Serum immunoreactive insulin responses to a glucose load in Asian Indian and European type 2 (non-insulin-dependent) diabetic patients and control subjects

Effects of almond consumption compared with the consumption of traditional isocaloric cereal/pulse-based snacks on glycaemic control and gut health in adults with pre-diabetes in rural India: protocol for a 16-week, parallel-arm, cluster randomised controlled trial

INTRODUCTION

Almonds have prebiotic potential to maintain gut health and regulate glycaemia. Western studies have shown their positive effects on preventing non-communicable diseases like diabetes and cardiovascular diseases. However, there is a lack of research involving Asian Indians, who have a higher predisposition to diabetes due to their unique 'Asian phenotype'. Therefore, this study aims to evaluate the impact of almond supplementation on glycaemic control and gut health in adults with pre-diabetes in rural India through a randomised clinical trial.

METHODS AND ANALYSIS

A parallel cluster randomised controlled trial with 178 participants with pre-diabetes (assigned 1:1) aged 20-50 years, of both genders, with a body mass index of 18.9-25 kg/m2, will be conducted in rural areas of Chikkaballapur, Kolar and Rural Bangalore districts in India. The intervention group will receive 56 g of almonds as mid-morning snacks for 16 weeks, while the control group will receive cereal/pulse-based traditional isocaloric snacks under the closed supervision of the study investigators. The primary outcome of the study is HbA1c measured at the 16th week. The secondary outcomes-anthropometry, clinical and other biochemical parameters-will be measured at 0th, 8th and 16th weeks, and a subgroup of 120 participants will undergo gut health analysis. Glucagon-like peptide 1 analysis will be conducted on 30 participants at 0th and 16th weeks. Statistical analysis will be performed using SPSS for Windows V.27.0, and both intention-to-treat and per-protocol analyses will be conducted.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Institutional Ethics Committee at Ramaiah Medical College, Bangalore, Karnataka, India (DRPEFP7672021). We will obtain the informed written consent of the participants prior to screening and enrolling them in the study. Results from this trial will be disseminated through publication in peer-reviewed journals and scientific gatherings.

TRIAL REGISTRATION NUMBER

Clinical Trial Registry of India (CTRI/2023/03/050421).

Insulin Resistance in Adolescents and Youth With Type 1 Diabetes: A Review of Problems and Solutions

Though insulin resistance (IR) was previously considered a feature of only type 2 Diabetes (T2DM), its development in type 1 Diabetes (T1DM) is not an uncommon occurrence, the causes of which are multifactorial (gender, pubertal status, diabetes duration, ethnicity, genetics, adiposity, glycemic control, chronic inflammation). Despite improvements in glucose, blood pressure and lipid profile, vascular complications (coronary artery disease and nephropathy) continue to remain common causes of morbidity and mortality in T1DM. Aggressive glycemic control reduces but does not eliminate the risk of IR. IR accelerates the development of micro and macrovascular complications, many of which can be potentially reversed if diagnosed and managed early. Lack of endogenous insulin production makes estimation of insulin sensitivity in T1DM difficult. As hyperinsulinemic-euglycemic clamp studies are cumbersome and invasive, the use of prediction equations for calculating estimated insulin sensitivity may prove to be useful. Along with intensive insulin therapy, dietary modifications and increasing physical activity, the role of Metformin in managing IR in T1DM is becoming increasingly popular. Metformin adjunct therapy in T1DM has been shown to improve insulin sensitivity, glycemic control, lipid profile, body composition, vascular smooth muscle function, thereby reducing the risk of vascular complications, as well as reversal of early vascular dysfunction. However, further studies to assess long-term efficacy and safety of Metformin use in adolescents and youth with T1DM are needed. This review aims at revisiting the pathophysiology of IR in T1DM and techniques of identifying those at risk so as to put into action various strategies for management of the same.

Study protocol for a cluster randomized controlled trial for 16 weeks to assess the effect of almond consumption on glycemic control and gut health in prediabetes adults in rural settings of India.. [DOI: 10.1101/2023.06.21.23291579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Introduction

Almonds have prebiotic potential to maintain gut health and regulate glycemia. Western studies have shown their positive effects in preventing non-communicable diseases like diabetes and CVDs. However, there is a lack of well-designed studies involving Asian Indians, who have a higher predisposition to diabetes due to their unique ‘Asian phenotype’. Therefore, this study aims to evaluate the impact of almond supplementation on glycemic control and gut health in prediabetic adults in rural India through a randomized clinical trial.

Methods and Analysis

A parallel cluster randomized controlled trial with 178 prediabetic participants aged 20-50, both genders, with a BMI of 18.9-25 kg/m2, will be conducted in rural areas of Chikkaballapur, Kolar, and rural Bangalore districts in India. The intervention group will receive 56g of almonds as mid-morning snacks for 16 weeks, while the control group will receive cereal pulse based traditional isocaloric snacks under the closed supervision of the study investigators. Anthropometry, clinical, and biochemical parameters will be measured at 0, 8th, and 16th weeks, and a subgroup of 120 participants will undergo gut health analysis. GLP 1 analysis will be conducted on 30 participants at 0 and 16th week. Statistical analysis will be performed using SPSS for Windows V 27.0, and both ITT and per-protocol analyses will be conducted.

Ethics and Dissemination

Ethics approval was obtained from the Institutional Ethics Committee at Ramaiah Medical College, Bangalore, Karnataka, India (DRPEFP7672021). Results from this trial will be disseminated through publication in peer-reviewed journals, national and international presentations.

Trial Registration Number

The trial is registered in the clinical trial registry of India (CTRI/2023/03/050421).

ARTICLE SUMMARY

Strengths and Limitations:

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The study is the first field-based trial in rural settings to assess the effect of almond consumption versus traditional cereal pulse-based snacks on prediabetes adults’ glycemic control and gut health.

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The compliance management is crucially designed by performing an intervention on one-to-one closed supervision, assessment of serum tocopherol levels, and regular follow up of any adverse events.

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The upcoming metagenomic analysis and the gut metabolites like short chain fatty acids (SCFA) and GLP 1 will significantly advance our understanding of the impact of almonds on the gut health of prediabetes adults.

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A potential limitation of the study is that it will not be feasible to follow the participants after the post intervention period.

South Asian ethnicity: What can we do to make this risk enhancer a risk equivalent?

South Asians account for around 25% of the global population and are the fastest-growing ethnicity in the US. This population has an increasing burden of atherosclerotic cardiovascular disease (ASCVD) which is also seen in the diaspora. Current risk prediction equations underestimate this risk and consider the South Asian ethnicity as a risk-enhancer among those with borderline-intermediate risk. In this review, we discuss why the South Asian population is at a higher risk of ASCVD and strategies to mitigate this increased risk.

Race/ethnicity and challenges for optimal insulin therapy

AIMS

We aimed to review insulin dosing recommendations, insulin regulation and its determinants, glycaemic response to carbohydrates, and the efficacy and safety of insulin therapy in different races/ethnicities.

