Associations of β-cell function and insulin resistance with youth-onset type 2 diabetes and prediabetes among Asian Indians

Association of pro-inflammatory cytokines, adipokines and hepatokine with incident diabetes in India: a nested case-control study within CARRS cohort

AIMS

To study the association of pro-inflammatory markers with incident diabetes in India.

METHODS

We did a nested case-control study within the CARRS (Centre for Ardiometabolic Risk Reduction in South Asia) cohort. Of the 5739 diabetes-free individuals at the baseline, 216 participants with incident diabetes and 432 age-, gender- and city-matched controls at 2-year follow-up were included. We measured high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 ( MCP-1), adiponectin, leptin and fetuin-A in the stored baseline blood samples. We did multivariate conditional logistic regression to estimate association of inflammatory markers (as quartiles) and incident diabetes. Covariates were baseline fasting plasma glucose (FPG) and lipids, body mass index (BMI), family history of diabetes, smoking and alcohol use.

RESULTS

Baseline hsCRP and TNF-α were higher, and IL-6 and adiponectin were lower among cases vs. controls. In multivariate conditional logistic regression models, only quartile-3 (odds ratio [OR]: 2.96 [95% CI:1.39, 6.30]) and quartile-4 (OR: 2.58 [95% CI: 1.15, 5.79]) of TNF-α and quartile-4 of MCP-1 (OR: 2.55 [95% CI: 1.06, 6.16]) were positively associated with diabetes after adjusting for baseline FPG and BMI. These associations did not remain after adjusting for family history. High level (quartile-4) of IL-6 was negatively associated with diabetes after adjusting for all factors (OR: 0.18 [95% CI: 0.06, 0.55]).

CONCLUSIONS

Higher TNF-α and MCP-1 levels and lower IL-6 were associated with higher risk of developing diabetes. Better understanding and potential methods of addressing these biomarkers, especially in relation to family history, are needed to address diabetes in South Asians.

Diabetes in South Asians: Uncovering Novel Risk Factors With Longitudinal Epidemiologic Data: Kelly West Award Lecture 2023

South Asian populations have a higher prevalence and earlier age of onset of type 2 diabetes and atherosclerotic cardiovascular diseases than other race and ethnic groups. To better understand the pathophysiology and multilevel risk factors for diabetes and cardiovascular disease, we established the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study in 2010. The original MASALA study cohort (n = 1,164) included 83% Asian Indian immigrants, with an ongoing expansion of the study to include individuals of Bangladeshi and Pakistani origin. We have found that South Asian Americans in the MASALA study had higher type 2 diabetes prevalence, lower insulin secretion, more insulin resistance, and an adverse body composition with higher liver and intermuscular fat and lower lean muscle mass compared with four other U.S. race and ethnic groups. MASALA study participants with diabetes were more likely to have the severe hyperglycemia subtype, characterized by β-cell dysfunction and lower body weight, and this subtype was associated with a higher incidence of subclinical atherosclerosis. We have found several modifiable factors for cardiometabolic disease among South Asians including diet and physical activity that can be influenced using specific social network members and with cultural adaptations to the U.S. context. Longitudinal data with repeat cardiometabolic measures that are supplemented with qualitative and mixed-method approaches enable a deeper understanding of disease risk and resilience factors. Studying and contrasting Asian American subgroups can uncover the causes for cardiometabolic disease heterogeneity and reveal novel methods for prevention and treatment.

A Cross-Sectional Multicentre Study to Validate Insulin Sensitivity Index Cut-Offs for Detection of Metabolic Syndrome in Indian Adolescents with Type-1 Diabetes

Background

A previous study compared insulin sensitivity indices for the detection of double diabetes (DD) in Indian adolescents with type-1 diabetes (T1D) and derived a cut-off to predict future risk for the development of metabolic syndrome (MS) in adolescents with T1D. We conducted the current study with the aim to validate these cut-offs for detecting DD among Indian subjects with T1D from various geographical locations.

Methods

This multicentric cross-sectional study included 161 Indian adolescents with T1D. Demographic, anthropometric, clinical, and biochemical data were collected using standard protocols. Insulin sensitivity (IS) was calculated using various equations developed to determine insulin sensitivity in subjects with T1D. Metabolic syndrome was diagnosed using International Diabetes Federation (IDF) Consensus Definition 2017.

Results

We report 4.3% prevalence of MS in Indian adolescents with T1D with an additional 29.8% of study participants at risk of development of MS. Low High density lipoprotein (HDL) (23.6%) was the commonest abnormal component of the MS definition. Insulin sensitivity calculated by an equation derived by the SEARCH group was the most appropriate index to identify MS and metabolic risk in Indian adolescents with T1D. The proposed cut-off of 5.48 had high specificity, positive predictive value, and negative predictive value in identifying the risk of the development of DD.

Conclusions

Insulin sensitivity calculated by the equation proposed by the SEARCH group together with cut-offs derived in earlier study may be used effectively to identify risk of development of MS/DD in Indian adolescents with T1D from various geographical locations.

Beta Cell Dysfunction in Youth- and Adult-Onset Type 2 Diabetes: An Extensive Narrative Review with a Special Focus on the Role of Nutrients

Traditionally a disease of adults, type 2 diabetes (T2D) has been increasingly diagnosed in youth, particularly among adolescents and young adults of minority ethnic groups. Especially, during the recent COVID-19 pandemic, obesity and prediabetes have surged not only in minority ethnic groups but also in the general population, further raising T2D risk. Regarding its pathogenesis, a gradually increasing insulin resistance due to central adiposity combined with a progressively defective β-cell function are the main culprits. Especially in youth-onset T2D, a rapid β-cell activity decline has been observed, leading to higher treatment failure rates, and early complications. In addition, it is well established that both the quantity and quality of food ingested by individuals play a key role in T2D pathogenesis. A chronic imbalance between caloric intake and expenditure together with impaired micronutrient intake can lead to obesity and insulin resistance on one hand, and β-cell failure and defective insulin production on the other. This review summarizes our evolving understanding of the pathophysiological mechanisms involved in defective insulin secretion by the pancreatic islets in youth- and adult-onset T2D and, further, of the role various micronutrients play in these pathomechanisms. This knowledge is essential if we are to curtail the serious long-term complications of T2D both in pediatric and adult populations.

Youth-onset type 2 diabetes mellitus: an urgent challenge

The incidence and prevalence of youth-onset type 2 diabetes mellitus (T2DM) and its complications are increasing worldwide. Youth-onset T2DM has been reported in all racial and ethnic groups, but Indigenous peoples and people of colour are disproportionately affected. People with youth-onset T2DM often have a more aggressive clinical course than those with adult-onset T2DM or those with type 1 diabetes mellitus. Moreover, the available treatment options for children and adolescents with T2DM are more limited than for adult patients. Intermediate complications of youth-onset T2DM, such as increased albuminuria, often develop in late childhood or early adulthood, and end-stage complications, including kidney failure, develop in mid-life. The increasing frequency, earlier onset and greater severity of childhood obesity in the past 50 years together with increasingly sedentary lifestyles and an increasing frequency of intrauterine exposure to diabetes are important drivers of the epidemic of youth-onset T2DM. The particularly high risk of the disease in historically disadvantaged populations suggests an important contribution of social and environmental factors, including limited access to high-quality health care, healthy food choices and opportunities for physical activity as well as exposure to stressors including systemic racism and environmental pollutants. Understanding the mechanisms that underlie the development and aggressive clinical course of youth-onset T2DM is key to identifying successful prevention and management strategies.

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.

Diabetes mellitus prediction and diagnosis from a data preprocessing and machine learning perspective

BACKGROUND AND OBJECTIVE

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia, which results from the inadequacy of the body to secrete and respond to insulin. If not properly managed or diagnosed on time, diabetes can pose a risk to vital body organs such as the eyes, kidneys, nerves, heart, and blood vessels and so can be life-threatening. The many years of research in computational diagnosis of diabetes have pointed to machine learning to as a viable solution for the prediction of diabetes. However, the accuracy rate to date suggests that there is still much room for improvement. In this paper, we are proposing a machine learning framework for diabetes prediction and diagnosis using the PIMA Indian dataset and the laboratory of the Medical City Hospital (LMCH) diabetes dataset. We hypothesize that adopting feature selection and missing value imputation methods can scale up the performance of classification models in diabetes prediction and diagnosis.

METHODS

In this paper, a robust framework for building a diabetes prediction model to aid in the clinical diagnosis of diabetes is proposed. The framework includes the adoption of Spearman correlation and polynomial regression for feature selection and missing value imputation, respectively, from a perspective that strengthens their performances. Further, different supervised machine learning models, the random forest (RF) model, support vector machine (SVM) model, and our designed twice-growth deep neural network (2GDNN) model are proposed for classification. The models are optimized by tuning the hyperparameters of the models using grid search and repeated stratified k-fold cross-validation and evaluated for their ability to scale to the prediction problem.

