Decreased beta cell function and insulin sensitivity contributed to increasing fasting glucose in Chinese

Association between depressive symptoms and prediabetes: NHANES 2007-2016 findings

INTRODUCTION

The association between diabetes and depressive symptoms is well recognized. However, the impact of depressive symptoms on prediabetes remains unclear. This study aims to explore the specific correlation between depressive symptoms and prediabetes.

METHODS

A total of 7467 participants from the National Health and Nutrition Examination Survey (NHANES) were included in this study, spanning five rounds of surveys conducted between 2007 and 2016. Weighted logistic regression was utilized to assess the relationship between depressive symptoms and prediabetes.

RESULTS

Compared with the normoglycemic population, individuals with prediabetes had a significantly higher probability of experiencing trouble sleeping (P = 0.020). After adjusting for non-glucose factors, there was no significant correlation between PHQ-9 and prediabetes; however, severe depressive symptoms were positively associated with abnormal fasting plasma glucose (FPG) levels (OR = 1.093 [95 % CI 1.002, 1.192]). There was a positive correlation between trouble concentrating and FPG abnormalities (OR = 1.065 [95 % CI 1.004, 1.129]).

LIMITATIONS

The cross-sectional design limits causal inference.

CONCLUSION

Individuals with depressive symptoms, especially severe cases, should be targeted for prediabetes prevention and management efforts. The diverse symptom presentations may have distinct impacts on glucose, necessitating personalized prevention and management strategies.

Relative importance of triglyceride glucose index combined with body mass index in predicting recovery from prediabetic state to normal fasting glucose: a cohort analysis based on a Chinese physical examination population

BACKGROUND

Prediabetes is a high-risk state for diabetes, and numerous studies have shown that the body mass index (BMI) and triglyceride-glucose (TyG) index play significant roles in risk prediction for blood glucose metabolism. This study aims to evaluate the relative importance of BMI combination with TyG index (TyG-BMI) in predicting the recovery from prediabetic status to normal blood glucose levels.

METHODS

A total of 25,397 prediabetic subjects recruited from 32 regions across China. Normal fasting glucose (NFG), prediabetes, and diabetes were defined referring to the American Diabetes Association (ADA) criteria. After normalizing the independent variables, the impact of TyG-BMI on the recovery or progression of prediabetes was analyzed through the Cox regression models. Receiver Operating Characteristic (ROC) curve analysis was utilized to visualize and compare the predictive value of TyG-BMI and its constituent components in prediabetes recovery/progression.

RESULTS

During the average observation period of 2.96 years, 10,305 individuals (40.58%) remained in the prediabetic state, 11,278 individuals (44.41%) recovered to NFG, and 3,814 individuals (15.02%) progressed to diabetes. The results of multivariate Cox regression analysis demonstrated that TyG-BMI was negatively associated with recovery from prediabetes to NFG and positively associated with progression from prediabetes to diabetes. Further ROC analysis revealed that TyG-BMI had higher impact and predictive value in predicting prediabetes recovering to NFG or progressing to diabetes in comparison to the TyG index and BMI. Specifically, the TyG-BMI threshold for predicting prediabetes recovery was 214.68, while the threshold for predicting prediabetes progression was 220.27. Additionally, there were significant differences in the relationship of TyG-BMI with prediabetes recovering to NFG or progressing to diabetes within age subgroups. In summary, TyG-BMI is more suitable for assessing prediabetes recovery or progression in younger populations (< 45 years old).

CONCLUSIONS

This study, for the first time, has revealed the significant impact and predictive value of the TyG index in combination with BMI on the recovery from prediabetic status to normal blood glucose levels. From the perspective of prediabetes intervention, maintaining TyG-BMI within the threshold of 214.68 holds crucial significance.

