Postchallenge Glucose Research Articles

Concordance of Glucose-Based and of HbA1c-Based Diagnoses of Diabetes in Patients with Peripheral Artery Disease—A Comparison between Two Age Groups

Concordance between glucose-based and HbA1c-based diagnoses of diabetes differ between populations. Here, we aimed at investigating their concordance in younger and in older patients with peripheral artery disease (PAD). We measured fasting glucose as well as HbA1c and performed 75g oral glucose tolerance tests in 188 consecutive patients, 113 older and 75 younger than 65 years, who had sonographically proven PAD but not previously diagnosed diabetes. Based on glucose values, diabetes was diagnosed with fasting plasma glucose (FPG) ≥126 mg/dl or post-challenge glucose ≥200 mg/dl 2 hours after the oral glucose load; based on HbA1c values diabetes was diagnosed with HbA1c ≥6.5%. Among PAD patients <65 years, 5 had diabetes based on glucose criteria, of whom 3 also had diabetes according to the HbA1c criterion, and 70 did not have diabetes according to glucose criteria, of whom 67 also did not have diabetes using HbA1c criteria; among those ≥65 years, 19 had diabetes based on glucose criteria, of whom 10 also had diabetes according to the HbA1c criterion and 94 did not have diabetes based on glucose criteria, of whom 93 also did not have diabetes according to HbA1c criteria. Concordance of glucose and HbA1c criteria was similar in younger and older PAD patients (93.3% and 91.2%; p=0.589). Applying glucose criteria as a standard, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the HbA1c criterion for PAD patients <65 years were 60.0%, 95.7%, 50.0%, and 97.1%, and for those ≥65 years 52.6%, 98.9%, 90.9%, and 91.2%. We conclude that the concordance of glucose and HbA1c criteria among patients with PAD is high and is similar in older and younger subjects. However, for both age groups the sensitivity of the HbA1c criterion is poor in this patient population. Disclosure C.H. Saely: None. A. Vonbank: None. C. Heinzle: None. D. Zanolin: None. B. Larcher: None. A. Mader: None. A. Leiherer: None. A. Muendlein: None. H. Drexel: None.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

Placental DNA Methylation Adaptation to Maternal Glycemic Response in Pregnancy.

Maternal hyperglycemia during pregnancy is associated with excess fetal growth and adverse perinatal and developmental outcomes. Placental epigenetic maladaptation may underlie these associations. We performed an epigenome-wide association study (>850,000 CpG sites) of term placentas and prenatal maternal glycemic response 2-h post oral glucose challenge at 24-30 weeks of gestation among 448 mother-infant pairs. Maternal 2-h glycemia postload was strongly associated with lower DNA methylation of four CpG sites (false discovery rate [FDR] q <0.05) within the phosphodiesterase 4B gene (PDE4B). Additionally, three other individual CpG sites were differentially methylated relative to maternal glucose response within the TNFRSF1B, LDLR, and BLM genes (FDR q <0.05). DNA methylation correlated with expression of its respective genes in placental tissue at three out of four independent identified loci: PDE4B (r = 0.31, P < 0.01), TNFRSF1B (r = -0.24, P = 0.013), and LDLR (r = 0.32, P < 0.001). In an independent replication cohort (N = 65-108 samples), results were consistent in direction but not significantly replicated among tested CpG sites in PDE4B and TNFRSF1B Our study provides evidence that maternal glycemic response during pregnancy is associated with placental DNA methylation of key inflammatory genes whose expression levels are partially under epigenetic control.

Risk factors for hyperglycemia in pregnancy in the DALI study differ by period of pregnancy and OGTT time point.