METHODS

We searched for articles in PubMed and Google Scholar databases up to 31 March 2021, with the following keywords: "ethnicity", "diabetes", "insulin", "history of insulin", "insulin therapy", "food/rice", "carbohydrate intake", "insulin resistance", "BMI", "insulin dosing", "insulin sensitivity", "insulin response", "glycaemic index", "glycaemic response", "efficacy and safety", with interposition of the Boolean operator "AND".In addition, we reviewed the reference lists of the articles found.

RESULTS

The differential effect of race/ethnicity has not yet been considered in current insulin therapy guidelines. Nevertheless, body size and composition, body mass index, fat distribution, diet, storage, and energy expenditure vary significantly across populations. Further, insulin sensitivity, insulin response, and glycaemicresponse to carbohydrates differ by ethnicity. These disparities may lead to different insulin requirements, adversely impacting the efficacy and safety of insulin therapy among ethnic groups.

CONCLUSIONS

Race/ethnicity affects glucose metabolism and insulin regulation.Until now, international guidelines addressing racial/ethnic-specific clinical recommendations are limited. Comprehensive updated insulin therapy guidelines by ethnicity are urgently needed.

Pathophysiological Mechanisms Underlying Excess Risk for Diabetes and Cardiovascular Disease in South Asians: The Perfect Storm

BACKGROUND

South Asians are at a significantly increased risk of type 2 diabetes (T2D) and cardiovascular disease (CVD), are diagnosed at relatively younger ages, and exhibit more severe disease phenotypes as compared with other ethnic groups. The pathophysiological mechanisms underlying T2D and CVD risk in South Asians are multifactorial and intricately related.

METHODS

A narrative review of the pathophysiology of excess risk of T2D and CVD in South Asians.

RESULTS

T2D and CVD have shared risk factors that encompass biological factors (early life influences, impaired glucose metabolism, and adverse body composition) as well as behavioral and environmental risk factors (diet, sedentary behavior, tobacco use, and social determinants of health). Genetics and epigenetics also play a role in explaining the increased risk of T2D and CVD among South Asians. Additionally, South Asians harbor several lipid abnormalities including high concentration of small-dense low-density lipoprotein (LDL) particles, elevated triglycerides, low high-density lipoprotein (HDL)- cholesterol levels, dysfunctional HDL particles, and elevated lipoprotein(a) that predispose them to CVD.

CONCLUSION

In this comprehensive review, we have discussed risk factors that provide insights into the pathophysiology of excess risk of T2D and CVD in South Asians.

Pathophysiological mechanisms underlying MAFLD

BACKGROUND AND AIMS

The pathophysiology underlying metabolic associated fatty liver disease (MAFLD) involves a multitude of interlinked processes, including insulin resistance (IR) underlying the metabolic syndrome, lipotoxicity attributable to the accumulation of toxic lipid species, infiltration of proinflammatory cells causing hepatic injury and ultimately leading to hepatic stellate cell (HSC) activation and fibrogenesis. The proximal processes, such as IR, lipid overload and lipotoxicity are relatively well established, but the downstream molecular mechanisms, such as inflammatory processes, hepatocyte lipoapoptosis, and fibrogenesis are incompletely understood.

METHODS

A literature search was performed with Medline (PubMed), Scopus and Google Scholar electronic databases till June 2020, using relevant keywords (nonalcoholic fatty liver disease; metabolic associated fatty liver disease; nonalcoholic steatohepatitis; NASH pathogenesis) to extract relevant studies describing pathogenesis of MAFLD/MASH.

RESULTS

Several studies have reported new concepts underlying pathophysiology of MAFLD. Activation of HSCs is the common final pathway for diverse signals from damaged hepatocytes and proinflammatory cells. Activated HSCs then secrete excess extracellular matrix (ECM) which accumulates and impairs structure and function of the liver. TAZ (a transcriptional regulator), hedgehog (HH) ligands, transforming growth factor-β (TGF-β), bone morphogenetic protein 8B (BMP8B) and osteopontin play important roles in activating these HSCs. Dysfunctional gut microbiome, dysregulated bile acid metabolism, endogenous alcohol production, and intestinal fructose handling, modify individual susceptibility to MASH.

CONCLUSIONS

Newer concepts of pathophysiology underlying MASH, such as TAZ/Ihh pathway, extracellular vesicles, microRNA, dysfunctional gut microbiome and intestinal fructose handling present promising targets for the development of therapeutic agents.

A genetic analysis identifies a haplotype at adiponectin locus: Association with obesity and type 2 diabetes

Adiponectin is a prime determinant of the status of insulin resistance. Association studies between adiponectin (ADIPOQ) gene single nucleotide polymorphisms (SNPs) and metabolic diseases have been reported earlier. However, results are ambiguous due to apparent contradictions. Hence, we investigated (1) the association between ADIPOQ SNPs: -11377C/G, +10211T/G, +45T/G and +276G/T for the risk towards type 2 diabetes (T2D) and, (2) genotype-phenotype association of these SNPs with various biochemical parameters in two cohorts. Genomic DNA of diabetic patients and controls from Gujarat and, Jammu and Kashmir (J&K) were genotyped using PCR-RFLP, TaqMan assay and MassArray. Transcript levels of ADIPOQ were assessed in visceral adipose tissue samples, and plasma adiponectin levels were estimated by qPCR and ELISA respectively. Results suggest: (i) reduced HMW adiponectin/total adiponectin ratio in Gujarat patients and its association with +10211T/G and +276G/T, and reduced ADIPOQ transcript levels in T2D, (ii) association of the above SNPs with increased FBG, BMI, TG, TC in Gujarat patients and (iii) increased GGTG haplotype in obese patients of Gujarat population and, (iv) association of -11377C/G with T2D in J&K population. Reduced HMW adiponectin, in the backdrop of obesity and ADIPOQ genetic variants might alter metabolic profile posing risk towards T2D.

Type 2 Diabetes and Atherosclerotic Cardiovascular Disease in South Asians: a Unique Population with a Growing Challenge

PURPOSE OF REVIEW

The purpose of this review is to summarize our current knowledge of factors that influence clinical decision making and management of type 2 diabetes mellitus (T2DM) and atherosclerotic cardiovascular disease (ASCVD) among South Asians (SA).

RECENT FINDINGS

ASCVD and T2DM in SAs have been examined in recent times. Pathophysiologic and genetic factors including the role of adiponectin, visceral adiposity, lower beta cell function, and psycho-social factors like sedentary lifestyle, poor adherence to medications, and carbohydrate dense meals play a role in early development and the high-risk presentation of both ASCVD and T2DM in SA. Recently, large population-based cohort studies have attempted to compare outcomes and interventions that can be translated to timely detection and targeted interventions in this high-risk group. SAs in the USA are more likely to be diagnosed with T2DM and ASCVD when compared to non-Hispanic whites, non-Hispanic Blacks, and Hispanic populations. The development of personalized ethnic risk assessment tools and better representation of SAs in prospective studies are essential to increasing our understanding and management of cardio-metabolic disease in SA living in the USA.

