glucose and insulin responses. After 1 week of washout period, treatments were inverted. NBS supplementation reduced the 48-h glycemia AUC in lean, obese, and in the combined group of lean and obese subjects in comparison with DCS. Postprandial glucose and insulin responses at MTT were reduced after NBS in comparison with DCS in all groups. However, no changes were observed in glycemic variability (GV) indexes between groups. In conclusion, acute NBS supplementation improved postprandial glucose and insulin responses in obese and lean subjects during 48 h of everyday life and at MTT. Further research to elucidate the mechanism behind these changes is required.

Relationships between obesity, glycemic control, and cardiovascular risk factors: a pooled analysis of cross-sectional data from Spanish patients with type 2 diabetes in the preinsulin stage

BACKGROUND

Obesity is associated with the onset of type 2 diabetes mellitus (T2D), but reports conflict regarding the association between obesity and macrovascular complications. In this study, we investigated associations between cardiovascular risk factors and body mass index (BMI) and glycemic control in non-insulin-treated patients with T2D.

METHODS

Authors gathered cross-sectional data from five observational studies performed in Spain. Generalized logit models were used to analyze the relationship between cardiovascular risk factors (independent variables) and 5 BMI strata (<25 kg/m2, 25 to <30 kg/m2, 30 to <35 kg/m2, 35 to <40 kg/m2, ≥40 kg/m2) and 5 glycated hemoglobin (HbA1c) strata (≤6.5%, >6.5-7%, >7-8%, >8-9%, >9%) (dependent outcomes).

RESULTS

In total, data from 6442 patients were analyzed. Patients generally had mean values of investigated cardiovascular risk factors outside recommended thresholds. Younger patients had higher BMI, triglyceride levels and HbA1c than their older counterparts. Diastolic blood pressure, systolic blood pressure and triglyceride levels were directly correlated with BMI strata, whereas an inverse correlation was observed between BMI strata and high-density lipoprotein cholesterol (HDL-C) levels, patient age, and duration of T2D. Increased duration of T2D and total cholesterol levels, and decreased HDL-C levels were associated with a higher HbA1c category. BMI and HbA1c levels were not associated with each other.

CONCLUSIONS

As insulin-naïve patients with T2D became more obese, cardiovascular risk factors became more pronounced. Higher BMI was associated with younger age and shorter duration of T2D, consistent with the notion that obesity at an early age may be key to the current T2D epidemic. Glycemic control was independent of BMI but associated with abnormal lipid levels. Further efforts should be done to improve modifiable cardiovascular risk factors.

Beyond fasting plasma glucose: the association between coronary heart disease risk and postprandial glucose, postprandial insulin and insulin resistance in healthy, nondiabetic adults

OBJECTIVE

Prediabetes is defined by elevations of plasma glucose concentration, and is aimed at identifying individuals at increased risk of type 2 diabetes and coronary heart disease (CHD). However, since these individuals are also insulin resistant and hyperinsulinemic, we evaluated the association between several facets of carbohydrate metabolism and CHD risk profile in apparently healthy, nondiabetic individuals.

METHODS

Plasma glucose and insulin concentrations were measured before and at hourly intervals for eight hours after two test meals in 281 nondiabetic individuals. Insulin action was quantified by determining the steady-state plasma glucose (SSPG) concentration during the insulin suppression test. CHD risk was assessed by measurements of blood pressure and fasting lipoprotein profile.

RESULTS

For purposes of analysis, the population was divided into tertiles, and the results demonstrated that the greater the 1) fasting plasma glucose (FPG) concentration, 2) incremental plasma insulin response to meals, and 3) SSPG concentration, the more adverse the CHD risk profile (p<0.05). In contrast, the CHD risk profile did not significantly worsen with increases in the incremental plasma glucose response to meals.

CONCLUSIONS

In nondiabetic individuals, higher FPG concentrations, accentuated daylong incremental insulin responses to meals, and greater degrees of insulin resistance are each associated with worse CHD risk profile (higher blood pressures, higher triglycerides, and lower high density lipoprotein cholesterol concentrations). Interventional efforts aimed at decreasing CHD in such individuals should take these abnormalities into consideration.