Association of Serum Uric Acid with Diabetes in Premenopausal and Postmenopausal Women-A Prospective Cohort Study in Shanghai, China

There have been few prospective studies on the association between serum uric acid (SUA) and the risk of diabetes in women, and there have been few large-scale Chinese studies based on menopause to investigate the association. Therefore, the present study aimed to investigate the above relationship in Chinese female adults without diabetes. Methods: Data from 5743 premenopausal women and 11,287 postmenopausal women aged 20−74 years were obtained from the Shanghai Suburban Adult Cohort and Biobank (SSACB) study conducted in China. Cox regression models were applied to evaluate the association between SUA levels and the risk of diabetes. Restricted cubic spline analysis and stratified analysis on the basis of menopausal status were performed to explore the dose−response association between SUA levels and diabetes. Results: Among 17,030 participants, incidence rates of diabetes were 3.44/1000 person-years in premenopausal and 8.90/1000 person-years in postmenopausal women. The SUA levels in postmenopausal women were higher than that in premenopausal women (p < 0.0001). In Cox regression analysis, after adjusting for confounding factors, for each 10 µmol/L increase in SUA levels, the adjusted HR of diabetes was 1.01 (95% CI: 0.97−1.04) in postmenopausal women, and 1.03 (95% CI: 1.01−1.04) in premenopausal women. Compared with the lowest quartile of SUA levels, the HR (95% CI) of diabetes in the highest quartile was 0.99 (0.55−1.79) in premenopausal women and 1.39 (1.07−1.81) in postmenopausal women. Compared with those without hyperuricemia, the HR (95% CI) for diabetes was 1.89 (0.67−5.31) in premenopausal women with hyperuricemia, and 1.55 (1.19−2.02) in postmenopausal women. Moreover, restricted cubic splines models showed that there was a linear relationship between SUA levels and diabetes risk in premenopausal (p for nonlinear = 0.99) and postmenopausal women (p for nonlinear = 0.95). Furthermore, the restricted cubic spline graph showed that the risk of diabetes in postmenopausal women increased with an increase in SUA levels (p = 0.002). Conclusions: In a cohort of Chinese adult women, SUA levels are associated with diabetes risk in postmenopausal women, but this association was not observed in premenopausal women.

Pathophysiology, phenotypes and management of type 2 diabetes mellitus in Indian and Chinese populations

Nearly half of all adults with type 2 diabetes mellitus (T2DM) live in India and China. These populations have an underlying predisposition to deficient insulin secretion, which has a key role in the pathogenesis of T2DM. Indian and Chinese people might be more susceptible to hepatic or skeletal muscle insulin resistance, respectively, than other populations, resulting in specific forms of insulin deficiency. Cluster-based phenotypic analyses demonstrate a higher frequency of severe insulin-deficient diabetes mellitus and younger ages at diagnosis, lower β-cell function, lower insulin resistance and lower BMI among Indian and Chinese people compared with European people. Individuals diagnosed earliest in life have the most aggressive course of disease and the highest risk of complications. These characteristics might contribute to distinctive responses to glucose-lowering medications. Incretin-based agents are particularly effective for lowering glucose levels in these populations; they enhance incretin-augmented insulin secretion and suppress glucagon secretion. Sodium-glucose cotransporter 2 inhibitors might also lower blood levels of glucose especially effectively among Asian people, while α-glucosidase inhibitors are better tolerated in east Asian populations versus other populations. Further research is needed to better characterize and address the pathophysiology and phenotypes of T2DM in Indian and Chinese populations, and to further develop individualized treatment strategies.

Gender Differences in the Association between Serum Uric Acid and Prediabetes: A Six-Year Longitudinal Cohort Study

This study aimed to examine gender differences in the association between serum uric acid (SUA) and the risk of prediabetes in a longitudinal cohort. A total of 8237 participants in the Beijing Health Management Cohort study were recruited and surveyed during 2008⁻2009, and followed up in 2011⁻2012 and 2014⁻2015 surveys. Generalized estimating equation (GEE) models were used to evaluate the association between SUA and prediabetes. Furthermore, subgroup analyses assessed the primary outcome according to status of abdominal obesity, age and status of hypertension. During six years of follow-up, we identified 1083 prediabetes events. The GEE analyses confirmed and clarified the association between SUA and prediabetes (RR = 1.362; 95% CI = 1.095⁻1.696; p = 0.006) after adjusting for other potential confounders, especially in females (RR = 2.109; 95% CI = 1.329⁻3.347; p = 0.002). In addition, this association was stronger in the subgroup of females aged ≥48 years old (RR = 2.384; 95% CI = 1.417⁻4.010; p = 0.001). The risk for prediabetes increased significantly with increasing SUA for females in the Chinese population. This association was strongly confirmed in older females aged ≥48 years old rather than in younger females, which may provide clues for pathogenic mechanisms of gender differences in the association between SUA and prediabetes.

