Elevated 1-h post-load plasma glucose levels in subjects with normal glucose tolerance are associated with a pro-atherogenic lipid profile

International Diabetes Federation Position Statement on the 1-hour post-load plasma glucose for the diagnosis of intermediate hyperglycaemia and type 2 diabetes

Many individuals with intermediate hyperglycaemia (IH), including impaired fasting glycaemia (IFG) and impaired glucose tolerance (IGT), as presently defined, will progress to type 2 diabetes (T2D). There is confirmatory evidence that T2D can be prevented by lifestyle modification and/or medications, in people with IGT diagnosed by 2-h plasma glucose (PG) during a 75-gram oral glucose tolerance test (OGTT). Over the last 40 years, a wealth of epidemiological data has confirmed the superior value of 1-h plasma glucose (PG) over fasting PG (FPG), glycated haemoglobin (HbA1c) and 2-h PG in populations of different ethnicity, sex and age in predicting diabetes and associated complications including death. Given the relentlessly rising prevalence of diabetes, a more sensitive, practical method is needed to detect people with IH and T2D for early prevention or treatment in the often lengthy trajectory to T2D and its complications. The International Diabetes Federation (IDF) Position Statement reviews findings that the 1-h post-load PG ≥ 155 mg/dL (8.6 mmol/L) in people with normal glucose tolerance (NGT) during an OGTT is highly predictive for detecting progression to T2D, micro- and macrovascular complications, obstructive sleep apnoea, cystic fibrosis-related diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, and mortality in individuals with risk factors. The 1-h PG of 209 mg/dL (11.6 mmol/L) is also diagnostic of T2D. Importantly, the 1-h PG cut points for diagnosing IH and T2D can be detected earlier than the recommended 2-h PG thresholds. Taken together, the 1-h PG provides an opportunity to avoid misclassification of glycaemic status if FPG or HbA1c alone are used. The 1-h PG also allows early detection of high-risk people for intervention to prevent progression to T2D which will benefit the sizeable and growing population of individuals at increased risk of T2D. Using a 1-h OGTT, subsequent to screening with a non-laboratory diabetes risk tool, and intervening early will favourably impact the global diabetes epidemic. Health services should consider developing a policy for screening for IH based on local human and technical resources. People with a 1-h PG ≥ 155 mg/dL (8.6 mmol/L) are considered to have IH and should be prescribed lifestyle intervention and referred to a diabetes prevention program. People with a 1-h PG ≥ 209 mg/dL (11.6 mmol/L) are considered to have T2D and should have a repeat test to confirm the diagnosis of T2D and then referred for further evaluation and treatment. The substantive data presented in the Position Statement provides strong evidence for redefining current diagnostic criteria for IH and T2D by adding the 1-h PG.

The Triglycerides and Glucose (TyG) Index Is Associated with 1-Hour Glucose Levels during an OGTT

BACKGROUND AND OBJECTIVES

Among individuals with normal glucose tolerance (NGT), subjects with high levels of plasma glucose (≥155 mg/dL) at sixty minutes during an oral glucose tolerance test (1h-OGTT) are at an increased risk of developing type 2 diabetes. We investigated the association between the triglycerides and glucose (TyG) index, a novel marker of insulin resistance, with 1h-OGTT glucose plasma concentrations.

MATERIAL AND METHODS

1474 non-diabetic Caucasian subjects underwent a 75 g OGTT and were divided into two groups according to the cutoff 1h-OGTT plasma glucose < 155 mg/dL (NGT-1h-low) and ≥ 155 mg/dL (NGT-1h-high). The TyG index was calculated as ln [fasting triglycerides (milligrams per deciliter) × fasting blood glucose (milligrams per deciliter)/2]. Multivariable linear and logistic regression analyses were used to establish the contribution of the TyG index to the variability of 1h-OGTT glucose, and how the former affected the risk of being NGT-1h-high.

RESULTS

1004 individuals were NGT-1h-low and 470 were NGT-1h-high. The TyG index was higher for NGT-1h-high (p = 0.001) individuals, and it was an independent factor influencing 1h-OGTT glycemia (β = 0.191, p < 0.001) after correcting for age, sex, and BMI. The TyG index was the strongest marker associated with the risk of being NGT-1h-high (OR = 1.703, CI 95% 1.34-2.17, p < 0.001) when compared with FPG (OR = 1.054, CI 95% 1.04-1.07, p < 0.001) and the HOMA-IR (OR = 1.156, CI 95% 1.08-1.23, p < 0.001).

