Study design of the Trial to Reduce IDDM in the Genetically at Risk (TRIGR)

Neglected Facts on Mycobacterium Avium Subspecies Paratuberculosis and Type 1 Diabetes

Civilization factors are responsible for the increasing of human exposure to mycobacteria from environment, water, and food during the last few decades. Urbanization, lifestyle changes and new technologies in the animal and plant industry are involved in frequent contact of people with mycobacteria. Type 1 diabetes is a multifactorial polygenic disease; its origin is conditioned by the mutual interaction of genetic and other factors. The environmental factors and certain pathogenetic pathways are shared by some immune mediated chronic inflammatory and autoimmune diseases, which are associated with triggers originating mainly from Mycobacterium avium subspecies paratuberculosis, an intestinal pathogen which persists in the environment. Type 1 diabetes and some other chronic inflammatory diseases thus pose the global health problem which could be mitigated by measures aimed to decrease the human exposure to this neglected zoonotic mycobacterium.

Dietary compliance in a randomized double-blind infant feeding trial during infancy aiming at prevention of type 1 diabetes

The international Trial to Reduce IDDM in the Genetically at Risk (TRIGR) tested the hypothesis whether extensively hydrolyzed casein-based versus regular cow's milk-based infant formula reduces the risk of type 1 diabetes. We describe dietary compliance in the trial in terms of study formula intake, feeding of nonrecommended foods, and serum cow's milk antibody concentration reflecting intake of cow's milk protein among 2,159 eligible newborn infants with a biological first-degree relative affected by type 1 diabetes and with HLA-conferred susceptibility to type 1 diabetes. The participating infants were introduced to the study formula feeding at the median age of 15 days with a median duration of study formula use of 63 days. During the intervention, 80% of the infants received study formula. Of these, 57% received study formula for at least 2 months. On average, 45.5 l of study formula were used per infant. Only 13% of the population had received a nonrecommended food by the age of 6 months. The dietary compliance was similar in the intervention and control arm. The reported cow's milk consumption by the families matched very well with measured serum casein IgA and IgG antibody concentration. To conclude, good compliance was observed in this randomized infant feeding trial. Compliance varied between the regions and those infants who were breastfed for a longer period of time had a shorter exposure to the study formula. High dietary compliance in infant feeding trial is necessary to allow accurate interpretation of study results.

Growth and development of islet autoimmunity and type 1 diabetes in children genetically at risk

AIMS/HYPOTHESIS

We aimed to evaluate the relationship between childhood growth measures and risk of developing islet autoimmunity (IA) and type 1 diabetes in children with an affected first-degree relative and increased HLA-conferred risk. We hypothesised that being overweight or obese during childhood is associated with a greater risk of IA and type 1 diabetes.

METHODS

Participants in a randomised infant feeding trial (N = 2149) were measured at 12 month intervals for weight and length/height and followed for IA (at least one positive out of insulin autoantibodies, islet antigen-2 autoantibody, GAD autoantibody and zinc transporter 8 autoantibody) and development of type 1 diabetes from birth to 10-14 years. In this secondary analysis, Cox proportional hazard regression models were adjusted for birthweight and length z score, sex, HLA risk, maternal type 1 diabetes, mode of delivery and breastfeeding duration, and stratified by residence region (Australia, Canada, Northern Europe, Southern Europe, Central Europe and the USA). Longitudinal exposures were studied both by time-varying Cox proportional hazard regression and by joint modelling. Multiple testing was considered using family-wise error rate at 0.05.

RESULTS

In the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) population, 305 (14.2%) developed IA and 172 (8%) developed type 1 diabetes. The proportions of children overweight (including obese) and obese only were 28% and 9% at 10 years, respectively. Annual growth measures were not associated with IA, but being overweight at 2-10 years of life was associated with a twofold increase in the development of type 1 diabetes (HR 2.39; 95% CI 1.46, 3.92; p < 0.001 in time-varying Cox regression), and similarly with joint modelling.

CONCLUSIONS/INTERPRETATION

In children at genetic risk of type 1 diabetes, being overweight at 2-10 years of age is associated with increased risk of progression from multiple IA to type 1 diabetes and with development of type 1 diabetes, but not with development of IA. Future studies should assess the impact of weight management strategies on these outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777.

Association between family history, early growth and the risk of beta cell autoimmunity in children at risk for type 1 diabetes

AIMS/HYPOTHESIS

The aim of this work was to examine the relationship between family history of type 1 diabetes, birthweight, growth during the first 2 years and development of multiple beta cell autoantibodies in children with a first-degree relative with type 1 diabetes and HLA-conferred disease susceptibility.

METHODS

In a secondary analysis of the Trial to Reduce IDDM in the Genetically at Risk (TRIGR), clinical characteristics and development of beta cell autoantibodies were compared in relation to family history of type 1 diabetes (mother vs father vs sibling) in 2074 children from families with a single affected family member.

RESULTS

Multiple autoantibodies (≥2 of 5 measured) developed in 277 (13%) children: 107 (10%), 114 (16%) and 56 (18%) born with a mother, father or sibling with type 1 diabetes, respectively (p < 0.001). The HR for time to multiple autoimmunity was 0.54 (95% CI 0.39, 0.75) in offspring of affected mothers (n = 107/1046, p < 0.001) and 0.81 (95% CI 0.59, 1.11) (n = 114/722, p = 0.19) in offspring of affected fathers, compared with participants with a sibling with type 1 diabetes (comparator group n = 56/306). The time to the first autoantibody present (to insulin, GAD, tyrosine phosphatase-related insulinoma-associated 2 molecules, islet cell or zinc transporter 8) was similar in the three groups. Height velocity (z score/year) in the first 24 months was independently associated with developing multiple antibodies in the total cohort (HR 1.31 [95% CI 1.01, 1.70], p = 0.04). A higher birthweight in children born to an affected mother vs affected father or an affected sibling was not related to the risk of multiple autoimmunity.

CONCLUSIONS/INTERPRETATION

The risk of developing multiple autoantibodies was lower in children with maternal type 1 diabetes. For the whole group, this risk of developing multiple autoantibodies was independent of birthweight but was greater in those with increased height velocity during the first 2 years of life. However, the risk associated with paternal type 1 diabetes was not linked to differences in birthweight or early growth.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777 Graphical abstract.

Association of diabetes-related autoantibodies with the incidence of asthma, eczema and allergic rhinitis in the TRIGR randomised clinical trial

AIMS/HYPOTHESIS

This paper presents the relationship between islet autoantibodies, precursors of type 1 diabetes, and the development of persistent asthma, allergic rhinitis and atopic eczema.

METHODS

A total of 2159 newborns who had a first-degree relative with type 1 diabetes and selected HLA genotypes were followed until the youngest participant reached 10 years of age. Islet cell antibodies (ICA) were detected using indirect immunofluorescence. Autoantibodies to insulin (IAA), GAD (GADA), the tyrosine phosphatase-related insulinoma-associated 2 molecule (IA-2A) and zinc transporter 8 (ZnT8A) were quantified with the use of specific radiobinding assays. As an ancillary study, the incidence of asthma, allergic rhinitis and eczema was assessed in 1106 of these children using the International Study of Asthma and Allergies in Childhood (ISAAC) core questionnaire when the children were 9-11 years old. HRs with 95% CIs were calculated to depict the incidence of these diseases following seroconversion to autoantibody positivity.

