Risk of diabetes in offspring of parents with non-insulin-dependent diabetes

Effectiveness of a culturally tailored diabetes education curriculum with real-time continuous glucose monitoring in a Latinx population with type 2 diabetes: the CUT-DM with CGM for Latinx randomised controlled trial study protocol

INTRODUCTION

The prevalence of type 2 diabetes (T2D) is increasing in the Latinx community. Despite telehealth and technology becoming more available, these resources are not reaching the Latinx population. Diabetes education is a cornerstone of treatment; however, access to culturally tailored content is a barrier to the Latinx population. Real-time continuous glucose monitoring (RT-CGM) is a patient-empowering tool that can improve glycaemic control, but it is not readily available for Latinx patients with T2D. We aim to evaluate a culturally tailored diabetes self-management education and support (DSMES) curriculum, using a team-based approach to improve glycaemic control, promote healthy behaviours and enhance patient access with the use of telehealth in Latinx individuals. The primary aim of the study is to evaluate the additive effectiveness of RT-CGM on glycaemia and behavioural changes among Latinx patients undergoing a culturally tailored DSMES. A sub aim of the study is to evaluate family members' change in behaviours.

METHODS

We propose a randomised controlled trial of blinded versus RT-CGM with 100 Latinx participants with T2D who will receive DSMES via telemedicine over 12 weeks (n=50 per group). The study will be conducted at a single large federally qualified health centre system. The control group will receive culturally tailored DSMES and blinded CGM. The intervention group will receive DSMES and RT-CGM. The DSMES is conducted by community health educators weekly over 12 weeks in Spanish or English, based on participant's language preference. Patients in the RT-CGM group will have cyclical use with a goal of 50 days wear time. The primary outcomes are changes in haemoglobin A1c and CGM-derived metrics at 3 and 6 months. The secondary outcomes include participants' self-management knowledge and behaviour and household members' change in lifestyle.

ETHICS AND DISSEMINATION

The study proposal was approved by the University of Washington ethics/institutional review board (IRB) Committee as minimal risk (IRB ID: STUDY00014396) and the Sea Mar IRB committee.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT05394844.

Neighborhood-Level Risk Factors for Severe Hyperglycemia among Emergency Department Patients without a Prior Diabetes Diagnosis

A person's place of residence is a strong risk factor for important diagnosed chronic diseases such as diabetes. It is unclear whether neighborhood-level risk factors also predict the probability of undiagnosed disease. The objective of this study was to identify neighborhood-level variables associated with severe hyperglycemia among emergency department (ED) patients without a history of diabetes. We analyzed patients without previously diagnosed diabetes for whom a random serum glucose value was obtained in the ED. We defined random glucose values ≥ 200 mg/dL as severe hyperglycemia, indicating probable undiagnosed diabetes. Patient addresses were geocoded and matched with neighborhood-level socioeconomic measures from the American Community Survey and claims-based surveillance estimates of diabetes prevalence. Neighborhood-level exposure variables were standardized based on z-scores, and a series of logistic regression models were used to assess the association of selected exposures and hyperglycemia adjusting for biological and social individual-level risk factors for diabetes. Of 77,882 ED patients without a history of diabetes presenting in 2021, 1,715 (2.2%) had severe hyperglycemia. Many geospatial exposures were associated with uncontrolled hyperglycemia, even after controlling for individual-level risk factors. The most strongly associated neighborhood-level variables included lower markers of educational attainment, higher percentage of households where limited English is spoken, lower rates of white-collar employment, and higher rates of Medicaid insurance. Including these geospatial factors in risk assessment models may help identify important subgroups of patients with undiagnosed disease.

The susceptibility of SERPINE1 rs1799889 SNP in diabetic vascular complications: a meta-analysis of fifty-one case-control studies

BACKGROUND

The serine protease inhibitor-1 (SERPINE1) rs1799889 single nucleotide polymorphism (SNP) has been constantly associated with diabetes mellitus (DM) and its vascular complications. The aim of this meta-analysis was to evaluate this association with combined evidences.

METHODS

The systematic search was performed for studies published up to March 2021 which assess the associations between SERPINE1 rs1799889 SNP and the risks of DM, diabetic retinopathy (DR), diabetic cardiovascular disease (CVD) and diabetic nephropathy (DN). Only case-control studies were identified, and the linkage between SERPINE1 rs1799889 polymorphism and diabetic vascular risks were evaluated using genetic models.

RESULTS

51 comparisons were enrolled. The results revealed a significant association with diabetes risk in overall population (allelic: OR = 1.34, 95 % CI = 1.14-1.57, homozygous: OR = 1.66, 95 % CI = 1.23-2.14, heterozygous: OR = 1.35, 95 % CI = 1.08-1.69, dominant: OR = 1.49, 95 % CI = 1.18-1.88, recessive: OR = 1.30, 95 % CI = 1.06-1.59) as well as in Asian descents (allelic: OR = 1.45, 95 % CI = 1.16-1.82, homozygous: OR = 1.88, 95 % CI = 1.29-2.75, heterozygous: OR = 1.47, 95 % CI = 1.08-2.00, dominant: OR = 1.64, 95 % CI = 1.21-2.24, recessive: OR = 1.46, 95 % CI = 1.09-1.96). A significant association was observed with DR risk (homozygous: OR = 1.25, 95 % CI = 1.01-1.56, recessive: OR = 1.20, 95 % CI = 1.01-1.43) for overall population, as for the European subgroup (homozygous: OR = 1.32, 95 % CI = 1.02-1.72, recessive: OR = 1.38, 95 % CI = 1.11-1.71). A significant association were shown with DN risk for overall population (allelic: OR = 1.48, 95 % CI = 1.15-1.90, homozygous: OR = 1.92, 95 % CI = 1.26-2.95, dominant: OR = 1.41, 95 % CI = 1.01-1.97, recessive: OR = 1.78, 95 % CI = 1.27-2.51) and for Asian subgroup (allelic: OR = 1.70, 95 % CI = 1.17-2.47, homozygous: OR = 2.46, 95 % CI = 1.30-4.66, recessive: OR = 2.24, 95 % CI = 1.40-3.59) after ethnicity stratification. No obvious association was implied with overall diabetic CVD risk in any genetic models, or after ethnicity stratification.

CONCLUSIONS

SERPINE1 rs1799889 4G polymorphism may outstand for serving as a genetic synergistic factor in overall DM and DN populations, positively for individuals with Asian descent. The association of SERPINE1 rs1799889 SNP and DR or diabetic CVD risks was not revealed.

Diabetic Uterine Environment Leads to Disorders in Metabolism of Offspring

Aims

Research evidence indicates that epigenetic modifications of gametes in obese or diabetic parents may contribute to metabolic disorders in offspring. In the present study, we sought to address the effect of diabetic uterine environment on the offspring metabolism.

Methods

Type 2 diabetes mouse model was induced by high-fat diet combined with streptozotocin (STZ) administration. We maintained other effect factors constant and changed uterine environment by zygote transfers, and then determined and compared the offspring numbers, symptoms, body weight trajectories, and metabolism indices from different groups.

Result

We found that maternal type 2 diabetes mice had lower fertility and a higher dystocia rate, accompanying the increased risk of offspring malformations and death. Compared to only a pre-gestational exposure to hyperglycemia, exposure to hyperglycemia both pre- and during pregnancy resulted in offspring growth restriction and impaired metabolism in adulthood. But there was no significant difference between a pre-gestational exposure group and a no exposure group. The deleterious effects, no matter bodyweight or glucose tolerance, could be rescued by transferring the embryos from diabetic mothers into normal uterine environment.

Conclusion

Our data demonstrate that uterine environment of maternal diabetes makes critical impact on the offspring health.