Intracellular adhesion molecule-1 K469E gene polymorphism and risk of diabetic microvascular complications: a meta-analysis

BACKGROUND

A number of studies evaluated the association of intracellular adhesion molecule-1 (ICAM-1) K469E (rs5498, A/G) gene polymorphism with diabetic microvascular complications (DMI) including diabetic nephropathy (DN) and diabetic retinopathy (DR) in different populations. However, the results of individual studies remain conflicting.

METHODS

A comprehensive search was conducted to identify all eligible studies of the above-mentioned associations. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were assessed using the fixed or random effect model.

RESULTS

Seven studies involving 3411 subjects were included. Overall, the meta-analysis showed a significant association of the A allele with increased risk of DMI susceptibility in a recessive model (OR = 1.37, 95% CI 1.04-1.80, P = 0.02). In the subgroup analysis stratified by ethnicity, significant association was found in Asians but not in Caucasians (OR = 1.78, 95% CI 1.13-2.81, P = 0.01; OR = 1.10, 95% CI 0.79-1.54, P = 0.58, respectively). Moreover, it showed a significant association between the A allele and risk of DN in a recessive model (OR = 1.25, 95% CI 1.02-1.55, P = 0.04).

CONCLUSIONS

This meta-analysis suggested that the K469E polymorphism in ICAM-1 gene might affect individual susceptibility to DMI and showed a discrepancy in different ethnicities. Further investigations are needed to validate the association.

Blockade of receptor activator of nuclear factor-κB (RANKL) signaling improves hepatic insulin resistance and prevents development of diabetes mellitus

Hepatic insulin resistance is a driving force in the pathogenesis of type 2 diabetes mellitus (T2DM) and is tightly coupled with excessive storage of fat and the ensuing inflammation within the liver. There is compelling evidence that activation of the transcription factor nuclear factor-κB (NF-κB) and downstream inflammatory signaling pathways systemically and in the liver are key events in the etiology of hepatic insulin resistance and β-cell dysfunction, although the molecular mechanisms involved are incompletely understood. We here test the hypothesis that receptor activator of NF-κB ligand (RANKL), a prototypic activator of NF-κB, contributes to this process using both an epidemiological and experimental approach. In the prospective population-based Bruneck Study, a high serum concentration of soluble RANKL emerged as a significant (P<0.001) and independent risk predictor of T2DM manifestation. In close agreement, systemic or hepatic blockage of RANKL signaling in genetic and nutritional mouse models of T2DM resulted in a marked improvement of hepatic insulin sensitivity and amelioration or even normalization of plasma glucose concentrations and glucose tolerance. Overall, this study provides evidence for a role of RANKL signaling in the pathogenesis of T2DM. If so, translation to the clinic may be feasible given current pharmacological strategies to lower RANKL activity to treat osteoporosis.

Differential pharmacology and benefit/risk of azilsartan compared to other sartans

Azilsartan, an angiotensin II type 1 (AT₁) receptor blocker (ARB), was recently approved by regulatory authorities for treatment of hypertension and is the 8th ARB to join the clinical market. This article discusses the medical reasons for introducing a new AT₁ receptor blocker and reviews the experimental and clinical studies that have compared the functional properties of azilsartan to those of other ARBs. The main question addressed is: Does azilsartan have distinguishing features that should motivate choosing it over any of the other sartans for use in clinical practice? Based on studies conducted to date in hypertensive patients without serious comorbidities, azilsartan appears to be characterized by a superior ability to control 24-hour systolic blood pressure (BP) relative to other widely used ARBs including valsartan, olmesartan, and candesartan, and presumably others as well (eg, losartan). Compared to these other ARBs, azilsartan may increase the BP target control and response rate by an absolute value of 8%–10%. Greater antihypertensive effects of azilsartan might be due in part to its unusually potent and persistent ability to inhibit binding of angiotensin II to AT₁ receptors. Preclinical studies have indicated that azilsartan may also have potentially beneficial effects on cellular mechanisms of cardiometabolic disease and insulin sensitizing activity that could involve more than just blockade of AT₁ receptors and/or reduction in BP. However, the clinical relevance of these additional actions is unknown. Given that the general ability of antihypertensive drugs to protect against target organ damage is largely mediated by their ability to decrease BP, the enhanced antihypertensive effects of azilsartan should serve to justify clinical interest in this ARB relative to other molecules in the class that have a lower capacity to reduce BP.