RESULTS

The cumulative incidence of atopic eczema, allergic rhinitis and persistent asthma were 22%, 9% and 7.5%, respectively, by 9-11 years of age. The occurrence of diabetes-related autoantibodies showed a protective association with subsequently reported incidence of asthma and eczema. The incidence of rhinitis was not significantly related to the occurrence of IAA or GADA (statistical power was limited), but demonstrated the same inverse relationship as did the other diseases with ICA or when multiple autoantibodies first appeared together.

CONCLUSIONS/INTERPRETATION

The findings add evidence to the relationships between these atopic diseases and diabetes-related autoimmunity and also suggest that, for eczema, the interaction depends upon which autoantibody appeared first.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777 Graphical abstract.

Molecular Concept of Diabetic Wound Healing: Effective Role of Herbal Remedies

The incidence of diabetes mellitus (DM) is on the rise, worldwide. One of the main complications in DM is delayed wound healing and it often requires amputation. Various drugs were used to treat DM but they presented with adverse effects. Often, patients failed to comply with such treatment. This opened the door for complementary and alternative medicine. In the present review, we explored the molecular concept of wound healing occurring in different stages with special emphasis to DM. We also highlighted the potential herbal products such as NF3 (Chinese 2-Herb Formula), Zicao, Jing Wan Hong ointment, Aleo vera, mixture of Adiantum capillus-veneris, Commiphora molmol, Aloe vera, and henna, Phenol-rich compound sweet gel, Jinchuang ointment, San-huang-sheng-fu (S) oil, Yi Bu A Jie extract, Astragali Radix (AR) and Rehmanniae Radix (RR), Yiqi Huayu, Tangzu yuyang ointment, Shengji Huayu recipe, Angelica sinensis, Lithospermun erythrorhison, Hippophae rhamnoides L., Curcuma longa and Momordica charantia that could be used effectively to treat DM wounds. Future clinical trials are needed for designing potential drugs which may be effective in treating DM wounds.

Milk feeding and first complementary foods during the first year of life in the TEDDY study

The aim was to describe milk feeding patterns and first weaning foods during the first year of life in a large prospective birth cohort of infants with increased genetic risk for Type 1 diabetes (T1D) recruited in 4 different countries: the United States, Finland, Germany, and Sweden. All enrolled children with dietary information (n = 8,673) were included in the analyses; 1,307 (15%) children who dropped out before the first birthday were excluded from some analyses. Supplementary milk feeding in the first 3 days of life was common in all the four countries, although the type of the supplementary milk differed by country and by maternal T1D. Donated human milk was commonly used only in Finland. In all the countries, the most common first supplementary food was cow's milk-based infant formula, especially among offspring of mothers with T1D. The use of specific types of infant formulas differed notably by country: Extensively hydrolysed formulas were most used in Finland, partially hydrolysed ones in the United States and in Germany, and soy formulas only in the United States. Infant formulas commonly included probiotics, prebiotics, and starches. During the first year of life, most of the infants received conventional cow's milk. Overall, milk feeding during the first 3 days of life and thereafter until the first birthday differed markedly by maternal T1D status and across countries. These descriptive data may be useful in understanding early infant feeding practices and in planning potential interventions, which affect infant feeding.

Sibling method increases risk assessment estimates for type 1 diabetes

We presented a risk assessment model to distinguish between type 1 diabetes (T1D) affected and unaffected siblings using only three single nucleotide polymorphism (SNP) genotypes. In addition we calculated the heritability from genome-wide identity-by-descent (IBD) sharing between full siblings. We analyzed 1,253 pairs of affected individuals and their unaffected siblings (750 pairs from a discovery set and 503 pairs from a validation set) from the T1D Genetics Consortium (T1DGC), applying a logistic regression to analyze the area under the receiver operator characteristic (ROC) curve (AUC). To calculate the heritability of T1D we used the Haseman-Elston regression analysis of the squared difference between the phenotypes of the pairs of siblings on the estimate of their genome-wide IBD proportion. The model with only 3 SNPs achieving an AUC of 0.75 in both datasets outperformed the model using the presence of the high-risk DR3/4 HLA genotype, namely AUC of 0.60. The heritability on the liability scale of T1D was approximately from 0.53 to 0.92, close to the results obtained from twin studies, ranging from 0.4 to 0.88.

Regional differences in milk and complementary feeding patterns in infants participating in an international nutritional type 1 diabetes prevention trial

Differences in breastfeeding, other milk feeding and complementary feeding patterns were evaluated in infants at increased genetic risk with and without maternal type 1 diabetes (T1D). The Trial to Reduce IDDM in the Genetically at Risk is an international nutritional primary prevention double-blinded randomized trial to test whether weaning to extensively hydrolyzed vs. intact cow's milk protein formula will decrease the development of T1D-associated autoantibodies and T1D. Infant diet was prospectively assessed at two visits and seven telephone interviews between birth and 8 months. Countries were grouped into seven regions: Australia, Canada, Northern Europe, Southern Europe, Central Europe I, Central Europe II and the United States. Newborn infants with a first-degree relative with T1D and increased human leukocyte antigen-conferred susceptibility to T1D were recruited. A lower proportion of infants born to mothers with than without T1D were breastfed until 6 months of age in all regions (range, 51% to 60% vs. 70% to 80%). Complementary feeding patterns differed more by region than by maternal T1D. In Northern Europe, a higher proportion of infants consumed vegetables and fruits daily compared with other regions. Consumption of meat was more frequent in all European regions, whereas cereal consumption was most frequent in Southern Europe, Canada and the United States. Maternal T1D status was associated with breastfeeding and other milk feeding patterns similarly across regions but was unrelated to the introduction of complementary foods. Infant feeding patterns differed significantly among regions and were largely inconsistent with current recommended guidelines.

Increasing trends in the incidence and prevalence rates of type 1 diabetes among children and adolescents in the Netherlands

OBJECTIVE

To assess the trends in the incidence and prevalence rates of type 1 diabetes (T1D) among children and adolescents in the Netherlands.

METHODS

A population-based cohort study was conducted in the Dutch PHARMO record linkage system (1998-2011). All children and adolescents aged ≤19 yr with at least one insulin dispensing (as a proxy for T1D) were identified and the numbers of incident and prevalent cases (numerators) were calculated. Overall age-adjusted (0-19 yr) incidence and prevalence rates together with age- and sex-specific rates of T1D and their 95% confidence intervals (CI) were calculated using data from the Dutch Central Bureau of Statistics as denominator. Trends over time were assessed using Joinpoint regression software (National Cancer Institute, Bethesda, MD, USA).