CONCLUSIONS

Our study demonstrated that the TyG index, an efficient and cost-effective marker of insulin resistance, is associated with the variability of early post-challenge glucose levels and is an independent marker of being NGT-1h-high.

One-hour plasma glucose as a long-term predictor of cardiovascular events and all-cause mortality in a Chinese older male population without diabetes: A 20-year retrospective and prospective study

Introduction

Elevated one-hour plasma glucose (1 h-PG) during oral glucose tolerance test predicts the development of type 2 diabetes mellitus and its complications. However, to date, there have been no studies investigating the predictive values of 1 h-PG for the risk of cardiovascular diseases (CVDs) and all-cause mortality in the elderly population in China. This study aimed to evaluate and compare the effectiveness of 1 h-PG and two-hour plasma glucose (2 h-PG) to predict the risk of CVD and all-cause mortality in the Chinese elderly population.

Materials and methods

This retrospective and prospective cohort study was conducted using data obtained from the Chinese People’s Liberation Army General Hospital. All the non-diabetic elderly participants, who had plasma glucose measured at 0, 1, and 2 h during an OGTT (75 g glucose), were followed for 20 years. The primary outcomes were all-cause mortality, myocardial infarction, unstable angina, and stroke. Multivariate-adjusted Cox proportional hazard regression models were performed to examine the association between risk factors and outcomes and to estimate the risk of CVD and all-cause mortality based on 1 h-PG levels.

Results

A total of 862 non-diabetic male individuals were included. The median age was 74.0 (25th–75th percentile: 68.0–79.0) years. There were 480 CVD events and 191 deaths during 15,527 person-years of follow-up. The adjusted hazard ratio (HR) of 1 h-PG as a continuous variable was 1.097 (95% CI 1.027–1.172; P = 0.006) for CVD events and 1.196 (95% CI 1.115–1.281; P < 0.001) for higher risk of mortality. When compared with the lowest 1 h-PG tertile, the other tertiles were associated with CVD events (HR 1.464, 95% CI 1.031–2.080; P = 0.033 and HR 1.538, 95% CI 1.092–2.166; P = 0.014, for tertile 2 and tertile 3 compared with tertile 1, respectively), and the highest 1 h-PG tertile had a significantly higher risk of mortality (HR 2.384, 95% CI 1.631–3.485; P < 0.001) after full adjustment. Compared with 1 h-PG, 2 h-PG had similar abilities to predict all-cause mortality. However, 2 h-PG was less closely associated with CVD when examined in the fully adjusted model, neither as a continuous variable nor as a categorical variable. Conversely, 1 h-PG remained an independent predictor of CVD and all-cause mortality after adjusting for various traditional risk factors.

Conclusion

Patients with higher 1 h-PG had a significantly increased risk of CVD and all-cause mortality regardless of prediabetes status or development of diabetes at follow-up. The 1 h-PG level might be a better predictor of cardiovascular risk than the 2 h-PG level for the Chinese elderly population.

Depressed myocardial mechano-energetic efficiency in subjects with dysglycemia

AIMS

Evidence indicate that 1 h post-load glucose levels (1hPG) ≥ 155 mg/dl identify amongst subjects with normal glucose tolerance (NGT) a new category of prediabetes (NGT 1 h-high). A compromised myocardial mechano-energetic efficiency (MEE) is associated with type 2 diabetes and predicts adverse cardiovascular outcomes. Herein, we explored the association between prediabetes conditions such as NGT 1 h-high, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and a decreased MEE.

METHODS

MEE was assessed by an echocardiography-derived measure in 1467 non-diabetic individuals subdivided according to their glucose tolerance: NGT and 1-hPG < 155 mg/dl (NGT 1 h-low, n = 617), NGT 1 h-high (n = 210), isolated IFG (n = 237), and IGT (n = 403).

