Lack of association between early exposure to cow's milk protein and beta-cell autoimmunity. Diabetes Autoimmunity Study in the Young (DAISY)

Associations of breastfeeding with childhood autoimmunity, allergies, and overweight: The Environmental Determinants of Diabetes in the Young (TEDDY) study

BACKGROUND

Breastfeeding has beneficial effects on numerous health outcomes.

OBJECTIVES

We investigated whether breastfeeding duration is associated with the development of early childhood autoimmunity, allergies, or obesity in a multinational prospective birth cohort.

METHODS

Infants with genetic susceptibility for type 1 diabetes (n = 8676) were followed for the development of autoantibodies to islet autoantigens or transglutaminase, allergies, and for anthropometric measurements to a median age of 8.3 y (IQR: 2.8-10.2 y). Information on breastfeeding was collected at 3 mo of age and prospectively thereafter. A propensity score for longer breastfeeding was calculated from the variables that were likely to influence any or exclusive breastfeeding. The risks of developing autoimmunity or allergy were assessed using Cox proportional hazards models, and the risk of obesity at 5.5 y of age was assessed using logistic regression with adjustment by the propensity score.

RESULTS

Breastfeeding duration was not associated with a lower risk of either islet or transglutaminase autoimmunity (any breastfeeding >6 mo, adjusted HR: 1.07; 95% CI: 0.96, 1.19; exclusive breastfeeding >3 mo, adjusted HR: 1.03; 95% CI: 0.92, 1.15). Exclusive breastfeeding >3 mo was associated with a decreased risk of seasonal allergic rhinitis (adjusted HR: 0.70; 95% CI: 0.53, 0.92; P < 0.01). Any breastfeeding >6 mo and exclusive breastfeeding >3 mo were associated with decreased risk of obesity (adjusted OR: 0.62; 95% CI: 0.47, 0.81; P < 0.001; and adjusted OR: 0.68; 95% CI: 0.47, 0.95; P < 0.05, respectively).

CONCLUSIONS

Longer breastfeeding was not associated with a lower risk of childhood (islet or transglutaminase) autoimmunity in genetically at-risk children but was associated with decreased risk of seasonal allergic rhinitis and obesity at 5.5 y of age.

Current understandings of the pathogenesis of type 1 diabetes: Genetics to environment

Type 1 diabetes (T1D) is an autoimmune disease that usually strikes early in life, but can affect individuals at almost any age. It is caused by autoreactive T cells that destroy insulin-producing beta cells in the pancreas. Epidemiological studies estimate a prevalence of 1 in 300 children in the United States with an increasing incidence of 2%-5% annually worldwide. The daily responsibility, clinical management, and vigilance required to maintain blood sugar levels within normal range and avoid acute complications (hypoglycemic episodes and diabetic ketoacidosis) and long term micro- and macro-vascular complications significantly affects quality of life and public health care costs. Given the expansive impact of T1D, research work has accelerated and T1D has been intensively investigated with the focus to better understand, manage and cure this condition. Many advances have been made in the past decades in this regard, but key questions remain as to why certain people develop T1D, but not others, with the glaring example of discordant disease incidence among monozygotic twins. In this review, we discuss the field’s current understanding of its pathophysiology and the role of genetics and environment on the development of T1D. We examine the potential implications of these findings with an emphasis on T1D inheritance patterns, twin studies, and disease prevention. Through a better understanding of this process, interventions can be developed to prevent or halt it at early stages.

Characteristics of slow progression to diabetes in multiple islet autoantibody-positive individuals from five longitudinal cohorts: the SNAIL study

AIMS/HYPOTHESIS

Multiple islet autoimmunity increases risk of diabetes, but not all individuals positive for two or more islet autoantibodies progress to disease within a decade. Major islet autoantibodies recognise insulin (IAA), GAD (GADA), islet antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A). Here we describe the baseline characteristics of a unique cohort of 'slow progressors' (n = 132) who were positive for multiple islet autoantibodies (IAA, GADA, IA-2A or ZnT8A) but did not progress to diabetes within 10 years.