RESULTS

In 2011, the overall age-adjusted incidence and prevalence rates of T1D were 25.2/100 000 (95% CI, 23.7-26.8) person-years (PY) and 174.4/100 000 (95% CI, 170.2-178.5) children, respectively. The average annual percentage change (AAPC) in the overall age-adjusted incidence and prevalence rate was 3.7% (95% CI, 1.8-5.7) and 3.8% (95% CI, 2.4-5.2), respectively. While during the study period the largest increases in the incidence and prevalence rates of T1D were observed for the oldest age groups (10-14 and 15-19 yr), a decreasing trend was detected for the 0- to 4-yr-old category (with AAPCs of -1.8 (95% CI, -9.9 to 7.1) and -6.9% (95% CI, -11.5 to -2.1) for incidence and prevalence, respectively).

CONCLUSION

Age-adjusted incidence (1999-2011) and prevalence rates (1998-2011) of T1D in Dutch children (aged 0-19 yr) continued to increase and a shift was observed to a later onset of the disease.

Heterogeneity in diabetes-associated autoantibodies and susceptibility to Type 1 diabetes: lessons for disease prevention

Autoantibodies against pancreatic islets are strong predictors of Type 1 diabetes. When persistent β-cell autoantibodies against at least two autoantigens are detected, the probability of diabetes is extremely high, although the time period before disease development can vary from days up to more than 20 years. Insulin autoantibodies or antibodies specific to glutamate decarboxylase 65 enzyme are in most cases, the first autoantibodies to appear. Insulin autoantibodies typically emerge very early with a peak at the age of 1.5 years, whereas the onset of glutamic acid decarboxylase 65 antibody positivity has a more even distribution, peaking later in childhood. These differences in the timing of appearance suggest that different environmental factors might be involved in the initiation of β-cell autoimmunity beginning either already in infancy or later on. This should be taken into account in studies aimed at identifying environmental factors triggering islet cell-specific autoimmunity and also in the design of prevention trials.

Feature ranking of type 1 diabetes susceptibility genes improves prediction of type 1 diabetes

AIMS/HYPOTHESIS

More than 40 regions of the human genome confer susceptibility for type 1 diabetes and could be used to establish population screening strategies. The aim of our study was to identify weighted sets of SNP combinations for type 1 diabetes prediction.

METHODS

We applied multivariable logistic regression and Bayesian feature selection to the Type 1 Diabetes Genetics Consortium (T1DGC) dataset with genotyping of HLA plus 40 SNPs within other type 1 diabetes-associated gene regions in 4,574 cases and 1,207 controls. We tested the weighted models in an independent validation set (765 cases, 423 controls), and assessed their performance in 1,772 prospectively followed children.

RESULTS

The inclusion of 40 non-HLA gene SNPs significantly improved the prediction of type 1 diabetes over that provided by HLA alone (p = 3.1 × 10(-25)), with a receiver operating characteristic AUC of 0.87 in the T1DGC set, and 0.84 in the validation set. Feature selection identified HLA plus nine SNPs from the PTPN22, INS, IL2RA, ERBB3, ORMDL3, BACH2, IL27, GLIS3 and RNLS genes that could achieve similar prediction accuracy as the total SNP set. Application of this ten SNP model to prospectively followed children was able to improve risk stratification over that achieved by HLA genotype alone.

CONCLUSIONS

We provided a weighted risk model with selected SNPs that could be considered for recruitment of infants into studies of early type 1 diabetes natural history or appropriately safe prevention.

Use of vitamin D supplements during infancy in an international feeding trial

OBJECTIVE

To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.

DESIGN

Longitudinal study.

SETTING

Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.

SUBJECTS

Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.

RESULTS

Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80% of the infants), with somewhat lower rates observed in Southern Europe (> 60%). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g., 71% v. 44% at 6 months of age). Less than 2% of infants in the U.S.A. and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.

CONCLUSIONS

Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the U.S.A. and Australia very few were given supplementation.

Modulation of the pancreatic islet-stress axis as a novel potential therapeutic target in diabetes mellitus

Loss of pancreatic islet function and insulin-producing beta cell mass is a central hallmark in the pathogenesis of both type 1 and type 2 diabetes. While in type 1 diabetes this phenomenon is due to an extensive destruction of beta cells caused by an autoimmune process, the mechanisms resulting in beta cell failure in type 2 diabetes are different and less clear. Also, beta cell destruction in type 1 diabetes occurs early and is the initial step in the pathogenetic process, while beta cell loss in type 2 diabetes after an initial phase of hyperinsulinemia due to the underlying insulin resistance occurs relatively late and it is less pronounced. Since diabetes mellitus is the most frequent endocrine disease, with an increasing high prevalence worldwide, huge efforts have been made over the past many decades to identify predisposing genetic, environmental, and nutritional factors in order to develop effective strategies to prevent the disease. In parallel, extensive studies in different cell systems and animal models have helped to elucidate our understanding of the physiologic function of islets and to gain insight into the immunological and non-immunological mechanisms of beta cell destruction and failure. Furthermore, currently emerging concepts of beta cell regeneration (e.g., the restoration of the beta cell pool by regenerative, proliferative and antiapoptotic processes, and recovery of physiologic islet function) apparently is yielding the first promising results. Recent insights into the complex endocrine and paracrine mechanisms regulating the physiologic function of pancreatic islets, as well as beta cell life and death, constitute an essential part of this new and exciting area of diabetology. For example, understanding of the physiological role of glucagon-like peptide 1 has resulted in the successful clinical implementation of incretin-based therapies over the last years. Further, recent data suggesting paracrine effects of growth hormone-releasing hormone and corticotropin-releasing hormone on the regulation of pancreatic islet function, survival, and proliferation as well as on local glucocorticoid metabolism provide evidence for a potential role of the pancreatic islet-stress axis in the pathophysiology of diabetes mellitus. In this chapter, we provide a comprehensive overview of current preventive and regenerative concepts as a basis for the development of novel therapeutic approaches to the treatment of diabetes mellitus. A particular focus is given on the potential of the pancreatic islet-stress axis in the development of novel regenerative strategies.

Large-scale prospective T cell function assays in shipped, unfrozen blood samples: experiences from the multicenter TRIGR trial

Broad consensus assigns T lymphocytes fundamental roles in inflammatory, infectious, and autoimmune diseases. However, clinical investigations have lacked fully characterized and validated procedures, equivalent to those of widely practiced biochemical tests with established clinical roles, for measuring core T cell functions. The Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR) type 1 diabetes prevention trial used consecutive measurements of T cell proliferative responses in prospectively collected fresh heparinized blood samples shipped by courier within North America. In this article, we report on the quality control implications of this simple and pragmatic shipping practice and the interpretation of positive- and negative-control analytes in our assay. We used polyclonal and postvaccination responses in 4,919 samples to analyze the development of T cell immunocompetence. We have found that the vast majority of the samples were viable up to 3 days from the blood draw, yet meaningful responses were found in a proportion of those with longer travel times. Furthermore, the shipping time of uncooled samples significantly decreased both the viabilities of the samples and the unstimulated cell counts in the viable samples. Also, subject age was significantly associated with the number of unstimulated cells and T cell proliferation to positive activators. Finally, we observed a pattern of statistically significant increases in T cell responses to tetanus toxin around the timing of infant vaccinations. This assay platform and shipping protocol satisfy the criteria for robust and reproducible long-term measurements of human T cell function, comparable to those of established blood biochemical tests. We present a stable technology for prospective disease-relevant T cell analysis in immunological diseases, vaccination medicine, and measurement of herd immunity.