RESULTS

Subjects with NGT 1 h-high, isolated IFG, and IGT displayed a higher myocardial oxygen consumption, and a decreased MEE in comparison to NGT 1 h-low group. MEE was inversely related to male sex, age, body mass index, total cholesterol, triglycerides, fasting and post-load glucose and insulin, C reactive protein, and positively correlated with insulin sensitivity estimated by the Matsuda index. In a stepwise multivariate linear regression model including several cardio-metabolic risk factors, 1hPG was the major predictor of MEE.

CONCLUSIONS

Subjects with NGT 1 h-high, isolated IFG, and IGT have a raised myocardial oxygen consumption and a reduced MEE.

Expert Group Recommendations on the Effective Use of Bolus Insulin in the Management of Type 2 Diabetes Mellitus

Evidence suggests a major contribution of postprandial glucose (PPG) excursions to the increased risk of micro- and macro-vascular complications in individuals with type 2 diabetes mellitus (T2DM). Administration of bolus insulin remains a very effective therapeutic option for PPG control. The aim of this expert group recommendation document was to provide practical and easy-to-execute guidelines for physicians on the appropriate use of bolus insulin in the management of T2DM. A panel of key opinion leaders from India reviewed and discussed the available clinical evidence and guideline recommendations on the following topics: (1) optimum control of PPG; (2) choice of bolus insulin; and (3) special situations and practical considerations. The expert panel critically analyzed the current literature and clinical practice guidelines and factored their rich clinical experience to develop a set of nine expert group recommendations for the effective use of bolus insulin. These recommendations will not only result in a more evidence-based application of bolus insulin in the clinical setting but also trigger further research and provide a valuable base for the development of future guidelines on the use of bolus insulin in the management of individuals with T2DM.

HDL (High-Density Lipoprotein) and ApoA-1 (Apolipoprotein A-1) Potentially Modulate Pancreatic α-Cell Glucagon Secretion

OBJECTIVE

Subjects with low levels of HDL (high-density lipoprotein) and ApoA-1 (apolipoprotein A-1) have increased risk to develop type 2 diabetes. HDL levels are an independent predictor of β-cell function and positively modulate it. Type 2 diabetes is characterized by defects in both β and α-cell function, but the effect of HDL and ApoA1 on α-cell function is unknown. Approach and Results: We observed a significant negative correlation (r=-0.422, P<0.0001) between HDL levels and fasting glucagon in a cohort of 132 Italian subjects. In a multivariable regression analysis including potential confounders such as age, sex, BMI, triglycerides, total cholesterol, fasting and 2-hour postload glucose, and fasting insulin, the association between HDL and fasting glucagon remained statistically significant (β=-0.318, P=0.006). CD1 mice treated with HDL or ApoA-1 for 3 consecutive days showed a 32% (P<0.001) and 23% (P<0.05) reduction, respectively, in glucagon levels following insulin-induced hypoglycemia, compared with controls. Treatment of pancreatic αTC1 clone 6 cells with HDL or ApoA-1 for 24 hours resulted in a significant reduction of glucagon expression (P<0.04) and secretion (P<0.01) after an hypoglycemic stimulus and increased Akt (RAC-alpha serine/threonine-protein kinase) and FoxO1 (forkhead/winged helix box gene, group O-1) phosphorylation. Pretreatment with Akt inhibitor VIII, PI3K (phosphatidylinositol 3-kinase) inhibitor LY294002, and HDL receptor SCARB-1 (scavenger receptor class B type 1) inhibitor BLT-1 (block lipid transport-1) restored αTC1 cell response to low glucose levels.

CONCLUSIONS

These results support the notion that HDL and ApoA-1 modulate glucagon expression and secretion by binding their cognate receptor SCARB-1, and activating the PI3K/Akt/FoxO1 signaling cascade in an in vitro α-cell model. Overall, these results raise the hypothesis that HDL and ApoA-1 may have a role in modulating glucagon secretion.

Metabolic characteristics of Africans with normal glucose tolerance and elevated 1-hour glucose: insight from the Africans in America study

INTRODUCTION

Risk of insulin resistance, dyslipidemia, diabetes and cardiac death is increased in Asians and Europeans with normal glucose tolerance (NGT) and 1-hour glucose ≥8.6 mmol/L. As African descent populations often have insulin resistance but a normal lipid profile, the implications for Africans with NGT and glucose ≥8.6 mmol/L (NGT-1-hour-high) are unknown.