Comparison of insulin lispro mix 25 with insulin lispro mix 50 as insulin starter in Chinese patients with type 2 diabetes mellitus (CLASSIFY study): Subgroup analysis of a Phase 4 open-label randomized trial

BACKGROUND

Premixed insulins are recommended starter insulins in Chinese patients after oral antihyperglycemic medication (OAM) failure. In the present study, we compared the efficacy and safety of insulin lispro mix 25 (LM25) twice daily (b.i.d.) and insulin lispro mix 50 (LM50) b.i.d. as a starter insulin regimen in Chinese patients with type 2 diabetes mellitus (T2DM) who had inadequate glycemic control with OAMs.

METHODS

The primary efficacy outcome in the present open-label parallel randomized clinical trial was change in HbA1c from baseline to 26 weeks. Patients were randomized in a ratio of 1:  1 to LM25 (n = 80) or LM50 (n = 76). A mixed-effects model with repeated measures was used to analyze continuous variables. The Cochran-Mantel-Haenszel test with stratification factor was used to analyze categorical variables.

RESULTS

At the end of the study, LM50 was more efficacious than LM25 in reducing mean HbA1c levels (least-squares [LS] mean difference 0.48; 95 % confidence interval [CI] 0.22, 0.74; P < 0.001). More subjects in the LM50 than LM25 group achieved HbA1c targets of <7.0 % (72.4 % vs 45.0 %; P = 0.001) or ≤6.5 % (52.6 % vs 20.0 %; P < 0.001). Furthermore, LM50 was more effective than LM25 at reducing HbA1c in patients with baseline HbA1c, blood glucose excursion, and postprandial glucose greater than or equal to median levels (P ≤ 0.001). The rate and incidence of hypoglycemic episodes and increase in weight at the end of the study were similar between treatment groups.

CONCLUSIONS

In Chinese patients with T2DM, LM50 was more efficacious than LM25 as a starter insulin.

β-Cell Function and Insulin Sensitivity in Normal Glucose-Tolerant Subjects Stratified by 1-Hour Plasma Glucose Values

AIM

This study was designed to assess β-cell function and insulin sensitivity indices among normal glucose tolerance (NGT) subjects stratified by 1-h plasma glucose (1hPG) values during an oral glucose tolerance test (OGTT).

MATERIALS AND METHODS

One hundred sixty-six NGT subjects underwent a five-point OGTT, and glucose and insulin levels were estimated. We calculated the following indices: (a) β-cell function (homeostasis assessment model-β-cell function [HOMA-β] and Insulinogenic Index [IGI]) and (b) insulin sensitivity (homeostasis assessment model-insulin resistance [HOMA-IR], Matsuda Index, and Insulin Sensitivity Index [ISI]).

RESULTS

NGT subgroups with elevated 1hPG values (i.e., 1hPG ≥143 to <155 mg/dL and 1hPG ≥155 mg/dL) did not differ from those with 1hPG <143 mg/dL by HOMA-β (P = 0.236) but had significantly lower IGIs (367 ± 239 vs. 257 ± 243 vs. 246 ± 239; P = 0.019). With respect to ISIs, HOMA-IR was not significantly different among the groups (P = 0.103). However, the Matsuda Index (11.2 ± 5.0 vs. 7.4 ± 4.8 vs. 5.5 ± 4.9; P < 0.001) and ISI (0.015 ± 0.010 vs. 0.012 ± 0.006 vs. 0.011 ± 0.011; P = 0.028) were significantly lower in subjects with elevated 1hPG values.

CONCLUSIONS

NGT subjects with elevated 1hPG levels have alterations in β-cell function and insulin sensitivity compared with those with normal 1hPG levels.