Diet and lifestyle-related factors associated with Apathyanimittaja Prameha (type 2 diabetes): A cross-sectional survey study

Background

Lifestyle disorders are the leading cause of death and disability worldwide. Type 2 diabetes is one such disease with high incidence in low- and middle-income countries such as India. Changed lifestyle, lack of exercise, increased consumption of fatty, fast-food items, improper dietary habits and sedentary life are the main contributory factors for this, which are showing upward trend in India.

Aims and Objectives

The aim of the study is to identify the lifestyle factors, physical activities and psychological factors associated with type 2 diabetes among the patient aged between 20-60 years.

Materials and Methods

A cross-sectional survey study was conducted on selected 150 patients of type 2 diabetes within 1 year of diagnosis. A survey questionnaire was used to collect the data for fulfilling the aims and objectives of the study.

Results and Observations

150 patients of type 2 diabetes were observed on various dietary factors, physical activities and life style factors.

Conclusion

On the basis of survey psychological factor association with type 2 diabetes and dietary factors, physical activities and psychological factors observed in survey study. The obtained data exposed that intake of heavy, high fatty food, physical inactivity, day sleep and psychological distress as the main lifestyle factors associated with type 2 diabetes.

Body fat, metabolic syndrome and hyperglycemia in South Asians

The prevalence of overweight and obesity is escalating in South Asian countries. South Asians display higher total and abdominal obesity at a lower BMI when compared to Whites. Consequently, metabolic dysfunction leading to metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) will account for a majority of the health burden of these countries. In this review, we discuss those factors that contribute to MetS and T2DM in South Asians when compared to whites, focusing on adiposity. Abdominal obesity is the single-most important risk factor for MetS and its predisposition to T2DM. Excessive ectopic fat deposition in the liver (non-alcoholic fatty liver disease) has been linked to insulin resistance in Asian Indians, while the effects of ectopic fat accumulation in pancreas and skeletal muscle need more investigation. South Asians also have lower skeletal muscle mass than Whites, and this may contribute to their higher risk T2DM. Lifestyle factors contributing to MetS and T2DM in South Asians include inadequate physical activity and high intakes of refined carbohydrates and saturated fats. These are reflective of the recent but rapid economic transition and urbanization of the South Asian region. There is need to further the research into genetic determinants of dysmetabolism as well as gene x environment interactions. Collectively, MetS and T2DM have multi-factorial antecedents in South Asians and efforts to combat it through low-cost and socio-culturally appropriate lifestyle interventions need to be supported.

Genetic association of ADIPOQ gene variants (-3971A>G and +276G>T) with obesity and metabolic syndrome in North Indian Punjabi population

BACKGROUND AND AIMS

At present obesity and metabolic syndrome (MetS) in India are the most challenging health problems. It is also well accepted that obesity is a significant risk factor for the development of metabolic syndrome and other degenerative diseases. Many studies have reported that single-nucleotide polymorphisms (SNPs) of the adiponectin (ADIPOQ) gene have been associated with obesity and its related disorders. Here, we aimed to investigate the association of two intronic variants in ADIPOQ gene, -3971A>G (rs822396) and +276G>T (rs1501299) with obesity and metabolic syndrome.

METHODS

Biochemical and anthropometric measurements were obtained from a total of 550 unrelated subjects (obese = 250 and non-obese = 300) of North Indian Punjabi population. Genotyping for the intron variants were performed by polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) methods. After genotyping, as a quality control measure 10% of the samples for each polymorphism were confirmed by Sanger Sequencing method. The distributions of genotypic and allelic frequencies among obese and non-obese groups were compared by chi-square test and the corresponding risk was calculated using binary logistic regression. The effects of multiple testing were controlled by applying Bonferroni corrections.

RESULTS

All the anthropometric and biochemical parameters except triglycerides (TG) and very low-density lipoproteins cholesterol (VLDL-C) have shown significant association with both GG and TT genotypes of -3971A>G (rs822396) and +276G>T (rs1501299) polymorphisms respectively. The frequencies of GG (-3971A>G) and TT (+276G>T) genotypes were higher among obese cases (p = 0.008 and p = 0.035 respectively). However, no significant association was found between allelic frequencies of ADIPOQ rs822396 and obesity, whereas the association of ADIPOQ rs1501299 attenuated and became marginally significant after Bonferroni correction (p>0.025). Both the variant genotypes of ADIPOQ gene polymorphisms (-3971GG and +276TT) significantly increased the risk of development of obesity (OR: 1.52, p = 0.03; OR: 1.58, p = 0.04 respectively) and MetS (OR: 1.42, p = 0.03; OR: 1.57, p = 0.01 respectively) in the present population, after adjusting the various covariates. The G-T haplotype model (possessing -3971G and +276T alleles) was shown toprovide ~ 3 fold risk towards the obesity susceptibility (OR: 2.69, p = 0.009) and MetS risk (OR: 2.73, p = 0.009) and the association persisted after adjusting for different confounding variables.

CONCLUSION

The present study has confirmed that ADIPOQ -3971A>G (rs822396) and +276G>T (rs1501299) polymorphism may be clinically helpful to estimate obesity and MetS risk in North Indian Punjabi population.

My 40-year journey in diabetes research: The power of collaboration

This article describes a 40 year journey in diabetes research of an Indian diabetologist, starting as an undergraduate medical student. The article describes how collaborations with multiple stake-holders is necessary if one is to advance one's research from the simple studies that one starts with and take it to higher and higher levels. It is also essential that the seeds for doing research are planted early in a medico's life even during undergraduate days, as only then will more doctors take up medical research as a career. Finally, the article demonstrates how it is possible to do good quality research in India if one has the passion and sustained interest in the field even if one is not in a university or academic setup.

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.

Role of lifestyle factors in the epidemic of diabetes: lessons learnt from India

The prevalence of type 2 diabetes (T2D) is increasing steadily globally with the largest increases occurring in developing countries like India. This is attributed to the changes in the lifestyle factors, including physical inactivity and unhealthy diet, both of which are modifiable. Existing evidence suggests that increasing physical activity reduces the risk of T2D. Improving the built environment can make it more conducive to people to increase physical activity. There is also a rapid nutrition transition with consumption of diets with higher intake of refined grains, higher fat, increased consumption of sugar and sweetened beverages, and lower intake of fruits and vegetables. A multisectoral approach promoting healthier diets and increasing physical activity can help in slowing down the diabetic epidemic. However, this requires political will to make necessary policy changes, as well as empowerment of the community, if the preventive measures are to be sustainable and scalable.

C-Peptide, Baseline and Postprandial Insulin Resistance after a Carbohydrate-Rich Test Meal - Evidence for an Increased Insulin Clearance in PCOS Patients?