RESULTS

Through experiments on the PIMA Indian and LMCH diabetes datasets, precision, sensitivity, F1-score, train-accuracy, and test-accuracy scores of 97.34%, 97.24%, 97.26%, 99.01%, 97.25 and 97.28%, 97.33%, 97.27%, 99.57%, 97.33, are achieved with the proposed 2GDNN model, respectively.

CONCLUSION

The data preprocessing approaches and the classifiers with hyperparameter optimization proposed within the machine learning framework yield a robust machine learning model that outperforms state-of-the-art results in diabetes mellitus prediction and diagnosis. The source code for the models of the proposed machine learning framework has been made publicly available.

Altered levels of neurobiological biomarkers at the interface of depression and gestational diabetes mellitus in Asian Indian women

AIM

Gestational diabetes mellitus (GDM) might predispose the mothers to depression. Studies have reported the role of biomarkers either in GDM or depression, but very few have examined them in GDM with depression. The present study profiled the circulating levels of brain-derived neurotrophic factor (BDNF), Beta Endorphin (BE) and nesfatin-1 in women with GDM (with and without depression).

METHODS

160 pregnant women at 24-28 weeks of pregnancy (NGT/GDM with & without depression, n = 40 each) were randomly selected from the ongoing STRiDE (STratification of Risk of Diabetes in Early pregnancy) study. Depression score was derived using PHQ-9 questionnaire and ELISA was used to quantify the biomarkers.

RESULTS

Circulatory levels of BDNF, BE and nesfatin-1 were lower in GDM women with or without depression compared to NGT without depression, however, nesfatin-1 levels were higher in NGT with depression. Notably, GDM with depression had the lowest levels of BDNF and BE. Both BDNF and BE levels were negatively correlated with depression, 1 h and 2 h plasma glucose. Regression analysis confirmed that each standard deviation decreases in BDNF and BE were independently associated with higher odds of GDM with or without depression even after adjusting for potential confounders.

CONCLUSION

Our study has identified altered levels of a panel of neurobiological biomarkers (BDNF/BE/nesfatin-1) in those with combined GDM and depression. BDNF/BE could be potential biomarkers to assess the higher risk of coexisting depression and GDM.

Assessing Insulin Sensitivity and Postprandial Triglyceridemic Response Phenotypes With a Mixed Macronutrient Tolerance Test

The use of meal challenge tests to assess postprandial responses in carbohydrate and fat metabolism is well established in clinical nutrition research. However, challenge meal compositions and protocols remain a variable. Here, we validated a mixed macronutrient tolerance test (MMTT), containing 56-g palm oil, 59-g sucrose, and 26-g egg white protein for the parallel determination of insulin sensitivity and postprandial triglyceridemia in clinically healthy subjects. The MMTT was administered in two study populations. In one, women with overweight/obese BMIs (n = 43) involved in an 8-week dietary intervention were administered oral glucose tolerance tests (OGTTs) and MMTTs within 2 days of each other after 0, 2, and 8 weeks of the dietary intervention. In the other, 340 men and women between 18 and 64 years of age, with BMI from 18–40 kg/m2, completed the MMTT as part of a broad nutritional phenotyping effort. Postprandial blood collected at 0, 0.5, 3, and 6 h was used to measure glucose, insulin, and clinical lipid panels. The MMTT postprandial insulin-dependent glucose disposal was evaluated by using the Matsuda Index algorithm and the 0- and 3 h blood insulin and glucose measures. The resulting MMTT insulin sensitivity index (ISIMMTT) was strongly correlated (r = 0.77, p < 0.001) with the OGTT-dependent 2 h composite Matsuda index (ISIComposite), being related by the following equation: Log (ISIComposite) = [0.8751 x Log(ISIMMTT)] –0.2115. An area under the triglyceride excursion curve >11.15 mg/mL h–1 calculated from the 0, 3, and 6 h blood draws established mild-to-moderate triglyceridemia in agreement with ∼20% greater prevalence of hypertriglyceridemia than fasting indications. We also demonstrated that the product of the 0 to 3 h and 3 to 6 h triglyceride rate of change as a function of the triglyceride incremental area under the curve optimally stratified subjects by postprandial response patterns. Notably, ∼2% of the population showed minimal triglyceride appearance by 6 h, while ∼25% had increasing triglycerides through 6 h. Ultimately, using three blood draws, the MMTT allowed for the simultaneous determination of insulin sensitivity and postprandial triglyceridemia in individuals without clinically diagnosed disease.

Clinical Trial Registration

[https://clinicaltrials.gov/], identifier [NCT02298725; NCT02367287].

Poor In Utero Growth, and Reduced β-Cell Compensation and High Fasting Glucose From Childhood, Are Harbingers of Glucose Intolerance in Young Indians

OBJECTIVE

India is a double world capital of early-life undernutrition and type 2 diabetes. We aimed to characterize life course growth and metabolic trajectories in those developing glucose intolerance as young adults in the Pune Maternal Nutrition Study (PMNS).

RESEARCH DESIGN AND METHODS

PMNS is a community-based intergenerational birth cohort established in 1993, with serial information on parents and children through pregnancy, childhood, and adolescence. We compared normal glucose-tolerant and glucose-intolerant participants for serial growth, estimates of insulin sensitivity and secretion (HOMA and dynamic indices), and β-cell compensation accounting for prevailing insulin sensitivity.

RESULTS

At 18 years (N = 619), 37% of men and 20% of women were glucose intolerant (prediabetes n = 184; diabetes n = 1) despite 48% being underweight (BMI <18.5 kg/m²). Glucose-intolerant participants had higher fasting glucose from childhood. Mothers of glucose-intolerant participants had higher glycemia in pregnancy. Glucose-intolerant participants were shorter at birth. Insulin sensitivity decreased with age in all participants, and those with glucose intolerance had consistently lower compensatory insulin secretion from childhood. Participants in the highest quintile of fasting glucose at 6 and 12 years had 2.5- and 4.0-fold higher risks, respectively, of 18-year glucose intolerance; this finding was replicated in two other cohorts.

CONCLUSIONS

Inadequate compensatory insulin secretory response to decreasing insulin sensitivity in early life is the major pathophysiology underlying glucose intolerance in thin rural Indians. Smaller birth size, maternal pregnancy hyperglycemia, and higher glycemia from childhood herald future glucose intolerance, mandating a strategy for diabetes prevention from early life, preferably intergenerationally.

Prediction of insulin treatment in women with gestational diabetes mellitus

INTRODUCTION

The identification of pregnant women with Gestational Diabetes Mellitus (GDM) who will require insulin therapy, may modify their management to closer monitoring and probable early interventions. The aim of the study was to develop a predictive model for the necessity of insulin treatment in women with GDM.

MATERIALS AND METHODS

This was a prospective cohort study. Data from 775 women diagnosed with GDM per the IADPSG criteria were analyzed using logistic regression and a machine learning algorithm, the Classification and Regression Trees (CART). Potential predictors routinely recorded at follow-up visits were tested and used for the development of the model. The resultant model was externally validated using the data from two different perinatology clinics.

RESULTS

Preconceptional maternal BMI and morning fasting blood glucose levels at baseline and at 1 h during an Oral Glucose Tolerance Test (OGTT) were independent significant predictors for the treatment modality of GDM. Baseline blood glucose greater than 98 mg/dl and preconceptional maternal Body Mass Index (BMI) between 26 and 31 kg/height2 increased substantially the probability of insulin therapy (odds ratio [OR] 4.04, 95% confidence interval [CI] CI 2.65-6.17 and 2.21, 95%CI 1.42-3.43, respectively). The area under the curve (AUC) for the internal and external validation of the predictive model was 0.74 and 0.77, respectively.

CONCLUSIONS

A simple model based on maternal characteristics and the values of an OGTT can predict the need for insulin treatment with accuracy. Overweight women with an abnormal baseline blood glucose at OGTT are at high likelihood for insulin treatment.

KEY MESSAGE

Fifteen to 30% of women with Gestational Diabetes Mellitus (GDM) require insulin therapy. Overweight women with baseline blood glucose greater than 98 mg/dl at OGTT are at increased risk for insulin treatment and close monitoring and increased physical exercise are required.

Evidence of dysregulated iron homeostasis in newly diagnosed diabetics, but not in pre-diabetics

AIM

Diabetes mellitus has been reported to be associated with increased serum levels of ferritin. The basis of this association is unclear. It is also not precisely known whether other iron-related parameters, including hepcidin (the central regulator of systemic iron homeostasis), are affected under these circumstances. This study attempted to determine this.

METHODS

Adult men (normoglycemic or newly diagnosed with diabetes or pre-diabetes) were recruited. Anthropometric, metabolic, and hematological and iron-related parameters in blood were measured. Indices of insulin resistance (HOMA-IR) and pancreatic beta cell function (HOMA-β) were calculated.