An investigation and comparison of the effectiveness of different exercise programmes in improving glucose metabolism and pancreatic β cell function of type 2 diabetes patients

BACKGROUND

Moderately intensive aerobic exercise can improve glucose metabolism and pancreatic β cell function in diabetic patients. To date, there is no evidence to support the long-term effectiveness of home-based exercise interventions on these outcomes.

OBJECTIVE

This study investigated the effectiveness of two moderately intense exercise programmes on glucose metabolism and pancreatic β cell function in type 2 diabetes mellitus (T2DM) patients.

METHODS

A randomised controlled trial of 120 T2DM patients (with a mean age of 55.54 ± 9.09 years) was conducted. Patients were assigned by block randomisation to either an aerobic exercise group (AEG), an accumulated million steps group (AMSG), or a control group (CG); each consisting of 40 patients. Glucose metabolism and pancreatic β cell function of patients were measured at three time intervals for 1 year.

RESULTS

There was no difference in baseline scores, and respective compliance rates for the AEG and AMSG were 94.4% and 99.2%. After generalised estimating equation analysis, the AMSG results for glycated haemoglobin (HbA1c) were significantly lower than those of the CG. The insulinogenic index-acute insulin response (BIGTT-AIR ) of both exercise groups was significantly higher than that of the CG. The AMSG group improved their overall HbA1c and BIGTT-AIR results compared with the AEG group after 3 months exercise programme (T1 ) and 12 months of implementation (T2 ).

CONCLUSION

This study demonstrates that regardless of the type of exercise intervention, it is potentially beneficially effective for glucose metabolism and pancreatic β cell function in T2DM patients. The AMSG had better glucose metabolism and pancreatic β cell function compared with those in the AEG. Nurses can easily integrate exercise interventions into T2DM patient care plans.

The oral disposition index is a strong predictor of incident diabetes in Asian Indian prediabetic men

AIMS

In this analysis, we sought to examine the prospective association of the disposition index (DIo) derived from oral glucose tolerance test with incident diabetes in Asian Indian men with impaired glucose tolerance (IGT).

METHODS

These post hoc analyses used data from a 2-year prospective study in primary prevention of diabetes using lifestyle intervention among 517 men with IGT. All the participants received standard lifestyle advice at baseline. The surrogate insulin sensitivity and insulin secretion measures were tested for their hyperbolic relationship. Predictive associations of various surrogate measures with incident diabetes were determined using receiver operating characteristic curves.

RESULTS

The combination of total area under the curve of insulin-to-glucose ratio (AUCinsulin/glucose) and Matsuda's insulin sensitivity index was the best equation to depict DIo [β: -0.954 (95 % CI -1.015 to -0.893)] compared to other measures tested in this cohort. There was an inverse association between change in DIo at the final follow-up and development of incident diabetes. Among the surrogate insulin measures studied, DIo [AUC (0.717 (95 % CI 0.675-0.756))] as a composite measure was superior than other surrogate indices.

CONCLUSIONS

Among the surrogate indices studied, DIo was the best measure associated with incident diabetes.

Ethnic differences in insulin sensitivity and beta-cell function among Asian men

BACKGROUND AND OBJECTIVES

Lean Asian Indians are less insulin sensitive compared with Chinese and Malays, but the pancreatic beta-cell function among these ethnic groups has yet to be studied in depth. We aimed to study beta-cell function in relation to insulin sensitivity among individuals of Chinese, Malay and Asian-Indian ethnicity living in Singapore.

SUBJECTS AND METHODS

This is a sub-group analysis of 59 normoglycemic lean (body mass index (BMI) <23 kg m(-)(2)) adult males (14 Chinese, 21 Malays and 24 Asian Indians) from the Singapore Adults Metabolism Study. Insulin sensitivity was determined using fasting state indices (homeostatic model assessment-insulin resistance), the euglycemic-hyperinsulinemic clamp (ISI-clamp) and a liquid mixed-meal tolerance test (LMMTT) (Matsuda insulin sensitivity index (ISI-Mat)). Beta-cell function was assessed using fasting state indices (homeostatic model assessment-beta-cell function) and from the LMMTT (insulinogenic index and insulin secretion index). The oral disposition index (DI), a measure of beta-cell function relative to insulin sensitivity during the LMMTT, was calculated as a product of ISI-Mat and insulin secretion index.