A Bittersweet Response to Infection in Diabetes; Targeting Neutrophils to Modify Inflammation and Improve Host Immunity

Chronic and recurrent infections occur commonly in both type 1 and type 2 diabetes (T1D, T2D) and increase patient morbidity and mortality. Neutrophils are professional phagocytes of the innate immune system that are critical in pathogen handling. Neutrophil responses to infection are dysregulated in diabetes, predominantly mediated by persistent hyperglycaemia; the chief biochemical abnormality in T1D and T2D. Therapeutically enhancing host immunity in diabetes to improve infection resolution is an expanding area of research. Individuals with diabetes are also at an increased risk of severe coronavirus disease 2019 (COVID-19), highlighting the need for re-invigorated and urgent focus on this field. The aim of this review is to explore the breadth of previous literature investigating neutrophil function in both T1D and T2D, in order to understand the complex neutrophil phenotype present in this disease and also to focus on the development of new therapies to improve aberrant neutrophil function in diabetes. Existing literature illustrates a dual neutrophil dysfunction in diabetes. Key pathogen handling mechanisms of neutrophil recruitment, chemotaxis, phagocytosis and intracellular reactive oxygen species (ROS) production are decreased in diabetes, weakening the immune response to infection. However, pro-inflammatory neutrophil pathways, mainly neutrophil extracellular trap (NET) formation, extracellular ROS generation and pro-inflammatory cytokine generation, are significantly upregulated, causing damage to the host and perpetuating inflammation. Reducing these proinflammatory outputs therapeutically is emerging as a credible strategy to improve infection resolution in diabetes, and also more recently COVID-19. Future research needs to drive forward the exploration of novel treatments to improve infection resolution in T1D and T2D to improve patient morbidity and mortality.

No detectable effect of a type 2 diabetes-associated TCF7L2 genotype on the incretin effect

The T allele of TCF7L2 rs7903146 is a common genetic variant associated with type 2 diabetes (T2D), possibly by modulation of incretin action. In this study, we evaluated the effect of the TCF7L2 rs7903146 T allele on the incretin effect and other glucometabolic parameters in normal glucose tolerant individuals (NGT) and participants with T2D. The rs7903146 variant was genotyped in cohorts of 61 NGT individuals (23 were heterozygous (CT) or homozygous (TT) T allele carriers) and 43 participants with T2D (20 with CT/TT). Participants were previously examined by an oral glucose tolerance test (OGTT) and a subsequent isoglycemic intravenous glucose infusion (IIGI). The incretin effect was assessed by quantification of the difference in integrated beta cell secretory responses during the OGTT and IIGI. Glucose and hormonal levels were measured during experimental days, and from these, indices of beta cell function and insulin sensitivity were calculated. No genotype-specific differences in the incretin effect were observed in the NGT group (P = 0.70) or the T2D group (P = 0.68). NGT T allele carriers displayed diminished glucose-dependent insulinotropic polypeptide response during OGTT (P = 0.01) while T allele carriers with T2D were characterized by lower C-peptide AUC after OGTT (P = 0.04) and elevated glucose AUC after OGTT (P = 0.04). In conclusion, our findings do not exclude that this specific TCF7L2 variant increases the risk of developing T2D via diminished incretin effect, but genotype-related defects were not detectable in these cohorts.

Barriers to intra-familial prevention of type 2 diabetes: A qualitative study on horizons of significance and social imaginaries

Objectives

In families living with type 2 diabetes, relatives have a significantly heightened risk of developing the disease. In many families, both the person with type 2 diabetes and his/her relatives lack detailed knowledge about this risk. One obstacle to constructive intra-familial prevention and risk reduction is the lack of perceived familial disease relevance. The objective of the present study is to explore barriers to prevention in families with at least one adult with type 2 diabetes.

Methods

Data were gathered during eight problem assessment and ideation workshops with families. The data were analyzed using radical hermeneutics and interpreted using Taylor’s concepts of social imaginaries and horizons of significance.

Results

The analysis revealed three main barriers: (1) Sole responsibilities and the absence of collective practices, (2) intra-familial differences in perceptions of risks and future health, and (3) lack of perceived disease significance and the ensuing lack of mutual care. The participating families all experienced one or more of the three identified primary barriers.

Discussion

The study has produced important knowledge about barriers to familial prevention of type 2 diabetes. The findings confirm that familial prevention is indeed a complex matter that calls for the use of complexity-oriented approaches in health care practice.

Demographic and Clinical Factors Associated with Development of Type 2 Diabetes: A Review of the Literature

Diabetes mellitus is a complex and chronic condition that requires lifelong management and interaction with a healthcare system. Failure to control risk factors through preventive care may lead to a host of diabetes-related complications. Underperforming healthcare systems and poor awareness among the general population/healthcare professionals has been suggested as reasons why so many patients remain undiagnosed. Due to the asymptomatic nature of early and even intermediate diabetes mellitus, several years may pass without any diagnosis before complications begin to manifest. Other factors include age, gender, ethnicity, education, marital and unemployment status which may also increase the risk of developing morbidity and mortality associated with diabetes mellitus. This review summarizes the current demographic risk factors and clinical characteristics associated with diabetes mellitus. A literature search was conducted using PubMed, MEDLINE, and Sabinet by using the following search terms: diabetes mellitus, risk factors, characteristics and complications.

"H" for Heterogeneity in the Algorithm for Type 2 Diabetes Management

PURPOSE OF REVIEW

Genetic, socioeconomic and clinical features vary considerably among individuals with type 2 diabetes (T2D) influencing disease development, progression and response to therapy. Although a patient-centred approach to pharmacologic therapy of T2D is widely recommended, patients are often treated similarly, irrespective of the differences that may affect therapeutic response. Addressing the heterogeneity of T2D is a major task of diabetes research to lower the high rate of treatment failure as well as to reduce the risk of long-term complications.

RECENT FINDINGS

A pathophysiology-based clustering system seems the most promising to help in the stratification of diabetes in terms of complication risk and response to treatment. This urges for clinical studies looking at novel biomarkers related to the different metabolic pathways of T2D and able to inform about the therapeutic cluster of each patient. Here, we review the main settings of diabetes heterogeneity, to what extent it has been already addressed and the current gaps in knowledge towards a personalized therapeutic approach that considers the distinctive features of each patient.

Implementing a research-based innovation to generate intra-familial involvement in type 2 diabetes self-management for use in diverse municipal settings: a qualitative study of barriers and facilitators

BACKGROUND

Involving family members in disease management is vital to people with type 2 diabetes. New innovations that support family members' involvement can help both the person with type 2 diabetes and the relatives to create the supportive environment they need. The objective of the present study is to examine what facilitates and obstructs implementation of an innovation that supports intra-familial involvement in life with type 2 diabetes.

METHODS

Of the 48 healthcare professionals trained in facilitating the innovation in municipal patient education courses, single, semi-structured interviews were conducted with 13 of them. The interviews were focused specifically on the implementation process. All interviews were transcribed verbatim and analyzed using radical hermeneutics.

RESULTS

The analysis revealed three distinct themes affecting implementation of the innovation. 1) Focusing on creating family involvement in patient education for people with type 2 diabetes was relevant and important to the healthcare professionals. 2) The dynamics of group-based patient education sessions changed when family members were involved, which affects healthcare professionals' group facilitation methods. 3) Implementing new methods in patient education requires great commitment and support from the organization and management.

CONCLUSION

Implementation of an innovation to involve families and close relatives in patient education in Danish municipalities is feasible, but highly dependent on the commitment of healthcare professionals and managers as well as their openness to new ways of facilitating group processes.

Are Malaysian Type 2 Diabetes patients willing to be trained to speak to their offspring about risk of diabetes and preventive measures?