RESULTS

Subjects in the 3 groups were similar in age, and anthropometric and hematological parameters. Serum ferritin and hepcidin levels were higher in diabetics, than in pre-diabetics and in control subjects. These elevations seen were not linked to the presence of inflammation. HOMA-IR was higher in diabetics, and HOMA-β lower in diabetics and pre-diabetics, than in control subjects. HOMA-IR and serum ferritin were positively correlated with one another.

CONCLUSION

Elevated levels of serum ferritin and hepcidin in newly diagnosed diabetics (but not pre-diabetics) indicate dysregulated iron homeostasis, with the former positively associated with insulin resistance in these patients.

Cardio-metabolic outcomes in South Asians compared to White Europeans in the United Kingdom: a matched controlled population-based cohort study

BACKGROUND

There appears to be an inequality in the risk of cardio-metabolic disease between those from a South Asian (SA) background when compared to those of White Europeans (WE) descendance, however, this association has not been explored in a large European cohort. This population-based open retrospective cohort explores the incidence of cardio-metabolic disease in those without pre-existing cardiometabolic disease taken from a large UK primary care database from 1st January 2007 to 31st December 2017.

METHODS

A retrospective open cohort matched population-based study using The Health Improvement Network (THIN) database. The outcomes of this study were the incidences of cardio-metabolic events (type 2 diabetes mellitus, hypertension, ischemic heart disease, stroke, heart failure, and atrial fibrillation).

RESULTS

A total of 94,870 SA patients were matched with 189,740 WE patients. SA were at an increased risk of developing: T2DM (adjusted hazard ratio (aHR) 3.1; 95% CI 2.97-3.23); HTN (1.34; 95% CI: 1.29-1.39); ischaemic heart disease (IHD) (1.81; 95% CI: 1.68-1.93) and heart failure (HF) (1.11; 95% CI: 1.003-1.24). However, they were at a lower risk of atrial fibrillation (AF) (0.53; 95% CI: 0.48-0.59) when compared to WE. Of those of SA origin, the Bangladeshi community were at the greatest risk of T2DM, HTN, IHD and HF, but were at the lowest risk of AF in when compared to Indians and Pakistanis.

CONCLUSION

Considering the high risk of cardio-metabolic diseases in the SA cohort, differential public health measures should be considered in these patients to reduce their risk of disease, which may be furthered tailored depending on their country of origin.

Lifestyle Interventions for Diabetes Prevention in South Asians: Current Evidence and Opportunities

PURPOSE OF REVIEW

This review summarizes the burden of diabetes in South Asian populations and reviews recent evidence for diabetes prevention through lifestyle modification among South Asians worldwide. We indicate important gaps in the current literature and point to opportunities for additional research in this area.

RECENT FINDINGS

Randomized, controlled, efficacy studies and implementation research show that lifestyle intervention can be an effective, cost-effective, and feasible method for reducing diabetes risk, improving cardiometabolic health, and improving lifestyle behaviors in South Asian populations, a population at high diabetes risk and elevated rates of diabetes risk factors. Additional research is needed to address diabetes risk reduction in normal-weight South Asians and individuals with impaired fasting glucose; improve community-level implementation, individual uptake, and dissemination of proven programs; and assess long-term outcomes of interventions.

Comparison of islet cell function, insulin sensitivity, and incretin axis between Asian-Indians with either impaired fasting glucose or impaired glucose tolerance, and normal healthy controls

AIMS

The objective of this study was to compare the islet cell function, insulin sensitivity, and incretin axis between Asian-Indian subjects with either impaired fasting glucose (IFG), or impaired glucose tolerance (IGT), and normal glucose tolerance (NGT).

MATERIALS AND METHODS

Prediabetes subjects underwent a mixed meal tolerance test(MMTT) after overnight fasting. Samples for glucose, insulin, glucagon, and glucagon-like peptide-1 (GLP-1) were collected at 0, 30, 60, and 120 min. Insulin secretion sensitivity index -2 (ISSI-2) for beta-cell function and Matsuda index for insulin sensitivity were assessed. Alpha cell function was assessed by measuring the area under the curve (AUC) _0-120 glucagon/AUC_0-120 glucose.

RESULTS

A total of sixty subjects were recruited with 20 in each group. The beta-cell function represented by ISSI-2 was impaired in prediabetes subjects as compared to NGT group (IFG: 2.09 ± 0.44 vs. NGT: 3.04 ± 0.80, P < 0.0001, and IGT: 2.33 ± 0.59 vs. NGT: 3.04 ± 0.80, P = 0.002). Similarly, AUC_0-120 glucagon/AUC_0-120 glucose was also lower in prediabetes group as compared to healthy controls (IFG: 0.41(0.54) vs. NGT: 1.07(0.39), P = 0.003 and IGT: 0.57(0.38) vs. NGT: 1.07(0.39), P = 0.001).

CONCLUSION

Asian-Indian prediabetes subjects have reduced beta-cell function with lesser glucagon secretion during MMTT as compared to normal healthy controls.

Augmentation of RBP4/STRA6 signaling leads to insulin resistance and inflammation and the plausible therapeutic role of vildagliptin and metformin

A role of Retinol Binding Protein-4 (RBP4) in insulin resistance is widely studied. However, there is paucity of information on its receptor viz., Stimulated by Retinoic Acid-6 (STRA6) with insulin resistance. To address this, we investigated the regulation of RBP4/STRA6 expression in 3T3-L1 adipocytes exposed to glucolipotoxicity (GLT) and in visceral adipose tissue (VAT) from high fat diet (HFD) fed insulin-resistant rats. 3T3-L1 adipocytes were subjected to GLT and other experimental maneuvers with and without vildagliptin or metformin. Real-time PCR and western-blot experiments were performed to analyze RBP4, STRA6, PPARγ gene and protein expression. Adipored staining and glucose uptake assay were performed to evaluate lipid and glucose metabolism. Oral glucose tolerance test (OGTT) and Insulin Tolerance Test (ITT) were performed to determine the extent of insulin resistance in HFD fed male Wistar rats. Total serum RBP4 was measured by quantitative sandwich enzyme-linked immunosorbent assay kit. Adipocytes under GLT exhibited significantly increased RBP4/STRA6 expressions and decreased insulin sensitivity/glucose uptake. Vildagliptin and metformin not only restored the above but also decreased the expression of IL-6, NFκB, SOCS-3 along with lipid accumulation. Furthermore, HFD fed rats exhibited significantly increased serum levels of RBP4 along with VAT expression of RBP4, STRA6, PPARγ, IL-6. These molecules were significantly altered by the vildagliptin/ metformin treatment. We conclude that RBP4/STRA6 pathway is primarily involved in mediating inflammation and insulin resistance in adipocytes and visceral adipose tissues under glucolipotoxicity and in insulin resistant rats.

The effect of curcumin and zinc co-supplementation on glycemic parameters in overweight or obese prediabetic subjects: A phase 2 randomized, placebo-controlled trial with a multi-arm, parallel-group design

Management of prediabetes is a critical step to prevent type-2 diabetes. Curcumin and zinc have been studied as an antioxidant, antiinflammatory, and antidiabetic agents. In this clinical trial, 84 subjects were randomized into curcumin (500 mg), zinc (30 mg), zinc and curcumin, and placebo groups for 90 days. At the baseline and the end of the study, the outcomes (fasting plasma glucose (FPG), 2-hour postprandial glucose (2hpp), HbA₁ C, insulin, insulin sensitivity (IS), insulin resistance (IR), β-cell function (BCF), weight, body mass index (BMI), dietary intake, and physical activity (PA)) were measured. A hypocaloric diet and PA were recommended for all subjects. In total, 82 subjects completed the study. After the intervention, dietary intake, PA, weight, and BCF% did not show a significant difference among the groups. However, subjects taking only zinc and zinc and curcumin groups experienced decreased BMI compared to the placebo (p = .01 and .007, respectively). The three treated groups had improved FPG (p = .01), 2hpp (p = .003), HbA1C (p = .004), insulin (p = .001), IS% (p = .001), and IR (p < .001) compared to the placebo. Based on these results, zinc and curcumin supplementation exerted a beneficial effect on several key glycemic parameters.

Incidence of diabetes in South Asian young adults compared to Pima Indians

INTRODUCTION

South Asians (SA) and Pima Indians have high prevalence of diabetes but differ markedly in body size. We hypothesize that young SA will have higher diabetes incidence than Pima Indians at comparable body mass index (BMI) levels.

RESEARCH DESIGN AND METHODS

We used prospective cohort data to estimate age-specific, sex, and BMI-specific diabetes incidence in SA aged 20-44 years living in India and Pakistan from the Center for Cardiometabolic Risk Reduction in South Asia Study (n=6676), and compared with Pima Indians, from Pima Indian Study (n=1852).