OBJECTIVE

We performed oral glucose tolerance tests (OGTTs) in 434 African born-blacks living in Washington, DC (male: 66%, age 38±10 years (mean±SD)) and determined in the NGT group if either glucometabolic or lipid profiles varied according to a 1-hour-glucose threshold of 8.6 mmol/L.

METHODS

Glucose tolerance category was defined by OGTT criteria. NGT was subdivided into NGT-1-hour-high (glucose ≥8.6 mmol/L) and NGT-1-hour-normal (glucose <8.6 mmol/L). Second OGTT were performed in 27% (119/434) of participants 10±7 days after the first. Matsuda Index and Oral Disposition Index measured insulin resistance and beta-cell function, respectively. Lipid profiles were obtained. Comparisons were by one-way analysis of variance with Bonferonni corrections for multiple comparisons. Duplicate tests were assessed by к-statistic.

RESULTS

One-hour-glucose ≥8.6 mmol/L occurred in 17% (47/272) with NGT, 72% (97/134) with pre-diabetes and in 96% (27/28) with diabetes. Both insulin resistance and beta-cell function were worse in NGT-1-hour-high than in NGT-1-hour-normal. Dyslipidemia occurred in both the diabetes and pre-diabetes groups but not in either NGT group. One-hour glucose concentration ≥8.6 mmol/L showed substantial agreement for the two OGTTs (к=0.628).

CONCLUSIONS

Although dyslipidemia did not occur in either NGT group, insulin resistance and beta-cell compromise were worse in NGT-1 hour-high. Subdividing the NGT group at a 1-hour glucose threshold of 8.6 mmol/L may stratify risk for diabetes in Africans.

Metabolic effects of α-lipoic acid supplementation in pre-diabetics: a randomized, placebo-controlled pilot study

Supplementation of health promoting nutraceuticals may be an effective adjunct strategy with other lifestyle and drug approaches to impede disease progression in prediabetic subjects. α-Lipoic acid, a naturally occurring short-chain fatty acid, has been extensively evaluated for its antioxidant and glycemic control properties but has rarely been investigated as a lipid-lowering strategy. We conducted a pilot study to examine the effects of α-lipoic acid supplementation on glycemic control and lipid profile in pre-diabetic, overweight/obese adults. The study was designed as a free-living, randomized, two-phase, placebo-controlled cross-over study with 12 pre-diabetic, dyslipidemic subjects. Eligible subjects completed two thirty-day phases (in random order) consisting of a placebo (600 mg cellulose per day) and α-lipoic acid treatment (600 mg day^-1). Although no change (p < 0.05) in serum glucose was observed, α-lipoic acid-supplemented subjects demonstrated reduced fasting serum insulin (p = 0.04) and HOMA-IR (p = 0.07) compared with the placebo group. However, no change (p > 0.05) in serum lipids (including total cholesterol, LDL-C, HDL-C, triglycerides, LDL-C/HDL-C, and TC/HDL-C) were observed. Study results suggest that α-lipoic acid supplementation may be a useful strategy to improve insulin sensitivity in pre-diabetic subjects but is not effective in modulating serum lipids.

1 h Postload Glycemia Is Associated with Low Endogenous Secretory Receptor for Advanced Glycation End Product Levels and Early Markers of Cardiovascular Disease

We investigated the correlation of the soluble receptor for advanced glycation end products (sRAGE) and endogenous secretory RAGE (esRAGE) with markers of cardiovascular disease in subjects with normal glucose tolerance (NGT) and 1 h postload glucose ≥155 mg/dL after an oral glucose tolerance test. We stratified 282 subjects without a previous diagnosis of diabetes into three groups: 123 controls (NGT and 1 h postload glycemia <155 mg/dL), 84 NGT and 1 h postload glycemia ≥155 mg/dL (NGT 1 h high), and 75 subjects with impaired fasting glucose and/or impaired glucose tolerance (IFG/IGT). NGT 1 h high subjects exhibited lower esRAGE (0.36 ± 0.18 vs. 0.4 5 ± 0.2, p < 0.05) and higher S100A12 levels than controls (5684 (3193.2–8295.6) vs. 3960.1 (2101.8–7419), p < 0.05). Furthermore, they showed an increased pulse wave velocity (PWV) and intima–media thickness (IMT). No differences were found between the NGT 1 h high group and the IFG/IGT group regarding cardiometabolic profiles. After multiple regression analyses, esRAGE was associated with glycated hemoglobin (HbA_1c) and high-sensitivity C-reactive protein (hs-CRP). Age, HbA_1c, and esRAGE were the determinants of IMT, whereas S100A12 and systolic pressure were the determinants of PWV. The NGT 1 h high group exhibited low esRAGE levels and an altered cardiometabolic profile. HbA_1c, S100A12, and hs-CRP were associated with these alterations. In conclusion, subjects with NGT are not a homogeneous population, and they present different cardiovascular and glycometabolic risks.