METHODS

Individuals were identified from five studies (BABYDIAB, Germany; Diabetes Autoimmunity Study in the Young [DAISY], USA; All Babies in Southeast Sweden [ABIS], Sweden; Bart's Oxford Family Study [BOX], UK and the Pittsburgh Family Study, USA). Multiple islet autoantibody characteristics were determined using harmonised assays where possible. HLA class II risk was compared between slow progressors and rapid progressors (n = 348 diagnosed <5 years old from BOX) using the χ² test.

RESULTS

In the first available samples with detectable multiple antibodies, the most frequent autoantibodies were GADA (92%), followed by ZnT8A (62%), IAA (59%) and IA-2A (41%). High risk HLA class II genotypes were less frequent in slow (28%) than rapid progressors (42%, p = 0.011), but only two slow progressors carried the protective HLA DQ6 allele.

CONCLUSION

No distinguishing characteristics of slow progressors at first detection of multiple antibodies have yet been identified. Continued investigation of these individuals may provide insights into slow progression that will inform future efforts to slow or prevent progression to clinical diabetes.

Genetics of type 1 diabetes

Type 1 diabetes (T1D) results from immune-mediated loss of pancreatic beta cells leading to insulin deficiency. It is the most common form of diabetes in children, and its incidence is on the rise. This article reviews the current knowledge on the genetics of T1D. In particular, we discuss the influence of HLA and non-HLA genes on T1D risk and disease progression through the preclinical stages of the disease, and the development of genetic scores that can be applied to disease prediction. Racial/ethnic differences, challenges and future directions in the genetics of T1D are also discussed.

The microbiome and autoimmune disease: Report from a Noel R. Rose Colloquium

Although the mechanisms by which the human microbiome influences the onset and progression of autoimmune diseases remain to be determined, established animal models of autoimmune diseases indicate that local and systemic bidirectional interactions with the microbiome play a signaling or promoting role through the immune system. Whether alterations in the microbiome are a pathogenic cause or simply an effect of inflammation and autoimmune disease remains an essential question to be addressed in disease-specific research, as well as whether particular conditions of the microbiome promote health or promote disease. Future research in this area needs to account for sex differences in microbiome composition because autoimmune diseases disproportionately affect women. Probiotic and other treatments that manipulate assemblage of the microbiome may offer methods of preventing or mitigating the effects of autoimmune disease.

Role of nutritional factors at the early life stages in the pathogenesis and clinical course of type 1 diabetes

Nutrition has been suggested as an important environmental factor other than viruses and chemicals in the pathogenesis of type 1 diabetes (T1D). Whereas various maternal dietary nutritional elements have been suggested and examined in T1D of both humans and experimental animals, the results largely remain controversial. In a series of studies using T1D model nonobese diabetic (NOD) mice, maternal dietary n-6/n-3 essential fatty acid ratio during pregnancy and lactation period, that is, early life stages of the offspring, has been shown to affect pathogenesis of insulitis and strongly prevent overt T1D of the offspring, which is consistent with its preventive effects on other allergic diseases.

The role of Toll-like receptors and vitamin D in diabetes mellitus type 1--a review

It is widely accepted that type 1 diabetes mellitus (T1DM) is an autoimmune disease resulting from an interaction between immunologic, genetic and environmental factors. However, the exact mechanism leading to the development of T1DM remains incomplete. There is a large body of evidence pointing towards the important role of toll-like receptor (TLR) activation and vitamin D deficiency in T1DM pathogenesis. In this article, we review the available data on the influence of TLRs' level of activation and vitamin D status on the risk of the development of T1DM in humans and rodent models. We also summarize the current information regarding the interactions between TLRs' level of activation, vitamin D status and various environmental factors, such as enteroviral infections, the gut microbiota and breastfeeding substitution, among others. Our results stipulate that vitamin D seems to protect against T1DM by reducing the TLRs' level of activation.