RESULTS

At baseline, SA were considerably less obese than Pima Indians (BMI (kg/m²): 24.4 vs 33.8; waist circumference (cm): 82.5 vs 107.0). Age-standardized diabetes incidence (cases/1000 person-years, 95% CI) was lower in SA than in Pima Indians (men: 14.2, 12.2-16.2 vs 37.3, 31.8-42.8; women: 14.8, 13.0-16.5 vs 46.1, 41.2-51.1). Risk of incident diabetes among 20-24-year-old Pima men and women was six times (relative risk (RR), 95% CI: 6.04, 3.30 to 12.0) and seven times (RR, 95% CI: 7.64, 3.73 to 18.2) higher as compared with SA men and women, respectively. In those with BMI <25 kg/m², however, the risk of diabetes was over five times in SA men than in Pima Indian men. Among those with BMI ≥30 kg/m², diabetes incidence in SA men was nearly as high as in Pima men. SA and Pima Indians had similar magnitude of association between age, sex, BMI, and insulin secretion with diabetes. The effect of family history was larger in SA, whereas that of insulin resistance was larger in Pima Indians CONCLUSIONS: In the background of relatively low insulin resistance, higher diabetes incidence in SA is driven by poor insulin secretion in SA men. The findings call for research to improve insulin secretion in early natural history of diabetes.

Incidence and pathophysiology of diabetes in South Asian adults living in India and Pakistan compared with US blacks and whites

INTRODUCTION

We compared diabetes incidence in South Asians aged ≥45 years in urban India (Chennai and Delhi) and Pakistan (Karachi), two low-income and middle-income countries undergoing rapid transition, with blacks and whites in the US, a high-income country.

RESEARCH DESIGN AND METHODS

We computed age-specific, sex-specific and body mass index (BMI)-specific diabetes incidence from the prospective Center for Cardiometabolic Risk Reduction in South Asia Study (n=3136) and the Atherosclerosis Risk in Communities Study (blacks, n=3059; whites, n=9924). We assessed factors associated with incident diabetes using Cox proportional hazards regression.

RESULTS

South Asians have lower BMI and waist circumference than blacks and whites (median BMI, kg/m²: 24.9 vs 28.2 vs 26.0; median waist circumference, cm 87.5 vs 96.0 vs 95.0). South Asians were less insulin resistant than blacks and whites (age-BMI-adjusted homeostatic model assessment of insulin resistance, µIU/mL/mmol/L: 2.30 vs 3.45 vs 2.59), and more insulin deficient than blacks but not whites (age-BMI-adjusted homeostasis model assessment of β-cell dysfunction, µIU/mL/mmol/L: 103.7 vs 140.6 vs 103.9). Age-standardized diabetes incidence (cases/1000 person-years (95% CI)) in South Asian men was similar to black men and 1.6 times higher (1.37 to 1.92) than white men (26.0 (22.2 to 29.8) vs 26.2 (22.7 to 29.7) vs 16.1 (14.8 to 17.4)). In South Asian women, incidence was slightly higher than black women and 3 times (2.61 to 3.66) the rate in white women (31.9 (27.5 to 36.2) vs 28.6 (25.7 to 31.6) vs 11.3 (10.2 to 12.3)). In normal weight (BMI <25 kg/m²), diabetes incidence adjusted for age was 2.9 times higher (2.09 to 4.28) in South Asian men, and 5.3 times (3.64 to 7.54) in South Asian women than in white women.

CONCLUSIONS

South Asian adults have lower BMI and are less insulin resistant than US blacks and whites, but have higher diabetes incidence than US whites, especially in subgroups without obesity. Factors other than insulin resistance (ie, insulin secretion) may play an important role in the natural history of diabetes in South Asians.

Association Between Age at Diagnosis of Type 2 Diabetes and Cardiovascular Diseases: A Nationwide, Population-Based, Cohort Study

OBJECTIVES

Nationwide studies focusing on the impact of early-onset type 2 diabetes and obesity on the development of cardiovascular diseases (CVD) are limited in China. We aimed to investigate the association between age at diagnosis of type 2 diabetes and the risk of CVD, and to further examine the modifying effect of obesity on this association among Chinese adults.

METHODS

This study included 23,961 participants with previously diagnosed diabetes from a large nationwide population-based cohort study across mainland China. With an interviewer-assisted questionnaire, we collected detailed information on CVDs. Logistic regression analysis was used to evaluate the risk of CVDs associated with age at diagnosis of diabetes.

RESULTS

Compared with patients with late-onset diabetes (≥60 years), those with earlier-onset diabetes had increased risks for CVD, with adjusted ORs (95% CIs) of 1.72 (1.36-2.17), 1.52 (1.31-1.75) and 1.33 (1.19-1.48) for patients diagnosed aged <40, 40-49 and 50-59 years, respectively. Each 5-year earlier age at diagnosis of type 2 diabetes was significantly associated with 14% increased risk of CVD (OR, 1.14; 95%CI, 1.11-1.18). This association was more prominent for patients with obesity than those with normal body mass index (BMI). Significant interaction was detected between age at diagnosis and BMI categories on CVD risk (P for interaction=0.0457).

CONCLUSION

Early-onset type 2 diabetes was significantly associated with higher risk of CVD, and this association was more prominent among patients with obesity.

Long noncoding RNAs as novel biomarkers for Type 2 diabetes

Type 2 diabetes (T2D) is a metabolic disease characterized by disordered glucagon secretion, insulin resistance in target tissues, and decreased islet β-cell mass and function. The routine diagnosis was based on measurements of metabolic markers, while genetic risk factors have been considered to increase the probability of predicting the development of the disease. Recent evidence suggests that long noncoding RNAs (lncRNAs) regulate gene expression in various physiological and pathological processes. As increasing lncRNAs are identified in β cells, understanding the regulatory roles of lncRNAs in T2D becomes indispensable. In this review, we discuss the potential role of lncRNAs contributing to β-cell identity and T2D susceptibility, which provide a perspective insight into the development of novel diagnosis biomarkers for T2D.

A comparative study on the cellular stressors in mesenchymal stem cells (MSCs) and pancreatic β-cells under hyperglycemic milieu

β-cell dysfunction is a critical determinant for both type 1 diabetes and type 2 diabetes and β-cells are shown to be highly susceptible to cellular stressors. Mesenchymal stem cells (MSCs) on the other hand are known to have immunomodulatory potential and preferred in clinical applications. However, there is paucity of a comparative study on these cells in relation to several cellular stressors in response to hyperglycemia and this forms the rationale for the present study. INS1 β-cells and MSCs were subjected to high-glucose treatment without and with Metformin, Lactoferrin, or TUDCA and assessed for stress signaling alterations using gene expression, protein expression, as well as functional read-outs. Compared to the untreated control cells, INS1 β-cells or MSCs treated with high glucose showed significant increase in mRNA expressions of ER stress, senescence, and proinflammation. This was accompanied by increased miR146a target genes and decreased levels of SIRT1, NRF2, and miR146a in both the cell types. Consistent with the mRNA results, protein expression levels do reflect the same alterations. Notably, the alterations are relatively less extent in MSCs compared to INS1 β-cells. Interestingly, three different agents, viz., Metformin, Lactoferrin, or TUDCA, were found to overcome the high glucose-induced cellular stresses in a concerted and inter-linked way and restored the proliferation and migration capacity in MSCs as well as normalized the glucose-stimulated insulin secretion in INS1 β-cells. While our study gives a directionality for potential supplementation of metformin/lactoferrin/TUDCA in optimization protocols of MSCs, we suggest that in vitro preconditioning of MSCs with such factors should be further explored with in-depth investigations to harness and enhance the therapeutic capacity/potential of MSCs.

Impact of type 2 diabetes variants identified through genome-wide association studies in early-onset type 2 diabetes from South Indian population

The prevalence of early-onset type 2 diabetes (EOT2D) is increasing in Asian countries. Genome-wide association studies performed in European and various other populations have identified associations of numerous variants with type 2 diabetes in adults. However, the genetic component of EOT2D which is still unexplored could have similarities with late-onset type 2 diabetes. Here in the present study we aim to identify the association of variants with EOT2D in South Indian population. Twenty-five variants from 18 gene loci were genotyped in 1,188 EOT2D and 1,183 normal glucose tolerant subjects using the MassARRAY technology. We confirm the association of the HHEX variant rs1111875 with EOT2D in this South Indian population and also the association of CDKN2A/2B (rs7020996) and TCF7L2 (rs4506565) with EOT2D. Logistic regression analyses of the TCF7L2 variant rs4506565(A/T), showed that the heterozygous and homozygous carriers for allele ‘T’ have odds ratios of 1.47 (95% confidence interval [CI], 1.17 to 1.83; p = 0.001) and 1.65 (95% CI, 1.18 to 2.28; p = 0.006) respectively, relative to AA homozygote. For the HHEX variant rs1111875 (T/C), heterozygous and homozygous carriers for allele ‘C’ have odds ratios of 1.13 (95% CI, 0.91 to 1.42; p = 0.27) and 1.58 (95% CI, 1.17 to 2.12; p = 0.003) respectively, relative to the TT homozygote. For CDKN2A/2B variant rs7020996, the heterozygous and homozygous carriers of allele ‘C’ were protective with odds ratios of 0.65 (95% CI, 0.51 to 0.83; p = 0.0004) and 0.62 (95% CI, 0.27 to 1.39; p = 0.24) respectively, relative to TT homozygote. This is the first study to report on the association of HHEX variant rs1111875 with EOT2D in this population.