The use of intermediate endpoints in the design of type 1 diabetes prevention trials

AIMS/HYPOTHESIS

This paper presents a rationale for the selection of intermediate endpoints to be used in the design of type 1 diabetes prevention clinical trials.

METHODS

Relatives of individuals diagnosed with type 1 diabetes were enrolled on the TrialNet Natural History Study and screened for diabetes-related autoantibodies. Those with two or more such autoantibodies were analysed with respect to increased HbA1c, decreased C-peptide following an OGTT, or abnormal OGTT values as intermediate markers of disease progression.

RESULTS

Over 2 years, a 10% increase in HbA1c, and a 20% or 30% decrease in C-peptide from baseline, or progression to abnormal OGTT, occurred with a frequency between 20% and 41%. The 3- to 5-year risk of type 1 diabetes following each intermediate endpoint was high, namely 47% to 84%. The lower the incidence of the endpoint being reached, the higher the risk of diabetes. A diabetes prevention trial using these intermediate endpoints would require a 30% to 50% smaller sample size than one using type 1 diabetes as the endpoint.

CONCLUSIONS/INTERPRETATION

The use of an intermediate endpoint in diabetes prevention is based on the generally held view of disease progression from initial occurrence of autoantibodies through successive immunological and metabolic changes to manifest type 1 diabetes. Thus, these markers are suitable for randomised phase 2 trials, which can more rapidly screen promising new therapies, allowing them to be subsequently confirmed in definitive phase 3 trials.

Risk factors and primary prevention trials for type 1 diabetes

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease resulting in the designated immune destruction of insulin producing β-cells, usually diagnosed in youth, and associated with important psychological, familial, and social disorders. Once diagnosed, patients need lifelong insulin treatment and will experience multiple disease-associated complications. There is no cure for T1DM currently. The last decade has witnessed great progress in elucidating the causes and treatment of the disease based on numerous researches both in rodent models of spontaneous diabetes and in humans. This article summarises our current understanding of the pathogenesis of T1DM, the roles of the immune system, genes, environment and other factors in the continuing and rapid increase in T1DM incidence at younger ages in humans. In addition, we discuss the strategies for primary and secondary prevention trials of T1DM. The purpose of this review is to provide an overview of this disorder's pathogenesis, risk factors that cause the disease, as well as to bring forward an ideal approach to prevent and cure the disorder.

Prevention versus intervention of type 1 diabetes

Type 1 diabetes (T1D) is a cell-mediated autoimmune disease. New cases of T1D are on the increase and exogenous insulin therapy is the only intervention regularly initiated for T1D patients. Though tremendous strides have been made in prediction of T1D, prevention and intervention strategies have not experienced the same success. In this review, we will discuss some possible reasons why new intervention therapies for T1D have not been implemented into the mainstream treatment regimen for T1D patients. We will also discuss potential caveats for why prevention and intervention trials in T1D may not have experienced the same success as prediction trials.

Pathogenesis of type 1 diabetes: lessons from natural history studies of high-risk individuals

Type 1 diabetes (T1D) is an autoimmune disease characterized by known genetic risk factors with T cell-mediated infiltration and destruction of the beta cells within pancreatic islets. Autoantibodies are the most significant preclinical marker of T1D, and birth cohort studies have provided important insights into the natural history of autoimmunity and T1D. While HLA remains the strongest genetic risk factor, a number of novel gene variants associated with T1D have been found through genome-wide studies, some of which have been linked to suspected environmental risk factors. Multiple environmental factors that have been suggested to play a role in the development of T1D await confirmation. Current risk-stratification models for T1D take into account genetic risk factors and autoantibodies. In the future, metabolic profiles, epigenetics, as well as environmental risk factors may be included in such models.

Primary and secondary prevention of Type 1 diabetes

Since type 1 diabetes is an immunologically mediated disease, immune intervention should alter the natural history of the disease. This article reviews prevention studies undertaken either prior to any evidence of autoimmunity (primary prevention) or after the development of islet autoantibodies (secondary prevention). Most immune intervention studies have been conducted in recent-onset type 1 diabetes (tertiary prevention), and these are not reviewed herein. The goal of primary and secondary intervention is to arrest the immune process and thus prevent or delay clinical disease. Primary prevention studies have been conducted in infants with high genetic risk. Interventions tested include several dietary manipulations, including infant formulas free of either cow's milk or of bovine insulin, infant formula supplemented with the omega-3-fatty acid docosahexaenoic acid, delayed introduction of gluten-containing foods, and vitamin D supplementation. Secondary prevention studies have been conducted in both children and adults with diabetes autoantibodies. Interventions tested include nicotinamide, insulin injections, oral insulin, nasal insulin, glutamic acid decarboxylase, and cyclosporine. Underway are secondary prevention studies with teplizumab and with abatacept.

Update on global intervention studies in type 1 diabetes

Remarkable progress has been made in strategies to arrest pancreatic β-cell destruction in type 1 diabetes. Although knowledge of the disease has increased, a safe therapeutic intervention to reverse or prevent it remains elusive. The interaction of genes, immune system, and environment result in a complex disease process that has delayed hopes for a cure. Several well-designed prevention and intervention studies have aspired to test potentially efficacious and safe therapies. This article updates the principles used to design prevention and intervention trials, reviews clinical trials, addresses controversial issues, and provides a framework for future efforts to interdict this condition.

Growth differences between North American and European children at risk for type 1 diabetes

AIM

To evaluate the relationships between early growth and regional variations in type 1 diabetes (T1D) incidence in an international cohort of children with familial and genetic risk for T1D.

METHODS

Anthropometric indices between birth to 5 yr of age were compared among regions and T1D proband in 2160 children participating in the Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk study.

RESULTS

Children in Northern Europe had the highest weight z-score between birth to 12 months of age, while those in Southern Europe and U.S.A. had the lowest weight and length/height z-scores at most time points (p < 0.005 to p < 0.001). Few differences in z-score values for weight, height, and body mass index were found by maternal T1D status. Using International Obesity Task Force criteria, the obesity rates generally increased with age and at 5 yr were highest in males in Northern Europe (6.0%) and in females in Canada (12.8%). However, no statistically significance difference was found by geographic region. In Canada, the obesity rate for female children of mothers with and without T1D differed significantly at 4 and 5 yr (6.0 vs. 0.0% and 21.3 vs. 1.9%, respectively; p < 0.0125) but no differences by maternal T1D status were found in other regions.

CONCLUSIONS

There are regional differences in early childhood growth that are consistent with the higher incidence of T1D in Northern Europe and Canada as compared to Southern Europe. Our prospective study from birth will allow evaluation of relationships between growth and the emerging development of autoimmunity and progression to T1D by region in this at-risk population of children.

