Conference on "Multidisciplinary approaches to nutritional problems". Symposium on "Diabetes and health". Nutrition interventions for the prevention of type 2 diabetes

The Genetic Contribution to Type 1 Diabetes

PURPOSE OF REVIEW

To provide an updated summary of discoveries made to date resulting from genome-wide association study (GWAS) and sequencing studies, and to discuss the latest loci added to the growing repertoire of genetic signals predisposing to type 1 diabetes (T1D).

RECENT FINDINGS

Genetic studies have identified over 60 loci associated with T1D susceptibility. GWAS alone does not specifically inform on underlying mechanisms, but in combination with other sequencing and omics-data, advances are being made in our understanding of T1D genetic etiology and pathogenesis. Current knowledge indicates that genetic variation operating in both pancreatic β cells and in immune cells is central in mediating T1D risk. One of the main challenges is to determine how these recently discovered GWAS-implicated variants affect the expression and function of gene products. Once we understand the mechanism of action for disease-causing variants, we will be well placed to apply targeted genomic approaches to impede the premature activation of the immune system in an effort to ultimately prevent the onset of T1D.

Translation of the Diabetes Prevention Program to Ethnic Communities in the United States

The Diabetes Prevention Program (DPP), an evidenced-based lifestyle intervention for type 2 diabetes (T2D), has been translated for use with ethnic minority communities throughout the United States that are disproportionately at-risk for T2D. The present paper sought to critically review ethnic translation studies of the DPP with respect to translation methods utilized, the success of these methods, and alternative or supplemental methodologies for future translation efforts. Manuscripts reviewed were found by searching PubMed and PsycINFO, using the terms: "diabetes prevention program" AND ["translation" or "ethnic"]. Of 89 papers found, only 6 described ethnic translations of the DPP in the United States, and were included in this review. Translations of the DPP to African American, Hispanic/Latino, Native Hawaiian and Other Pacific Islander, Arab American, and American Indian and Native Alaskan communities were identified and reviewed. The most common translation strategies included group-based delivery and use of bilingual study personnel. Generally, these factors appeared to increase acceptability of the intervention within the ethnic communities reviewed, and should be considered in future efforts to implement and translate the DPP to ethnic communities in the United States.

Rationale and design of the DP-TRANSFERS project: diabetes prevention-transferring findings from European research to society in Catalonia

BACKGROUND

Compelling evidence has been accumulated to support the effectiveness of intensive lifestyle intervention in delaying progression to Type 2 diabetes even in people identified as being at high risk determined by the Finnish diabetes risk score. The DE-PLAN-CAT project (diabetes in Europe-prevention using lifestyle, physical activity and nutritional intervention-Catalonia) evidenced that intensive lifestyle intervention was feasible and cost-effective on a short scale in real-life primary care settings, at least over 4 years. However, transferring such lifestyle interventions to society remains the major challenge of research in the field of diabetes prevention.

METHODS/DESIGN

The derived DP-TRANSFERS (diabetes prevention-transferring findings from European research to society) is a large scale national programme aimed at translating a tailored lifestyle intervention to the maximum of primary care centres where feasible through a core proposal agreed with all the partners. The method is built upon a 3-step (screening, intervention and follow-up) real-life, community-wide structure on the basis of a dual intensity lifestyle intervention (basic and continuity modules) and supported by a 4-channel transfer strategy (institutional relationships, facilitators' workshops, collaborative groupware and programme WEB page). Participation will initially cover nine health departments (7 million inhabitants) through nine coordinating centres located in metropolitan (3.2 million), semi-urban (2.9 million) and rural (0.9 million) areas from which it is expected accessing 25 % of all primary care settings, equivalent to 90 associated centres (1.6-1.8 million people) with an estimate of 0.32 million participants aged 45-75 years at high risk of future development of diabetes. To ascertain sustainability, effect, satisfaction and quality of the translation programme statistical analyses will be performed from both the entire population (facilitators and participants) and a stratified representative sample obtained by collecting data from at least 920 participants.