A Prospective Study of Leukocyte Telomere Length and Risk of Gestational Diabetes in a Multiracial Cohort

BACKGROUND

Short telomere length (TL), an indicator of cellular aging and oxidative stress, has been implicated in glucose homeostasis. Additionally, studies have illustrated that the association of TL with health outcomes may vary by age. Yet, data on the association between TL and gestational diabetes mellitus (GDM) are sparse and the potential effect modification by age remains unknown.

METHODS

We prospectively investigated TL in early pregnancy in relation to the subsequent GDM risk in a case-control study of 93 women with GDM and 186 randomly selected controls matched on age, race/ethnicity, and gestational weeks at blood collection. TL was measured using blood samples collected at 10-14 gestational weeks and reported as the T/S ratio, a ratio of telomere repeat length T to copy number of a single copy gene S. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression adjusted for major risk factors.

RESULTS

Overall, TL was not significantly associated with GDM risk. The TL-GDM association was significantly modified by age (Pinteraction = 0.02). Shorter TL in early pregnancy was associated with an increased GDM risk among women <30 years old (adjusted OR comparing the shortest vs. longest tertile: 3.1, 95% CI = 1.2, 8.1), but not associated with GDM risk among women ≥30 years.

CONCLUSION

Our findings suggest that TL in early pregnancy may be implicated in GDM development, particularly among younger women.

Is Laparoscopic Roux-en-Y Gastric Bypass Still the Gold Standard Procedure for Indians? Mid- to Long-Term Outcomes from a Tertiary Care Center

PURPOSE

Laparoscopic Roux-en-Y gastric bypass (RYGB) is the oldest and most widely performed bariatric surgery worldwide. There is, however, a scarcity of mid- to long-term data of RYGB, especially from the Indian subcontinent.

MATERIALS AND METHODS

The study was a single-center, retrospective analysis from patients who underwent RYGB between January 2009 and November 2014 from a tertiary care center in India. Percent of total weight loss (%TWL) was taken as the primary outcome of the study. Secondary outcomes included type 2 diabetes mellitus (T2DM) remission, comorbidity resolution, revisional surgeries, and complications related to RYGB at 1 year, at 3 years, and during the long term, following surgery. Postoperative visits took place at 1 and 3 years, while the long-term outcome was at median 8.3 years (range 5.4-11.2 years), with a follow-up of 92.4% (488/528), 80.5% (424/527) and 69.5% (363/522), respectively.

RESULTS

Out of 528 patients studied, 56% were females. The mean body mass index (BMI) was 40.6 ± 6.9 kg/m². The %TWL in the long-term follow-up was 21.8 ± 11.3%. T2DM remission rates at 1 year, at 3 years, and during the long term were 84.5%, 70.0%, and 60.0%, respectively. Preoperative HBA1c (p = 0.002) and insulin usage (p = 0.016) had a significant predictive effect on T2DM remission. Gastroesophageal reflux disease (GERD) improved significantly (p < 0.001). Early (< 30 days) and late (> 30 days) complications were observed in 2.3% and 4.3% of the patients, respectively.

CONCLUSION

Weight loss during mid to long-term follow-up was maintained in the majority of the patients after RYGB. However, a small proportion had significant weight regain in the long term. T2DM, GERD, and other comorbidities were well improved after RYGB.

Why are South Asians prone to type 2 diabetes? A hypothesis based on underexplored pathways

South Asians have a high prevalence of type 2 diabetes, even at a lower BMI. This review sets out our perspective and hypothesis on the reasons for this. Emerging data from epidemiological studies indicate that South Asians may have a lower ability to secrete insulin, and thus may have less compensatory reserves when challenged with unhealthy lifestyles. Thus, insulin resistance may not be the primary driver of type 2 diabetes in this population. Furthermore, data also suggest that South Asians, on average, have lower muscle mass, and may have a specific propensity to ectopic hepatic fat accumulation and for intramyocellular fat deposition, which cause further disruption in insulin action. We hypothesise that the high diabetes susceptibility in South Asians is evolutionarily set through dual parallel and/or interacting mechanisms: reduced beta cell function and impaired insulin action owing to low lean mass, which is further accentuated by ectopic fat deposition in the liver and muscle. These areas warrant further research.

Phenotypic characteristics and risk factors in a multi-ethnic cohort of young adults with type 2 diabetes

Background: Early onset of type 2 diabetes (T2DM) is associated with prolonged exposure to hyperglycaemia and increased propensity to chronic complications. The aim of this study was to characterize and compare the phenotypic characteristics and risk factors in a multi-ethnic cohort of young adults with type 2 diabetes (T2DMY). Methods: One hundred young adults (White European [WE], South Asian [SA] and African-Caribbean [AC]) diagnosed with T2DM before the age of 40 years were recruited. Demographics, family history, diabetes related complications, co-morbidities, anthropometry (body mass index [BMI], body composition), physical activity and biochemistry (HbA1c, lipid profile, liver and renal function) and autoantibodies (anti GAD, anti islet cell) were collected for all participants. Data were analysed for the most represented ethnic groups: (WE, N = 36 and SA, N = 53) using SPSS version 23. Results: Mean (± standard deviation) age at diagnosis was 32.5 ± 5.5 years and mean diabetes duration was 7.7 ± 3.8 years. Overweight/obesity was present in 95% of participants, history of maternal diabetes in 68%, deprivation 75%, low physical activity 40%, polycystic ovarian disease 29% (in females), acanthosis nigricans 12% and non-alcoholic fatty liver 11%. There was considerable clustering of risk factors within the cohort with over 75% of all subjects having three or more of the above risk factors and 52% required insulin within 3 years of diagnosis. Two-thirds of the patients had evidence of at least one diabetes related microvascular complication. Conclusion: T2DMY is characterized by a high burden of commonly associated risk factors for both the disease and its long-term complications.

Ethnicity and Type 2 diabetes in the UK

Type 2 diabetes is a major UK public health priority. Among minority ethnic communities, the prevalence is alarmingly high, approximately three to five times higher than in the white British population. Particularly striking is the earlier onset of Type 2 diabetes, which occurs some 10-12 years younger, with a significant proportion of cases being diagnosed before the age of 40 years. This review focuses on the UK context and Type 2 diabetes in adult populations, exploring the available evidence regarding the complex interplay of biological, lifestyle, social, clinical and healthcare system factors that are known to drive these disparities.

Assessment of insulin sensitivity and secretion in patients with fibrocalculous pancreatic diabetes

Background: Fibrocalculous pancreatic diabetes (FCPD) is a secondary form of diabetes seen in patients with tropical chronic pancreatitis. Insulin deficiency plays a major role in the etiopathogenesis of FCPD. Limited data suggest a possible role of insulin resistance (IR) in the pathogenesis of FCPD. Sparse data exist on measures of insulin sensitivity (IS) and secretion in patients with FCPD and its comparison to type 2 diabetes mellitus (T2D) patients. Method: Eighty patients with FCPD, 36 patients with T2D and 36 healthy subjects were included. A 75 g oral glucose tolerance test (OGTT) was performed in the morning after an overnight fast. We evaluated IS and secretion using indices derived from fasting (homeostasis model assessment of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI] and homeostasis model assessment of beta-cell function [HOMA-ß]) and OGTT (Matsuda, insulin sensitivity index by Kanauchi [ISI-K], oral glucose insulin sensitivity index [OGIS], Stumvoll, insulinogenic index and oral disposition index [ODI]) measurements of glucose and insulin. Results: HOMA-IR was significantly higher and QUICKI significantly lower in patients with FCPD and T2D than in healthy controls (P<0.001). Matsuda, ISI-K, OGIS and Stumvoll were significantly lower in patients with FCPD and T2D than in healthy controls (P<0.001), indicating reduced IS in both FCPD and T2D patients. HOMA-ß, insulinogenic index and ODI were significantly lower in patients with FCPD and T2D compared to healthy controls (P<0.001). Conclusion: FCPD is associated with reduced IS as assessed by fasting and OGTT-based indices. FCPD is also associated with a greater degree of impairment in insulin secretion than in T2D. IR may play a role in the pathogenesis of FCPD.