The next big idea

George S. Eisenbarth will remain in our memories as a brilliant scientist and great collaborator. His quest to discover the cause and prevention of type 1 (autoimmune) diabetes started from building predictive models based on immunogenetic markers. Despite his tremendous contributions to our understanding of the natural history of pre-type 1 diabetes and potential mechanisms, George left us with several big questions to answer before his quest is completed.

The association between IgG4 antibodies to dietary factors, islet autoimmunity and type 1 diabetes: the Diabetes Autoimmunity Study in the Young

Background

Infant dietary exposures have been linked to type 1 diabetes (T1D) development. IgG4 antibody responses to food antigens are associated with food intolerances but have not been explored prospectively in the period preceding T1D.

Methods

Using a case-cohort design, IgG4 antibodies to ß-lactoglobulin, gluten, and ovalbumin were measured in plasma collected annually from 260 DAISY participants. Of those, 77 developed islet autoimmunity (IA), defined as positive for either insulin, GAD65 or IA-2 autoantibodies on two consecutive visits, and 22 developed T1D.

Results

In mixed model analysis adjusting for HLA-DR status, T1D family history, age and ethnicity, higher ß-lactoglobulin IgG4 concentrations were associated with shorter breastfeeding duration (beta = −0.03, 95% Confidence Interval: −0.05, −0.006) and earlier first cow’s milk exposure (beta = −0.04, 95% Confidence Interval: −0.08, 0.00). Higher gluten IgG4 was associated with older age at gluten introduction (beta = 0.06, 95% Confidence Interval: 0.00, 0.13). In proportional hazards analysis adjusting for HLA-DR status, T1D family history and ethnicity, IgG4 against individual or multiple dietary antigens throughout childhood were not associated with IA. In addition, mean antigen-specific IgG4 concentrations in infancy (age <2 years) were not associated with risk of IA nor progression to T1D. Higher ovalbumin IgG4 at first IA positive visit was marginally associated with progression to T1D (Hazard Ratio: 1.39, 95% Confidence Interval: 1.00, 1.92).

Conclusion

We found no association between the IgG4 response to β-lactoglobulin, gluten, and the development of either IA or T1D. The association between higher ovalbumin and progression to T1D in children with IA should be explored in other populations.

The environment and the origins of islet autoimmunity and Type 1 diabetes

Type 1 diabetes involves the specific destruction of the pancreatic islet β-cells, eventually resulting in a complete dependency of exogenous insulin. The clinical onset of diabetes is preceded by the appearance of autoantibodies against β-cell antigens. The human leukocyte antigen (HLA) region is the single most important genetic determinant of Type 1 diabetes susceptibility, yet variability in the HLA region has been estimated to explain only approximately 60% of the genetic influence of the disease. Over 50 identified non-HLA genetic polymorphisms support the notion that genetics alone cannot explain Type 1 diabetes. Several lines of evidence indicate that environmental triggers may be integral in inducing the onset of islet autoimmunity in genetically susceptible individuals. The association between environmental factors and the clinical onset is complicated by observation that the rate of progression to clinical onset may be affected by environmental determinants. Hence, the environment may be aetiological as well as pathogenic. Putative inductive mechanisms include viral, microbial, diet-related, anthropometric and psychosocial factors. Ongoing observational cohort studies such as The Environmental Determinants of Diabetes in the Young (TEDDY) study aim to ascertain environmental determinants that may trigger islet autoimmunity and either speed up or slow down the progression to clinical onset in subjects with persistent islet autoimmunity.