DISCUSSION

The DP-TRANSFERS will use a strategy of approach to society consistent with the impact of the disease and the fast accessibility provided by primary care settings in Catalonia. Both the widespread effect of the lifestyle intervention and the translational process itself could be assessed.

African vs. Caucasian and Asian difference for the association of interleukin-10 promotor polymorphisms with type 2 diabetes mellitus (a meta-analysis study)

Background

Interleukin-10 (IL-10) is a multifunctional regulatory cytokine that might be associated with increased risk of type 2 diabetes mellitus (T2DM). IL-10 gene polymorphisms have been reported to be associated with T2DM in several ethnic populations with controversial results.

Objectives

This work is an updated meta-analysis aiming at the evaluation of the association between IL-10 gene polymorphisms: rs1800872 (− 592 C > A), rs1800896 (− 1082 A > G) and rs1800871 (− 819 C > T) with the risk of T2DM.

Methods

All available full text studies published up to July 2015 were included in this meta-analysis. Mainly Pubmed and Science Direct databases were searched for all eligible studies pertinent to testing the association between IL-10 gene polymorphisms with the susceptibility to T2DM. Further analyses of the pooled and stratified data in terms of individual polymorphic types and subject ethnicity were done and assessed using varied genetic models.

Results

Fifteen case-control studies with a total of 26 comparisons (10 for IL-10 − 592 C > A rs1800872, 11 for IL-10 − 1082 A > G rs1800896 and 5 for IL-10 − 819 C > T rs1800871 polymorphisms) met our inclusion criteria. IL-10 − 1082 A > G polymorphism was the only one to show an association with T2DM in all pooled sample particularly among Asian and European (high frequency of the G allele) ethnic groups. On the other hand, IL-10 − 592 C > A and − 819 C > T were significantly associated with T2DM only among African subjects.

Conclusions

This meta-analysis demonstrated that IL-10 − 1082 A > G polymorphism was associated with increased risk of development of T2DM in total subjects no matter was their ethnic background, while both IL-10 − 592 C > A and − 819 C > T polymorphisms were associated with that risk only among African subjects.

Significance of CXCL12 in type 2 diabetes mellitus and its associated complications

Immune responses are extensively accepted as primitive etiological leading causes involved in immune system diseases. It is now well established that chemokines as the main arms of the immune system play critical roles in the regulation of immune responses in the pathogenesis of different diseases. Several environmental and genetic elements of the immune system are also believed to potentially affect both the onsets of immunological diseases. The stromal cell-derived factor-1 alpha (SDF-1α) which in new nomenclature is nominated as C-X-C motif ligand 12 (CXCL12) is involved in the development and progression of immune responses. The CXCL12 is an extensively active chemokine that serves as a recruiter for migration and trafficking of leukocytes and hematopoietic progenitor cells. Patients suffering type 2 diabetes (T2D) that ascribe heterozygous SDF-1 3'A genotype (801G/A in the 3' untranslated region) have increased insulin-dependent mobilization of adult progenitor cells, which are known to participate in angiogenesis and vascular repair. Conversely, homing of progenitor cells contributes to the diabetes vascular complications. Because carriers of the SDF-1 3'A genotype show increased levels of the CXCL12 messenger RNA (mRNA) in their peripheral blood mononuclear cells. Genetic variations of CXCL12 gene might affect trafficking of inflammatory cells or defected precursors and hence induced tendency to diabetic complications. The SDF-1 3'A genetic variation of CXCL12 influences the development of late vascular diabetic complications, and previous studies reported that this genetic variation regulates the expression of CXCL12. Therefore, the main goal of the present study was to collect the most recent reports regarding the relation between serum concentrations and SDF-1 3'A genetic variation of CXCL12 in T2D.

Development of a behaviour change communication tool for medical students: the 'Tent Pegs' booklet

OBJECTIVE

To describe the development and validation of a behaviour change communication tool for medical students.

METHODS

Behaviour change techniques (BCTs) were identified within the literature and used to inform a communication tool to support medical students in discussing health-related behaviour change with patients. BCTs were organized into an accessible format for medical students (the 'Tent Pegs' booklet) and validated using discriminant content validity methods with 11 expert judges.