Expansion of CD4+CD25+FOXP3+ regulatory T cells in infants of mothers with type 1 diabetes

BACKGROUND

Reduced risk for type 1 diabetes (T1D) has been reported in the offspring of mothers with T1D when compared with children of affected fathers.

OBJECTIVE

To evaluate the hypothesis that exposure of the offspring to maternal insulin therapy induces regulatory mechanisms in utero, we compared the FOXP3 expressing regulatory T cells in cord blood (CB) of infants born to mothers with or without T1D.

SUBJECTS AND METHODS

Cord blood mononuclear cells (CBMCs) from 20 infants with maternal T1D and from 20 infants with an unaffected mother were analyzed for the numbers of CD4+CD25+FOXP3+ cells ex vivo and after in vitro stimulation with human insulin by flow cytometry. The mRNA expression of FOXP3, NFATc2, STIM1, interleukin (IL)-10, and transforming growth factor (TGF)-β was measured by real-time reverse transcription polymerase chain reaction.

RESULTS

The percentage of FOXP3+ cells in CD4+CD25(high) cells was higher in the CB of the infants with maternal T1D when compared with the infants of unaffected mothers (p = 0.023). After in vitro insulin stimulation an increase in the percentage of FOXP3+ cells in CD4+CD25(high) cells (p = 0.0002) as well as upregulation of FOXP3, NFATc2, STIM1, IL-10, and TGF-β transcripts in CBMCs (p < 0.013 for all; Wilcoxon test) was observed only in the offspring of mothers with T1D, in whom the disease-related PTPN22 allele was associated with reduced STIM1 and NFATc2 response in insulin-stimulated CBMCs (p = 0.007 and p = 0.014).

CONCLUSIONS

We suggest that maternal insulin treatment induces expansion of regulatory T cells in the fetus, which might contribute to the lower risk of diabetes in children with maternal vs. paternal diabetes.

Early feeding and risk of type 1 diabetes: experiences from the Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR)

Short-term breastfeeding and early exposure to complex dietary proteins, such as cow milk proteins and cereals, or to fruit, berries, and roots have been implicated as risk factors for β cell autoimmunity, clinical type 1 diabetes, or both. The Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR) is an international, randomized, double-blind, controlled intervention trial designed to answer the question of whether weaning to an extensively hydrolyzed formula in infancy will decrease the risk of type 1 diabetes later in childhood. In our pilot study, weaning to a highly hydrolyzed formula decreased by ≈ 50% the cumulative incidence of one or more diabetes-associated autoantibodies by a mean age of 4.7 y. This finding was confirmed in a recent follow-up analysis to 10 y of age. Currently, the full-scale TRIGR takes place in 77 centers in 15 countries. The TRIGR initially recruited 5606 newborn infants with a family member affected by type 1 diabetes and enrolled 2159 eligible subjects who carried a risk-conferring HLA genotype. All recruited mothers were encouraged to breastfeed. The intervention lasted for 6-8 mo with a minimum study formula exposure time of 2 mo, and hydrolyzed casein and standard cow milk-based weaning formulas were compared. Eighty percent of the participants were exposed to the study formula. The overall retention rate over the first 5 y was 87%, and protocol compliance was 94%. The randomization code will be opened when the last recruited child turns 10 y of age (ie, in 2017).

Immune intervention for type 1 diabetes mellitus

The major form of type 1 diabetes (T1D) is characterised by immune-mediated pancreatic islet β-cell destruction, and has also been called type 1A diabetes to distinguish it from idiopathic forms of islet β-cell loss. Since the first demonstration of islet cell antibodies in 1974, the concept has been that this form of diabetes is autoimmune in nature. The commonly accepted concept is that antibodies (representing the humoral arm of the immune system) do not mediate the β-cell destruction but rather serve as markers of that destruction, while the cellular arm of the immune system, specifically T-lymphocytes, mediate the β-cell destruction. Yet, the T-lymphocytes do not act alone. They receive help in initiating the response from antigen-presenting cells such as dendritic cells and macrophages, and appear to receive help also from B-lymphocytes. In addition, the initial immune response engenders secondary and tertiary responses - involving the whole immunological army - which collectively result in impairment of β-cell function, progressive destruction of β-cells, and consequent development of type 1A diabetes. The process is insidious and may evolve over many years, with the overt expression of clinical symptoms becoming apparent only when most β-cells have been destroyed. Yet, the process clearly evolves at different speeds - much more rapidly in young children, much more slowly in older individuals. And, although it has been thought that ultimately there is complete β-cell destruction, several studies have now demonstrated some degree of persistent β-cell function or existence (at autopsy) in long-standing T1D. A major focus of investigation in T1D is the preservation of β-cell function (and, it is hoped, of β-cells themselves), in the expectation that continuing endogenous insulin secretion will contribute towards better glycaemic control, reduce episodes of severe hypoglycaemia, and slow the development of complications such as retinopathy and nephropathy. Thus, there have been many studies designed to interdict the T1D disease process, mostly by altering the immune system, both during the stage of evolution of the disease and at the time of disease onset. This chapter of the Yearbook of Advanced Technology and Treatments in Diabetes reviews the key papers that have appeared in this field between July 2009 and June 2010. Articles selected were confined to studies in human beings. All immune intervention studies reported in this time frame were included. In addition, the author selected other relevant articles dealing with mechanisms, markers, triggers, and pathology of human type 1 diabetes.

Prevention of type 1 diabetes

Prevention of loss of b cells in type 1 diabetes is a major goal of current research. Knowledge of the genetic susceptibility, increasing ability to predict who may be at risk, recognition of the potential clinical impact of residual insulin secretion after diagnosis, and development of new immunomodulatory agents have supported an increasing number of clinical trials to prevent b-cell loss. Interventions can be targeted at 3 stages: before the development of autoimmunity (primary prevention), after autoimmunity is recognized (secondary prevention), or after diagnosis when significant numbers of b cells remain (tertiary prevention). Thus far, several agents show promise when given shortly after diagnosis, but no interventions before diagnosis have shown benefit. Knowledge in this area has grown quickly in recent years and will continue to grow rapidly with several international collaborative efforts underway.

The Trial to Reduce IDDM in the Genetically at Risk (TRIGR) study: recruitment, intervention and follow-up

AIMS/HYPOTHESIS

The Trial to Reduce IDDM in the Genetically at Risk (TRIGR) study was designed to establish whether weaning to a highly hydrolysed formula in infancy subsequently reduces the risk of type 1 diabetes.

METHODS

The study population comprises newborn infants who have first-degree relatives with type 1 diabetes and meet the increased risk HLA inclusion, but not exclusion criteria. The study is being performed in 15 countries in three continents. First-degree relatives of patients with type 1 diabetes were identified from diabetes clinics, diabetes registries, and from other endocrinology or obstetrics offices and websites. HLA typing was performed at birth from cord or heel stick blood, and the results sent to the study's Data Management Unit within 2 weeks for communication of eligibility to the clinical study centre. All mothers recruited were encouraged to breastfeed. The intervention lasted for 6 to 8 months, and weaning formulas based on hydrolysed casein and standard cow's milk were compared.