Introduction Known characteristics of patients with PCOS include infertility, menstrual disorders, hirsutism and also often insulin resistance. These symptoms increase with increasing body weight. In the LIPCOS study (Lifestyle Intervention for Patients with Polycystic Ovary Syndrome [PCOS]) long-term changes of the PCOS in dependence on pregnancy and parenthood were systematically assessed. In the framework of the LIPCOS study, PCOS patients were given a standardised carbohydrate-rich test meal in order to examine glucose homeostasis and insulin secretion. The results were compared with those of a eumenorrhoeic control group who all had corresponding BMI values and corresponding ages. Methods and Patients 41 PCOS patients (without diabetes) and 68 controls received a standardised carbohydrate-rich test meal (260 kcal, 62 % carbohydrates, 32 % fat, 6 % proteins) in order to generate a submaximal insulin and glucose stimulation. The values were determined at baseline and postprandial after 60, 120 and 180 minutes. In addition, the corresponding C-peptide levels were recorded. Results In the PCOS patients (n = 41), the insulin secretion test after a standardised test meal showed almost identical baseline and postprandial insulin levels when compared with those of the age- and BMI-matched eumenorrhoeic controls (n = 68). In the PCOS patients, the baseline and postprandial glucose levels were significantly elevated (92.88 ± 10.28 [PCOS] vs. 85.07 ± 9.42 mg/dL [controls]; p < 0.001) so was C-peptide (p < 0.025). Conclusions In the present study we have shown for the first time that, after consumption of a standardised test meal, PCOS patients formally exhibit a higher fasting insulin resistance than controls. In spite of the higher stimulated C-peptide levels, the insulin levels did not increase more strongly with increasing glucose levels than in controls which may be indicative of a higher insulin clearance in PCOS patients.

High fat diet modifies the association of lipoprotein lipase gene polymorphism with high density lipoprotein cholesterol in an Asian Indian population

Background

Single nucleotide polymorphisms (SNPs) in lipoprotein lipase gene (LPL) have been shown to influence metabolism related to lipid phenotypes. Dietary factors have been shown to modify the association between LPL SNPs and lipids; however, to date, there are no studies in South Asians. Hence, we tested for the association of four common LPL SNPs with plasma lipids and examined the interactions between the SNPs and dietary factors on lipids in 1,845 Asian Indians.

Methods

The analysis was performed in 788 Type 2 diabetes cases and 1,057 controls randomly chosen from the cross-sectional Chennai Urban Rural Epidemiological Study. Serum triacylglycerol (TAG), serum total cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured using a Hitachi-912 autoanalyzer (Roche Diagnostics GmbH, Mannheim, Germany). Dietary intake was assessed using a semi-quantitative food frequency questionnaire. The SNPs (rs1121923, rs328, rs4922115 and rs285) were genotyped by polymerase chain reaction followed by restriction enzyme digestion and 20% of samples were sequenced to validate the genotypes obtained. Statistical Package for Social Sciences for Windows version 22.0 (SPSS, Chicago, IL) was used for statistical analysis.

Results

After correction for multiple testing and adjusting for potential confounders, SNPs rs328 and rs285 showed association with HDL-C (P = 0.0004) and serum TAG (P = 1×10⁻⁵), respectively. The interaction between SNP rs1121923 and fat intake (energy %) on HDL-C (P = 0.003) was also significant, where, among those who consumed a high fat diet (28.4 ± 2.5%), the T allele carriers (TT + XT) had significantly higher HDL-C concentrations (P = 0.0002) and 30% reduced risk of low HDL-C levels compared to the CC homozygotes. None of the interactions on other lipid traits were statistically significant.

Conclusion

Our findings suggest that individuals carrying T allele of the SNP rs1121923 have increased HDL-C levels when consuming a high fat diet compared to CC homozygotes. Our finding warrants confirmation in prospective studies and randomized controlled trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-016-0155-1) contains supplementary material, which is available to authorized users.

Replication of genome-wide association signals in Asian Indians with early-onset type 2 diabetes

AIMS

To evaluate the association of 87 genetic variants previously associated with type 2 diabetes mellitus (T2DM) in genome-wide association studies of populations of European ancestry in an Asian Indian population with early-onset type 2 diabetes mellitus (EOT2DM).

METHODS

The study groups comprised of 877 type 2 diabetes individuals, 436 individuals with EOT2DM (age at diagnosis below 35 years), 441 individuals with older T2DM (diagnosis at 35 years or greater) and controls with normal glucose tolerance (NGT) (n = 400 younger than 35 years; n = 438 older than 35 years). The participants were genotyped for 87 SNPs from 44 genes and 27 intergenic loci. Associations were tested using logistic regression.

RESULTS

All the variants in TCF7L2 and CDKN2A/2B showed study-wide significance (p < 1.4 × 10^-4) with T2DM, but only rs7903146, rs12243326, rs12255372 of TCF7L2 and rs7020996 of CDKN2A/2B showed study-wide significance (p < 1.4 × 10^-4) with EOT2DM in this population. In addition, an intergenic SNP on chromosome 1 (rs10493685) was also shown to be study-wide significant (p = 7.1 × 10^-6). Several additional SNPs previously associated with T2DM reached borderline significance in this study, but may have been limited by relatively low sample numbers. Various other SNPs of T2DM were not associated with EOT2DM.

CONCLUSIONS

Some of the variants in TCF7L2 and CDKN2A/2B associated with T2DM are associated with EOT2DM as well. An intergenic SNP on chromosome 1p31 showed association only with early-onset T2DM in this Asian Indian population. The lack of association with many other SNPs of T2DM may be a reflection of the lack of power of the study, sample size, differences in the frequencies of genetic polymorphisms in different ethnic groups, effect sizes, as well as ancestral differences in pattern of LD between the genetic variants involved in early- and late-onset T2DM.

Association of Soluble (Pro) Renin Receptor with Gestational Diabetes Mellitus

OBJECTIVE

There is a need to identify biomarkers for gestational diabetes mellitus (GDM). Recently the soluble pro-renin receptor (s[Pro]RR) has been shown to be associated with GDM. We investigated the association of s(Pro) RR levels in Asian Indians with GDM.

METHODS

We recruited 222 pregnant females, 147 without GDM (non-GDM) and 75 with GDM visiting antenatal clinics in Tamilnadu in South India. We included singleton pregnancy and excluded those with pre-existing diabetes mellitus or hypertension. Oral glucose tolerance tests (OGTTs) were performed, and GDM was diagnosed using the International Association of Diabetes and Pregnancy Study Group criteria. s(Pro)RR was measured by enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristic (ROC) curves were used to identify s(Pro) RR cut-off points to identify GDM.

RESULTS

The mean levels of the s(Pro)RR were significantly higher in subjects with GDM (34.0 ± 12 ng/mL, P<.001) compared to non-GDM (21.4 ± 6.5 ng/mL). The proportions of subjects with GDM were 11 (15%) in the first tertile of s(Pro)RR (<19.61 ng/mL), 20 (27%) in the second (19.62-26.8 ng/mL), and 44 (59%) in the third tertile (>26.8 ng/mL). In multiple logistic regression analysis, s(Pro)RR showed a significant association with GDM (odds ratio [OR]: 1.201, 95% confidence interval [CI]: 1.065-1.355, P = .003) after adjusting for potential confounders. A s(Pro)RR cut-off of 23.3 ng/mL had a C statistic of 0.828 (95% CI: 0.738-0.918, P<.001), sensitivity of 68%, and specificity of 70% to identify GDM.