RESULTS

One-sample t-tests showed that judges reliably mapped BCTs onto six of the seven Tent Pegs domains (confidence rating means ranged from 4.0 to 5.1 out of 10, all p≤0.002). Only BCTs within the 'empowering people to change' domain were not significantly different from the value zero (mean confidence rating=1.2, p>0.05); these BCTs were most frequently allocated to the 'addressing thoughts and emotions' domain instead.

CONCLUSION

BCTs within the Tent Pegs booklet are reliably allocated to corresponding behaviour change domains with the exception of those within the 'empowering people to change' domain.

PRACTICE IMPLICATIONS

The existing evidence-base on BCTs can be used to directly inform development of a communication tool to support medical students facilitate health behaviour change with patients.

Genes involved in type 1 diabetes: an update

Type 1 Diabetes (T1D) is a chronic multifactorial disease with a strong genetic component, which, through interactions with specific environmental factors, triggers disease onset. T1D typically manifests in early to mid childhood through the autoimmune destruction of pancreatic β cells resulting in a lack of insulin production. Historically, prior to genome-wide association studies (GWAS), six loci in the genome were fully established to be associated with T1D. With the advent of high-throughput single nucleotide polymorphism (SNP) genotyping array technologies, enabling investigators to perform high-density GWAS, many additional T1D susceptibility genes have been discovered. Indeed, recent meta-analyses of multiple datasets from independent investigators have brought the tally of well-validated T1D disease genes to almost 60. In this mini-review, we address recent advances in the genetics of T1D and provide an update on the latest susceptibility loci added to the list of genes involved in the pathogenesis of T1D.

Genetic variation of IL-12B (+1188 region) is associated with its decreased circulating levels and susceptibility to Type 2 diabetes

BACKGROUND

Type 2 diabetes mellitus is one of the most common types of endocrine disease and the immune system plays a predominant role in its pathogenesis.

AIMS

The present study aimed to examine known gene polymorphisms within IL-12B (+1188) region and its circulating serum levels in Type 2 diabetic patients from the southeastern region of Iran and compare them with unrelated controls.

MATERIALS & METHODS

In this clinical study, peripheral blood was collected from 114 Type 2 diabetic patients and 100 healthy controls. Serum levels of IL-12B were measured by ELISA. Genomic DNA was extracted from peripheral blood samples and polymorphisms at the +1188 position of the IL-12B gene were assessed using PCR restriction fragment-length polymorphism.

RESULTS

Our findings demonstrated that the AA genotype and the A allele of IL-12B were increased significantly in Type 2 diabetic patients when compared with controls. Our results also showed that the circulating levels of IL-12B were significantly decreased in Type 2 diabetic patients when compared with controls.

CONCLUSION

According to the findings of the current study, we concluded that IL-12B and its +1188 polymorphism may play a prominent role in the pathogenesis of Type 2 diabetes. Further replicative investigations using a larger sample size are essential to identify additional IL-12B genetic variants associated with a risk of Type 2 diabetes.

Be Well: results of a nutrition, exercise, and weight management intervention among at-risk older adults

The objective of this article is to test the effectiveness of a multifaceted exercise and nutritional education intervention for chronically ill, community-dwelling older adults. A pre/post cohort design was implemented with measures of physical activity, fitness, depression, and anthropometry collected via 4-month in-person interview and telephone follow-up. The study was conducted at two community-based senior centers in the Los Angeles area and participants (n=62) were older adults aged 60 or older, with multiple chronic conditions, with one or more emergency department visits or hospital admissions in the previous 6 months, and at nutritionally moderate to high risk. The intervention was a fitness program providing nutritional counseling, low-impact exercise, and weight management. Results revealed significant improvements for hours of weekly exercise (Z = -4.3, p < .001), daily walking distance (Z = -5.7, p < .001), performance on fitness tests, depression (Z = 3.9, p < .001), and body measurements were observed. Findings speak to the healthy benefits of exercise and good nutrition as possible alternatives or adjuncts to pharmacotherapy for weight loss and depression.