RESULTS

Asian Indians had higher waist circumference and percent body fat than Chinese and Malays despite similar BMI. Overall, Asian Indians were the least insulin sensitive whereas the Chinese were most insulin sensitive. Asian Indians had higher beta-cell function compared with Chinese or Malays but these were not statistically different. Malays had the highest incremental area under the curve for glucose during LMMTT compared with Asian Indians and Chinese. However, there were no significant ethnic differences in the incremental insulin area under the curve. The oral DI was the lowest in Malays, followed by Asian Indians and Chinese.

CONCLUSION

Among lean Asians, Chinese are the most insulin sensitive whereas Asian Indians are the least insulin sensitive. However, Malays demonstrate higher postprandial glucose excursion with lower beta-cell response compare with Chinese or Asian Indians. The paths leading to type 2 diabetes mellitus might differ between these Asian ethnic groups.

Efficacy of metformin-based oral antidiabetic drugs is not inferior to insulin glargine in newly diagnosed type 2 diabetic patients with severe hyperglycemia after short-term intensive insulin therapy

BACKGROUND

Insulin therapy should be strongly considered in newly diagnosed type 2 diabetic (T2D) patients with severe hyperglycemia. However, whether insulin be continued or patients switched to an oral antidiabetic drug (OAD) after short-term intensive insulin therapy (ITT) is not clear.

METHODS

After ITT for 10-14 days, 47 patients were randomized into either a glargine (n = 21) or metformin-based OAD (n = 26) group for a 6-month intervention. After these 6 months, patients in the glargine group were switched to metformin-based OAD therapy, whereas treatment in the OAD group was unchanged. Patients were followed-up for another 6 months.

RESULTS

At the end of the 6-month intervention, HbA1c was similarly reduced in both the glargine (from 11.81 ± 1.70% to 6.48 ± 0.79%; P < 0.001) and OAD (from 11.71 ± 1.89% to 6.16 ± 0.52%; P < 0.001) groups. At the end of 12 months, HbA1c was at comparable and near optimal levels in both groups. Similar increases were seen in homeostatic model assessment of β-cell function in the two groups after 6 months. There were no significant differences between the two groups in insulin sensitivity improvement, hypoglycemic episodes, weight change, treatment satisfaction and quality of life after the 6-month intervention.

CONCLUSIONS

The effects of metformin-based OAD therapy on glycemic control and improvements in β-cell function are not inferior to glargine in newly diagnosed T2D patients with severe hyperglycemia after short-term ITT. Considering the superiority of metformin in terms of safety, cost, and convenience, metformin-based OAD therapy is strongly recommended for these patients.

Impact of variants of the EXT2 gene on Type 2 diabetes and its related traits in the Chinese han population

PURPOSE/AIM OF THE STUDY

Exostosin 2 (EXT2) is involved in early pancreatic development and the regulation of insulin synthesis. In this study, we aim to evaluate the contribution of EXT2 to the genetic pathogenesis of type 2 diabetes and its related traits in the Chinese population.

MATERIALS AND METHODS

A case-control study in a Chinese Han population was conducted that included 4766 patients with type 2 diabetes and 4596 control subjects from 14 different regions of China. Three single nucleotide polymorphism (SNP), rs3740878, rs11037909 and rs1113132, in the EXT2 gene were genotyped using the Illumina GoldenGate Genotyping assay.

RESULTS

After adjusting for sex, age and body mass index, logistic regression analysis revealed that the EXT2 gene had no association with type 2 diabetes using an additive genetic model [rs3740878 (Odds Ratio (OR) = 0.996, 95% confidence interval (CI) 0.928-1.069, p = 0.910), rs11037909 (OR = 1.003, 95%CI 0.933-1.078, p = 0.931), and rs1113132 (OR = 0.993, 95% CI 0.925-1.065, p = 0.842)]. None of these SNPs were associated with beta cell function as determined using the baseline disposition index, early phase insulin secretion and Oral Glucose Tolerance Test (OGTT) total disposition index.