Background

Offspring of type 2 diabetes patients have an absolute risk of 20–40% of developing the condition. Type 2 diabetes patients should be encouraged to speak to their offspring regarding diabetes risk and prevention strategies. The Health Belief Model conceptualises that the higher the perceived risk, the more likely an individual will modify their behaviour. The objectives of this study were to i) determine the distribution of type 2 diabetes patients regarding their willingness to accept training to speak to their offspring, ii) determine the distribution of type 2 diabetes patients regarding their willingness to accept training based on the HBM and iii) to determine the factors associated with their willingness to accept training.

Methods

This was a cross-sectional study amongst type 2 diabetes patients attending two primary care clinics in Malaysia. Sociodemographic data and knowledge of diabetes risk factors were collected. The adapted, translated and validated Diabetes Mellitus in the Offspring Questionnaire-Malay version (DMOQ-Malay) was self-administered. Statistical analysis included descriptive statistics, univariate and multiple logistic regression (MLogR).

Results

A total of 425 participants were recruited. Of these, 61.6% were willing to accept training. In MLogR, six variables were found to be significantly associated with willingness to accept training. These were i) positive family history [Adj. OR 2.06 (95% CI: 1.27, 3.35)], ii) having the correct knowledge that being overweight is a risk factor [Adj. OR 1.49 (95%CI: 1.01, 2.29)], iii) correctly identifying age ≥ 40 years old as a risk factor [Adj. OR 1.88 (95%CI: 1.22, 2.90)], iv) agreeing that speaking to their offspring would help them to prevent type 2 diabetes [Adj. OR 4.34 (95%: 1.07, 17.73)], v) being neutral with the statement ‘I do not have much contact with my offspring’ [Adj. OR: 0.31 (95% CI: 0.12, 0.810] and vi) being neutral with the statement ‘my offspring are not open to advice from me’ [Adj. OR: 0.63 (95% CI: 0.31, 0.84].

Conclusion

The majority of type 2 diabetes patients were willing to accept training to speak to their offspring to prevent diabetes. A training module should be designed to enhance their knowledge, attitude and skills to become family health educators.

Mutual Involvement in Families Living with Type 2 Diabetes: Using the Family Toolbox to Address Challenges Related to Knowledge, Communication, Support, Role Confusion, Everyday Practices and Mutual Worries

Family involvement plays a key role in diabetes management. Challenges related to type 2 diabetes (T2D) often affect the whole family, and relatives are at increased risk of developing diabetes themselves. Creating family involvement in families living with T2D is a complex matter. This article studies potential effects of working with dialogue tools specifically developed to create family involvement. The data consist of 18 semi-structured family interviews. The data were analyzed using radical hermeneutics and theories on family identity and healthcare authenticity. The analysis revealed five themes: (1) Working with the tools created better and broader intra-familial involvement; (2) the tools enabled new roles and self-understandings for all family members; (3) the tools facilitated mutual insights into each other’s thoughts and worries; (4) after working with the tools, it was easier to discover potential challenges and possible behavior change; and (5) gaining new knowledge and the motivation to seek more knowledge was easier after working with the tools. Working with the tools changed how the families perceive themselves and the ways in which they can affect their own T2D-related health behavior together. This has direct implications for healthcare practitioners working with people with T2D.

Exercise as 'precision medicine' for insulin resistance and its progression to type 2 diabetes: a research review

Type 2 diabetes and obesity epidemics are in effect in the United States and the two pathologies are linked. In accordance with the growing appreciation that ‘exercise is medicine,’ it is intuitive to suggest that exercise can play an important role in the prevention and/or treatment of these conditions. However, if exercise is to truly be considered as a viable alternative to conventional healthcare prevention/treatment strategies involving pharmaceuticals, it must be prescribed with similar scrutiny. Indeed, it seems reasonable to posit that the recent initiative calling for ‘precision medicine’ in the US standard healthcare system should also be applied in the exercise setting. In this narrative review, we consider a number of explanations that have been forwarded regarding the pathological progression to type 2 diabetes both with and without the concurrent influence of overweight/obesity. Our goal is to provide insight regarding exercise strategies that might be useful as ‘precision medicine’ to prevent/treat this disease. Although the etiology of type 2 diabetes is complex and cause/consequence characteristics of associated dysfunctions have been debated, it is well established that impaired insulin action plays a critical early role. Consequently, an exercise strategy to prevent/treat this disease should be geared toward improving insulin sensitivity both from an acute and chronic standpoint. However, research suggests that a chronic improvement in insulin sensitivity only manifests when weight loss accompanies an exercise intervention. This has resonance because ectopic fat accumulation appears to represent a central component of disease progression regardless of whether obesity is also part of the equation. The cause/consequence characteristics of the relationship between insulin resistance, pathological fat deposition and/or mobilsation, elevated and/or poorly-distributed lipid within myocytes and an impaired capacity to use lipid as fuel remains to be clarified as does the role of muscle mitochondria in the metabolic decline. Until these issues are resolved, a multidimensional exercise strategy (e.g., aerobic exercise at a range of intensities and resistance training for muscular hypertrophy) could provide the best alternative for prevention/treatment.

Just Living With Obese Family Members Increases Your Risk of Type 2 Diabetes

IN BRIEF In this new era of accountable care and population health, large provider organizations are looking for new ways to predict diseases in their population, especially for people with diabetes. Although diabetes has been associated with the incidence of obesity, many diabetes patients are not obese. However, we find that just living in a household with one or more obese biologically related family members is a major risk factor for diabetes, even after accounting for all the other traditional risk factors.

Microbial Regulation of Glucose Metabolism and Insulin Resistance

Type 2 diabetes is a combined disease, resulting from a hyperglycemia and peripheral and hepatic insulin resistance. Recent data suggest that the gut microbiota is involved in diabetes development, altering metabolic processes including glucose and fatty acid metabolism. Thus, type 2 diabetes patients show a microbial dysbiosis, with reduced butyrate-producing bacteria and elevated potential pathogens compared to metabolically healthy individuals. Furthermore, probiotics are a known tool to modulate the microbiota, having a therapeutic potential. Current literature will be discussed to elucidate the complex interaction of gut microbiota, intestinal permeability and inflammation leading to peripheral and hepatic insulin resistance. Therefore, this review aims to generate a deeper understanding of the underlying mechanism of potential microbial strains, which can be used as probiotics.

Dynamics of Glucose Metabolism After Kidney Transplantation

BACKGROUND/AIMS

Posttransplantation diabetes mellitus (PTDM) impacts patient and allograft survival after kidney transplantation. Prediabetes, which is an independent risk factor for PTDM, is modifiable also in a post-transplant setting. Understanding the risks and dynamics of impaired glucose metabolism after transplantation is a key component for targeted intervention.

METHODS

A retrospective chart analysis of all adult non-diabetic renal allograft recipients (n=251, 2007-2014) was performed. Longitudinal follow-up included fasting plasma glucose and HbA1c, as well as data on allograft function and immunosuppression at consecutive time points (months 3-6 to >5 years post transplantation).

RESULTS

Throughout follow-up, median prevalence of prediabetes and PTDM was 53.3 [52.4-55.7]% and 15.4 [15.0-16.5]%, respectively. Continuously high fluxes between states of glucose metabolism, with individual patients' state deteriorating or improving over time, resulted in a high number of incident patients even long after transplantation. The greatest number of patients shifted between normal glucose tolerance and prediabetes, followed by those between prediabetes and PTDM.

CONCLUSION

Prediabetes and PTDM are highly prevalent after kidney transplantation and incidences remain relevant throughout follow-up. Patient fluxes into and out of the prediabetic state show that glucose metabolism is highly dynamic after transplantation. This provides a continuous opportunity for intervention in an aim to reduce diabetes-associated complications.

Involvement of family members in life with type 2 diabetes: Six interconnected problem domains of significance for family health identity and healthcare authenticity

Objectives:

Family involvement plays a key role in diabetes management. Problems and challenges related to type 2-diabetes often affect the whole family, and relatives are at increased risk of developing diabetes themselves. We highlight these issues in our objectives: (1) to uncover specific family problems associated with mutual involvement in life with type 2-diabetes and (2) to analytically look at ways of approaching these problems in healthcare settings.