Genome-wide association studies (GWAS): impact on elucidating the aetiology of diabetes

It has proven to be challenging to isolate the genes underlying the genetic components conferring susceptibility to type 1 and type 2 diabetes. Unlike previous approaches, 'genome-wide association studies' have extensively delivered on the promise of uncovering genetic determinants of complex diseases, with a number of novel disease-associated variants being largely replicated by independent groups. This review provides an overview of these recent breakthroughs in the context of type 1 and type 2 diabetes, and outlines strategies on how these findings will be applied to impact clinical care for these two highly prevalent disorders.

A genome-wide meta-analysis of six type 1 diabetes cohorts identifies multiple associated loci

Diabetes impacts approximately 200 million people worldwide, of whom approximately 10% are affected by type 1 diabetes (T1D). The application of genome-wide association studies (GWAS) has robustly revealed dozens of genetic contributors to the pathogenesis of T1D, with the most recent meta-analysis identifying in excess of 40 loci. To identify additional genetic loci for T1D susceptibility, we examined associations in the largest meta-analysis to date between the disease and ∼2.54 million SNPs in a combined cohort of 9,934 cases and 16,956 controls. Targeted follow-up of 53 SNPs in 1,120 affected trios uncovered three new loci associated with T1D that reached genome-wide significance. The most significantly associated SNP (rs539514, P = 5.66×10⁻¹¹) resides in an intronic region of the LMO7 (LIM domain only 7) gene on 13q22. The second most significantly associated SNP (rs478222, P = 3.50×10⁻⁹) resides in an intronic region of the EFR3B (protein EFR3 homolog B) gene on 2p23; however, the region of linkage disequilibrium is approximately 800 kb and harbors additional multiple genes, including NCOA1, C2orf79, CENPO, ADCY3, DNAJC27, POMC, and DNMT3A. The third most significantly associated SNP (rs924043, P = 8.06×10⁻⁹) lies in an intergenic region on 6q27, where the region of association is approximately 900 kb and harbors multiple genes including WDR27, C6orf120, PHF10, TCTE3, C6orf208, LOC154449, DLL1, FAM120B, PSMB1, TBP, and PCD2. These latest associated regions add to the growing repertoire of gene networks predisposing to T1D.

Despite the fact that there is clearly a large genetic component to type 1 diabetes (T1D), uncovering the genes contributing to this disease has proven challenging. However, in the past three years there has been relatively major progress in this regard, with advances in genetic screening technologies allowing investigators to scan the genome for variants conferring risk for disease without prior hypotheses. Such genome-wide association studies have revealed multiple regions of the genome to be robustly and consistently associated with T1D. More recent findings have been a consequence of combining of multiple datasets from independent investigators in meta-analyses, which have more power to pick up additional variants contributing to the trait. In the current study, we describe the largest meta-analysis of T1D genome-wide genotyped datasets to date, which combines six large studies. As a consequence, we have uncovered three new signals residing at the chromosomal locations 13q22, 2p23, and 6q27, which went on to be replicated in independent sample sets. These latest associated regions add to the growing repertoire of gene networks predisposing to T1D.

The effect of ready-to-eat cereal consumption on energy intake, body weight and anthropometric measurements: results from a randomized, controlled intervention trial

The objective of this work was to determine the effect of consumption of ready-to-eat cereal (RTEC) in the evening in place of a normal evening snack on body weight, anthropometric measurements and energy intake in overweight individuals. Seventy overweight participants who were self-reported habitual evening snackers were assigned to either the control or treatment group. For 6 weeks the treatment group consumed RTEC instead of their normal evening snack. Body weight, anthropometric and food intake measurements were taken at 2-week intervals. There were no significant differences between groups in any anthropometric measurements; however, within the treatment group, body weight (p = 0.030) and waist circumference (p = 0.0003) were reduced after 6 weeks compared with baseline. Evening energy intake was lower in the treatment group compared with the control group (p = 0.007). These data indicate that replacing evening snacks with RTEC in overweight habitual evening snackers significantly reduces post dinner energy intake and may assist with weight management.