Risk factors are widely used to identify women at risk for gestational diabetes mellitus (GDM) without clear distinction by pregnancy period or oral glucose tolerance test (OGTT) time points. We aimed to assess the clinical risk factors for Hyperglycemia in pregnancy (HiP) differentiating by these two aspects. Nine hundred seventy-one overweight/obese pregnant women, enrolled in the DALI study for preventing GDM. OGTTs were performed at ≤19 + 6, 24-28 and 35-37 weeks (IADPSG/WHO2013 criteria). Women with GDM or overt diabetes at one time point did not proceed to further OGTTs. Potential independent variables included baseline maternal and current pregnancy characteristics. Multivariate logistic regression. Clinical characteristics independently associated with GDM/overt diabetes were at ≤19 + 6 weeks, previous abnormal glucose tolerance (odds ratio (OR): 3.11; 95% CI: 1.41-6.85), previous GDM (OR: 2.22; 95% CI: 1.20-4.11), neck circumference (NC) (OR: 1.58; 95% CI: 1.06-2.36 for the upper tertile), resting heart rate (RHR, OR: 1.99; 95% CI: 1.31-3.00 for the upper tertile) and recruitment site; at 24-28 weeks, previous stillbirth (OR: 2.92; 95% CI: 1.18-7.22), RHR (OR: 3.32; 95% CI: 1.70-6.49 for the upper tertile) and recruitment site; at 35-37 weeks, maternal height (OR: 0.41; 95% CI: 0.20-0.87 for upper tertile). Clinical characteristics independently associated with GDM/overt diabetes differed by OGTT time point (e.g. at ≤19 + 6 weeks, NC was associated with abnormal fasting but not postchallenge glucose). In this population, most clinical characteristics associated with GDM/overt diabetes were non-modifiable and differed by pregnancy period and OGTT time point. The identified risk factors can help define the target population for future intervention trials.

Ethnic differences in insulin secretory function between black African and white European men with early type 2 diabetes.

To test the hypothesis that men of black (West) African ethnicity (black African men [BAM]) with early type 2 diabetes (T2D) would have greater insulin secretory deficits compared with white European men (WEM), following prediabetic hypersecretion. In 19 BAM and 15 WEM, matched for age, body mass index and duration of diabetes, we assessed and modelled insulin secretory responses to hyperglycaemia stimulated intravenously (hyperglycaemic clamp) and orally (meal tolerance test). With similar post-challenge glucose responses, BAM had lower second-phase C-peptide responses to intravenous glucose (BAM 70.6 vs WEM 115.1 nmol/L/min [ratio of geometric mean 0.55, 95% confidence interval {CI} 0.37, 0.83]; P = .006) and to oral glucose (BAM 65.4 vs WEM 88.5 nmol/L/min [mean difference -23.2, 95% CI -40.0, -6.3]; P = .009). Peripheral insulin response in BAM to oral glucose was preserved (BAM 47.4 vs WEM 59.4 nmol/L/min [ratio of geometric mean 0.89, 95% CI 0.59, 1.35]; P = .566), with relative reductions in insulin clearance (BAM 506.2 vs WEM 630.1 mL/m2 BSA/min [mean difference -123.9, 95% CI -270.5, 22.6]; P = .095), associated with enhanced incretin responses (gastric inhibitory polypeptide incremental area under the curve: BAM 46.8 vs WEM 33.9 μg/L/min [mean difference 12.9, 95% CI 2.1, 23.7]; P = .021). In early T2D, BAM had significantly lower insulin secretory responses to intravenous and oral stimulation than WEM. Lower insulin clearance, potentially driven by increased incretin responses, may act to preserve peripheral insulin concentrations. Tailoring early management strategies to reflect distinct ethnic-specific pathophysiology may improve outcomes in this high-risk population.

Impairments in Adipose Tissue Microcirculation in Type 2 Diabetes Mellitus Assessed by Real-Time Contrast-Enhanced Ultrasound.