Clinical management of type 2 diabetes in south Asia

Compared with other ethnic groups, south Asian people with type 2 diabetes tend to develop the disease at a younger age and manifest with higher glycaemia, dyslipidaemia, nephropathy, and cardiovascular diseases. Additionally, specific issues that can affect treatment of type 2 diabetes in south Asia include poor awareness of the disease, delay in diagnosis, inadequate treatment, the use of ineffective and often harmful alternative medicines, and frequent non-compliance with lifestyle recommendations and drug treatment. Disease development at younger ages, delayed diagnosis, and inadequate management result in early development of severe complications and premature mortality. In this Series paper, we describe the challenges associated with the increasing burden of type 2 diabetes in south Asia and discuss ways to improve clinical care of people with the disorder in the region (defined to include Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka). Treatment of diabetes in south Asia needs to be individualised on the basis of diverse and heterogeneous lifestyle, phenotype, environmental, social, cultural, and economic factors. Aggressive management of risk factors from diagnosis is necessary to reduce the risk of microvascular and macrovascular complications, focusing on provision of basic treatments (eg, metformin, low-cost statins, and blood pressure-lowering drugs) and other interventions such as smoking cessation. Strengthening of the primary care model of care, better referral linkages, and implementation of rehabilitation services to care for patients with chronic complications will be important. Finally, improvement of physicians' skills, provision of relevant training to non-physician health-care workers, and the development and regular updating of national clinical management guidelines will also be crucial to improve diabetes care in the region.

Linking a role of lncRNAs (long non-coding RNAs) with insulin resistance, accelerated senescence, and inflammation in patients with type 2 diabetes

Background

Studying epigenetics is expected to provide precious information on how environmental factors contribute to type 2 diabetes mellitus (T2DM) at the genomic level. With the progress of the whole-genome resequencing efforts, it is now known that 75–90% of the human genome was transcribed to generate a series of long non-coding RNAs (lncRNAs). While lncRNAs are gaining widespread attention as potential and robust biomarkers in the genesis as well as progression of several disease states, their clinical relevance and regulatory mechanisms are yet to be explored in the field of metabolic disorders including diabetes. Despite the fact that Asian Indians are highly insulin resistant and more prone to develop T2DM and associated vascular complications, there is virtually lack of data on the role of lncRNAs in the clinical diabetes setting. Therefore, we sought to evaluate a panel of lncRNAs and senescence-inflammation signatures in peripheral blood mononuclear cells (PBMCs) from patients with type 2 diabetes (T2DM; n = 30) compared to individuals with normal glucose tolerance (NGT; n = 32).

Results

Compared to control subjects, expression levels of lncRNAs in PBMCs from type 2 diabetes patients showed significantly (p < 0.05) increased levels of HOTAIR, MEG3, LET, MALAT1, MIAT, CDKN2BAS1/ANRIL, XIST, PANDA, GAS5, Linc-p21, ENST00000550337.1, PLUTO, and NBR2. In contrast, lncRNA expression patterns of THRIL and SALRNA1 were significantly (p < 0.05) decreased in patients with T2DM compared to control subjects. At the transcriptional level, senescence markers (p53, p21, p16, and β-galactosidase), proinflammatory markers (TNF-α, IL6, MCP1, and IL1-β), and epigenetic signature of histone deacetylase-3 (HDAC3) were significantly (p < 0.05) elevated in patients with type 2 diabetes compared to control subjects. Interestingly, mRNA expression of Sirt1 and telomere length were significantly (p < 0.05) decreased in patients with type 2 diabetes compared to control subjects. Majority of the altered lncRNAs were positively correlated with poor glycemic control, insulin resistance, transcriptional markers of senescence, inflammation, and HDAC3 and negatively correlated with telomere length. Logistic regression analysis revealed a significant association of altered lncRNA signatures with T2DM, but this association was lost after adjusting for insulin resistance (HOMA-IR) and senescence markers.

Conclusion

Our study provides a clinically relevant evidence for the association of altered lncRNAs with poor glycemic control, insulin resistance, accelerated cellular senescence, and inflammation.

Electronic supplementary material

The online version of this article (10.1186/s40246-018-0173-3) contains supplementary material, which is available to authorized users.

Diabetes Among Non-Overweight Individuals: an Emerging Public Health Challenge

PURPOSE OF REVIEW

Overweight and obesity are well-established risk factors for type 2 diabetes. However, a substantial number of individuals develop the disease at underweight or normal weight. In this review, we discuss the epidemiology of type 2 diabetes in non-overweight adults; pose questions about etiology, pathophysiology, diagnosis, and prognosis; and examine implications for prevention and treatment.

RECENT FINDINGS

In population-based studies, the prevalence of type 2 diabetes ranged from 1.4-10.9%. However, the prevalence of type 2 diabetes in individuals with BMI < 25 kg/m² ranged from 1.4-8.8%. In countries from Asia and Africa, the proportion of individuals with diabetes who were underweight or normal weight ranged from 24 to 66%, which is considerably higher than the US proportion of 10%. Impairments in insulin secretion, in utero undernutrition, and epigenetic alterations to the genome may play a role in diabetes development in this subgroup. A substantial number of individuals with type 2 diabetes, particularly those with recent ancestry from Asia or Africa, are underweight or normal weight. Future research should consist of comprehensive studies of the prevalence of type 2 diabetes in non-overweight individuals; studies aimed at understanding gaps in the mechanisms, etiology, and pathophysiology of diabetes development in underweight or normal weight individuals; and trials assessing the effectiveness of interventions in this population.

Diabetes in South Asians: Phenotype, Clinical Presentation, and Natural History

PURPOSE OF REVIEW

South Asia is one of the epicenters of the global diabetes pandemic. Diabetes in south Asians has certain peculiar features with respect to its pathophysiology, clinical presentation, and management. This review aims to summarize some of the recent evidence pertaining to the distinct diabetes phenotype in south Asians.

RECENT FINDINGS

South Asia has high incidence and prevalence rates of diabetes. The progression from "pre-diabetes" to diabetes also occurs faster in this population. Pancreatic beta cell dysfunction seems to be as important as insulin resistance in the pathophysiology of diabetes in south Asians. Recent evidence suggests that the epidemic of diabetes in south Asia is spreading to rural areas and to less affluent sections of society. Diabetes in south Asians differs significantly from that in white Caucasians, with important implications for prevention, diagnosis, and management.

Type 2 diabetes in adolescents and young adults

The prevalence of type 2 diabetes in adolescents and young adults is dramatically increasing. Similar to older-onset type 2 diabetes, the major predisposing risk factors are obesity, family history, and sedentary lifestyle. Onset of diabetes at a younger age (defined here as up to age 40 years) is associated with longer disease exposure and increased risk for chronic complications. Young-onset type 2 diabetes also affects more individuals of working age, accentuating the adverse societal effects of the disease. Furthermore, evidence is accumulating that young-onset type 2 diabetes has a more aggressive disease phenotype, leading to premature development of complications, with adverse effects on quality of life and unfavourable effects on long-term outcomes, raising the possibility of a future public health catastrophe. In this Review, we describe the epidemiology and existing knowledge regarding pathophysiology, risk factors, complications, and management of type 2 diabetes in adolescents and young adults.

Effect of lifestyle improvement program on the biomarkers of adiposity, inflammation and gut hormones in overweight/obese Asian Indians with prediabetes

AIMS

While lifestyle modification is known to offer several metabolic benefits, there is paucity of comprehensive data on changes in biomarkers of adiposity, inflammation as well as gut hormones. We investigated these biomarkers in overweight/obese individuals with prediabetes randomized to either 4 months of a lifestyle improvement program or standard care and followed them up for a year.

METHODS

Participants [standard care and intervention arm (n = 75 each)] were randomly selected from the Diabetes Community Lifestyle Improvement Program trial. Glycemic and lipid control and anthropometric measurements were assessed by standard protocols. Adipokines, inflammatory markers and gut hormones were measured using multiplex and standard ELISA kits.

RESULTS

Along with modest benefits in primary outcomes (glycemic and lipid control and weight reduction), participants in the intervention group showed significant reductions (p < 0.001) in plasma levels of leptin (17.6%), TNF-α (35%), IL-6 (33.3%), MCP-1 (22.3%) and PYY (28.3%) and increased levels of adiponectin (33.1%) and ghrelin (23.6%) at the end of 4 months of lifestyle intervention. The changes were independent of weight and persisted even at 1 year of follow-up. In contrast, participants from the standard care arm did not show any statistically significant improvements on the above parameters.

CONCLUSIONS

Participants who underwent an intensive lifestyle improvement program showed metabolic benefits as well as favorable beneficial changes in systemic levels of adipokines, cytokines and gut hormones, not only during the intervention period, but also during 12-month follow-up period.