RESULTS

TRIGR recruited 5,606 infants, of whom 2,160 were enrolled as eligible participants, 6% more than the target of 2,032. Of those enrolled, 80% were exposed to the study formula. The overall retention rate over the first 5 years is 87%, with protocol compliance at 94%. The randomisation code will be opened when the last recruited child turns 10 years of age, i.e. in 2017.

CONCLUSIONS/INTERPRETATION

The TRIGR experience demonstrates the feasibility and successful implementation of an international dietary intervention study. TRIGR is the first ever primary prevention trial for type 1 diabetes and, if completed successfully, will provide a definite answer to the research question.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777

FUNDING

The study was funded by the National Institute of Child Health and Development (NICHD) and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH) (grant numbers HD040364, HD042444 and HD051997), Canadian Institutes of Health Research, the Juvenile Diabetes Research Foundation International and the Commission of the European Communities (specific RTD programme 'Quality of Life and Management of Living Resources', contract number QLK1-2002-00372 'Diabetes Prevention'. Other funding came from the EFSD/JDRF/Novo Nordisk Focused Research Grant, Academy of Finland, Dutch Diabetes Research Foundation and Finnish Diabetes Research Foundation).

Prediction and prevention of Type 1 diabetes mellitus

Type 1A diabetes mellitus (T1DM) is caused by autoimmune islet β-cell destruction with consequent severe insulin deficiency. We can now predict the development of T1DM by determining four biochemically characterized islet autoantibodies, namely those antibodies against insulin, glutamic acid decarboxylase 65, insulinoma antigen (IA)-2 (ICA512) and the zinc transporter ZnT8. We can also prevent T1DM in animal models, but the final goal is the prevention of T1DM in humans. Multiple clinical trials are underway investigating methods to prevent β-cell destruction.

Rapid increase in the incidence of type 1 diabetes in Polish children from 1989 to 2004, and predictions for 2010 to 2025

AIMS/HYPOTHESIS

We analysed the temporal changes in the incidence of childhood type 1 diabetes and its demographic determinants in Poland from 1989 to 2004, validating the model with data from 1970 to 1989. We also estimated a predictive model of the trends in childhood diabetes incidence for the near future.

METHODS

Children under 15 years with newly diagnosed type 1 diabetes mellitus and drawn from seven regional registries in Poland were ascertained prospectively using the Epidemiology and Prevention of Diabetes study (EURODIAB) criteria. The type 1 diabetes incidence rates (IRs) were analysed in dependency of age, sex, seasonality, geographical region and population density. Time trends in IR were modelled using several approaches.

RESULTS

The average incidence, standardised by age and sex, for 1989 to 2004 was 10.2 per 100,000 persons per year and increased from 5.4 to 17.7. No difference was found between boys and girls, or between urban and rural regions. In children above 4 years, IR was significantly higher in the population of northern Poland than in that of the country's southern part, as well as in the autumn-winter season, this finding being independent of child sex. Based on the trend model obtained, almost 1,600 Polish children aged 0 to 14 years are expected to develop type 1 diabetes in 2010, rising to more than 4,800 in 2025. The estimates suggest at least a fourfold increase of IR between 2005 and 2025, with the highest dynamics of this increment in younger children.

CONCLUSIONS/INTERPRETATION

These estimates show that Poland will have to face a twofold higher increase in childhood type 1 diabetes than predicted for the whole European population. The dramatic increase could have real downstream effects on Poland's healthcare system.

The changing epidemiology of type 1 diabetes: why is it going through the roof?

The incidence of type 1 diabetes is increasing and this may double the burden of disease in our youngest by 2020. The recent increase in incidence is mostly happening in the very young and those with moderate genetic susceptibility. Many environmental factors have been implicated, but no major determinants have been clearly identified, and the mechanisms of involvement remain elusive. This review summarizes current research efforts directed at understanding the possible reasons for this increase, including the role of viruses, gut microbiota, early life feeding patterns, perinatal factors and childhood growth patterns. It also provides a road map for future research directions.

Type 1 Diabetes: Etiology, Immunology, and Therapeutic Strategies

Type 1 diabetes (T1D) is a chronic autoimmune disease in which destruction or damaging of the beta-cells in the islets of Langerhans results in insulin deficiency and hyperglycemia. We only know for sure that autoimmunity is the predominant effector mechanism of T1D, but may not be its primary cause. T1D precipitates in genetically susceptible individuals, very likely as a result of an environmental trigger. Current genetic data point towards the following genes as susceptibility genes: HLA, insulin, PTPN22, IL2Ra, and CTLA4. Epidemiological and other studies suggest a triggering role for enteroviruses, while other microorganisms might provide protection. Efficacious prevention of T1D will require detection of the earliest events in the process. So far, autoantibodies are most widely used as serum biomarker, but T-cell readouts and metabolome studies might strengthen and bring forward diagnosis. Current preventive clinical trials mostly focus on environmental triggers. Therapeutic trials test the efficacy of antigen-specific and antigen-nonspecific immune interventions, but also include restoration of the affected beta-cell mass by islet transplantation, neogenesis and regeneration, and combinations thereof. In this comprehensive review, we explain the genetic, environmental, and immunological data underlying the prevention and intervention strategies to constrain T1D.

Dietary intervention in infancy and later signs of beta-cell autoimmunity

BACKGROUND

Early exposure to complex dietary proteins may increase the risk of beta-cell autoimmunity and type 1 diabetes in children with genetic susceptibility. We tested the hypothesis that supplementing breast milk with highly hydrolyzed milk formula would decrease the cumulative incidence of diabetes-associated autoantibodies in such children.

METHODS

In this double-blind, randomized trial, we assigned 230 infants with HLA-conferred susceptibility to type 1 diabetes and at least one family member with type 1 diabetes to receive either a casein hydrolysate formula or a conventional, cow's-milk-based formula (control) whenever breast milk was not available during the first 6 to 8 months of life. Autoantibodies to insulin, glutamic acid decarboxylase (GAD), the insulinoma-associated 2 molecule (IA-2), and zinc transporter 8 were analyzed with the use of radiobinding assays, and islet-cell antibodies were analyzed with the use of immunofluorescence, during a median observation period of 10 years (mean, 7.5). The children were monitored for incident type 1 diabetes until they were 10 years of age.

RESULTS

The unadjusted hazard ratio for positivity for one or more autoantibodies in the casein hydrolysate group, as compared with the control group, was 0.54 (95% confidence interval [CI], 0.29 to 0.95), and the hazard ratio adjusted for an observed difference in the duration of exposure to the study formula was 0.51 (95% CI, 0.28 to 0.91). The unadjusted hazard ratio for positivity for two or more autoantibodies was 0.52 (95% CI, 0.21 to 1.17), and the adjusted hazard ratio was 0.47 (95% CI, 0.19 to 1.07). The rate of reported adverse events was similar in the two groups.

CONCLUSIONS

Dietary intervention during infancy appears to have a long-lasting effect on markers of beta-cell autoimmunity--markers that may reflect an autoimmune process leading to type 1 diabetes. (ClinicalTrials.gov number, NCT00570102.).