In obesity and type 2 diabetes mellitus (T2D), adipose tissue expansion (because of larger adipocytes) results in reduced microvascular density which is thought to lead to adipocyte hypoxia, inflammation, and reduced nutrient delivery to the adipocyte. Adipose tissue microvascular responses in humans with T2D have not been extensively characterized. Furthermore, it has not been determined whether impaired microvascular responses in human adipose tissue are most closely associated with adiposity, inflammation, or altered metabolism. Overnight-fasted healthy controls (n=24, 9 females/15 males) and people with T2D (n=21, 8 females/13 males) underwent a body composition scan (dual-energy X-ray absorptiometry), an oral glucose challenge (50 g glucose) and blood analysis of clinical chemistries and inflammatory markers. Abdominal subcutaneous adipose tissue microvascular responses were measured by contrast-enhanced ultrasound at baseline and 1-hour post-oral glucose challenge. Adipose tissue microvascular blood volume was significantly elevated in healthy subjects 1-hour post-oral glucose challenge; however, this effect was absent in T2D. Adipose tissue microvascular blood flow was lower in people with T2D at baseline and was significantly blunted post-oral glucose challenge compared with controls. Adipose tissue microvascular blood flow was negatively associated with truncal fat (%), glucoregulatory function, fasting triglyceride and nonesterified fatty acid levels, and positively associated with insulin sensitivity. Truncal fat (%), systolic blood pressure, and insulin sensitivity were the only correlates with microvascular blood volume. Systemic inflammation was not associated with adipose tissue microvascular responses. Impaired microvascular function in adipose tissue during T2D is not conditionally linked to systemic inflammation but is associated with other characteristics of the metabolic syndrome (obesity, insulin resistance, hyperglycemia, and dyslipidemia).

42.1 BODY AND MIND: CARDIO-METABOLIC AND IMMUNE FUNCTION IN FIRST EPISODE PSYCHOSIS AND COMPARISON WITH CENTRAL NEUROFUNCTIONAL MEASURES

BackgroundPeople with schizophrenia die on average 15–20 years earlier than the general population, and the mortality gap has grown in recent years. Non-CNS, particularly cardio-metabolic, causes account for the majority of this premature mortality. Abnormalities in the cardio-metabolic and immune system are well established in patients with schizophrenia, but it is unknown if abnormalities are present in people at risk of psychosis and at illness onset prior to antipsychotic treatment, and how they compare to neurofunctional measures. To address this, we conducted a series of meta-analyses and meta-regressions to determine the magnitude and consistency of findings and influence of antipsychotic treatment, exercise and other factors across cardio-metabolic parameters at onset of psychosis.MethodsWe conducted a meta-analysis of peripheral gluco-regulatory, immune and lipid measures and comparison with brain neurofunctional outcomes (including N-acetyl aspartate, gray matter volume and auditory P300 measures) in studies of clinical high risk samples and first episode psychosis, focusing on drug naïve patients. The entire PubMed, EMBase and PsychInfo databases were searched to identify relevant studies. Then we conducted a meta-review statistical comparison of cardio-metabolic and immune function with neurofunctional measures.Results35 studies (>1500 patients and controls) were included in the meta-analyses. Interleukin-6 (g=2.2, p=0.013), and TNF-alpha (g=0.94, p<0.01) levels and fasting insulin and post-challenge glucose levels were elevated with moderate-large effect sizes (g=0.4, p=0.01; g=0.6, p=0.007 respectively) and cholesterol and low density lipoprotein levels were reduced (g=-0.2, p=0.005, and g=-0.22, p=0.001 respectively), whilst triglyceride levels were increased (g=0.14, p<0.05). These findings remained significant in drug naïve patients and after adjusting for the influence of a number of potential confounders (including body mass, exercise levels, smoking). N-acetyl aspartate levels in frontal cortex and auditory P300 amplitude (g=0.83, p<0.0001) were significantly altered in first episode patients relative to controls. The median effect sizes for cardiometabolic dysfunction (g=0.41) was comparable to that of the neurofunctional measures (g=0.42, p>0.3). Moreover, the median effect size for immune alterations (g=1.3) was significantly greater than that for neurofunctional measures (p=0.002).DiscussionWe demonstrate that effect sizes for markers of cardio-metabolic and immune disturbance are comparable in magnitude to those for markers of neurofunctional CNS disturbances from the onset of psychosis, suggesting schizophrenia involves multiple organ systems from illness onset. The three main pathoetiological models by which CNS and non-CNS abnormalities may co-occur in schizophrenia will be discussed. The shared genetic and environmental risk architecture between schizophrenia and cardiometabolic disorders suggests common aspects of pathoetiology.