CONCLUSIONS

s(Pro)RR levels are higher in females with GDM, and this could be used as a potential biomarker.

Nonalcoholic Fatty Liver Disease in South Asia

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the West, and is also increasing alarmingly in South Asia, reaching an epidemic proportion of 30% because of epidemic of obesity and metabolic syndrome (MS) in younger South Asians in the last two decades. Prevalence of MS and fatty liver is escalating in geometric progression in South Asian countries, such as India, Pakistan, Sri Lanka, Bangladesh, Nepal, Bhutan, Burma, and Maldives because of sedentary lifestyle, poor health awareness, socioeconomic growth, affluence, urbanization, and dietary westernization. Almost 20% of world's population resides in South Asia, making it the most populous and most densely populated geographic region in the world, thereby having most of MS and NAFLD cases within its territory. The risk factors and course of NAFLD do not differ between South Asians and other ethnic populations, but the obesity epidemic is more recent in South Asia than elsewhere in the world. Nonalcoholic fatty liver disease may progress through stages of simple bland steatosis, nonalcoholic steatohepatitis (NASH), hepatic fibrosis, cirrhosis, and finally hepatocellular carcinoma (HCC). It is frequently associated with obesity, MS, dyslipidemia, insulin resistance (IR), and type-2 diabetes mellitus (DM). Nonalcoholic fatty liver disease is frequently diagnosed with abdominal ultrasonography (US) study. Despite its high prevalence in the community till now, no definitive pharmacotherapy is available for NAFLD. However, modification of risk factors, such as dyslipidemia, control of diabetes, and weight reduction do help to some extent. The nonobese South Asians are also at increased risk of having NAFLD and NASH as, despite of absence of frank obesity in South Asians, they are metabolically more obese compared to other ethnic population and more prone to develop NAFLD-related complications. Therefore, the cost-effective US abdomen should be included in the list of tests for persons undergoing preemployment or master health checkups for early diagnosis of NAFLD in this resource-constraint South Asian region, so that early necessary measures can be undertaken to reduce NAFLD associated morbidity and mortality in the community.

HOW TO CITE THIS ARTICLE

Pati GK, Singh SP. Nonalcoholic Fatty Liver Disease in South Asia. Euroasian J Hepato-Gastroenterol 2016;6(2):154-162.

Diabetes mellitus and its complications in India

India is one of the epicentres of the global diabetes mellitus pandemic. Rapid socioeconomic development and demographic changes, along with increased susceptibility for Indian individuals, have led to the explosive increase in the prevalence of diabetes mellitus in India over the past four decades. Type 2 diabetes mellitus in Asian Indian people is characterized by a young age of onset and occurrence at low levels of BMI. Available data also suggest that the susceptibility of Asian Indian people to the complications of diabetes mellitus differs from that of white populations. Management of this disease in India faces multiple challenges, such as low levels of awareness, paucity of trained medical and paramedical staff and unaffordability of medications and services. Novel interventions using readily available resources and technology promise to revolutionise the care of patients with diabetes mellitus in India. As many of these challenges are common to most developing countries of the world, the lessons learnt from India's experience with diabetes mellitus are likely to be of immense global relevance. In this Review, we discuss the epidemiology of diabetes mellitus and its complications in India and outline the advances made in the country to ensure adequate care. We make specific references to novel, cost-effective interventions, which might be of relevance to other low-income and middle-income countries of the world.

Changes in characteristics and management of Asian and Anglo-Celts with type 2 diabetes over a 15-year period in an urban Australian community: The Fremantle Diabetes Study

BACKGROUND

The aim of the present study was to determine temporal changes in characteristics and management of Asians with type 2 diabetes (T2D) compared with those of the majority Anglo-Celt (AC) patients in an urban Australian community.

METHODS

Cross-sectional data from the observational Fremantle Diabetes Study (FDS) collected in 1993-96 (Phase I; FDS1) and 2008-11 (Phase II; FDS2) were analyzed for patients classified as Asian (n = 44 and 65 in FDS1 and FDS2, respectively) or AC (n = 796 and 793, respectively). Between-group differences in changes in key variables between FDS phases were analyzed by generalized linear modeling with adjustment for age and gender.

RESULTS

Asians patients were significantly younger at diagnosis and recruitment and had a lower body mass index and smaller waist circumference than the AC participants in both FDS phases. They were also less likely to be treated for hypertension. Cardiovascular risk factors and their management and macrovascular complications were similar in the two groups over time. A greater propensity to retinopathy with Asian ethnicity in FDS1 (27.3% vs 13.5%; P = 0.23) was attenuated in FDS2 (23.7% vs 19.0%; P = 0.39). Asians had a significantly lower prevalence of peripheral sensory neuropathy in FDS2 (33.8% vs 63.3%; P < 0.001; adjusted P = 0.011 for between-group temporal change).

CONCLUSIONS

There were persistent differences between the phenotypic features of Asian migrants with T2D versus AC patients in an Australian urban community over 15 years of follow-up, but management of diabetes and non-glycemic risk factors remained comparable. Ethnicity-specific differences in susceptibility to microvascular complications should be considered in clinical management.

Incidence of Diabetes and Prediabetes and Predictors of Progression Among Asian Indians: 10-Year Follow-up of the Chennai Urban Rural Epidemiology Study (CURES)

OBJECTIVE

There are few data on the incidence rates of diabetes and prediabetes (dysglycemia) in Asian Indians. This article presents the incidence of diabetes and prediabetes and the predictors of progression in a population-based Asian Indian cohort.

RESEARCH DESIGN AND METHODS

Data on progression to diabetes and prediabetes from 1,376 individuals, a subset of 2,207 of the Chennai Urban Rural Epidemiology Study (CURES) cohort (phase 3) with normal glucose tolerance (NGT) or prediabetes at baseline, who were followed for a median of 9.1 years (11,629 person-years), are presented. During follow-up, 534 died and 1,077 with NGT and 299 with prediabetes at baseline were reinvestigated in a 10-year follow-up study. Diabetes and prediabetes were diagnosed based on the American Diabetes Association criteria. Incidence rates were calculated and predictors of progression to prediabetes and/or diabetes were estimated using the Cox proportional hazards model.

RESULTS

The incidence rates of diabetes, prediabetes, and "any dysglycemia" were 22.2, 29.5, and 51.7 per 1,000 person-years, respectively. Among those with NGT, 19.4% converted to diabetes and 25.7% to prediabetes, giving an overall conversion rate to dysglycemia of 45.1%. Among those with prediabetes, 58.9% converted to diabetes. Predictors of progression to dysglycemia were advancing age, family history of diabetes, 2-h plasma glucose, glycated hemoglobin (HbA1c), low HDL cholesterol, and physical inactivity.