Methods:

Qualitative data were gathered in participatory problem assessment workshops. The data were analysed in three rounds using radical hermeneutics.

Results:

Problems were categorized in six domains: knowledge, communication, support, everyday life, roles and worries. The final cross-analysis focusing on the link between family identity and healthcare authenticity provided information on how the six domains can be approached in healthcare settings.

Conclusion:

The study generated important knowledge about problems associated with family involvement in life with type 2 diabetes and about how family involvement can be supported in healthcare practice.

Interventions for prevention of type 2 diabetes in relatives: A systematic review

The relatives and partners of people with type 2 diabetes are at increased risk of developing type 2 diabetes. This systematic review examines randomized controlled trials, written in English that tested an intervention, which aimed to modify behaviors known to delay or prevent type 2 diabetes, among the relatives or partners of people with type 2 diabetes. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias. Seven studies met the inclusion criteria. The majority of studies were at low risk of bias. Six studies tested an intervention in first-degree relatives of people with type 2 diabetes and one in partners. Intervention components and intervention intensity across studies varied, with those targeting diet and physical activity reporting the most significant changes in primary outcomes. Only one study did not observe significant changes in primary outcomes. There were three main recruitment approaches: advertising in the community, recruiting people through their relatives with diabetes, or identifying people as high risk by screening of their own health care contacts. Some evidence was found for potentially successful interventions to prevent type 2 diabetes among the relatives and partners of people with type 2 diabetes, although finding simple and effective methods to identify and recruit them remains a challenge. Future studies should explore the effect of patients' perceptions on their family members' behavior and capitalize on family relationships in order to increase intervention effectiveness.

Understanding Genetic Heterogeneity in Type 2 Diabetes by Delineating Physiological Phenotypes: SIRT1 and its Gene Network in Impaired Insulin Secretion

Type 2 diabetes (T2D) is a chronic metabolic disease which shows an exponential increase in all parts of the world. However, the disease is controllable by early detection and modified lifestyle. A series of factors have been associated with the pathogenesis of diabetes, and genes are considered to play a critical role. The individual risk of developing T2D is determined by an altered genetic background of the en-zymes involved in several metabolism-related biological mechanisms, including glucose homeostasis, insulin metab-olism, the glucose and ion transporters involved in glucose uptake, transcription factors, signaling intermediates of insulin signaling pathways, insulin production and secretion, pancreatic tissue development, and apoptosis. However, many candidate genes have shown heterogeneity of associations with the disease in different populations. A possible approach to resolving this complexity and under-standing genetic heterogeneity is to delineate the physiological phenotypes one by one as studying them in combination may cause discrepancies in association studies. A systems biology approach involving regulatory proteins, transcription factors, and microRNAs is one way to understand and identify key factors in complex diseases such as T2D. Our earlier studies have screened more than 100 single nucleotide polymorphisms (SNPs) belonging to more than 60 globally known T2D candidate genes in the Indian population. We observed that genes invariably involved in the activity of pancreatic β-cells provide susceptibility to type 2 diabetes (T2D). Encouraged by these results, we attempted to delineate in this review one of the commonest physiological phenotypes in T2D, namely impaired insulin secretion, as the cause of hyperglycemia. This review is also intended to explain the genetic basis of the pathophysiology of insulin secretion in the context of variations in the SIRT1 gene, a major switch that modulates insulin secretion, and a set of other genes such as HHEX, PGC-α, TCF7L2, UCP2, and ND3 which were found to be in association with T2D. The review aims to look at the genotypic and transcriptional regulatory relationships with the disease phenotype.

Mitochondrial dysfunction as a central event for mechanisms underlying insulin resistance: the roles of long chain fatty acids

Insulin resistance is characterized by hyperglycaemia, dyslipidaemia and oxidative stress prior to the development of type 2 diabetes mellitus. To date, a number of mechanisms have been proposed to link these syndromes together, but it remains unclear what the unifying condition that triggered these events in the progression of this metabolic disease. There have been a steady accumulation of data in numerous experimental studies showing the strong correlations between mitochondrial dysfunction, oxidative stress and insulin resistance. In addition, a growing number of studies suggest that the raised plasma free fatty acid level induced insulin resistance with the significant alteration of oxidative metabolism in various target tissues such as skeletal muscle, liver and adipose tissue. In this review, we herein propose the idea of long chain fatty acid-induced mitochondrial dysfunctions as one of the key events in the pathophysiological development of insulin resistance and type 2 diabetes. The accumulation of reactive oxygen species, lipotoxicity, inflammation-induced endoplasmic reticulum stress and alterations of mitochondrial gene subset expressions are the most detrimental that lead to the developments of aberrant intracellular insulin signalling activity in a number of peripheral tissues, thereby leading to insulin resistance and type 2 diabetes.

Impact of PTBP1 rs11085226 on glucose-stimulated insulin release in adult Danes

BACKGROUND

The variant rs11085226 (G) within the gene encoding polypyrimidine tract binding protein 1 (PTBP1) was reported to associate with reduced insulin release determined by an oral glucose tolerance test (OGTT) as well as an intravenous glucose tolerance test (IVGTT). The aim of the present study was to validate the association of the rs11085226 G-allele of PTBP1 with previously investigated OGTT- and IVGTT-derived diabetes-related metabolic quantitative phenotypes, to conduct exploratory analyses of additional measures of beta-cell function, and to further investigate a potential association with type 2 diabetes.

METHODS

PTBP1 rs11085226 was genotyped in 20,911 individuals of Danish Caucasian ethnicity ascertained from 9 study samples. Case control analysis was performed on 5,634 type 2 diabetic patients and 11,319 individuals having a normal fasting glucose level as well as 4,641 glucose tolerant controls, respectively. Quantitative trait analyses were performed in up to 13,605 individuals subjected to an OGTT or blood samples obtained after an overnight fast, as well as in 596 individuals subjected to an IVGTT.

RESULTS

Analyses of fasting and OGTT-derived quantitative traits did not show any significant associations with the PTBP1 rs11085226 variant. Meta-analysis of IVGTT-derived quantitative traits showed a nominally significant association between the variant and reduced beta-cell responsiveness to glucose (β = -0.1 mmol · kg(-1) · min(-1); 95% CI: -0.200.20 - -0.024; P = 0.01) assuming a dominant model of inheritance, but failed to replicate a previously reported association with area under the curve (AUC) for insulin. Case control analysis did not show an association of the PTBP1 rs11085226 variant with type 2 diabetes.

CONCLUSIONS

Despite failure to replicate the previously reported associations of PTBP1 rs11085226 with OGTT- and IVGTT-derived measures of beta-cell function, we did find a nominally significant association with reduced beta-cell responsiveness to glucose during an IVGTT, a trait not previously investigated, leaving the potential influence of this variant in PTBP1 on glucose stimulated insulin release open for further investigation. However, the present study does not support the hypothesis that the variant confers risk of type 2 diabetes.

Beta cell connectivity in pancreatic islets: a type 2 diabetes target?

Beta cell connectivity describes the phenomenon whereby the islet context improves insulin secretion by providing a three-dimensional platform for intercellular signaling processes. Thus, the precise flow of information through homotypically interconnected beta cells leads to the large-scale organization of hormone release activities, influencing cell responses to glucose and other secretagogues. Although a phenomenon whose importance has arguably been underappreciated in islet biology until recently, a growing number of studies suggest that such cell-cell communication is a fundamental property of this micro-organ. Hence, connectivity may plausibly be targeted by both environmental and genetic factors in type 2 diabetes mellitus (T2DM) to perturb normal beta cell function and insulin release. Here, we review the mechanisms that contribute to beta cell connectivity, discuss how these may fail during T2DM, and examine approaches to restore insulin secretion by boosting cell communication.