The epidemiology of type 1 diabetes in children

Type 1 diabetes is one of the most common chronic diseases of childhood and adolescence. Multiple registries have assessed its epidemiology and have noted a steady increase in incidence of the disease. This article addresses the epidemiology of type 1 diabetes in children aged 0 to 19 years, by reviewing the available, current data from both US and international registries. The prevalence and incidence data by race, ethnicity, age of onset, sex, season of onset, and temporal trends of the disease are presented. Multiple risk factors have been implicated for the increasing incidence in type 1 diabetes, and these genetic and environmental risk factors are discussed.

The pathogenesis and natural history of type 1 diabetes

The purpose of this article is to provide an overview that summarizes much in the way of our current state of knowledge regarding the pathogenesis and natural history of type 1 diabetes in humans. This information is presented to the reader as a series of seminal historical discoveries that, when advanced through research, transformed our understanding of the roles for the immune system, genes, and environment in the formation of this disease. In addition, where longitudinal investigations of these three facets occurred, their roles within the development of type 1 diabetes, from birth to symptomatic onset and beyond, are discussed, including their most controversial elements. Having an understanding of this disorder's pathogenesis and natural history is key for attempts seeking to understand the issues of what causes type 1 diabetes, as well as to develop a means to prevent and cure the disorder.

Interaction of enterovirus infection and cow's milk-based formula nutrition in type 1 diabetes-associated autoimmunity

BACKGROUND

Enteral virus infections and early introduction of cow's milk (CM)-based formula are among the suggested triggers of type 1 diabetes (T1D)-associated autoimmunity, although studies on their role have remained contradictory. Here, we aimed to analyse whether interactions between these factors might clarify the controversies.

MATERIALS

The study population comprised 107 subjects developing positivity for at least two T1D-associated autoantibodies and 446 control subjects from the Finnish diabetes prediction and prevention cohort. Enterovirus, rotavirus, adenovirus, respiratory syncytial virus and bovine insulin-binding antibodies were analysed from prospective serum samples at 3-24 months of age. Data on infant cow's milk exposure were available for 472 subjects: 251 subjects were exposed to cow's milk before 3 months of age and 221 subjects later in infancy.

RESULTS

Signs of an enterovirus infection by 12 months of age were associated with the appearance of autoimmunity among children who were exposed to cow's milk before 3 months of age. Cox regression analysis revealed a combined effect of enterovirus infection and early cow's milk exposure for the development of ICA and any of the biochemically defined autoantibodies (p = 0.001), of IAA (p = 0.002), GADA (p = 0.001) and IA-2A (p = 0.013).

CONCLUSIONS

The effect of enterovirus infection on the appearance of T1D-associated autoimmunity seems to be modified by exposure to cow's milk in early infancy suggesting an interaction between these factors. Moreover, these results provide an explanation for the controversial findings obtained when analysing the effect of any single one of these factors on the appearance of T1D-associated autoimmunity.

Antibodies recognizing Mycobacterium avium paratuberculosis epitopes cross-react with the beta-cell antigen ZnT8 in Sardinian type 1 diabetic patients

The environmental factors at play in the pathogenesis of type 1 diabetes (T1D) remain enigmatic. Mycobacterium avium subspecies paratuberculosis (MAP) is transmitted from dairy herds to humans through food contamination. MAP causes an asymptomatic infection that is highly prevalent in Sardinian T1D patients compared with type 2 diabetes (T2D) and healthy controls. Moreover, MAP elicits humoral responses against several mycobacterial proteins. We asked whether antibodies (Abs) against one of these proteins, namely MAP3865c, which displays a sequence homology with the β-cell protein zinc transporter 8 (ZnT8) could be cross-reactive with ZnT8 epitopes. To this end, Ab responses against MAP3865c were analyzed in Sardinian T1D, T2D and healthy subjects using an enzymatic immunoassay. Abs against MAP3865c recognized two immunodominant transmembrane epitopes in 52-65% of T1D patients, but only in 5-7% of T2D and 3-5% of healthy controls. There was a linear correlation between titers of anti-MAP3865c and anti-ZnT8 Abs targeting these two homologous epitopes, and pre-incubation of sera with ZnT8 epitope peptides blocked binding to the corresponding MAP3865c peptides. These results demonstrate that Abs recognizing MAP3865c epitopes cross-react with ZnT8, possibly underlying a molecular mimicry mechanism, which may precipitate T1D in MAP-infected individuals.