Short-Term Sitagliptin-Metformin Therapy Is More Effective Than Metformin Or Placebo In Prior Gestational Diabetic Women With Impaired Glucose Regulation

Our pilot study examined the effectiveness of sitagliptin-metformin (SITA-MET), metformin (MET), and placebo (P) therapy on fasting and post-glucose challenge glucose levels in postpartum women with prior gestational diabetes mellitus (GDM) and impaired glucose regulation. Prediabetic women (N = 36, age 18 to 42 years) with recent GDM were randomized to P (one pill twice a day), MET (1,000 mg twice a day), or SITA-MET (50 mg SITA, 1,000 mg MET twice a day) for 16 weeks in a single-blind fashion. An individualized diet and exercise plan were provided to all participants. At baseline and 16 weeks, oral glucose tolerance tests were performed to assess glycemia, mean blood glucose (MBG), and calculate insulin sensitivity (IS) and secretion (SI) indexes. Lipid profile, thyroid-stimulating hormone level, and pregnancy test were performed in the baseline sample. Thirty-three (92%) participants completed the study. At study end, 15 participants had normal glycemia (SITA-MET vs. MET, P; P = .035). MBG, IS, IS-SI index, and waist to height ratio were significantly improved with SITA-MET compared with MET and P treatment. SITAMET therapy was more effective in lowering body mass index and waist circumference compared to P treatment. Our pilot study is the first to evaluate the use of a dipeptidyl peptidase 4 inhibitor combined with MET in glucose-impaired women with a history of GDM. In this investigation, combination SITA-MET was found to be superior to MET and P in improving glycemia and metabolic measures in this prediabetic population. BID = twice a day; BMI = body mass index; BP = blood pressure; BW = body weight; CHOL = cholesterol; DI = disposition index; DM = diabetes mellitus; DPP-4i = dipeptidyl peptidase 4 inhibitor; FBG = fasting blood glucose; GDM = gestational diabetes mellitus; GLP-1 = glucagon-like peptide 1; HDL-C = high-density-lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance; IGI = insulinogenic index; IGR = impaired glucose regulation; IGT = impaired glucose tolerance; IR = insulin resistance; IS = insulin sensitivity; LDL-C = low-density-lipoprotein cholesterol; MBG = mean blood glucose; MET = metformin; OGTT = oral glucose tolerance test; P = placebo; SI = insulin secretion; SIOGTT = Matsuda's insulin sensitivity index; TRG = triglycerides; WC = waist circumference; WHR = waist to hip ratio; WHtR = waist to height ratio.

High-normal estimated glomerular filtration rate and hyperuricemia positively correlate with metabolic impairment in pediatric obese patients.

BackgroundChildhood obesity represents a major health concern worldwide due to its well established detrimental effect on cardiovascular and its potential negative effect on kidney functions. However, biomarkers that can help diagnose early stages of kidney damage in obese children represent an unmet clinical need.ObjectivesIn this study, we asked whether the prevalence of microalbuminuria, estimated glomerular filtration rate (eGFR) or hyperuricemia recorded in a wide cohort of obese children and adolescents would positively correlate with cardiometabolic dysfunction in these subjects.MethodsWe carried out a cross-sectional study on 360 obese children and adolescents between the ages of 3–18 years, enrolled in a tertiary care center. Clinical and biochemical evaluations including oral glucose tolerance tests (OGTTs) were performed on all patients. Microalbuminuria was defined as urinary albumin-to-creatinine ratio (u-ACR) of 30–300 mg/g. All data are expressed as mean ± standard deviation (SD), absolute values or percentages. Sex age-specific and eGFR SDs were used for statistical analyses. Serum uric acid ≥ 5.5 mg/dL was considered abnormal.ResultsThe prevalence of microalbuminuria was 6.4%. Except for a lower insulinogenic-index, no correlations between microalbuminuria and cardiometabolic risk factors were detected. eGFR was < -1 SD and > 1 SD in 1.4% and 60.8% of subjects, respectively. Subjects with an eGFR > 1 SD had higher systolic blood pressure, liver enzymes, insulin resistance, glucose and insulin during OGTT, lower insulin sensitivity and a more prevalent microalbuminuria. Hyperuricemia (27.5%) increased the odds of hypertension, HDL ≤ 10th percentile and glucose ≥ 155.0 mg/dL after 60 minutes of OGTT.ConclusionsA worse cardiometabolic profile was observed in subjects with an eGFR > 1 SD compared to other subgroups. Therefore, pediatric obese patients with eGFR > 1 SD or hyperuricemia should be closely monitored for microalbuminuria and post-challenge glucose and insulin secretion, all potential indicators of renal dysfunction in these young patients.