Initial and subsequent therapy for newly diagnosed type 2 diabetes patients treated in primary care using data from a vendor-based electronic health record

BACKGROUND

Diabetes is a leading cause of death and disability, and its prevalence is increasing. When diet fails, patients with type 2 diabetes mellitus (T2DM) are prescribed oral hypoglycemics for glycemic control. Few studies have explored initial use or change from initial oral hypoglycemic therapy in the primary care setting. We aimed to describe the utilization of initial oral hypoglycemics among newly diagnosed patients with diabetes from 1998-2009 and changes from initial to subsequent therapy among patients prescribed older oral hypoglycemic agents using electronic health records.

METHODS

This observational cohort study used electronic health records from newly diagnosed patients with T2DM between 1 January 1998 and 31 March 2009 at two large health systems in the USA. Oral hypoglycemics included older (biguanide, sulfonylurea, and thiazolidinedione) and newer agents (incretin mimetic agents, alpha-glucosidase inhibitors, and D-phenylalanine derivatives). Multinomial regression models were fit to evaluate initial older oral hypoglycemic medication. We used incidence density sampling and conditional logistic regression models to evaluate predictors of regimen change.

RESULTS

Most patients were treated from the biguanide class of oral hypoglycemics (67%), but there were differences in initial prescribing by age and race. HbA1c (Odds Ratio for HbA1c 7.0-8.9 vs < 7.0, 5.87 [95% Confidence Interval: 3.62-9.52]; Odds Ratio for HbA1c ≥ 9 vs < 7.0, 20.25 [95% Confidence Interval: 8.32-49.29] and Black people (Odds Ratio, 0.29 [95% Confidence Interval: 0.14, 0.60]) versus White people were associated with regimen change in the adjusted analysis.

CONCLUSIONS

Clinical and demographic characteristics influence choice and duration of initial oral hypoglycemic treatment as well as regimen changes.

Hemoglobin A1c as a diagnostic tool: public health implications from an actor-network perspective

Public health arguments for collecting hemoglobin A1c (HbA1c) data, particularly in clinical settings, should be reframed to place more emphasis on nonmedical determinants of population health. We compare individual- with population-level interpretations of HbA1c titers. This comparison reveals that public health researchers need to pay close attention to diagnostic tests and their uses, including rhetorical uses. We also synthesize historical and current evidence to map out 2 possible scenarios for the future. In the first scenario, prevention efforts emphasize primary care and focus almost entirely downstream. The second scenario anticipates downstream interventions but also upstream interventions targeting environments. Our analysis adapts actor-network theory to strategic planning and forecasting in public health.

Oxidative DNA damage: antioxidant response in postprandial hyperglycaemia in type 2 diabetes mellitus

The mechanism by which postprandial glucose load and sudden cardiac death are linked is not fully understood. This study compares the postprandial response of 8-hydroxy-deoxy-guanosine (8-OHdG)and erythrocyte glutathione (GSH) in control and type 2 diabetes groups. 8-OHdG was significantly elevated in type 2 diabetic patients (824.1±331.2 and 1087±273.1 pg/ml at the first and second hours respectively, p<0.05, versus 600.4±214.4 pg/ml at baseline) following a glucose load. This was associated with a significant reduction in the level of erythrocyte GSH after the first hour (59.1±9 mg/100ml; p<0.001) compared with the basal level (72.1±9 mg/100ml), followed by a significant elevation in the second hour (71.5±11.1 mg/100ml; p<0.001) compared with the first hour, bringing the GSH level only back to base level. The increase in 8-OHdG in people with type 2 diabetes during the postprandial period further supports previous evidence of a defective antioxidant response and greater risk of heart attack due to blood vessel endothelial cell damage and smooth muscle proliferation.

Screening for type 2 diabetes in a multiethnic setting using known risk factors to identify those at high risk: a cross-sectional study

Introduction

Screening enables the identification of type 2 diabetes mellitus (T2DM) during its asymptomatic stage and therefore allows early intervention which may lead to fewer complications and improve outcomes. A targeted screening program was carried out in a United Kingdom (UK) multiethnic population to identify those with abnormal glucose tolerance.