CONCLUSIONS

Our study suggests that the EXT2 gene might not have a major role in the development of type 2 diabetes in the Chinese population.

Causes of type 2 diabetes in China

The prevalence of diabetes in China has increased substantially over recent decades, with more than 100 million people estimated to be affected by the disease presently. During this period there has been an increase in the rates of obesity and a reduction in physical activity. Many of the changes in lifestyle and diet are a result of increased economic development and urbanisation. In addition to an increasingly westernised diet, the traditional Chinese diet also plays a part, with the quantity and quality of rice intake linked to the risk of type 2 diabetes. Familial factors including inherited genetic variants are important, although differences in the genetic architecture suggest a different combination of genetic variants could be most relevant in Chinese when compared with Europeans. Recent advances have also emphasised the role of early life factors in the epidemic of diabetes and non-communicable diseases: maternal undernutrition, maternal obesity, and gestational diabetes are all linked to increased risk of diabetes in offspring. A mismatch between developmentally programmed biology and the modern environment is relevant for countries like China where there has been rapid economic transformation. Multisectoral efforts to address the risks will be needed at different stages throughout the lifecourse to reduce the burden of diabetes.

Pharmacokinetic properties and effects of PT302 after repeated oral glucose loading tests in a dose-escalating study

BACKGROUND

PT302 is a sustained-release exenatide under clinical development for the treatment of type 2 diabetes mellitus.

OBJECTIVE

The aim of this study was to evaluate the pharmacokinetic properties, pharmacodynamic properties, and tolerability of PT302 after a single subcutaneous injection in healthy individuals.

METHODS

A dose-block randomized, double-blind, placebo-controlled, dose-escalating study (0.5, 1, 2, and 4 mg) was performed in 34 healthy individuals. The plasma concentrations of exenatide in serial blood samples were quantified for 56 days after dosing with an exendin-4 fluorescent immunoassay kit. Noncompartmental analysis was performed to assess the pharmacokinetic characteristics of PT302. Oral glucose tolerance tests were repeated weekly until day 42; the concentrations of serum glucose, serum C-peptide, plasma insulin, and plasma glucagon were measured for 2 hours to evaluate the pharmacodynamic characteristics of PT302. Clinical laboratory tests, vital signs, physical examinations, 12-lead ECGs, and adverse events were monitored to evaluate the safety profile and tolerability.

RESULTS

PT302 exhibits a biphasic pharmacokinetic profile, with the initial peak occurring 2 hours after administration. PT302 was quantifiable in the plasma until days 23, 30, 32, and 55 (median) in the 0.5-mg, 1-mg, 2-mg, and 4-mg dosage groups of PT302, respectively. Systemic exposure increased proportionally to the dose during the entire dose range investigated. The pharmacodynamic effect of PT302 on the postprandial response of insulin and C-peptide was significant on days 21 to 28 at the 4-mg dose and was positively correlated with plasma exenatide concentrations, whereas the correlations with glucose and glucagon were not significant. The fasting levels of these pharmacodynamic biomarkers were not altered by PT302. The most common adverse events were injection site induration and pruritus related to inflammatory foreign body reaction, which were mild and spontaneously resolved within several weeks.

CONCLUSION

The pharmacokinetic characteristics of PT302 were biphasic and dose proportional. A single 4-mg dose of PT302 significantly increased the insulin and C-peptide response to oral glucose loading and was well tolerated in healthy individuals.

Evidence of reduced β-cell function in Asian Indians with mild dysglycemia

OBJECTIVE

To examine β-cell function across a spectrum of glycemia among Asian Indians, a population experiencing type 2 diabetes development at young ages despite low BMI.

RESEARCH DESIGN AND METHODS

One-thousand two-hundred sixty-four individuals without known diabetes in the Diabetes Community Lifestyle Improvement Program in Chennai, India, had a 75-g oral glucose tolerance test, with glucose and insulin measured at 0, 30, and 120 min. Type 2 diabetes, isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT), combined impaired fasting glucose and impaired glucose tolerance, and normal glucose tolerance (NGT) were defined by American Diabetes Association guidelines. Measures included insulin resistance and sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR], modified Matsuda Index, 1/fasting insulin) and β-cell function (oral disposition index = [Δ insulin0-30/Δ glucose 0-30] × [1/fasting insulin]).