Preserved glucagon-like peptide-1 responses to oral glucose, but reduced incretin effect, insulin secretion and sensitivity in young Asians with type 2 diabetes mellitus

OBJECTIVE

Youth onset type 2 diabetes mellitus (YT2DM) is a globally rising phenomenon with substantial Asians representation. The understanding of its pathophysiology is derived largely from studies in the obese African-American and Caucasian populations, while studies on incretin effect are scarce. We examined the insulin resistance, β-cell function (BC), glucagon-like peptide (GLP)-1 hormone and incretin effect in Asian YT2DM.

RESEARCH DESIGN AND METHODS

This case-control study recruited 25 Asian YT2DM and 15 healthy controls, matched for gender, ethnicity and body mass index. Serum glucose, insulin, C peptide and GLP-1 were sampled during 2-hour oral glucose tolerance tests (OGTTs) and 1-hour intravenous glucose tolerance tests (IVGTTs). Insulin sensitivity was derived from the Quantitative Insulin Sensitivity Check Index (QUICKI), Oral Glucose Insulin Sensitivity Index (OGIS) in OGTT and surrogate index of SI from the minimal model (calculated SI, CSI). Acute insulin response (AIR) was obtained from IVGTT. Total BC was computed as incremental area under the curve of insulin/incremental area under the curve of glucose, during OGTT (BC_OG) and IVGTT (BC_IV), respectively. Disposition index (DI) was calculated using the product of insulin sensitivity and insulin secretion. GLP-1 response to oral glucose was calculated as incremental area under the curve of GLP-1 (ΔAUC_GLP-1). Per cent incretin effect was estimated as 100×(BC_OG-BC_IV)/BC_OG).

RESULTS

The YT2DM had marked impairment in BC (>80% reduction in AIR and BC_OG, p<0.001) and lower QUICKI (p<0.001), OGIS (p<0.001) and CSI (p=0.015) compared with controls. There was no difference in GLP-1 at all time points and ΔAUC_GLP-1 but the per cent incretin effect was reduced in the YT2DM compared with controls (12.1±8.93 vs 70.0±4.03, p<0.001).

CONCLUSIONS

Asian YT2DM showed similar GLP-1 response to oral glucose as controls but reduced incretin effect, BC and insulin sensitivity. The lack of compensatory mechanisms, as shown by the DI may be partly ascribed to the impaired incretin effect, similar to that of adult T2DM.

TRIAL REGISTRATION NUMBER

NMRR-12-1042-13254.

Challenges in diagnosis and management of diabetes in the young

The prevalence of diabetes in children and adolescents is increasing worldwide, with profound implications on the long-term health of individuals, societies, and nations. The diagnosis and management of diabetes in youth presents several unique challenges. Although type 1 diabetes is more common among children and adolescents, the incidence of type 2 diabetes in youth is also on the rise, particularly among certain ethnic groups. In addition, less common types of diabetes such as monogenic diabetes syndromes and diabetes secondary to pancreatopathy (in some parts of the world) need to be accurately identified to initiate the most appropriate treatment. A detailed patient history and physical examination usually provides clues to the diagnosis. However, specific laboratory and imaging tests are needed to confirm the diagnosis. The management of diabetes in children and adolescents is challenging in some cases due to age-specific issues and the more aggressive nature of the disease. Nonetheless, a patient-centered approach focusing on comprehensive risk factor reduction with the involvement of all concerned stakeholders (the patient, parents, peers and teachers) could help in ensuring the best possible level of diabetes control and prevention or delay of long-term complications.

The Stepwise Approach to Diabetes Prevention: Results From the D-CLIP Randomized Controlled Trial

OBJECTIVE

This study tests the effectiveness of expert guidelines for diabetes prevention: lifestyle intervention with addition of metformin, when required, among people with prediabetes.

RESEARCH DESIGN AND METHODS

The Diabetes Community Lifestyle Improvement Program (D-CLIP) is a randomized, controlled, translation trial of 578 overweight/obese Asian Indian adults with isolated impaired glucose tolerance (iIGT), isolated impaired fasting glucose (iIFG), or IFG+IGT in Chennai, India. Eligible individuals were identified through community-based recruitment and randomized to standard lifestyle advice (control) or a 6-month, culturally tailored, U.S. Diabetes Prevention Program-based lifestyle curriculum plus stepwise addition of metformin (500 mg, twice daily) for participants at highest risk of conversion to diabetes at ≥4 months of follow-up. The primary outcome, diabetes incidence, was assessed biannually and compared across study arms using an intention-to-treat analysis.

RESULTS

During 3 years of follow-up, 34.9% of control and 25.7% of intervention participants developed diabetes (P = 0.014); the relative risk reduction (RRR) was 32% (95% CI 7-50), and the number needed to treat to prevent one case of diabetes was 9.8. The RRR varied by prediabetes type (IFG+IGT, 36%; iIGT, 31%; iIFG, 12%; P = 0.77) and was stronger in participants 50 years or older, male, or obese. Most participants (72.0%) required metformin in addition to lifestyle, although there was variability by prediabetes type (iIFG, 76.5%; IFG+IGT, 83.0%; iIGT, 51.3%).

CONCLUSIONS

Stepwise diabetes prevention in people with prediabetes can effectively reduce diabetes incidence by a third in community settings; however, people with iIFG may require different interventions.

A Proposed India-Specific Algorithm for Management of Type 2 Diabetes

Several algorithms and guidelines have been proposed by countries and international professional bodies; however, no recent updated management algorithm is available for Asian Indians. Specifically, algorithms developed and validated in developed nations may not be relevant or applicable to patients in India because of several factors: early age of onset of diabetes, occurrence of diabetes in nonobese and sometimes lean people, differences in the relative contributions of insulin resistance and β-cell dysfunction, marked postprandial glycemia, frequent infections including tuberculosis, low access to healthcare and medications in people of low socioeconomic stratum, ethnic dietary practices (e.g., ingestion of high-carbohydrate diets), and inadequate education regarding hypoglycemia. All these factors should be considered to choose appropriate therapeutic option in this population. The proposed algorithm is simple, suggests less expensive drugs, and tries to provide an effective and comprehensive framework for delivery of diabetes therapy in primary care in India. The proposed guidelines agree with international recommendations in favoring individualization of therapeutic targets as well as modalities of treatment in a flexible manner suitable to the Indian population.

Ethnic Variations in Diabetes and Prediabetes Prevalence and the roles of Insulin Resistance and β-cell Function: The CARRS and NHANES Studies

•

We compared the hyperglycemia prevalence in Asian Indians to other ethnic groups.

•

The prevalence of diabetes was higher in Indians compared to other ethnic groups.

•

The prevalence of prediabetes was lower in Indians compared to other ethnic groups.

•

These differences may be driven by impaired β-cell function.

Aims

It is unclear how the prevalence of diabetes in Asian Indians in urban India compares to that of race/ethnic groups in the US that may have different underlying susceptibilities. Therefore, we examined ethnic variations in the prevalence of type 2 diabetes, iIFG, iIGT, IFG + IGT, and the associated risk factors in Asian Indians in Chennai, India, and Whites, Blacks, and Hispanics in the United States.

Methods

Cross-sectional analyses, using representative samples of 4867 Asian Indians aged 20–74 years from Chennai, India, in the Centre for Cardiometabolic Risk Reduction in South-Asia study (CARRS) (2010–2011) and 6512 US Whites, Blacks, and Hispanics aged 20–74 years from the National Health and Nutrition Examination Survey (NHANES) (2007–2012).

Results

The age-adjusted prevalence of type 2 diabetes was highest in Asian Indians (men: 28.4, 95% CI: 25.9, 31.0; women: 30.6, 95% CI, 27.5, 33.9) and lowest in Caucasians (men: 12.2, 95% CI, 10.3, 14.4, women: 9.5, 95% CI, 7.9, 11.5). Asian Indians had the lowest prediabetes prevalence (men: 19.0, 95% CI, 17.2, 20.8; women: 27.2, 95% CI, 22.8, 32.1) and Caucasians had the highest (men; 46.5, 95% CI, 43.5, 49.6, women: 34.4, 95% CI, 31.7, 37.3). However, there were differences in prediabetes prevalence by gender and prediabetes state. The inclusion of HOMA-β in standardized polytomous logistic regression models resulted in a greater odds of diabetes in Blacks and Hispanics compared to Asian Indians.

Conclusions

The high prevalence of diabetes in Asian Indians may be due to innate susceptibilities for β-cell dysfunction in this high risk population.