Elevated 1-hour post-load plasma glucose identifies obese youth with abnormal glucose metabolism and an unfavourable inflammatory profile

CONTEXT

Adults with plasma glucose levels at one hour (1h-GL) ≥8.6 mmol/L during an oral glucose tolerance test (OGTT) are at increased risk for type 2 diabetes mellitus and present an unfavourable cardiometabolic and inflammatory profile, but relevant data on children are scarce.

OBJECTIVE

To investigate if elevated 1h-GL during OGTT in obese children and adolescents is associated with insulin resistance and specific pro-inflammatory biomarkers.

RESEARCH DESIGN AND METHODS

The study group comprised 88 obese children who attended the Outpatient Pediatric Clinic of our Hospital between January and December 2016. Children were divided into two groups according to 1h-GL during an OGTT: group 1 (n = 57) consisted of those with 1h-GL <8.6 mmol/L and group 2 (n = 31) of those with 1h-GL ≥8.6 mmol/L. Arterial blood pressure, body mass index (BMI) and waist circumference (WC) z-scores were measured in all participants. Specific insulin resistance (IR) indices, that is HOMA-IR, Matsuda index and Cederholm insulin sensitivity index (ISI) were calculated. Further, pro-inflammatory biomarkers that have been correlated with obesity complications, namely adiponectin, leptin, visfatin and interleukin (IL)-6 together with lipid levels were measured in all participants. Logistic regression analysis was used.

RESULTS

Children in group 2 had higher insulin (15.5 ± 6.4 vs 10.9 ± 4.8 μU/mL), HOMA-IR (3.41 ± 1.4 vs 2.34 ± 1.05) and lower Matsuda index [4.7 (3.1) vs 18.4 (17) median plus IQR] and Cederholm ISI (38 ± 6 vs 56 ± 11), than children in group 1 (all P < 0.001). They also had higher visfatin (15.4 ± 5.2 vs 10.1 ± 7 ng/mL), and IL-6 [12.5 (6.7) vs 4.8 (4.4) pg/mL], and lower adiponectin (5.9 ± 3.4 vs 11.8 ± 4.7 μg/mL) than children in group 1 (all P < 0.001). Logistic regression showed that these differences between the two groups were independent of age, sex, Tanner stage, BMI and WC z-scores.

CONCLUSIONS

In obese children, 1h-GL ≥8.6 mmol/L during an OGTT is correlated with worsened IR, and an unfavourable metabolic and inflammatory profile. Thus, 1h-GL could be used as an additional marker to identify obese children and adolescents at increased risk of developing obesity complications.

Petition to replace current OGTT criteria for diagnosing prediabetes with the 1-hour post-load plasma glucose ≥ 155 mg/dl (8.6 mmol/L)

Many individuals with prediabetes, as presently defined, will progress to diabetes (T2D) despite the considerable benefit of lifestyle modification. Therefore, it is paramount to screen individuals at increased risk with a more sensitive method capable of identifying prediabetes at an even earlier time point in the lengthy trajectory to T2D. This petition reviews findings demonstrating that the 1-hour (1-h) postload plasma glucose (PG) ≥ 155 mg/dl (8.6 mmol/L) in those with normal glucose tolerance (NGT) during an oral glucose tolerance test (OGTT) is highly predictive for detecting progression to T2D, micro- and macrovascular complications and mortality in individuals at increased risk. Furthermore, the STOP DIABETES Study documented effective interventions that reduce the future risk of T2D in those with NGT and a 1-h PG ≥ 155 mg/dl (8·6 mmol/L). The 1-h OGTT represents a valuable opportunity to extend the proven benefit of diabetes prevention to the sizeable and growing population of individuals at increased risk of progression to T2D. The substantial evidence provided in this petition strongly supports redefining current diagnostic criteria for prediabetes with the elevated 1-h PG level. The authors therefore advocate a 1-h OGTT to detect prediabetes and hence, thwart the global diabetes epidemic.