Selective disruption of Tcf7l2 in the pancreatic β cell impairs secretory function and lowers β cell mass

Type 2 diabetes (T2D) is characterized by β cell dysfunction and loss. Single nucleotide polymorphisms in the T-cell factor 7-like 2 (TCF7L2) gene, associated with T2D by genome-wide association studies, lead to impaired β cell function. While deletion of the homologous murine Tcf7l2 gene throughout the developing pancreas leads to impaired glucose tolerance, deletion in the β cell in adult mice reportedly has more modest effects. To inactivate Tcf7l2 highly selectively in β cells from the earliest expression of the Ins1 gene (∼E11.5) we have therefore used a Cre recombinase introduced at the Ins1 locus. Tcfl2^fl/fl::Ins1Cre mice display impaired oral and intraperitoneal glucose tolerance by 8 and 16 weeks, respectively, and defective responses to the GLP-1 analogue liraglutide at 8 weeks. Tcfl2^fl/fl::Ins1Cre islets displayed defective glucose- and GLP-1-stimulated insulin secretion and the expression of both the Ins2 (∼20%) and Glp1r (∼40%) genes were significantly reduced. Glucose- and GLP-1-induced intracellular free Ca²⁺ increases, and connectivity between individual β cells, were both lowered by Tcf7l2 deletion in islets from mice maintained on a high (60%) fat diet. Finally, analysis by optical projection tomography revealed ∼30% decrease in β cell mass in pancreata from Tcfl2^fl/fl::Ins1Cre mice. These data demonstrate that Tcf7l2 plays a cell autonomous role in the control of β cell function and mass, serving as an important regulator of gene expression and islet cell coordination. The possible relevance of these findings for the action of TCF7L2 polymorphisms associated with Type 2 diabetes in man is discussed.

Parent-of-origin effects on glucose homeostasis in polycystic ovary syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a highly heritable complex trait. Parents of affected women have reproductive and metabolic phenotypes.

OBJECTIVE

We tested the hypothesis that there are parental effects on the heritability of fasting dysglycemia in women with PCOS.

DESIGN AND SETTING

This was a cross-sectional study at an academic medical center.

PARTICIPANTS

PARTICIPANTS included 367 women with PCOS and their parents (1101 total subjects).

MAIN OUTCOME MEASURES

We compared maternal and paternal contributions to heritability of fasting dysglycemia and to transmission of the PCOS susceptibility allele of D19S884 within the fibrillin-3 gene (D19S884-A8) on fasting dysglycemia.

RESULTS

Fathers had higher fasting glucose levels, prevalence of fasting dysglycemia and proinsulin to insulin molar ratios (P < .0001), a marker of defective insulin processing, compared with mothers. Heritability of fasting dysglycemia was significant in PCOS families (h(2) = 37%, SE = 10%, P = .001). Maternal heritability (h(2) = 51%, SE = 15%, P = .0009) was higher than paternal heritability (h(2) = 23 %, SE = 23%, P = .186) of fasting dysglycemia after adjustment for age and body mass index. Within dysglycemic probands, there was increased maternal compared with paternal transmission of D19S884-A8 (maternal 84% vs paternal 45%, χ(2) = 6.51, P = .011).

CONCLUSIONS

There was a sex difference in the parental metabolic phenotype with fathers having an increased risk of fasting dysglycemia and evidence for pancreatic β-cell dysfunction compared with mothers. However, only maternal heritability had significant effects on the prevalence of fasting dysglycemia in women with PCOS. Furthermore, there were maternal parent-of-origin effects on transmission of D19S884-A8 probands with fasting dysglycemia. These findings suggest that maternal factors, genetic and perhaps epigenetic, contribute to the metabolic phenotype in affected women.

Family and Community Influences on Diabetes-Related Dietary Change in a Low-Income Urban Neighborhood

Purpose

The purpose of this study is to explore the influence of the social environment, including family and community relationships, on diabetes-related dietary change behaviors in a low-income, predominantly African American community with limited access to healthy foods.

Methods

Study methods included interviews and focus groups with adults with diabetes and family members of individuals with diabetes in a low-income African American community. In this analysis, interview participants included 11 participants with diabetes, one with prediabetes, and 8 family members or close friends with diabetes. Information from 4 participants with diabetes and 6 with family members with diabetes was included from 6 focus groups. Transcripts were analyzed via thematic iterative coding influenced by social cognitive theory to understand the influence of family and community relationships on dietary change.

Results

Participants’ social environments strongly influenced diet-related behavioral change. Family members without diabetes provided reinforcements for dietary change for those with diabetes by preparing healthy food and monitoring intake, as well as by adopting dietary changes made by those with diabetes. Family and community members served as sources of observational learning about the potential impacts of diabetes and enhanced behavioral capability for dietary change among people with diabetes by providing dietary advice and strategies for making healthy choices.

Conclusions

This study demonstrates the ways in which family and community members can influence dietary change in people with diabetes. Interventions targeting diabetes management should incorporate families and communities as sources of information, learning, and support.

Forecasting the burden of type 2 diabetes in Singapore using a demographic epidemiological model of Singapore

OBJECTIVE

Singapore is a microcosm of Asia as a whole, and its rapidly ageing, increasingly sedentary population heralds the chronic health problems other Asian countries are starting to face and will likely face in the decades ahead. Forecasting the changing burden of chronic diseases such as type 2 diabetes in Singapore is vital to plan the resources needed and motivate preventive efforts.

METHODS

This paper describes an individual-level simulation model that uses evidence synthesis from multiple data streams-national statistics, national health surveys, and four cohort studies, and known risk factors-aging, obesity, ethnicity, and genetics-to forecast the prevalence of type 2 diabetes in Singapore. This comprises submodels for mortality, fertility, migration, body mass index trajectories, genetics, and workforce participation, parameterized using Markov chain Monte Carlo methods, and permits forecasts by ethnicity and employment status.

RESULTS

We forecast that the obesity prevalence will quadruple from 4.3% in 1990 to 15.9% in 2050, while the prevalence of type 2 diabetes (diagnosed and undiagnosed) among Singapore adults aged 18-69 will double from 7.3% in 1990 to 15% in 2050, that ethnic Indians and Malays will bear a disproportionate burden compared with the Chinese majority, and that the number of patients with diabetes in the workforce will grow markedly.

CONCLUSIONS

If the recent rise in obesity prevalence continues, the lifetime risk of type 2 diabetes in Singapore will be one in two by 2050 with concomitant implications for greater healthcare expenditure, productivity losses, and the targeting of health promotion programmes.

Familial Clustering of Type 2 Diabetes among Omanis

OBJECTIVE

The aim of this study was to screen Omani individuals for the familial aggregation of type 2 diabetes mellitus.

METHODS

A random cohort of 1182 Omani individuals visiting the Family Medicine Clinic at Sultan Qaboos University Hospital (SQUH), Muscat, Oman, for regular medical checkup, aged ≥40 years, were sampled. Patients were categorized into three groups: (1) individuals who claim not to have diabetes and had no family history of diabetes; (2) individuals who claim not to have diabetes but had family history of diabetes; (3) individuals with diabetes. Only 16% of these Omani individuals had no diabetes and no family history of diabetes. Another separate random cohort of 234 Omani type 2 diabetes mellitus patients, from the Diabetes Clinic at SQUH, were interviewed and questioned about their family history of type 2 diabetes mellitus.

RESULTS

Ninety five percent of the patients had a family history of diabetes. Eighty percent had first degree relatives with diabetes and 46% had second degree relatives with diabetes. At least one parent with diabetes was reported among 55% of these diabetics, while maternal diabetes (55%) was found to be higher than paternal diabetes (47%). However, only 15% had both parents with diabetes. Furthermore, almost half of the 234 diabetics were having at least one of the following relatives with diabetes: brother, sister, aunt or an uncle.