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.

Demographic, breast-feeding, and nutritional trends among children with type 1 diabetes mellitus

BACKGROUND

The pathogenesis of type 1 diabetes mellitus (T1DM) requires a genetic predisposition to particular environmental triggers that may activate mechanisms leading to progressive loss of pancreatic beta cells.

AIMS

We tried to compare the impact of some demographic and environmental factors and breast-feeding on children (aged < 18 years) with recent onset diabetes mellitus (≤1 year) with that on age, sex, and socioeconomic status-matched controls.

MATERIAL AND METHODS

A total of 43 consecutive patients (male, 24, mean age ± SD = 12.58 ± 9.6 years) and equal number of controls without diabetes mellitus or dysglycemia were included in this hospital-based case-control study.

RESULTS AND CONCLUSIONS

A distinct peak in the incidence noted in the early adolescence with segregation in the winter months. Our patients did not differ significantly from the controls with regard to birth order, mode of delivery, parental age, parental education, dietary practices, breast-feeding, and migration in the family. Growth characteristics and nutritional status were also similar. A population study with more power will be better equipped to answer such queries.

Maternal dietary n-6/n-3 fatty acid ratio affects type 1 diabetes development in the offspring of non-obese diabetic mice

Environment factors, including maternal or infant dietary nutrition have been reported to have an influence on the pathogenesis of type 1 diabetes. In the present study, to investigate the effect of maternal or post-weaning offspring's nutrition, in particular the essential fatty acid ratio (n-6/n-3) on the development of type 1 diabetes, we prepared two kinds of chows with n-6/n-3 ratios of 3.0 (L) and 14.5 (H), and provided them to mothers of non-obese diabetic (NOD) mice during gestation and lactation and to the offspring after weaning. The n-6/n-3 ratios in breast milk and erythrocyte membrane of NOD offspring became nearly the same with that of the maternal diet at 2 weeks after birth. In the L chow-fed offspring from L chow-fed mother (LLL), levels of insulitis were higher than those in the H chow-fed offspring from H chow-fed mother (HHH) at 4 weeks of age, while the levels in the LLL offspring became lower than those in the HHH after 6 weeks. Early insulin autoantibody expressions were found from 2 to 6 weeks in the HHH offspring, but not in the LLL. The LLL offspring exhibited strong suppression of overt diabetes development in regard to the onset and accumulated incidence of diabetes compared to the HHH. The study with combined L and H chows during gestation, lactation in mother and in post-weaning offspring revealed that only the LLH chow significantly suppressed the development of diabetes with similar kinetics to LLL chow, although the other combinations may delay the onset of diabetes. The present findings suggest that n-6/n-3 ratio of the maternal diet during gestation and lactation rather than that of offspring after weaning strongly affects the development of overt diabetes in NOD mice.

Preclinical rheumatoid arthritis: identification, evaluation, and future directions for investigation

Rheumatoid arthritis (RA) likely develops in several phases, beginning with genetic risk, followed by asymptomatic autoimmunity, then finally, clinically apparent disease. Investigating the phases of disease that exist prior to the onset of symptoms (ie, the preclinical period of RA) will lead to understanding of the important relationships between genetic and environmental factors that may lead to disease, as well as allow for the development of predictive models for disease, and ultimately preventive strategies for RA.