Methods

A sample of individuals aged 25–75 years (40–75 white European) with at least one risk factor for T2DM were invited for screening from 17 Leicestershire (UK) general practices or through a health awareness campaign. All participants received a 75 g oral glucose tolerance test, cardiovascular risk assessment, detailed medical and family histories and anthropometric measurements.

Results

In the 3,225 participants who were screened. 640 (20%) were found to have some form of abnormal glucose tolerance of whom 4% had T2DM, 3% impaired fasting glucose (IFG), 10% impaired glucose tolerance (IGT) and 3% both IFG and IGT. The odds of detecting IGT was approximately 60% greater (confounder-adjusted odds ratios [OR] 1.67 [1.22–2.29]) in the South Asian population.

Conclusions

Around one in five people who had targeted screening have IGT, IFG or T2DM, with a higher prevalence in those of South Asian origin. The prevalence of undetected T2DM is lower in South Asians compared to previously published studies and maybe due to increased awareness of this group being at high risk.

Prediabetes: the importance of early identification and intervention

Prediabetes is a state of abnormal glucose homeostasis characterized by the presence of impaired fasting glucose, impaired glucose tolerance, or both. Individuals with prediabetes are at increased risk for type 2 diabetes, compared with individuals with normal glucose values (normal fasting plasma glucose, < 100 mg/dL [5.6 mmol/L]). The increased risk for cardiovascular disease in prediabetes is multifactorial, with etiologies including insulin resistance, hyperglycemia, dyslipidemia, hypertension, systemic inflammation, and oxidative stress. The preferred treatment is intensive lifestyle management and aggressive pharmacologic therapies directed toward individual coronary heart disease risk factors. The use of antihyperglycemic agents in this setting is a topic of intense debate. This review discusses the pathophysiology of prediabetes and its clinical implications, highlighting the importance of early identification and intervention.

Optimizing lipid-lowering therapy in the prevention of coronary heart disease

Optimized lipid-lowering therapy is laid out in guidelines from national and international bodies. Statins are first-line treatment and instituted early in secondary prevention. The challenge in primary prevention is identification of the person at risk. This can be achieved by using scoring systems that assess classical risk factors, and then by adding information from predictive panels of biomarkers related to atherogenic pathways and by noninvasive imaging of vascular beds. At present, outcome trials validate the widespread use of statins in the population but studies of other agents have not generated proof of efficacy. Levels of high-density lipoprotein are related inversely to coronary heart disease risk but, so far, it is unclear if increasing high-density lipoprotein leads to a reduction in risk. Clinical trials on the utility of high-density lipoprotein raising on a background of statin therapy are underway.

Advances in the treatment of prediabetes

Type 2 diabetes mellitus (T2DM) is epidemic in most developed and many developing countries. Owing to the associated morbidity, mortality and high costs of care, T2DM is an important global public health challenge and target for prevention. Patients at high risk for T2DM (referred to as having prediabetes) can be easily identified based on fasting glucose levels or responses to an oral glucose tolerance test (OGTT). More recently, glycosylated hemoglobin (i.e. HbA1c, which is also termed A1C in the US) has also been introduced as a diagnostic tool for both prediabetes and diabetes. Such patients are also at risk for cardiovascular disease (CVD). Since obesity and physical inactivity are important risk factors for T2DM, lifestyle interventions, emphasizing modest weight loss and increases in physical activity, should be recommended for most patients with prediabetes. Such interventions are safe and effective and also reduce risk factors for CVD. A number of oral antidiabetic agents have been shown to be effective at delaying onset of T2DM in patients with prediabetes. Thiazolidinediones (TZDs) are the most effective, reducing incident diabetes by up to 80%. Metformin, acarbose and orlistat also reduce incident diabetes, but their efficacy is much lower than the TZDs. Pharmacologic interventions may be appropriate for patients at particular risk for developing diabetes, but the benefits of treatment need to be balanced against the safety and tolerability of the intervention. If pharmacologic treatment is warranted, metformin should be considered first because of its favorable overall safety, tolerability, efficacy and cost profile.