One-Hour Postload Hyperglycemia: Implications for Prediction and Prevention of Type 2 Diabetes

CONTEXT

Recently, a value of 1-hour postload glucose concentration (1-h-PG) ≥155 mg/dL (8.6 mmol/L) in individuals with normal glucose tolerance (NGT) has been found to be associated with an increased risk for future type 2 diabetes mellitus (T2DM). In this review, we analyze the implication of 1-h-PG determination in prediction of T2DM and cardiovascular disease.

DESIGN

A literature search was performed using MEDLINE. We included all English studies published up to February 2018 in peer-reviewed journals that examined the relationship between 1-h-PG and diabetes, cardiometabolic alterations, organ damage, and cardiovascular disease.

RESULTS

Several longitudinal studies have consistently shown that 1-h-PG ≥155 mg/dL can recognize individuals at increased risk for future T2DM among subjects with NGT. Additionally, we describe the pathophysiological abnormalities associated with 1-h-PG ≥155 mg/dL including impaired insulin sensitivity, β-cell dysfunction, and increased glucose intestinal absorption, which are known to be involved in T2DM pathogenesis. Importantly, numerous studies have demonstrated that a value of 1-h-PG ≥155 mg/dL in individuals with NGT is not only linked to an increased risk for future T2DM, but also able to identify those having a worse cardiovascular phenotype and an increased risk of adverse cardiovascular outcomes.

CONCLUSIONS

Although 1-h-PG determination is not currently recommended by the American Diabetes Association for identifying high-risk individuals, the available evidence indicates that a value of 1-h-PG ≥155 mg/dL may be a useful tool to recognize, among subjects with NGT, those at increased risk of T2DM and cardiovascular disease.

Lessons learned from the 1-hour post-load glucose level during OGTT: Current screening recommendations for dysglycaemia should be revised

This perspective covers a novel area of research describing the inadequacies of current approaches for diagnosing dysglycaemia and proposes that the 1-hour post-load glucose level during the 75-g oral glucose tolerance test may serve as a novel biomarker to detect dysglycaemia earlier than currently recommended screening criteria for glucose disorders. Considerable evidence suggests that a 1-hour post-load plasma glucose value ≥155 mg/dl (8.6 mmol/L) may identify individuals with reduced β-cell function prior to progressing to prediabetes and diabetes and is highly predictive of those likely to progress to diabetes more than the HbA_1c or 2-hour post-load glucose values. An elevated 1-hour post-load glucose level was a better predictor of type 2 diabetes than isolated 2-hour post-load levels in Indian, Japanese, and Israeli and Nordic populations. Furthermore, epidemiological studies have shown that a 1-hour PG ≥155 mg/dl (8.6 mmol/L) predicted progression to diabetes as well as increased risk for microvascular disease and mortality when the 2-hour level was <140 mg/dl (7.8 mmol/L). The risk of myocardial infarction or fatal ischemic heart disease was also greater among subjects with elevated 1-hour glucose levels as were risks of retinopathy and peripheral vascular complications in a Swedish cohort. The authors believe that the considerable evidence base supports redefining current screening and diagnostic recommendations with the 1-hour post-load level. Measurement of the 1-hour PG level would increase the likelihood of identifying a larger, high-risk group with the additional practical advantage of potentially replacing the conventional 2-hour oral glucose tolerance test making it more acceptable in a clinical setting.

The 1-h post-load plasma glucose as a novel biomarker for diagnosing dysglycemia

Identifying the earliest moment for intervention to avert progression to prediabetes and diabetes in high-risk individuals is a substantial challenge. As β-cell function is already compromised in prediabetes, attention should therefore be focused on identifying high-risk individuals earlier in the so-called pre-prediabetes stage. Biomarkers to monitor progression and identify the time point at which β-cell dysfunction occurs are therefore critically needed. Large-scale population studies have consistently shown that the 1-h plasma glucose (1-h PG) ≥ 155 mg/dl (8.6 mmol/l) during the oral glucose tolerance test detected incident type 2 diabetes and associated complications earlier than fasting plasma glucose or 2-h plasma glucose levels. An elevated 1-h PG level appears to be a better alternative to HbA1c [5.7-6.4% (37-47 mmol/mol)] or traditional glucose criteria for identifying high-risk individuals at a stage when ß-cell function is substantially more intact than in prediabetes. Diagnosing high-risk individuals earlier proffers the opportunity for potentially reducing progression to diabetes, development of microvascular complications and mortality, thereby advancing benefit beyond that which has been demonstrated in global diabetes prevention programs.