CONCLUSION

The findings of this study confirm familial aggregation of diabetes among the Omani population. Compared to other populations, familial aggregation of type 2 diabetes mellitus among Omanis is relatively very high, and is perhaps due to the very high degree of consanguinity among Omanis. Since almost everyone seems to have a genetic predisposition to diabetes, the dramatic lifestyle changes over the past 25 years, could tip the population into an epidemic of type 2 diabetes mellitus.

Epidemiology and genetic determinants of progressive deterioration of glycaemia in American Indians: the Strong Heart Family Study

AIMS/HYPOTHESIS

Type 2 diabetes is a chronic, heterogeneous disease and a major risk factor for cardiovascular diseases. The underlying mechanisms leading to progression to type 2 diabetes are not fully understood and genetic tools may help to identify important pathways of glycaemic deterioration.

METHODS

Using prospective data on American Indians from the Strong Heart Family Study, we identified 373 individuals defined as progressors (diabetes incident cases), 566 individuals with transitory impaired fasting glucose (IFG) and 1,011 controls (normal fasting glycaemia at all visits). We estimated the heritability (h(2)) of the traits and the evidence for association with 16 known variants identified in type 2 diabetes genome-wide association studies.

RESULTS

We noted high h(2) for diabetes progression (h(2) = 0.65 ± 0.16, p = 2.7 × 10(-6)) but little contribution of genetic factors to transitory IFG (h(2) = 0.09 ± 0.10, p = 0.19) for models adjusted for multiple risk factors. At least three variants (in WFS1, TSPAN8 and THADA) were nominally associated with diabetes progression in age- and sex-adjusted analyses with estimates showing the same direction of effects as reported in the discovery European ancestry studies.

CONCLUSIONS/INTERPRETATION

Our findings do not exclude these loci for diabetes susceptibility in American Indians and suggest phenotypic heterogeneity of the IFG trait, which may have implications for genetic studies when diagnosis is based on a single time-point measure.

Exploring risk, prevention and educational approaches for the non-diabetic offspring of patients with type 2 diabetes--a qualitative study

AIM

To understand the knowledge and perceptions of type 2 diabetes and to explore preferable educational strategies in the non-diabetic offspring of patients with the disease.

BACKGROUND

Type 2 diabetes is an increasingly prevalent disease with significant long-term consequences. Offspring of patients with type 2 diabetes have an increased risk of developing the disease compared with the general population. Previous studies have shown that offspring have a poor perception of their own risk.

DESIGN

A qualitative study was carried out using semi-structured one-to-one interviews. Analysis was completed using a structured framework approach.

METHODS

Research was carried out during January-March 2011 in the north east of UK. Six offspring of patients diagnosed with the disease were interviewed.

RESULTS

Participants balanced positive and negative aspects of their lifestyle behaviours to estimate their own risk. They had adequate knowledge of healthy lifestyle behaviours, but were uncertain about the long-term effects and seriousness of the disease and the role of inheritance. Behavioural changes at an individual level would only be motivated by an event, which would impact on their own health. Participants believed that 'fear'-based strategies to health promotion would be most effective to encourage behaviour change.

CONCLUSION

Knowledge of individual risk and why diabetes was serious was limited and variable. The health behaviours of this at-risk group were complex. Nurses engaged in the care of at-risk individuals must take this complexity into account when developing and implementing multi-faceted strategies to improve awareness.

Abnormal glucose tolerance and insulin secretion in pancreas-specific Tcf7l2-null mice

AIMS/HYPOTHESIS

Individuals carrying type 2 diabetes risk alleles in TCF7L2 display decreased beta cell levels of T cell factor 7 like-2 (TCF7L2) immunoreactivity, and impaired insulin secretion and beta cell sensitivity to glucagon-like peptide 1 (GLP-1). Here, we sought to determine whether selective deletion of Tcf7l2 in mouse pancreas impairs insulin release and glucose homeostasis.

METHODS

Pancreas-specific Tcf7l2-null (pTcf7l2) mice were generated by crossing mice carrying conditional knockout alleles of Tcf7l2 (Tcf7l2-flox) with mice expressing Cre recombinase under the control of the Pdx1 promoter (Pdx1.Cre). Gene expression was assessed by real-time quantitative PCR and beta cell mass by optical projection tomography. Glucose tolerance, insulin secretion from isolated islets, and plasma insulin, glucagon and GLP-1 content were assessed by standard protocols.

RESULTS

From 12 weeks of age, pTcf7l2 mice displayed decreased oral glucose tolerance vs control littermates; from 20 weeks they had glucose intolerance upon administration of glucose by the intraperitoneal route. pTcf7l2 islets displayed impaired insulin secretion in response to 17 (vs 3.0) mmol/l glucose (54.6 ± 4.6%, p < 0.01) or to 17 mmol/l glucose plus 100 nmol/l GLP-1 (44.3 ± 4.9%, p < 0.01) compared with control islets. Glp1r (42 ± 0.08%, p < 0.01) and Ins2 (15.4 ± 4.6%, p < 0.01) expression was significantly lower in pTcf7l2 islets than in controls. Maintained on a high-fat (but not on a normal) diet, pTcf7l2 mice displayed decreased expansion of pancreatic beta cell volume vs control littermates. No differences were observed in plasma insulin, proinsulin, glucagon or GLP-1 concentrations.

CONCLUSIONS/INTERPRETATION

Selective deletion of Tcf7l2 in the pancreas replicates key aspects of the altered glucose homeostasis in human carriers of TCF7L2 risk alleles, indicating the direct role of this factor in controlling beta cell function.

Type 2 diabetes in pediatrics and adults: thoughts from a clinical pharmacology perspective

Type 2 diabetes results when insulin secretion is unable to keep the plasma glucose levels as per acceptable range. This leads to chronic hyperglycemia and its associated microvascular complications such as renal impairment (diabetic nephropathy), retinal abnormalities (diabetic retinopathy), and autonomic, sensory, and motor neuropathies (diabetic neuropathy) and macrovascular disease. Historically, type 2 diabetes is well known as an adult-onset disease; however, lately, the incidence of the disease is reported to be increasing in children. Despite the wealth of information concerning type 2 diabetes in adults, data unique to the pediatric age group regarding the pathophysiology and therapy for type 2 diabetes are limited. For treatment in pediatric type 2 diabetes, metformin and insulin are the only antidiabetic agents approved currently. There are data of use of other oral antidiabetic drugs including glimepiride, rosiglitazone, and glyburide (in combination with metformin) in pediatric patients; however, formal clinical trials to establish the safety and efficacy have not been conducted. This review will compare the clinical pharmacology aspects of the oral type 2 diabetic drugs in pediatric and adult populations in order to determine any differences between the two patient groups.

Changing the odds. What do we learn from prevention studies targeted at people with a positive family history of type 2 diabetes?

People with a positive family history of type 2 diabetes (T2DM) are at high risk of developing diabetes. We set out to review the literature reporting on the development and/or evaluation of lifestyle interventions specifically aimed at prevention of T2DM in this group. Targeting people with a positive family history of T2DM seems so far an underutilized prevention strategy. They can and should be approached with the aim to raise risk awareness and promote healthy eating, weight loss and physical activity, thereby reducing their risk of developing diabetes.

Anthropometry and physical fitness in individuals with family history of type-2 diabetes mellitus: A comparative study

CONTEXT

The risk of becoming a diabetic for an individual with a positive family history of diabetes increases by two- to fourfold.

AIM

To record the anthropometric indices and the physical fitness in individuals with family history of type-2 diabetes mellitus and compare these results with those of controls.

SETTINGS AND DESIGN

This is a comparative study done in the department of physiology.