Are We in the Same Risk of Diabetes Mellitus? Gender- and Age-Specific Epidemiology of Diabetes in 2001 to 2014 in the Korean Population

In the early 2000s, the prevalence of diabetes in adults aged ≥30 years in Korea was about 9% to 10%, and it remained stable. However, a nationwide survey showed that this prevalence increased over the past few years. After age-standardization using the Korean population of the year 2010, the prevalence of diabetes in adults aged ≥30 years was 10.0% to 10.8% between 2001 and 2012, which increased to 12.5% in 2013 and 11.6% in 2014. During that period, there have been changes in the gender- and age-specific prevalence of diabetes in Korean adults. The prevalence of diabetes in the elderly population increased significantly, while this prevalence in young adults, especially in young women, did not change significantly. The contribution of each diabetic risk factor, such as obesity, β-cell dysfunction, sarcopenia, and socioeconomic status, in developing diabetes has also changed during that period in each gender and age group. For young women, obesity was the most important risk factor; by contrast, for elderly diabetic patients, sarcopenia was more important than obesity as a risk factor. Considering the economic burden of diabetes and its associated comorbidities, a public health policy targeting the major risk factors in each population might be more effective in preventing diabetes.

Type 2 Diabetes: Why We Are Winning the Battle but Losing the War? 2015 Kelly West Award Lecture

Diabetes is among the biggest of the 21st-century global health challenges. In the U.S. and other high-income countries, thanks to investments in science, dedication to implementing these findings, and measurement of quality of care, there have been improvements in diabetes management and declines in rate of diabetes complications and mortality. This good news, however, is overshadowed by the ever-increasing absolute numbers of people with diabetes and its complications and the unprecedented growth of diabetes in low- and middle-income countries of the world. To comprehensively win the war against diabetes requires 1) concerted attention to prevention and 2) expansion of global research to better inform population-level policies to curb diabetes but also to better understand individual- and population-level variations in pathophysiology and phenotypes globally so that prevention and treatment can be tailored. For example, preliminary data show that thin people in low- and middle-income countries such as India commonly experience type 2 diabetes. Global studies comparing these thin Asian Indians with other high-risk groups such as Pima Indians, a population with a high mean BMI, suggest that type 2 diabetes may not be a single pathophysiological entity. Pima Indians may represent the well-studied phenotype of poor insulin action (type 2A), whereas Asian Indians represent the grossly understudied phenotype of poor insulin secretion (type 2B). This has major implications for diagnosis, prevention, and treatment and highlights the mismatch between where diabetes burdens occur (i.e., low- and middle-income countries) and where research happens (i.e., high-income countries). Correcting this imbalance will advance our knowledge and arsenal to win the global war against diabetes.

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.

Diabetes in India: what is different?

PURPOSE OF REVIEW

The purpose of this study was to review the epidemiology and pathogenesis of diabetes in Asian Indians with a particular focus on 'Asian Indian type 2 diabetes phenotype'.

RECENT FINDINGS

The prevalence of diabetes is rapidly increasing among Asian Indians, particularly in the past two decades. The diabetes rates in urban India now exceed that seen in Indians migrated to developed nations. Urbanization, changes from traditional healthier diets to high-refined carbohydrate intake, and sedentary lifestyle have contributed to this steep increase in the prevalence of diabetes in India. Type 2 diabetes among Asian Indians is characterized by onset at a younger age, greater abdominal obesity despite relatively lower BMI, greater insulin resistance, and early decline in beta cell function. Asian Indians are also at a higher risk for premature coronary artery disease.

SUMMARY

The clinical profile of type 2 diabetes in Asian Indians differs from Caucasians with higher central obesity, increased inflammatory markers such as high sensitive C-reactive protein, greater insulin resistance, early loss of beta cell function, and a higher risk of coronary artery disease. Mechanistic studies are needed to characterize the pathophysiology of the Asian Indian phenotype.

Insulin sensitivity and secretion in youth onset type 2 diabetes with and without visceral adiposity

AIM

To investigate insulin sensitivity and insulin secretion patterns among Asian Indian youth without and with type 2 diabetes (T2DM-y defined as onset of diabetes at or below 25 years) with normal and high visceral fat (VF) levels.

METHODS

We recruited 74 T2DM-y individuals, within 18 months of diagnosis and compared them to 77 age-matched controls with normal glucose tolerance (NGT). Using L4/L5 abdominal CT images, VF levels were categorized as normal or high according to their median values. Oral glucose tolerance tests (glucose and insulin measures) were used to derive Matsuda index, insulin resistance (HOMA-IR) and oral disposition index (DIo). Relationships between measures of insulin sensitivity and secretion and T2DM-y by VF level were assessed using standardized multinomial regression models.

RESULTS

Participants were categorized into four groups: NGT-normal VF; NGT-high VF; T2DM-normal VF, and T2DM-high VF. Among NGTs, those with high VF had significantly lower insulin sensitivity (0.013 vs.0.019 pM(-1)) and Matsuda index (10.2 vs.13.8), than normal VF. When compared, T2DM-high VF had lowest insulin sensitivity (0.009 vs.0.019, 0.013, 0.012 pM-1; p<0.001), Matsuda index (6.4 vs. 13.8, 10.2, 8.6; p<0.001), OGIS120 (305 vs. 396, 382, 316; p<0.001) and DIo (0.48 vs. 3.75, 3.20, 0.55 mmol/L; p<0.001). At every category of 2 h PG values, NGT-high VF had lower DIo than NGT-normal VF participants. In standardized multinomial models, that included DIo and Matsuda index adjusted for age, gender, BMI, and leptin, DIo (Odds ratio: 0.001; 95%Confidence interval: 0.000-0.020), matsuda index (0.26; 0.07-0.93), age (2.92; 1.18-7.19) and leptin (3.17; 1.12-8.99) were associated with high VF among T2DM.

CONCLUSION

Lower DIo and Matsuda index, younger age and higher leptin were independently associated with high visceral fat among T2DM participants. Also, lower DIo was seen with increasing 2 h PG values even among normal glucose tolerant individuals.

Relationship of betatrophin with youth onset type 2 diabetes among Asian Indians

BACKGROUND AND AIMS

Betatrophin is emerging as a marker for compensatory beta cell proliferation. While betatrophin has been mainly investigated in adults, there is a lack of data on betatrophin levels in youth-onset type 2 diabetes mellitus (T2DM-Y). The aim of this study was to determine levels of betatrophin and its association with T2DM-Y in Asian Indian participants.

METHODS

We recruited 100 individuals with normal glucose tolerance (NGT; n=50) and newly-diagnosed cases (within 18 months of first diagnosis) of T2DM-Y (n=50) with onset between 12 and 24 years of age from a large tertiary diabetes center in Chennai in southern India. Insulin resistance was measured by homeostatic model (HOMA-IR) and insulin secretion by oral disposition index (DIO). Betatrophin levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Betatrophin levels were significantly lower in the T2DM-Y group compared with the NGT group (803 vs 1104 pg/ml, p<0.001). Betatrophin showed a significant inverse correlation with waist circumference (p=0.035), HOMA-IR (p<0.001), fasting and 2 h postprandial glucose (p<0.01), glycated hemoglobin (p=0.019) and a positive correlation with fasting C-peptide (p<0.001) and DIO (p=0.012). In regression analysis, betatrophin was independently associated with T2DM-Y even after adjustment for age, gender, and waist circumference (OR per standard deviation: 0.562, 95% CI: 0.342-0.899, p=0.019). However, the association was lost when HOMA-IR was included in the model (OR: 1.141, 95% CI: 0.574-2.249; p=0.646).

CONCLUSION

Betatrophin levels are lower in T2DM-Y and this association is likely mediated through insulin resistance.

Circulating MiRNAs of 'Asian Indian Phenotype' Identified in Subjects with Impaired Glucose Tolerance and Patients with Type 2 Diabetes

Several omics technologies are underway worldwide with an aim to unravel the pathophysiology of a complex phenotype such as type 2 diabetes mellitus (T2DM). While recent studies imply a clinically relevant and potential biomarker role of circulatory miRNAs in the etiology of T2DM, there is lack of data on this aspect in Indians--an ethnic population characterized to represent 'Asian Indian phenotype' known to be more prone to develop T2DM and cardiovascular disease than Europeans. We performed global serum miRNA profiling and the validation of candidate miRNAs by qRT-PCR in a cohort of subjects comprised of normal glucose tolerance (NGT), impaired glucose tolerance (IGT) and patients with T2DM. Our study revealed 4 differentially expressed miRNAs (miR-128, miR-130b-3p, miR-374a-5p, miR-423-5p) in subjects with IGT and T2DM patients compared to control subjects. They were positively or negatively correlated to cholesterol levels, HbA1C, HOMA-IR and fasting insulin. Interestingly, circulating level of miR-128 and miR-130b-3p were also altered in serum of diet-induced diabetic mice compared to control animals. Among the altered circulating miRNAs, miR-128 had never been described in previous studies/populations and appeared to be a 'New Lead' in Indians. It was positively correlated with cholesterol both in prediabetic subjects and in diet-induced diabetic mice, suggesting that its increased level might be associated with the development of dyslipedemia associated with T2DM. Our findings imply directionality towards biomarker potential of miRNAs in the prevention/diagnosis/treatment outcomes of diabetes.