Novel gene associations in type 1 diabetes

Recent genome-wide association studies have been able to identify multiple new gene loci affecting type 1 diabetes susceptibility, but the impact of these new defined loci seems to decrease in parallel with their number. The HLA gene region remains the main nominator of genetic susceptibility, although the identity of important genes and especially the mechanisms of their action are still largely unclear. Products of HLA and most other known risk genes are involved in regulation of the immune system in accordance with the autoimmune nature of the disease. The multitude of genes involved in the pathogenesis implies complex pathways where multiple steps in each may be essential in turning the balance of immune response to beta-cell destructing autoimmunity.

Efforts to prevent and halt autoimmune beta cell destruction

Despite improvements in understanding of the natural history of type 1 diabetes (T1D), an intervention capable of consistently and safely preventing or reversing the disease has not been developed. The inability to cure this disorder is largely because of the complex pathophysiology of T1D, continued struggles to identify its precise etiologic triggers, and voids in understanding of the immunologic mechanisms that specifically target pancreatic beta cells. Rapidly improving technologies for managing T1D require critical discussions about equipoise, especially when considering interventions deemed high risk in terms of their safety. This article reviews the conceptual basis for prevention versus intervention trials in settings of T1D, past experiences of clinical trials studying these purposes, and controversial issues regarding disease interdiction, and seeks to provide a roadmap for future efforts to cure this disorder.

Designing and implementing sample and data collection for an international genetics study: the Type 1 Diabetes Genetics Consortium (T1DGC)

BACKGROUND AND PURPOSE

The Type 1 Diabetes Genetics Consortium (T1DGC) is an international project whose primary aims are to: (a) discover genes that modify type 1 diabetes risk; and (b) expand upon the existing genetic resources for type 1 diabetes research. The initial goal was to collect 2500 affected sibling pair (ASP) families worldwide.

METHODS

T1DGC was organized into four regional networks (Asia-Pacific, Europe, North America, and the United Kingdom) and a Coordinating Center. A Steering Committee, with representatives from each network, the Coordinating Center, and the funding organizations, was responsible for T1DGC operations. The Coordinating Center, with regional network representatives, developed study documents and data systems. Each network established laboratories for: DNA extraction and cell line production; human leukocyte antigen genotyping; and autoantibody measurement. Samples were tracked from the point of collection, processed at network laboratories and stored for deposit at National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repositories. Phenotypic data were collected and entered into the study database maintained by the Coordinating Center.

RESULTS

T1DGC achieved its original ASP recruitment goal. In response to research design changes, the T1DGC infrastructure also recruited trios, cases, and controls. Results of genetic analyses have identified many novel regions that affect susceptibility to type 1 diabetes. T1DGC created a resource of data and samples that is accessible to the research community.

LIMITATIONS

Participation in T1DGC was declined by some countries due to study requirements for the processing of samples at network laboratories and/or final deposition of samples in NIDDK Central Repositories. Re-contact of participants was not included in informed consent templates, preventing collection of additional samples for functional studies.

CONCLUSIONS

T1DGC implemented a distributed, regional network structure to reach ASP recruitment targets. The infrastructure proved robust and flexible enough to accommodate additional recruitment. T1DGC has established significant resources that provide a basis for future discovery in the study of type 1 diabetes genetics.

Revisiting infant growth prior to childhood onset type 1 diabetes

OBJECTIVE

Accelerated early growth prior to childhood type 1 diabetes onset is associated with an increased risk for type 1 diabetes (T1D). We aimed to study early growth, correcting for the previously neglected confounder of familial effects.

DESIGN

Infant growth was studied in a retrospective family case-control study of diabetic children in which siblings acted as matched familial controls allowing correction for confounders related to family particulars.

PATIENTS

Weight and height data were collected from 213 juvenile onset type 1 diabetic children and their 255 healthy siblings. Growth in the first 4 years of life was studied using repeated measurement. The degree of early overgrowth was correlated with age of clinical onset.

RESULTS

Birth weight and length did not differ between later diabetic children and their siblings. In the first year of life, weight standard deviation score (SDS) differed between patients and sibs (P = 0.0001). After the first year, both diabetic children and sibs showed parallel enhanced weight and height gain SDS until age 4 years. Earlier onset diabetes was associated with a higher weight SDS at 6 months of age.

CONCLUSION

In this family case-control study the association of increased growth with development of T1D is limited to the first year of life implying that increased growth beyond the first year can be attributed to familial growth patterns, rather than predisposition to T1D per se. Age at disease onset correlated with increased weight in the first 6 months of life, indicating importance of features very early in life on later development of T1D.

Breastfeeding patterns of mothers with type 1 diabetes: results from an infant feeding trial

BACKGROUND

Both the initiation and maintenance of breastfeeding have been reported to be negatively affected by maternal type 1 diabetes (T1D). The aim of this study was to prospectively examine the breastfeeding patterns among mothers with and without T1D participating in a large international randomized infant feeding trial (TRIGR).

METHODS

Families with a member affected by T1D and with a newborn infant were invited into the study. Those who had HLA-conferred genetic susceptibility for T1D tested at birth with gestation > 35 weeks and were healthy were eligible to continue in the trial. Among the 2160 participating children, 1096 were born to women with T1D and 1064 to unaffected women. Information on infant feeding was acquired from the family by frequent prospective dietary interviews.

RESULTS

Most (>90%) of the infants of mothers with and without T1D were initially breastfed. Breastfeeding rates declined more steeply among mothers with than without T1D being 50 and 72% at 6 months, respectively. Mothers with T1D were younger, less educated and delivered earlier and more often by caesarean section than other mothers (p < 0.01). After adjusting for all these factors associated with the termination of breastfeeding, there was no difference in the duration of breastfeeding among mothers with and without T1D.

CONCLUSIONS

Maternal diabetes status per se was not associated with shorter breastfeeding. The lower duration of breastfeeding in mothers with T1D is largely explained by their more frequent caesarean sections, earlier delivery and lower age and education.

Epidemiology of type 1 diabetes among Silesian children aged 0-14 years, 1989-2005

The aim of this study was to estimate the present Polish incidence rate of diabetes mellitus type 1 in children aged 0-14. The research was conducted between 1989 and 2005 among the children of Upper Silesia region (Poland), being the part of the EURODIAB program, according to all criteria of this project. During this period, 1,385 new cases (720 boys) of diabetes mellitus type 1 were recognized. The analysis of the standardized incidence rates performed after dividing into shorter periods (1989-1994, 1995-1999, 2000-2005) showed a sharp increase from 5.80/10(5)/year through 9.54/10(5)/year to 15.26/10(5)/year, respectively, in the periods. Analysis of age subgroups showed the greatest increase in the incidence rate among the younger children: 3.59 times for children aged 0-4, 3.40 times for children aged 5-9 and 2.08 times for children aged 10-14. No significant difference of incidence rate between boys and girls was established. Such high increase of incidence rate of diabetes mellitus type 1 (above 260%) noted since 1989 shows a secular trend of an epidemic of diabetes mellitus type 1 in Poland and a conversion from countries with the lower incidence rates in Europe to the countries with the highest incidence rates.