CONCLUSIONS

Asian Indians have one of the highest incidence rates of diabetes, with rapid conversion from normoglycemia to dysglycemia. Public health interventions should target modifiable risk factors to slow down the diabetes epidemic in this population.

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.

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.

ALTERED CIRCULATING LEVELS OF RETINOL BINDING PROTEIN 4 AND TRANSTHYRETIN IN RELATION TO INSULIN RESISTANCE, OBESITY, AND GLUCOSE INTOLERANCE IN ASIAN INDIANS

OBJECTIVE

Retinol binding protein 4 (RBP4) has been implicated in metabolic disorders including type 2 diabetes mellitus (T2DM), but few studies have looked at transthyretin (TTR) with which RBP4 is normally bound to in the circulation. We report on the systemic levels of RBP4 and TTR and their associations with insulin resistance, obesity, prediabetes, and T2DM in Asian Indians.

METHODS

Age-matched individuals with normal glucose tolerance (NGT, n = 90), impaired glucose tolerance (IGT, n = 70) and T2DM (n = 90) were recruited from the Chennai Urban Rural Epidemiology Study (CURES). Insulin resistance was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). RBP4 and TTR levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Circulatory RBP4 and TTR levels (in μg/mL) were highest in T2DM (RBP4: 13 ± 3.9, TTR: 832 ± 310) followed by IGT (RBP4: 10.5 ± 3.2; TTR: 720 ± 214) compared to NGT (RBP4: 8.7 ± 2.5; TTR: 551 ± 185; P<.001). Compared to nonobese NGT individuals, obese NGT, nonobese T2DM, and obese T2DM had higher RBP4 (8.1 vs. 10.6, 12.1, and 13.2 μg/mL, P<.01) and TTR levels (478 vs. 737, 777, and 900 μg/mL, P<.01). RBP4 but not TTR was significantly (P<.001) correlated with insulin resistance even among NGT subjects. In regression analysis, RBP4 and TTR showed significant associations with T2DM after adjusting for confounders (RBP4 odds ratio [OR]: 1.107, 95% confidence interval [CI]: 1.008-1.216; TTR OR: 1.342, 95% CI: 1.165-1.547).

CONCLUSION

Circulatory levels of RBP4 and TTR showed a significant associations with glucose intolerance, obesity, T2DM and RBP4 additionally, with 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.

Diabetes and associated complications in the South Asian population

The rising prevalence of diabetes in South Asians has significant health and economic implications. South Asians are predisposed to the development of diabetes due to biologic causes which are exacerbated by lifestyle and environmental factors. Furthermore, they experience significant morbidity and mortality from complications of diabetes, most notably coronary artery disease, cerebrovascular disease, and chronic kidney disease. Therefore, understanding the pathophysiology and genetics of diabetes risk factors and its associated complications in South Asians is paramount to curbing the diabetes epidemic. With this understanding, the appropriate screening, preventative and therapeutic strategies can be implemented and further developed. In this review, we discuss in detail the biologic and lifestyle factors that predispose South Asians to diabetes and review the epidemiology and pathophysiology of microvascular and macrovascular complications of diabetes in South Asians. We also review the ongoing and completed diabetes prevention and management studies in South Asians.

CTTTA Deletion/Insertion polymorphism in 3'-UTR of LEPR gene in type 2 diabetes subjects belonging to Kashmiri population

Background

Type 2 diabetes mellitus is a multi-factorial disease in which both genetic and non-genetic factors interact in order to precipitate the diabetic phenotype. Among various predisposing genetic loci, a pentanucleotide (CTTTA) Del/Ins variant in the 3'-UTR of the LEPR gene is associated with type 2 diabetes and its related traits. This study was done to explicate for the first time the association of this Del/Ins polymorphism of LEPR gene in type 2 diabetes patients belonging to the ethnic population of Kashmir valley.

Methods

670 unrelated subjects comprising of 320 type 2 diabetes patients and 350 healthy controls were included in the study. Genotyping of the untranslated region of LEPR gene encompassing this Del/Ins variant was done by PCR-RFLP technique and results were validated by direct sequencing.

Results

Genotype frequencies for both type 2 diabetes cases and healthy controls were consistent with Hardy-Weinberg equilibrium (χ² = 3.09 and 2.37, P = NS). The Del/Del genotype was predominantly found in cases than controls (P = 0.003, OR: 0.62, CI: 0.45-0.85). Carriers of Ins/Ins genotype were relatively protected against the risk factors (P = 0.0004, OR: 0.31, 95% CI: 0.15-0.61). A positive association was observed between the Del allele and the risk factors of type 2 diabetes.

Conclusion

The results elucidate that the CTTTA Del allele is a genotypic risk factor of type 2 diabetes in the Kashmiri population.

Understanding the high prevalence of diabetes in U.S. south Asians compared with four racial/ethnic groups: the MASALA and MESA studies

OBJECTIVE

We compared South Asians with four other racial/ethnic groups in the U.S. to determine whether sociodemographic, lifestyle, or metabolic factors could explain the higher diabetes prevalence and whether insulin resistance and β-cell dysfunction occurred at younger ages and/or lower adiposity levels compared with other groups.

RESEARCH DESIGN AND METHODS

We performed a cross-sectional analysis of two community-based cohorts, the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study and the Multi-Ethnic Study of Atherosclerosis (MESA); all participants had no known cardiovascular disease and were between 44 and 84 years of age. We compared 799 South Asians with 2,611 whites, 1,879 African Americans, 1,493 Latinos, and 801 Chinese Americans. Type 2 diabetes was classified by fasting plasma glucose ≥126 mg/dL or use of a diabetes medication. Insulin resistance was estimated by the homeostasis model assessment (HOMA) and β-cell function was measured by the HOMA-β model.

RESULTS

South Asians had significantly higher age-adjusted prevalence of diabetes (23%) than the MESA ethnic groups (6% in whites, 18% in African Americans, 17% in Latinos, and 13% in Chinese Americans). This difference increased further after adjustment for potential confounders. HOMA of insulin resistance (HOMA-IR) levels were significantly higher and HOMA-β levels were lower among South Asians compared with all other racial/ethnic groups after adjustment for age and adiposity.

CONCLUSIONS

The higher prevalence of diabetes in South Asians is not explained by traditionally measured risk factors. South Asians may have lower β-cell function and an inability to compensate adequately for higher glucose levels from insulin resistance.

Lean people with dysglycemia have a worse metabolic profile than centrally obese people without dysglycemia

AIM

This study compared metabolic profiles of Asian Indians with normal waist circumference (WC) and dysglycemia versus those with high WC without dysglycemia.