Correction to: Two-hour post-challenge glucose is a better predictor of adverse outcome after myocardial infarction than fasting or admission glucose in patients without diabetes

Unfortunately, name of co-author "Thozhukat" was misspelled in the original publication and the same is corrected here. The original article has been corrected.

Circulating PCSK9 levels and 2-hPG are positively correlated in metabolic diseases in a Chinese Han population

BackgroundProprotein convertase subtilisin/kexin type 9 (PCSK9), which plays a crucial role in lipoprotein metabolism, has been also regarded as an important marker for atherosclerosis. Available evidence indicated that 2-h postchallenge plasma glucose (2-hPG) could be another biomarker for atherosclerosis. However, currently the association between circulating PCSK9 and 2-hPG remains unclear. Here, we explored this potential link in a Chinese Han population.MethodsTotally, 600 Chinese Han subjects from Nanjing district, China, were enrolled for the 75-g oral glucose tolerance test (OGTT), and they included normal glucose tolerance (NGT, n = 200), impaired glucose regulation (IGR, n = 200), and type 2 diabetes (T2DM, n = 200). Anthropometric and biochemical determinations such as serum lipid measurements were made. A sandwich ELISA assay was performed to measure serum PCSK9 levels in all subjects.ResultsSerum PCSK9 concentrations were higher in IGR group (77.63 ± 28.14 ng/ml) and T2DM group (90.62 ± 39.96 ng/ml) than in NGT group (65.33 ± 32.68 ng/ml), and it was significantly higher in T2DM group than in IGR group (p < 0.01). Serum PCSK9 levels positively correlated with 2-hPG and LDL-C in all subgroups, but presented a positive correlation with fasting blood glucose (FBG) only in T2DM group. Using multiple regression model analysis, we also found that PCSK9 levels closely correlated with 2-hPG in all tested groups. According to multinomial logistic regression analysis, PCSK9 levels positively correlated with T2DM (OR = 1.017[1.010–1.025], p < 0.001) even after adjustment for lipid levels. Moreover, in subjects with normal FBG level, 2-hPG gradually and significantly increased across PCSK9 tertiles (6.68 ± 2.01, 7.48 ± 2.10 and 8.27 ± 2.41 mmol/L, respectively, p < 0.01); however, in subjects with normal 2-hPG levels, no such difference was observed.ConclusionsPCSK9 levels increase as glucose metabolism deteriorated. Serum PCSK9 levels positively correlated with 2-hPG in patients with metabolic diseases.

Clinical Implications of Using Post-Challenge Plasma Glucose Levels for Early Diagnosis of Type 2 Diabetes Mellitus in Older Individuals.

BackgroundThe aim of this study was to explore the differences in the clinical characteristics and diagnostic rates of diabetes mellitus (DM) according to various criteria in different age groups and to evaluate the efficacy of each criterion for screening older patients.MethodsWe studied 515 patients and measured the fasting plasma glucose level (FPG), 2-hour plasma glucose level after the 75 g oral glucose tolerance test (2-hour postload glucose [2-h PG]), and glycosylated hemoglobin (HbA1c) for re-evaluation of hyperglycemia without a history of diabetes. Patients with newly diagnosed DM were grouped by age as younger (<65 years) or older (≥65 years).ResultsOlder patients had significantly lower HbA1c, FPG, and 2-h PG levels and a higher homeostatic level of pancreatic β-cell function compared with younger patients (P<0.001). The older group had the lowest diagnostic rate when using the FPG level (45.5%) and the highest diagnostic rate when using the 2-h PG level (84.6%). These results were mostly due to the higher frequency of isolated post-challenge hyperglycemia in the older patients than in the younger group (28.8% vs. 9.2%). The use of both the FPG and HbA1c levels significantly enhanced the low diagnostic power when employing only the FPG levels in the older group (71.2% vs. 45.5%).ConclusionIn the older patients, the 2-h PG level was the most accurate diagnostic criterion. When we consider the costs and convenience, a combination of the FPG and HbA1c criteria may be recommended as a screening test for DM in older people.