Egg consumption and risk of type 2 diabetes in older adults

BACKGROUND

Type 2 diabetes (T2D) remains an important public health issue in the United States. There are limited and inconsistent data on the association between egg consumption and fasting glucose or incident diabetes.

OBJECTIVES

We assessed the association between egg intake and incident diabetes in older adults.

DESIGN

In this prospective study of 3898 men and women from the Cardiovascular Health Study (1989-2007), we assessed egg consumption by using a picture-sorted food questionnaire and ascertained incident T2D annually by using information on hypoglycemic agents and plasma glucose. We used Cox proportional hazards models to estimate adjusted relative risks.

RESULTS

During a mean follow-up of 11.3 y, 313 new cases of T2D occurred. Crude incidence rates of T2D were 7.39, 6.83, 7.00, 6.72, and 12.20 per 1000 person-years in people who reported egg consumption of never, <1 egg/mo, 1-3 eggs/mo, 1-4 eggs/wk, and almost daily, respectively. In multivariable-adjusted models, there was no association between egg consumption and increased risk of T2D in either sex and overall. In a secondary analysis, dietary cholesterol was not associated with incident diabetes (P for trend = 0.47). In addition, egg consumption was not associated with clinically meaningful differences in fasting glucose, fasting insulin, or measures of insulin resistance despite small absolute analytic differences that were significant.

CONCLUSION

In this cohort of older adults with limited egg intake, there was no association between egg consumption or dietary cholesterol and increased risk of incident T2D.

Physical activity's impact on the association of fat and fiber intake with survival after breast cancer

This study examined whether, after a breast cancer diagnosis, high intake of animal fat was associated with increased breast cancer mortality and high intake of fiber was associated with decreased breast cancer mortality. Participants were 3,846 US female nurses diagnosed with stages I-III breast cancer between 1976 and 2001 and followed until death or May 2006. Breast cancer mortality was calculated according to dietary intake quintiles first assessed at least 12 months after diagnosis and was cumulatively averaged and updated. There were 446 breast cancer deaths. In simple models adjusted for time since diagnosis, age, and energy intake, animal fat intake was associated with increased breast cancer death, and cereal fiber intake was associated with reduced breast cancer death. However, no associations were found in fully adjusted models: for animal fat, the relative risks for increasing quintiles were 1.00, 0.89, 0.86, 0.85, and 0.89 (95% confidence interval: 0.61, 1.28), P = 0.68; for cereal fiber, they were 1.00, 0.95, 0.76, 0.81, and 1.00 (95% confidence interval: 0.71, 1.40), P = 0.59. Results of simple models adjusted additionally for physical activity were similar to those for full multivariate models. Results show that physical activity strongly confounds the association between diet and survival.

Biphasic insulin aspart 30/70 (BIAsp 30) in the treatment of type 1 and type 2 diabetes

The pharmacological advantages of the rapid-acting analog, insulin aspart, over human insulin have contributed to the widespread prescription of the premix, biphasic insulin aspart 30/70 (BIAsp 30), in type 1 (T1DM) and type 2 diabetes (T2DM). This article reviews the available literature on the pharmacology, efficacy and safety of BIAsp 30 in T1DM and T2DM from an online search of the PubMed database. Following injection, BIAsp 30 reaches higher plasma insulin levels more quickly than human premix or basal insulin, giving effective reduction of postprandial hyperglycemia. In T1DM patients, randomized controlled trials (RCTs) have shown that HbA(1c) reduction is similar, but postprandial glycemic control is better, with BIAsp 30 than with human insulin regimens. In T2DM patients, lowering of HbA(1c) and postprandial hyperglycemia with BIAsp 30 compare favorably with optimized oral antidiabetes drug treatment, insulin glargine, and, in obese patients, human premix. An increase in minor hypoglycemia with BIAsp 30 relative to basal insulin has been reported in T2DM patients, but major and nocturnal hypoglycemia rates are generally low. Findings from RCTs in T2DM patients are supported by large observational studies. In summary, BIAsp 30 once to three times daily represents a simple and effective tool for the modern management of diabetes.