RESULTS

Mean age was 44.2 years (SD, 9.3) and BMI 27.4 kg/m(2) (SD, 3.8); 341 individuals had NGT, 672 had iIFG, IGT, or IFG plus IGT, and 251 had diabetes. Patterns of insulin resistance or sensitivity were similar across glycemic categories. With mild dysglycemia, the absolute differences in age- and sex-adjusted oral disposition index (NGT vs. iIFG, 38%; NGT vs. iIGT, 32%) were greater than the differences in HOMA-IR (NGT vs. iIFG, 25%; NGT vs. iIGT, 23%; each P < 0.0001). Compared with NGT and adjusted for age, sex, BMI, waist circumference, and family history, the odds of mild dysglycemia were more significant per SD of oral disposition index (iIFG: odds ratio [OR], 0.36; 95% CI, 0.23-0.55; iIGT: OR, 0.37; 95% CI, 0.24-0.56) than per SD of HOMA-IR (iIFG: OR, 1.69; 95% CI, 1.23-2.33; iIGT: OR, 1.53; 95% CI, 1.11-2.11).

CONCLUSIONS

Asian Indians with mild dysglycemia have reduced β-cell function, regardless of age, adiposity, insulin sensitivity, or family history. Strategies in diabetes prevention should minimize loss of β-cell function.

Contribution of insulin deficiency and insulin resistance to the development of type 2 diabetes: nature of early stage diabetes

At the time of diagnosis of type 2 diabetes (T2D), patients already have varying degrees of beta-cell dysfunction and insulin resistance and the defects continue to deteriorate despite treatment. We examined insulin secretion impairment and insulin resistance in overweight patients with T2D who had metformin failure, with elevated HbA1c at maximal metformin dose. Patients (N = 1,039) were examined at entry to the European Exenatide (EUREXA) clinical trial of add-on exenatide versus sulphonylurea. Mean (±SD) age was 57 ± 10 years, and BMI was 32.4 ± 4.1 kg/m(2). All patients underwent an oral glucose tolerance test; HOMA-IR, HOMA-B, ∆I(30)/∆G(30), disposition index and pro-insulin/insulin ratio were evaluated in relation to stratified HbA1c levels (≤7.3, >7.3-8.2, >8.2%) and duration of diabetes (<3, ≥3-<6, ≥6 years) using non-parametric analysis of variance. Patients overall had a wide range of impaired insulin secretion (HOMA-B: median 50.4, interquartile range 32.8-78.8) and insulin resistance (HOMA-IR: 4.8, 3.0-7.4). With increasing HbA1c levels, there was a statistically significant decrease in HOMA-B (P < 0.001), ∆I(30)/∆G(30) (P = 0.003) and disposition index (P < 0.001), and increase in pro-insulin/insulin (P < 0.001) and HOMA-IR (P < 0.001). With increasing duration since diabetes diagnosis, there was a significant decrease in HOMA-B (P < 0.001), but no significant trend in HOMA-IR, ∆I(30)/∆G(30), disposition index or pro-insulin/insulin. Metformin failure in these patients was associated with beta-cell dysfunction to a greater extent than insulin resistance. Loss of the first-phase insulin release, indicated by a low ∆I(30)/∆G(30), would indicate that this patient cohort requires add-on therapy that can maintain beta-cell function.