Plasma Asprosin Concentrations Are Increased in Individuals with Glucose Dysregulation and Correlated with Insulin Resistance and First-Phase Insulin Secretion.

Background Adipokines are reported to participate in many common pathologic processes of glucose dysregulation, such as insulin resistance, β-cell dysfunction, and chronic inflammation. Objective To detect the concentrations of plasma asprosin in subjects with impaired glucose regulation (IGR) and newly diagnosed type 2 diabetes (nT2DM) and its relationship to parameters of glucose and lipid metabolism, insulin resistance, and pancreatic β-cell function. Methods 143 eligible participants were included and were divided into three groups including normal glucose regulation (NGR, n = 52), IGR (n = 40), and nT2DM group (n = 51). The intravenous glucose tolerance test (IVGTT) and clinical and biochemical parameters were measured in all participants. Results Plasma asprosin levels were higher in IGR (82.40 ± 91.06 ng/mL, P < 0.001) and nT2DM (73.25 ± 91.69 ng/mL, P < 0.001) groups compared with those in the NGR (16.22 ± 9.27 ng/mL) group, especially in IGR subjects. Correlation analysis showed that plasma asprosin levels were positively correlated with waist circumference (Wc), fasting plasma glucose (FPG), postchallenge plasma glucose (2hPG), HbA1c, triglyceride (TG), and homeostasis model assessment for insulin resistance (HOMA-IR) and negatively correlated with homeostasis model assessment for β-cell function (HOMA-β), area under the curve of the first-phase (0–10 min) insulin secretion (AUC), acute insulin response (AIR), and glucose disposition index (GDI) (all P < 0.05). Multiple logistical regression analyses revealed that plasma asprosin concentrations were significantly correlated with IGR and nT2DM after controlling for age, sex, BMI, and WHR. Conclusions Circulating asprosin might be a predictor of early diagnosis in DM and might be a potential therapeutic target for prediabetes and T2DM.

Utility of HbA1c and fasting plasma glucose for screening of Type 2 diabetes: a meta-analysis of full ROC curves.

There is still debate on the optimal threshold for population-based screening of diabetes (diagnosed by the oral glucose tolerance test) using tests like HbA1c or fasting plasma glucose. Meta-analyses provide meaningful input in such situations. The aim of this article is to perform a meta-analysis that includes the complete information reported in the individual studies of two existing systematic reviews. We screened the individual studies from two systematic reviews and reconstructed the full four-fold tables for every reported threshold. Using a recently proposed meta-analysis model for the comparison of two diagnostic tests, we compared HbA1c with fasting plasma glucose, and estimated meta-analytic receiver operating characteristic curves for both tests using the 11.1 mmol/l threshold of the 2-h post-challenge glucose level (2 h-PG) as the gold standard. We included nine studies from two existing systematic reviews in our analysis. Based on our data set, the optimal threshold lies between 42 and 44 mmol/mol (6.0-6.2%) for HbA1c , and 6.2-6.4 mmol/l for fasting plasma glucose choosing the Youden index as the technical criterion. In addition, we found that there is no relevant difference in the performance of HbA1c and fasting plasma glucose. In our meta-analysis, we found that the optimal threshold with reference to the 2 h-PG should be chosen between 42 and 44 mmol/mol (6.0-6.2%) for HbA1c , and 6.2-6.4 mmol/l for fasting plasma glucose on the basis of maximal sensitivity and specificity.

Relationship between several surrogate estimates of insulin resistance and a direct measure of insulin-mediated glucose disposal: Comparison of fasting versus post-glucose load measurements