MATERIALS AND METHODS

Thirty-two apparently healthy medical students with family history of type-2 Diabetes Mellitus were chosen for the study and matched with equal number of controls. Anthropometric measurements (height, weight, waist circumference, hip circumference, thigh circumference, upper segment and lower segment) were recorded. Body mass index (BMI), waist-hip ratio (WHR), waist-thigh ratio (WTR), and upper to lower segment ratio (US/LS ratio) were calculated. Blood pressure and heart rate were measured. Physical fitness was evaluated using Queen's College step test protocol. Rate Pressure Product (RPP) and Physical Fitness Index (PFI) were calculated before and after exercise.

STATISTICAL ANALYSIS

Statistical analysis was done using SPSS software.

RESULTS

BMI, WHR, US/LS ratio, and RPP at rest were significantly higher (P < 0.05), whereas WTR, PFI, and RPP after exercise lower (P > 0.05) in cases as compared to controls.

CONCLUSIONS

It can be concluded that apparently healthy individuals with family history of type-2 diabetes mellitus have higher anthropometric values and lower physical fitness than the controls.

DiAlert: a lifestyle education programme aimed at people with a positive family history of type 2 diabetes and overweight, study protocol of a randomised controlled trial

Background

Family history is a known risk factor for type 2 diabetes (T2DM), and more so in the presence of overweight. This study aims to develop and evaluate the effectiveness of a new lifestyle education programme 'DiAlert' targeted at 1st degree relatives of people with T2DM and overweight. In view of the high risk for diabetes and cardiovascular disease in immigrants from Turkish origin living in Western Europe, a culturally appropriate Turkish version of DiAlert will be developed and tested.

Methods/design

In this RCT, 268 (134 Dutch and 134 Turkish) overweight 1st degree relatives of patients with T2DM will be allocated to either the intervention or control group (leaflet). The intervention DiAlert aims to promote intrinsic motivation to change lifestyle, and sustain achieved behaviour changes during follow-up. Primary outcome is weight loss. Secondary outcomes include biological, behavioural and psychological indices, along with process indicators. Measurements will take place at baseline and after 3 and 9 months. Changes in outcomes are tested between intervention and control group at 3 months; effects over time are tested within and between both ethnic groups at 3 and 9 months.

Discussion

The DiAlert intervention is expected to be more effective than the control condition in achieving significant weight loss at 3 months, in both Dutch and Turkish Dutch participants.

Trial registration

Netherlands National Trial Register (NTR): NTR2036

New type 2 diabetes risk genes provide new insights in insulin secretion mechanisms

Type 2 diabetes results from the inability of beta cells to increase insulin secretion sufficiently to compensate for insulin resistance. Insulin resistance is thought to result mainly from environmental factors, such as obesity. However, there is compelling evidence that the decline of both insulin sensitivity and insulin secretion have also a genetic component. Recent genome-wide association studies identified several novel risk genes for type 2 diabetes. The vast majority of these genes affect beta cell function by molecular mechanisms that remain unknown in detail. Nevertheless, we and others could show that a group of genes affect glucose-stimulated insulin secretion, a group incretin-stimulated insulin secretion (incretin sensitivity or secretion) and a group proinsulin-to-insulin conversion. The most important so far type 2 diabetes risk gene, TCF7L2, interferes with all three mechanisms. In addition to advancing knowledge in the pathophysiology of type 2 diabetes, the discovery of novel genetic determinants of diabetes susceptibility may help understanding of gene-environment, gene-therapy and gene-gene interactions. It was also hoped that it could make determination of the individual risk for type 2 diabetes feasible. However, the allelic relative risks of most genetic variants discovered so far are relatively low. Thus, at present, clinical criteria assess the risk for type 2 diabetes with greater sensitivity and specificity than the combination of all known genetic variants.

Type 2 diabetes across generations: from pathophysiology to prevention and management

Type 2 diabetes is now a pandemic and shows no signs of abatement. In this Seminar we review the pathophysiology of this disorder, with particular attention to epidemiology, genetics, epigenetics, and molecular cell biology. Evidence is emerging that a substantial part of diabetes susceptibility is acquired early in life, probably owing to fetal or neonatal programming via epigenetic phenomena. Maternal and early childhood health might, therefore, be crucial to the development of effective prevention strategies. Diabetes develops because of inadequate islet β-cell and adipose-tissue responses to chronic fuel excess, which results in so-called nutrient spillover, insulin resistance, and metabolic stress. The latter damages multiple organs. Insulin resistance, while forcing β cells to work harder, might also have an important defensive role against nutrient-related toxic effects in tissues such as the heart. Reversal of overnutrition, healing of the β cells, and lessening of adipose tissue defects should be treatment priorities.

Genetics of type 2 diabetes: pathophysiologic and clinical relevance

BACKGROUND

Recent genome-wide association studies enlarged our knowledge about the genetic background of type 2 diabetes.

AIMS

This review provides an overview of the role of these novel genetic findings for the pathophysiology, prediction and treatment of type 2 diabetes.

RESULTS

The genetic susceptibility to type 2 diabetes appears to be determined by many common variants in multiple gene loci with low effect sizes. Although at least 36 diabetes-associated genes were identified, only about 10% of the heritability of type 2 diabetes can be explained. Most of the discovered gene variants have been linked to beta-cell dysfunction rather than insulin resistance, which might challenge established thinking of type 2 diabetes as a predominant disorder of insulin action. Genetic data can lead to statistically significant, but not to clinically relevant contributions to risk prediction for type 2 diabetes. Nevertheless, preliminary evidence suggests interactions between genotypes and response to lifestyle changes or drug treatment.

CONCLUSIONS

Future studies need to target the issue of hidden heritability and to detect the causal gene variants within the identified gene loci. Improved understanding of the genetic contribution to type 2 diabetes may then help addressing the questions whether genotyping is useful to predict individual diabetes risk, identifies individual responsiveness to preventive and therapeutic interventions or at least allows for breaking down type 2 diabetes into smaller, clinically meaningful subtypes.

Cultural variations in attitudes towards family risk of diabetes

AIMS

To examine differences in attitudes and behaviours towards familial risk of type 2 diabetes in populations in Ireland and Bahrain.

METHODS

Cross-sectional ecological study. Questionnaires were developed and administered to patients with diabetes and their first degree relatives in both Bahrain and Ireland. Data was analysed using non-parametric tests of association.

RESULTS

Responses were compared between 297 patients with diabetes from Ireland and 201 from Bahrain and between 364 relatives of patients with diabetes in Ireland and 244 from Bahrain. Relatives in Bahrain had more knowledge of risk factors for diabetes and an increased perception of the seriousness of diabetes but a more external, chance locus of control and perceived more barriers to changing lifestyles than those in Ireland. There was no difference in perception of personal risk of diabetes.

CONCLUSIONS

Knowledge of risk factors and seriousness of diabetes are higher in Bahrain than in Ireland but perception of personal risk of diabetes and intention to adopt risk reducing behaviours are no different. There is a need to develop models of behavioural change that are more relevant to the needs of the Bahraini population in reducing their risk of diabetes.

Reducing health risk in family members of patients with type 2 diabetes: views of first degree relatives

Background

Patients with type 2 diabetes can have an important role in discussing health risk within families. This study aimed to establish the acceptability to first degree relatives towards their relative with type 2 diabetes intervening as health promoters in their own families, using the Health Belief Model as a theoretical framework for evaluation.

Methods

Cross-sectional questionnaire design. Survey questionnaire for first degree relative (sibling or child) mailed to a random sample of patients with type 2 diabetes registered with an urban hospital diabetes clinic (n = 607 eligible patients). Patients were asked to pass on questionnaires to one to two first degree relatives.