Prevention of beta-cell destruction in autoimmune diabetes: current approaches and future prospects

Type 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of pancreatic beta-cells. The main aim of treatment should be to prevent beta-cell destruction and preserve existing beta-cells in individuals with progressive autoimmunity. This can be achieved in several ways and in this chapter the authors have reviewed recent approaches that are currently being tested in animal models and human T1D patients under the following categories: i) antigen based therapy, ii) antibody-based therapy iii) other forms of therapy and iv) failed therapies.

Prevention of type 1 diabetes

Prevention of loss of beta cells in type 1 diabetes is a major goal of current research. Knowledge of the genetic susceptibility, increasing ability to predict who may be at risk, recognition of the potential clinical impact of residual insulin secretion after diagnosis, and development of new immunomodulatory agents have supported an increasing number of clinical trials to prevent beta-cell loss. Interventions can be targeted at 3 stages: before the development of autoimmunity (primary prevention), after autoimmunity is recognized (secondary prevention), or after diagnosis when significant numbers of beta cells remain (tertiary prevention). Thus far, several agents show promise when given shortly after diagnosis, but no interventions before diagnosis have shown benefit. Knowledge in this area has grown quickly in recent years and will continue to grow rapidly with several international collaborative efforts underway.

Strategies to prevent type 1 diabetes

Type 1 diabetes is a chronic autoimmune condition resulting from T cell-mediated destruction of the insulin-producing cells in the islets of Langerhans. Its primary cause remains unknown, but it has been established that the clinical presentation is preceded by a long prodrome. This enables individuals at high risk of disease to be identified and offers the possibility of intervention to prevent clinical disease. Many groups are working in this field, concentrating on manipulation of environmental exposures that are potential triggers of autoimmunity and on immunomodulation strategies that aim to prevent destruction of beta-cells. Some interventions have shown promising results in early trials, but effective disease prevention remains elusive. This article reviews current progress in the field.

The road not taken: a path to curing type 1 diabetes?

The past quarter century has seen a rapid increase in our knowledge about the natural history of autoimmune type 1 diabetes. However, we stand unable to achieve our ultimate goal of preventing or reversing this disease. This viewpoint discusses controversies in current management of type 1 diabetes, the challenges in translating promising studies from mouse models of the disease to humans, hurdles faced in designing optimal prevention and intervention studies, and potential strategies to overcome these obstacles.

Breast-feeding: A commentary by the ESPGHAN Committee on Nutrition

This medical position article by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition summarises the current status of breast-feeding practice, the present knowledge on the composition of human milk, advisable duration of exclusive and partial breast-feeding, growth of the breast-fed infant, health benefits associated with breast-feeding, nutritional supplementation for breast-fed infants, and contraindications to breast-feeding. This article emphasises the important role of paediatricians in the implementation of health policies devised to promote breast-feeding.The European Society for Paediatric Gastroenterology, Hepatology, and Nutrition Committee on Nutrition recognises breast-feeding as the natural and advisable way of supporting the healthy growth and development of young children. This article delineates the health benefits of breast-feeding, reduced risk of infectious diarrhoea and acute otitis media being the best documented. Exclusive breast-feeding for around 6 months is a desirable goal, but partial breast-feeding as well as breast-feeding for shorter periods of time are also valuable. Continuation of breast-feeding after the introduction of complementary feeding is encouraged as long as mutually desired by mother and child.The role of health care workers, including paediatricians, is to protect, promote, and support breast-feeding. Health care workers should be trained in breast-feeding issues and counselling, and they should encourage practices that do not undermine breast-feeding. Societal standards and legal regulations that facilitate breast-feeding should be promoted, such as providing maternity leave for at least 6 months and protecting working mothers.

The TrialNet Natural History Study of the Development of Type 1 Diabetes: objectives, design, and initial results

OBJECTIVES

TrialNet's goal to test preventions for type 1 diabetes has created an opportunity to gain new insights into the natural history of pre-type 1 diabetes. The TrialNet Natural History Study (NHS) will assess the predictive value of existing and novel risk markers for type 1 diabetes and will find subjects for prevention trials.

RESEARCH DESIGN AND METHODS

The NHS is a three-phase, prospective cohort study. In phase 1 (screening), pancreatic autoantibodies (glutamic acid decarboxylase, insulin, ICA-512, and islet cell antibodies) are measured. Phase 2 (baseline risk assessment) includes oral glucose tolerance tests (OGTTs) in antibody-positive subjects and estimation of 5-yr diabetes risks according to the OGTT and number of confirmed positive antibody tests. Phase 3 (follow-up risk assessments) requires OGTTs every 6 months. In phases 2 and 3, samples are collected for future tests of T-lymphocyte function, autoantibody isotypes, RNA gene expression, and proteomics. The primary outcome is diabetes onset.

RESULTS

Of 12 636 relatives screened between March 2004 and December 2006, 605 (4.8%) were positive for at least one biochemical antibody. Of these, 322 were confirmed antibody positive and completed phase 2, of whom 296 subjects were given preliminary 5-yr diabetes risks of <25% (n = 132), > or =25% (n = 36), and > or =50% (n = 128) where the latter two categories represent different subjects based on number of confirmed positive antibodies (2, > or =25%; 3 or more, > or =50%) and/or an abnormal OGTT (> or =50%).

CONCLUSIONS

The NHS is identifying potential prevention trial subjects and is assembling a large cohort that will provide new natural history information about pre-type 1 diabetes. Follow-up to diabetes will help establish the biological significance and clinical value of novel type 1 diabetes risk markers.

Type 1 diabetes mellitus: primary, secondary, and tertiary prevention

We have entered the era of clinical trials to prevent type 1 diabetes mellitus (T1DM). Before 1922, when insulin was first given to a patient with diabetes, a diagnosis of T1DM was considered a death sentence. Advances in treatment for subjects with diabetes are not yet sufficient to prevent the deleterious impact of diabetes on both day-to-day activities and the early morbidity and mortality still associated with the disease. We now understand a great deal about blood glucose regulation and potential health complications associated with long-term T1DM, but the mystery of why, or the pathogenesis of this devastating disease, remains elusive. Great strides toward unraveling this mystery have been made over the past several decades. Even without definitive answers, we are moving from the period of discovery and animal research to the era of clinical trials. In this review, we wish to convey the palpable excitement in the field. It is time to determine if we can safely change the course of T1DM.

Update on worldwide efforts to prevent type 1 diabetes

This paper reviews worldwide efforts to interdict the type 1 diabetes (T1D) disease process, during the stage of evolution of the disease prior to the time of disease onset. The goal of intervention before disease onset is to arrest immune destruction and thus prevent or delay clinical disease. In this regard, there have been several large-scale multicenter randomized controlled clinical trials designed to prevent T1D. These have tested nicotinamide, parenteral insulin, oral insulin, nasal insulin, and the elimination of cow's milk from infant feeding.