AimsThe study aim was to determine the correlation of several surrogate estimates of insulin resistance with a direct measure of insulin action and the ability of these estimates to identify insulin resistant persons. MethodsRetrospective analysis of 454 apparently healthy individuals studied in a clinical research center. The correlations between 11 surrogate estimates of insulin resistance, using either fasting or post-oral glucose challenge values, and a direct measure of insulin-mediated glucose uptake (SSPG concentration during the Insulin Suppression Test) were determined as well as the ability of the surrogate estimates to identify insulin resistant individuals. ResultsAll surrogate estimates were significantly (P < .001) correlated with SSPG concentrations and successfully identified insulin resistant persons. These relationships were of lesser magnitude when estimates were based on fasting data, with the exception of the McAuley index—derived from fasting data, but resembling post-glucose challenge estimates. Moreover, correlation with SSPG concentration, and positive identification of insulin resistance, varied considerably among estimates. ConclusionAll 11 surrogate estimates of insulin resistance significantly correlated with insulin-mediated glucose disposal and identified insulin resistant persons with a reasonable degree of sensitivity and specificity. For identification of insulin resistant individuals, indices based on post-glucose challenge measurements performed better than those based on fasting measurements, with the exception of McAuley index. The quantitative information derived from this analysis should help investigators select the surrogate marker of insulin resistance best suited for their study.

Associations of Physical Activity Intensities with Markers of Insulin Sensitivity.

Objectively measured physical activity (PA) intensity has traditionally been categorized as light, moderate, and vigorous using laboratory calibrated cut points. The relative contribution of time spent across a spectrum of accelerometer-determined intensities on health outcomes is less clear. This study aimed to assess the relationship between objectively measured PA intensity on a continuous scale and markers of insulin sensitivity (IS). Participants at high risk of type 2 diabetes mellitus were recruited from primary care (Leicestershire, UK). PA was measured using an ActiGraph accelerometer. Fasting and postchallenge glucose and insulin levels were assessed using an oral glucose tolerance test. IS was calculated using the Matsuda-IS and the HOMA-IS indices. Log-linear regression modeling was used to assess the relationship between PA intensity, in increments of 500 counts per minute, with markers of IS. Models were controlled for known confounders. Complete data were available for 569 participants. PA intensity was favorably associated with fasting and 2 h of insulin and IS, with the association increasing in magnitude with each increment of 500 counts per minute. Differences in HOMA-IS per 10 min of PA ranged from 12.4% (95% confidence interval = 3.7%-21.8%) to 26.8% (11.0%-44.7%) within the moderate-intensity PA category (from 2000-2499 to 3500-3999 counts per minute). For Matsuda-IS, these differences were 22.0% (10.3%-34.9%) and 34.7% (13.9%-59.3%), respectively. Significant associations for fasting insulin were no longer observed after controlling for body mass index, whereas differences associated with 2-h insulin and IS were attenuated but still significant. PA of any intensity may positively influence glucose regulation and insulin sensitivity in individuals at high risk of type 2 diabetes mellitus in a dose-response manner. Further research is required to identify the intensity thresholds at which clinically relevant benefits occur in this population.

Effect of chronic liraglutide therapy and its withdrawal on time to postchallenge peak glucose in type 2 diabetes.

Delayed timing of peak serum glucose following an oral glucose challenge can predict declining β-cell function and worsening glucose tolerance over time. Accordingly, postchallenge peak glucose is typically delayed in patients with type 2 diabetes (T2DM). However, little is known about the capacity of antidiabetic medications to reverse this delay. Thus, we sought to evaluate the effect of the glucagon-like peptide-1 agonist liraglutide on time to peak glucose in early T2DM. In this secondary analysis of a double-blind placebo-controlled trial, 51 patients with T2DM of 2.6 ± 1.9 yr duration were randomized to daily subcutaneous liraglutide or placebo injection for 48 wk, with oral glucose tolerance test (OGTT) performed every 12 wk while on therapy and after a 2-wk washout. On each OGTT, time to peak glucose was determined from venous glucose measurements at 0, 10, 20, 30, 60, 90, and 120 min. At randomization, most patients in both arms exhibited peak glucose at 90 min postchallenge. By 12 wk, 65.4% of the liraglutide arm had shifted to an earlier peak (vs. 36% on placebo; P = 0.19), with little change thereafter at 24, 36, and 48 wk. After the 2-wk washout, however, 57.7% of those who had been on liraglutide reverted to a later peak (vs. 4.5% on placebo; P < 0.001). This shift was associated with declining β-cell function ( P = 0.001), resulting in higher 2-h blood glucose at washout in the liraglutide arm compared with placebo ( P = 0.001). Thus, although liraglutide possibly might improve the delay in peak glucose, its cessation yielded a worsening thereof and higher glycemia. The mechanisms underlying these observations and their clinical implications warrant further investigation.