SUBJECTS AND METHODS

In 2,350 subjects ≥20 years of age from the Chennai Urban Rural Epidemiology Study with full anthropometric and biochemical characterization, high WC was defined as ≥90 cm in males and ≥80 cm in females. Dysglycemia was defined as prediabetes (fasting plasma glucose ≥100 mg/dL and/or 2-h plasma glucose ≥140 mg/dL) or diabetes (fasting plasma glucose ≥126 mg/dL, 2-h plasma glucose ≥200 mg/dL, or treatment for diagnosed diabetes). Coronary artery disease (CAD) was defined as known myocardial infarction or Q waves on electrocardiography. Multivariable logistic regression models were used to explore factors associated with CAD.

RESULTS

Of the subjects, 260 (11.1%) had dysglycemia with normal WC, and 679 (28.9%), had high WC without dysglycemia. Compared with subjects with high WC without dysglycemia, those with dysglycemia/normal WC, adjusted for age, were more likely to be males (P<0.001) and have higher systolic blood pressure (P<0.05), higher serum triglycerides (P<0.001), higher tumor necrosis factor-α (P<0.001), lower high-density lipoprotein cholesterol (P<0.05), and higher prevalence of CAD (6.3% vs. 2.0%; odds ratio 3.25 [95% confidence interval 1.52-6.94]; P=0.002).

CONCLUSIONS

Dysglycemia is associated with a worse cardiometabolic profile than central obesity alone.

Genetic association of ADIPOQ gene variants with type 2 diabetes, obesity and serum adiponectin levels in south Indian population

OBJECTIVE

To investigate the genetic association of eight variants of the adiponectin gene with type 2 diabetes mellitus (T2DM), obesity and serum adiponectin level in the south Indian population.

METHODS

The study comprised of 1100 normal glucose tolerant (NGT) and 1100 type 2 diabetic, unrelated subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), in southern India. Fasting serum adiponectin levels were measured by radioimmunoassay. The variants were screened by polymerase chain reaction-restriction fragment length polymorphism. Linkage disequilibrium was estimated from the estimates of haplotype frequencies.

RESULTS

Of the 8 variants, four SNPs namely, +276 G/T (rs1501299), -4522 C/T (rs822393), -11365 C/G (rs266729), and +712 G/A (rs3774261) were significantly associated with T2DM in our study population. The -3971 A/G (rs822396) and -11391 G/A (rs17300539) SNPs' association with T2DM diabetes was mediated through obesity (where the association with type 2 diabetes was lost after adjusting for BMI). There was an independent association of +276 G/T (rs1501299) and -3971 A/G (rs822396) SNPs with generalized obesity and +349 A/G (rs2241767) with central obesity. Four SNPs, -3971 A/G (rs822396), +276 G/T (rs1501299), -4522 C/T (rs822393) and Y111H T/C (rs17366743) were significantly associated with hypoadiponectinemia. The haplotypes GCCATGAAT and AGCGTGGGT conferred lower risk of T2DM in this south Indian population.

CONCLUSION

The adiponectin gene variants and haplotype contribute to the genetic risk towards the development of type 2 diabetes, obesity and hypoadiponectinemia in the south Indian population.

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.

Association of hepatic lipase gene polymorphisms with hypertriglyceridemia and low high-density lipoprotein-cholesterol levels among South Indian subjects without diabetes

AIM

The aim of this study was to investigate the association of four variants of the hepatic lipase (HL [or LIPC]) gene with various lipid parameters among South Indian subjects with normal glucose tolerance (NGT).

SUBJECTS AND METHODS

In total, 747 NGT subjects were randomly selected from the Chennai Urban Rural Epidemiological Study (CURES). Serum triglycerides, serum cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured using a Hitachi-912 autoanalyzer (Roche Diagnostics GmbH, Mannheim, Germany). Genotyping of HL gene variants was done by the polymerase chain reaction-restriction fragment length polymorphism method, and 20% of samples were sequenced to validate the genotypes obtained. Haplotype analysis was also carried out.

RESULTS

The TT genotype of the rs1800588 C/T (C-480T) polymorphism was significantly associated with hypertriglyceridemia, with an adjusted odds ratio of 2.58 (95% confidence interval 1.38-4.85, P=0.003), whereas those with the CC genotype of the rs6074 A/C (Thr479Thr) had significantly lower HDL-C levels (41.3±9.8 mg/dL) compared with the AA genotype (43.6±10.2 mg/dL, P=0.02). Haplotype analysis showed the TGC haplotype was significantly associated with low HDL-C levels.

CONCLUSIONS

Among South Indian subjects without diabetes, the rs1800588 C/T (C-480T) and rs6074 C/A (Thr479Thr) variants of the HL gene are associated with hypertriglyceridemia and low HDL-C, respectively. The TGC haplotype was significantly associated with low HDL-C.

Type 2 diabetes in South Asians: similarities and differences with white Caucasian and other populations

Type 2 diabetes mellitus (T2DM) is one of the leading causes of morbidity and mortality. While all ethnic groups are affected, the prevalence of T2DM in South Asians, both in their home countries and abroad, is extremely high and is continuing to rise rapidly. Innate biological susceptibilities coupled with rapid changes in physical activity, diet, and other lifestyle behaviors are contributing factors propelling the increased burden of disease in this population. The large scope of this problem calls for investigations into the cause of increased susceptibility and preventative efforts at both the individual and population level that are aggressive, culturally sensitive, and start early. In this review, we outline the biological and environmental factors that place South Asians at elevated risk for T2DM, compared with Caucasian and other ethnic groups.

Effect of low-dose omega-3 fatty acids substitution on blood pressure, hyperinsulinemia and dyslipidemia in Indians with essential hypertension: A pilot study

The present study comprised 100 patients of essential hypertension who were screened for fasting hyperinsulinemia, which was detected in 77% cases. Twenty such hyperinsulinemic cases were subjected to 4 weeks of dietary control phase followed by 6 weeks of omega-3 fatty acids substitution [either 0.6 g/d (group 1) or 1.2 g/d (group 2)]. The mean basal fasting plasma insulin levels were significantly higher (p<0.001) in patients of hypertension when compared to normal controls (126.51±80.36 and 19.35±12.61 μU/ml respectively). At the end of 4 weeks of diet control only, no significant change was observed in any parameter. After substitution of omega-3 fatty acid, a significant reduction of fasting plasma insulin levels in both group 1 (29%) and group 2 (22.8%) was observed (p<0.001). Significant reduction of systolic and diastolic blood pressure (16.4% and 25% respectively), serum cholesterol, triglycerides and low density lipoprotein was also noted in both groups (p<0.001), while high density lipoprotein increased by ∼8 mg% in both groups. Thus omega-3 fatty acid substituion in low dose along-with curtailment of dietary omega-6 fatty acid may be used as an adjunctive measure in the management of essential hypertension.

Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes-related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. 'Westernization', acculturation, socio-economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic-specific cut-off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries.

GLUT4 gene polymorphisms and their association with type 2 diabetes in south Indians

BACKGROUND AND OBJECTIVES

The GLUT4 gene, which encodes glucose transporter 4, is a candidate gene for type 2 diabetes mellitus (T2DM). The aim of this study was to screen the GLUT4 gene for polymorphisms and to study association of such polymorphisms with T2DM in an Asian Indian population in southern India.