Epidemiology of type 1 diabetes

This article describes the epidemiology of type 1 diabetes mellitus (T1D) around the world and across the lifespan. Epidemiologic patterns of T1D by demographic, geographic, biologic, cultural, and other factors in populations are presented to gain insight about the causes, natural history, risks, and complications of T1D. Data from large epidemiologic studies worldwide indicate that the incidence of T1D has been increasing by 2% to 5% worldwide and that the prevalence of T1D is approximately 1 in 300 in the United States by 18 years of age. Research on risk factors for T1D is an active area of research to identify genetic and environmental triggers that could potentially be targeted for intervention. Although significant advances have been made in the clinical care of T1D with resultant improvements in quality of life and clinical outcomes, much more needs to be done to improve care of, and ultimately find a cure for, T1D. Epidemiologic studies have an important ongoing role to investigate the complex causes, clinical care, prevention, and cure of T1D.

Metabolic imprinting, programming and epigenetics – a review of present priorities and future opportunities

Metabolic programming and metabolic imprinting describe early life events, which impact upon on later physiological outcomes. Despite the increasing numbers of papers and studies, the distinction between metabolic programming and metabolic imprinting remains confusing. The former can be defined as a dynamic process whose effects are dependent upon a critical window(s) while the latter can be more strictly associated with imprinting at the genomic level. The clinical end points associated with these phenomena can sometimes be mechanistically explicable in terms of gene expression mediated by epigenetics. The predictivity of outcomes depends on determining if there is causality or association in the context of both early dietary exposure and future health parameters. The use of biomarkers is a key aspect of determining the predictability of later outcome, and the strengths of particular types of biomarkers need to be determined. It has become clear that several important health endpoints are impacted upon by metabolic programming/imprinting. These include the link between perinatal nutrition, nutritional epigenetics and programming at an early developmental stage and its link to a range of future health risks such as CVD and diabetes. In some cases, the evidence base remains patchy and associative, while in others, a more direct causality between early nutrition and later health is clear. In addition, it is also essential to acknowledge the communication to consumers, industry, health care providers, policy-making bodies as well as to the scientific community. In this way, both programming and, eventually, reprogramming can become effective tools to improve health through dietary intervention at specific developmental points.

Interplay between PTPN22 C1858T polymorphism and cow's milk formula exposure in type 1 diabetes

Genetic heterogeneity may affect the analysis of risk factors associated with type 1 diabetes (T1D). We studied the effect of the INS -23A/T, PTPN22 1858C/T, and CTLA-4 +49A/G polymorphisms on the emergence of T1D-associated autoimmunity in children exposed to cow's milk (CM) based formula during early or late infancy. The study comprised of 156 children from the Finnish DIPP cohort who had developed >or= 2 types of autoantibodies (ICA, IAA, GADA or IA-2A) or clinical T1D and 563 control children. The PTPN22 1858T allele was associated with the appearance of the autoantibodies and clinical T1D among children exposed to CM formula before the age of 6 months (PTPN22: for all P <or= 0.001, Log Rank test), but not among children exposed later on. Cox regression analysis showed an interaction between early CM exposure and 1858T allele and enhanced appearance of ICA, IAA and IA-2A (for all P <or= 0.04). Our results imply that the PTPN22 polymorphism affects the development of T1D-associated autoimmunity only if children are exposed to CM formula during early infancy suggesting an interplay between genetic and environmental factors. This may provide an explanation for the contradictory findings on the significance of CM formula exposure in T1D.

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.

Environmental factors in the development of Type 1 diabetes

Environmental factors appear to play an important role in the pathogenesis of childhood-onset type 1 diabetes (T1D). The most important factors are thought to be infectious, dietary, perinatal, and psychosocial. Enteroviruses (especially Coxsackie B virus), breastfeeding, the early presence or lack of certain foods, birth weight, childhood over-nutrition, maternal islet autoimmunity, and negative stress events have been shown to be related to the prevalence of T1D. However, clear conclusions to date are limited because most studies lacked power to detect exposure/disease associations, were not prospective or long-term, did not start in infancy, had imprecise or infrequent exposure estimates, had confounding exposures, and failed to account for genetic susceptibility. In addition to the identification of specific antigenic triggers, several more general hypotheses, including the accelerator and hygiene hypotheses, are testable approaches worth pursuing.