Effect of Lactobacillus casei strain Shirota-fermented milk on metabolic abnormalities in obese prediabetic Japanese men: a randomised, double-blind, placebo-controlled trial

An obesity-related prediabetic state is characterised by metabolic abnormalities such as post-glucose load hyperglycaemia and dyslipidaemia and consequently increases the risk for type 2 diabetes and cardiovascular disease. This study aimed to investigate the effects of Lactobacillus casei strain Shirota (LcS) on metabolic abnormalities in obese prediabetic subjects in a randomised, double-blind, placebo-controlled trial. Herein, 100 obese subjects (body mass index ≥25), who had moderate post-load hyperglycaemia (1-hr post-load plasma glucose (PG) levels ≥180 mg/dl during the oral glucose tolerance test), consumed LcS-fermented milk or placebo milk daily for 8 weeks. The post-load PG and fasting blood markers were evaluated. Although post-load PG levels were not significantly different between the groups, 1-hr post-load PG, glycoalbumin, and HbA1c levels decreased at 8 weeks compared with the baseline levels only in the LcS group (p=0.036, p=0.002, and p=0.006, respectively). The reduction in glycoalbumin levels was statistically significantly greater in the LcS group than in the placebo group (p=0.030). Stratified analyses revealed significantly improved 1-hr post-load PG and glycoalbumin levels in the LcS group compared with the placebo group among subjects with severe glucose intolerance (2-hr post-load PG levels higher than the median at baseline; p=0.036 and p=0.034, respectively). In terms of lipidic outcomes, total, low-density lipoprotein, and non-high-density lipoprotein cholesterol levels were significantly lower in the LcS group than in the placebo group (p=0.023, p=0.022, and p=0.008, respectively). These findings suggest that LcS may favourably affect metabolic abnormalities in obese prediabetic subjects, though the effects on glycaemic control may be limited.

Elevated 1-h post-challenge plasma glucose levels in subjects with normal glucose tolerance or impaired glucose tolerance are associated with whole blood viscosity

AIM

It has been suggested that glucose levels ≥155 mg/dl at 1-h during an oral glucose tolerance test (OGTT) may predict development of type 2 diabetes and cardiovascular events among adults with normal glucose tolerance (NGT 1 h-high). Studies showed a link between increased blood viscosity and type 2 diabetes. However, whether blood viscosity is associated with dysglycemic conditions such as NGT 1 h-high, impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) is unsettled.

METHODS

1723 non-diabetic adults underwent biochemical evaluation and OGTT. A validated formula based on hematocrit and total plasma proteins was employed to estimate whole blood viscosity. Subjects were categorized into NGT with 1 h glucose <155 mg/dL (NGT-1 h-low), NGT-1 h-high, IFG and/or IGT.

RESULTS

Hematocrit and blood viscosity values appeared significantly higher in individuals with NGT 1 h-high, IFG and/or IGT as compared to NGT 1 h-low subjects. Blood viscosity was significantly correlated with age, waist circumference, blood pressure, HbA1c, fasting, 1- and 2-h post-challenge insulin levels, total cholesterol and low-density lipoprotein, triglycerides, fibrinogen, white blood cell, and inversely correlated with high-density lipoprotein and insulin sensitivity. Of the four glycemic parameters, 1-h post-challenge glucose showed the strongest correlation with blood viscosity (β = 0.158, P < 0.0001) in a multivariate regression analysis model including several atherosclerosis risk factors.

CONCLUSIONS

Our results demonstrate a positive relationship between blood viscosity and 1-h post-challenge plasma glucose. They also suggest that a subgroup of NGT individuals with 1-h post-challenge plasma >155 mg/dl have increased blood viscosity comparable to that observed in subjects with IFG and/or IGT.