Results

Questionnaires were returned from 257 families (42% response rate) with two responses provided by 107 families (a total of 364 questionnaires). The majority (94%) of first degree relatives of patients with type 2 diabetes would like to be informed about reducing their risk. Half (48%) of respondents reported being spoken to by a relative with type 2 diabetes about their risk of diabetes. Those spoken to were more likely to see themselves at risk of diabetes, to worry about developing diabetes and to view diabetes as a serious condition.

Conclusions

A role for patients with type 2 diabetes in discussing health risk in their family appears to be acceptable to many relatives. Discussion of risk and interventions to reduce health risk with their relatives should be encouraged in patients with type 2 diabetes.

Management of progressive type 2 diabetes: role of insulin therapy

Insulin is an effective treatment for achieving tight glycemic control and improving clinical outcomes in patients with diabetes. While insulin therapy is required from the onset of diagnosis in type 1 disease, its role in type 2 diabetes requires consideration as to when to initiate and advance therapy. In this article, we review a case study that unfolds over 5 years and discuss the therapeutic decision points, initiation and advancement of insulin regimens, and analyze new data regarding the advantages and disadvantages of tight management of glucose levels.

Family history and parents' beliefs about consequences of childhood overweight and their influence on children's health behaviors

OBJECTIVES

The aims of this study were to examine factors related to 1) parental perception of health risks for overweight children and 2) parents' self-efficacy for influencing their children's dietary and physical activity behaviors, especially in relation to family history (FH) of diabetes and cardiovascular disease (CVD).

METHODS

A consecutive sample of parents was surveyed at 7 primary care practices about FH, perceptions of childhood obesity-related health risks, health beliefs, and perceptions. Generalized estimated equation models clustering on practice were developed to examine associations with perceptions and self-efficacy.

RESULTS

Analyses included 386 parents of children aged 2 to 17 years. Sixty-seven percent had FH of CVD and 33% had FH of diabetes. Children were 57% white, 23% Hispanic, 12% African American, and 8% other race/ethnicity; 17% were overweight and 18% were obese. Parents whose child had FH of diabetes more often perceived higher risk of diabetes for overweight children than those with neither FH risk (adjusted odds ratio [OR] 1.4, 95% confidence interval [95% CI], 1.2-1.7), as did those with FH of CVD (adjusted OR 2.0, 95% CI, 1.6-2.5) and those with an obese child. Parents with less than college education or having African American and female children perceived risk less often. Parents had high self-efficacy for influencing their child if they had a strong belief in parental modeling and their child was aged <12 years.

CONCLUSIONS

Family history of diabetes and CVD and other factors are associated with parents' perceptions of health risks for overweight children. Strategies to use FH to motivate families with overweight children toward behavior change are needed.

Type 2 diabetes among persons with schizophrenia and other psychotic disorders in a general population survey

Schizophrenia and other psychotic disorders are associated with increased risk of developing type 2 diabetes. However, previous studies are mainly based on clinical samples where the comorbidity may be stronger. We investigated in a general population survey the prevalence of type 2 diabetes in persons with psychotic disorders and in users of antipsychotic medication. The study was based on a nationally representative two-stage cluster sample of 8,028 persons aged 30 or over from Finland. Diagnostic assessment of psychotic disorders combined SCID-I interview and case note data. Prevalences of type 2 diabetes, adjusting for age and sex, were estimated by calculating predicted marginals. The prevalence estimate of type 2 diabetes was 22.0% among subjects with schizophrenia, 13.4% among subjects with other nonaffective psychosis and 6.1% in subjects without psychotic disorders. Only two subjects (3.4%) with affective psychosis had type 2 diabetes. Users of all types of antipsychotic medication had increased prevalence of type 2 diabetes. Our results suggest that type 2 diabetes is a major health concern among persons with schizophrenia and other nonaffective psychotic disorders and also in users of antipsychotic medication, but persons with affective psychosis in the general population may not have increased prevalence of type 2 diabetes.

Effect of parental hypertension and/or parental diabetes on hypertension in Taiwanese diabetic patients

BACKGROUND

Both type 2 diabetes mellitus (T2DM) and hypertension aggregate in families. It is a common thought that diabetic patients with parental diabetes and/or parental hypertension are more likely to develop hypertension. This study evaluated the separate and joint effects of parental hypertension and parental diabetes on the prevalence of hypertension in patients with T2DM.

MATERIALS AND METHODS

A total of 89 956 patients from a national cohort were interviewed by telephone. Information about age, sex, onset age of diabetes, body height, body weight, systolic (SBP) and diastolic blood pressure (DBP), smoking, hypertension, and paternal and maternal history of diabetes and hypertension were obtained. Hypertension was defined in two ways: (1) a positive history; or (2) a positive history or a reported SBP > or = 140 mmHg and/or DBP > or = 90 mmHg in patients without a hypertension history.

RESULTS

While analysed separately in logistic models, both parental diabetes and parental hypertension were positively associated with hypertension. However, when both were analysed together, only parental hypertension was positively associated with hypertension, with paternal and maternal hypertension exerting a similar effect of an approximately 2.5-fold higher risk. While considering the effect of parental hypertension, both paternal and maternal diabetes was significantly associated with a lower risk of hypertension with odds ratios of approximately 0.8. Parental hypertension was also significantly associated with increased SBP and DBP; and parental diabetes with lower values in multiple linear regression.

CONCLUSIONS

Parental hypertension is strongly associated with hypertension. However, parental diabetes may be protective if the effect of parental hypertension is considered.

Genes, diet and type 2 diabetes mellitus: a review

Diabetes mellitus is widely recognized as one of the leading causes of death and disability. While insulin insensitivity is an early phenomenon partly related to obesity, pancreatic beta-cell function declines gradually over time even before the onset of clinical hyperglycemia. Several mechanisms have been proposed to be responsible for insulin resistance, including increased non-esterified fatty acids, inflammatory cytokines, adipokines, and mitochondrial dysfunction, as well as glucotoxicity, lipotoxicity, and amyloid formation for beta-cell dysfunction. Moreover, the disease has a strong genetic component, although only a handful of genes have been identified so far. Diabetic management includes diet, exercise and combinations of antihyperglycemic drug treatment with lipid-lowering, antihypertensive, and antiplatelet therapy. Since many persons with type 2 diabetes are insulin resistant and overweight, nutrition therapy often begins with lifestyle strategies to reduce energy intake and increase energy expenditure through physical activity. These strategies should be implemented as soon as diabetes or impaired glucose homoeostasis (pre-diabetes) is diagnosed.

Type 2 diabetes and inheritance: what information do diabetes organizations provide on the Internet?

AIMS

The worldwide epidemic of Type 2 diabetes necessitates preventive actions. Providing information to high-risk populations is key. In an international comparison of websites, we aimed to investigate the presence and quality of information provided by diabetes organizations on inheritance of Type 2 diabetes and the benefits of a healthy lifestyle targeted at those with a family history or belonging to a specific ethnic population.

METHODS

All websites included in the International Diabetes Federation member list in English, German, French, Dutch, Spanish, Portuguese, Swedish, Norwegian, Finnish, Danish and Japanese were included for assessment. Using qualitative content analysis, we reviewed 34 websites which provided health-related information on diabetes.

RESULTS

Most websites mention family history as a risk factor. However, an explanation of the interaction of lifestyle factors and increased genetic susceptibility is lacking. Ethnicity is mentioned in only half of the sites describing risk factors. Although most websites do provide information on the importance of a healthy lifestyle, they do not address specific high-risk groups. Only two websites encourage Type 2 diabetic patients to inform family members of the familial character of diabetes.

CONCLUSIONS

Information on inheritance of Type 2 diabetes and prevention specifically targeted at high-risk groups on the Internet by diabetes organizations is often of poor quality or indeed is lacking. Efforts should be made to disseminate information on heredity of Type 2 diabetes and preventive options to the general public and high-risk populations.