Association between different dietary polyphenol subclasses and the improvement in cardiometabolic risk factors: evidence from a randomized controlled clinical trial.

Due to their different chemical structures and metabolism, polyphenol subclasses may have specific impact on cardiometabolic risk factors. Our aim was to evaluate whether the intake of different polyphenol subclasses is associated with clinical outcomes beneficially improved by polyphenols in a nutritional trial performed by our group (postprandial lipid response, glucose homeostasis, early insulin secretion and oxidative stress). The present study is a secondary analysis of a nutritional intervention study with a diet naturally rich in polyphenols. The data are derived from 78 participants at high cardiovascular risk who completed the ETHERPATH trial. The associations between variations in polyphenol subclasses (phenolic acids, anthocyanidins, flavones, flavan-3-ols, flavonols and flavanones) and clinical outcomes beneficially influenced by polyphenols were firstly explored by Spearman's correlation. Thereafter, adjustment for gender, age and body mass index (BMI) was run. Linear regression analysis was used to assess the class of polyphenols that best predicted the outcome. Flavanone intake was inversely correlated with postprandial lipid response, whereas flavone intake was related to postchallenge glucose response. Anthocyanidins and flavan-3-ols associated positively with early insulin secretion. The decrease in urinary isoprostanes correlated with anthocyanidins, flavan-3-ols and flavonols. Correlations did not change after adjustment for gender, age, and BMI. Linear regression analysis showed an independent association between flavonols and urinary isoprostanes, whereas early insulin secretion was mainly associated with flavan-3-ols intake. The results of this study show that a polyphenol-rich diet may have a pleiotropic effect on cardiometabolic risk factors thanks to the specific action of different polyphenol subclasses.

Higher dietary total antioxidant capacity is inversely related to prediabetes: A case-control study.

Dietary total antioxidant capacity (DTAC) has been proposed as a tool for assessing theintake of antioxidants. The relationship between DTAC and blood glucose levels has been investigated mostly in healthy people. The aim of this study was to evaluate the association between DTAC and prediabetes morbidity in a case-control study. We examined 300 individuals with and without prediabetes (n=150/group) who attended a Diabetes Screening Center in Shahreza, Iran. The anthropometric measures, physical activity, and blood glucose levels of all participants were measured. Food intake over the previous year was determined using a semiquantitative food frequency questionnaire, and sex-specific, energy-adjusted DTAC was calculated using the U.S. Department of Agriculture's database. Logistic reg/ression was used to model the relationship between DTAC and prediabetes morbidity. The mean DTAC was significantly lower in individuals with prediabetes than in the control group (P<0.001). Across increasing DTAC quartiles, the participants had lower fasting blood glucose and 2-h postchallenge plasma glucose (Ptrend<0.02). After adjustment for body mass index; physical activity; education; dietary intake of fiber, fat, energy, and coffee; participants in the fourth quartile of DTAC were less likely to experience prediabetes compared with those in the first quartile (odds ratio, 0.18; 95% confidence interval, 0.07-0.49). The DTAC score appears useful when assessing the antioxidant capacity of diet and to better understand the relationship between diet and prediabetes morbidity. Future studies are needed to confirm the findings from the present study in other populations.

Genetic aetiology of glycaemic traits: approaches and insights.

Glycaemic traits such as fasting and post-challenge glucose and insulin measures, as well as glycated haemoglobin (HbA1c), are used to diagnose and monitor diabetes. These traits are risk factors for cardiovascular disease even below the diabetic threshold, and their study can additionally yield insights into the pathophysiology of type 2 diabetes. To date, a diverse set of genetic approaches have led to the discovery of over 97 loci influencing glycaemic traits. In this review, we will focus on recent advances in the genetic aetiology of glycaemic traits, and the resulting biological insights. We will provide a brief overview of results ranging from common, to low- and rare-frequency variant-trait association studies, studies leveraging the diversity across populations, and studies harnessing the power of genetic and genomic approaches to gain insights into the biological underpinnings of these traits.