METHODS

The GLUT4 gene was sequenced in 25 normal glucose tolerance (NGT) and 25 T2DM subjects, and the variants found were then genotyped by polymerase chain reaction-restriction fragment length polymorphism in a pilot study population of 552 NGT and 643 T2DM subjects, randomly selected from the Chennai Urban Rural Epidemiology Study. Two of the variants (rs5435 and the novel variant), which showed significantly higher minor allele frequency in T2DM compared with NGT individuals in the pilot study population, were then retested with an additional 465 NGT and 363 T2DM subjects, giving a final sample size of 1,017 NGT and 1,006 T2DM subjects.

RESULTS

Sequencing of the GLUT4 gene revealed three known polymorphisms (rs5418, rs5421, and rs5435) and one novel T→G variant in the 3' untranslated region (UTR) at nucleotide position 6787483. The rs5418 and rs5421 polymorphisms did not show any association with diabetes. The rs5435 [Asn130Asn(C→T)] polymorphism was found to be associated with diabetes, with the odds ratio for the CT+TT genotype being 1.26 (95% confidence interval, 1.00-1.57; P=0.043) when the CC genotype was taken as reference. The frequency of the TG genotype of the novel 3'UTR T→G variant was significantly higher in diabetes subjects (1%) compared with NGT subjects (0.2%) (P=0.021). There was a significant difference in the proportion of the ACGT haplotype of the rs5418(A→G), rs5435(C→T), rs5421(C→G), and the T→G 3'UTR variant between the NGT (7.5%) and diabetes (5%) groups (P=0.003).

CONCLUSION

The rs5435 (C→T) polymorphism of the GLUT4 gene is associated with type 2 diabetes in this south Indian population.

High sensitivity C-reactive protein, tumor necrosis factor-α, interleukin-6, and vascular cell adhesion molecule-1 levels in Asian Indians with metabolic syndrome and insulin resistance (CURES-105)

AIM

The aim of this study was to assess levels of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1) in South Indian subjects with and without MS and among MS subjects with and without insulin resistance (IR).

METHODOLOGY

From the population-based Chennai Urban Rural Epidemiology Study, 334 subjects with MS and 342 subjects without MS were selected. Metabolic syndrome was diagnosed based on modified National Cholesterol Education Program criteria. High-sensitivity C-reactive protein, TNF-α, IL-6, and VCAM-1 were measured by enzyme-linked immunosorbent assay. Insulin resistance was calculated using the homeostasis model assessment (HOMA-IR) using the following formula: fasting insulin (µIU/ml) × fasting glucose (mmol/liter)/22.5.

RESULTS

Subjects with MS had significantly higher levels of all four inflammatory markers compared to those without MS: hs-CRP (2.57 vs 2.19 mg/liter) (p < .05), TNF-α (4.47 vs 3.89 pg/ml) (p < .05), IL-6 (16.22 vs 10.96 pg/ml) (p < .05), and VCAM-1 (13.8 vs 7.94 pg/ml) (p < .05). In the total study subjects, hs-CRP (r = 0.089, p = .047), TNF-α (r = 0.113, p = .040), IL-6 (r = 0.176, p = .042), and VCAM-1 (r = 0.230, p = .06) were significantly correlated with MS. With increasing quartiles of IR, mean levels of hs-CRP (p for trend <.001) and TNF-α (p for trend <.05) increased linearly. MS subjects with IR had higher levels of hs-CRP (p < .001) and TNF-α (p < .05) compared to MS subjects without IR.

CONCLUSION

In Asian Indians, inflammatory cytokines hs-CRP, TNF-α, IL-6, and VCAM-1 are elevated in subjects with MS while hs-CRP and TNF-α are further elevated in those with MS and IR.

Genetic variations in the FTO gene are associated with type 2 diabetes and obesity in south Indians (CURES-79)

AIM

the present study investigated the association of six variants-rs9940128, rs7193144, and rs8050136 (in intron 1), rs918031 and rs1588413 (in intron 8), and rs11076023 (3' untranslated region)-across three regulatory regions of the fat mass and obesity-associated (FTO) gene with obesity and type 2 diabetes mellitus (T2DM) in a South Indian population.

METHODS

unrelated study subjects (n = 1,852; 1,001 normal glucose-tolerant [NGT] controls and 851 cases [T2DM]) were randomly selected from the Chennai Urban Rural Epidemiological Study (CURES). Genotyping was done by the polymerase chain reaction-restriction fragment length polymorphism method, and 20% of samples were sequenced to validate the genotypes obtained. Haplotype analysis was also carried out.

RESULTS

the three polymorphisms rs9940128 A/G, rs1588413 C/T, and rs11076023 A/T of the FTO gene were associated with T2DM in our study population. The rs8050136 C/A variant was associated with obesity, and its association with T2DM was also mediated through obesity. The rs1588413 C/T variant showed an association with obesity in the total study subjects, but when the NGT subjects alone were analyzed, the association with obesity was lost. The haplotype ACCTCT confers a lower risk of T2DM in this South Indian population.

CONCLUSIONS

among South Indians, the rs9940128 A/G, rs11076023 A/T, and rs1588413 C/T variants of the FTO gene were associated with T2DM, whereas the rs8050136 C/A variant was associated with obesity.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Clustering of cardiometabolic risk factors in Asian Indian women: Santiniketan women study

OBJECTIVE

The aim of the present cross-sectional study was to investigate the clustering of cardiometabolic risk factors in premenopausal and postmenopausal Asian Indian women.

METHODS

A total of 214 healthy women (25-65 y) from the Bolpur-Santiniketan area, West Bengal, India, took part in the study. The women were categorized into two groups, namely, premenopausal (n = 161) and postmenopausal (n = 53). Anthropometric measures, namely, minimum waist circumference (WC) and the sum of four (biceps + triceps + subscapular + suprailiac) skinfolds (SF4), were measured accordingly. Intra-abdominal visceral fat (IVF) was also measured. Left arm systolic (SBP) and diastolic (DBP) blood pressure was taken in participants. Metabolic profiles, namely, total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), fasting plasma glucose (FPG), insulin, testosterone, and estrogen, were measured accordingly.

RESULTS

The four factors identified in premenopausal women were factor 1: WC, SF4, IVF, TC, and TG; factor 2: HDL, SBP, DBP, and insulin; factor 3: TC, TG, LDL, and testosterone; and factor 4: FPG, testosterone, and estrogen. These four factors cumulatively explained 72.97% of the total phenotypic variation. In postmenopausal women, the four factors identified were factor 1: TC, TG, HDL, LDL, and DBP; factor 2: FPG, SBP, and DBP; factor 3: WC, SF4, and IVF; and factor 4: FPG, insulin, testosterone, and estrogen. These four factors together explained 90.71% of the total phenotypic variation in cardiometabolic risk factors.

CONCLUSIONS

No common underlying physiological variables in premenopausal and postmenopausal women indicate that a single risk axis for clustering of cardiometabolic phenotypes is highly unlikely.