Sitagliptin reduces hyperglycemia and increases satiety hormone secretion more effectively when used with a novel polysaccharide in obese Zucker rats

The novel polysaccharide (NPS) PolyGlycopleX (PGX) has been shown to reduce glycemia. Pharmacological treatment with sitagliptin, a dipeptidyl peptidase 4 (DPP4) inhibitor, also reduces glycemia by increasing glucagon-like peptide-1 (GLP-1). Our objective was to determine if using NPS in combination with sitagliptin reduces hyperglycemia in Zucker diabetic fatty (ZDF) rats more so than either treatment alone. Male ZDF rats were randomized to: 1) cellulose/vehicle [control (C)]; 2) NPS (5% wt:wt)/vehicle (NPS); 3) cellulose/sitagliptin [10 mg/(kg · d) (S)]; or 4) NPS (5%) + S [10 mg/(kg · d) (NPS+S)]. Glucose tolerance, adiposity, satiety hormones, and mechanisms related to DPP4 activity and hepatic and pancreatic histology were examined. A clinically relevant reduction in hyperglycemia occurred in the rats treated with NPS+S (P = 0.001) compared with NPS and S alone. Blood glucose, measured weekly in fed and feed-deprived rats and during an oral glucose tolerance test, was lower in the NPS+S group compared with all other groups (all P = 0.001). At wk 6, glycated hemoglobin was lower in the NPS+S group than in the C and S (P = 0.001) and NPS (P = 0.06) groups. PGX (P = 0.001) and S (P = 0.014) contributed to increased lean mass. Active GLP-1 was increased by S (P = 0.001) and GIP was increased by NPS (P = 0.001). Plasma DPP4 activity was lower in the NPS+S and S groups than in the NPS and C groups (P = 0.007). Insulin secretion and β-cell mass was increased with NPS (P < 0.05). NPS alone reduced LDL cholesterol and hepatic steatosis (P < 0.01). Independently, NPS and S improve several metabolic outcomes in ZDF rats, but combined, their ability to markedly reduce glycemia suggests they may be a promising dietary/pharmacological co-therapy for type 2 diabetes management.

Type 2 diabetes in Asians: prevalence, risk factors, and effectiveness of behavioral intervention at individual and population levels

This review summarizes the current data on diabetes risk factors, prevalence, and prevention efforts in Asia and Asian migrant populations. Studies indicate that type 2 diabetes mellitus is a large and growing threat to public health in Asian populations. Furthermore, Asian subgroups (e.g., South Asians/Asian Indians, Chinese) have unique risk factor profiles for developing diabetes, which differ from other populations and between Asian ethnic groups. Lifestyle intervention programs are effective in preventing diabetes in Asians, as with other ethnicities. The strength of these findings is lessened by the lack of systematically collected data using objective measurements. Large epidemiologic studies of diabetes prevalence and risk factor profiles and translational trials identifying sustainable and culturally acceptable lifestyle programs for Asian subgroups are needed.

Association of β-cell function and insulin sensitivity with fasting and 2-h plasma glucose in a large Chinese population

AIM

Our aim was to provide a quantitative analysis of the changes in the principal determinants of insulin sensitivity and secretion in relation to fasting plasma glucose (FPG) or 2-h plasma glucose (2h PG) in a Chinese population with a wide range of glucose tolerance.

METHODS

A total of 5728 adults spanning the entire range of glucose tolerance were included. Insulin sensitivity was measured by Matsuda insulin sensitivity index (ISI(M)) and homeostasis model assessment of 1/homeostasis model assessment of insulin resistance (HOMA-IR). β-Cell function adjusted by insulin sensitivity was assessed from disposition index (DI) at early-phase DI(30) and total DI(120). The exponential curve was established as the best fit for the relationship between insulin sensitivity or β-cell function and FPG or 2h PG.

RESULTS

Relative to the trend classified as increasing 2h PG, hepatic insulin sensitivity and insulin secretion showed a decreasing trend to a substantial degree as FPG increased. A 1 mmol/l increase in FPG and 2h PG concentration was associated with a -22 and -21% decline in ISI(M), -16 and -4% in 1/HOMA-IR, -38 and -35% in DI(30) and -36 and -26% in DI(120). The decay constant of ISI(M) and DI(30) in IFG or ISI(M), 1/HOMA-IR, DI(30) and DI(120) in IGT was lower than that in normal glucose tolerance. Significant interactions between sex and glucose levels determining DI were found.

CONCLUSIONS

We conclude that impairment of insulin sensitivity and insulin secretion contributes to both FPG or 2h PG hyperglycaemia in a Chinese population, but that the decline in insulin secretion is more pronounced with increasing fasting than 2h PG.