Prevention strategies for type 1 diabetes

Type 1 diabetes (T1D) is a common chronic disease of childhood. Patients with T1D are at significant risk for developing serious health complications. Understanding of the genetics, environmental factors, and natural history of diabetes has lead to greater understanding of the etiology and epidemiology of T1D. Furthermore, technology has greatly improved glycemic control and reduction of complications. However, prevention of the development of diabetes remains elusive. This review article describes the past, current and upcoming strategies for diabetes prevention for patients at risk for developing autoimmunity, after antibody production, and patients with new onset diabetes.

The stages of type 1A diabetes

We can now predict the development of type 1 diabetes in man because it is a chronic autoimmune disorder with defined stages of disease. We can also readily prevent the disorder in animal models. A major goal is safe prevention in man, and for this we will almost certainly need a better understanding of pathogenesis, coupled with rigorous clinical trials.

Immunotherapeutic approaches to prevent, ameliorate, and cure type 1 diabetes

Type 1A diabetes (T1D) is caused by autoimmune islet beta cell destruction precipitated by environmental triggers in genetically predisposed individuals. Islet beta cells produce insulin and are the primary target of this autoimmune disorder. Insulin, glutamic acid decarboxylase, and insulinoma associated-2 autoantibodies (IAA, GAD65, and IA-2) are the autoantibodies that have been associated most clearly with the development of T1D. Despite our current ability to predict T1D using genetic markers and detecting islet autoantibodies, we have yet to find a safe way to prevent the disease. However, there are more than 100 different therapies that prevent T1D in the nonobese diabetic (NOD) mouse model or the BioBreeding (BB) rats. This paper reviews a few select therapeutic approaches that have been or are being evaluated as possibilities for the prevention, amelioration, or cure of T1D.

Allaitement maternel : les bénéfices pour la santé de l'enfant et de sa mère

Breast milk contains hormones, growth factors, cytokines, cells, etc., and offers many advantages over cow's milk or soy protein infant formulae. The composition of breast milk is influenced by gestational and postnatal age. Prevalence of breastfeeding in France is one of the lowest in Europe: in 2003, only 58% of infants were breastfed when leaving the maternity ward, for a median duration of 10 weeks. Breastfeeding allows normal growth until at least 6 months of age, and can be prolonged until the age of 2 years or more, provided that complementary feeding is started after 6 months. Breastfeeding is associated with slightly enhanced performance on tests of cognitive development. Exclusive breastfeeding for at least 3 months is associated with a lower incidence and severity of diarrhoea, otitis media and respiratory infection. Exclusive breastfeeding for at least 6 months is associated with a lower incidence of allergic disease in at-risk infants (infants with at least one first-degree relative presenting with allergy). Breastfeeding is also associated with a lower incidence of obesity during childhood and adolescence, as well as with a lower incidence of hypertension and hypercholesterolemia in adulthood. Maternal infection with hepatitis B and C virus is not a contraindication to breastfeeding, as opposed to HIV infection and galactosemia. A supplementation with vitamin D and K is necessary in the breastfed infant. Very few medications contraindicate breastfeeding. Premature babies can be breastfed and/or receive mother's milk and/or bank milk, provided they receive energy, protein and mineral supplements. Return to prepregnancy weight is earlier in breastfeeding mothers. Breastfeeding is also associated with a decreased risk of breast and ovarian cancer in the premenopausal period, and of hip fractures and osteoporosis in the postmenopausal period.

Type 1 diabetes mellitus: etiology, presentation, and management

This article reviews our current understanding of the etiology, presentation, and management of type 1 diabetes. The discussion includes a review of the natural history of diabetes, the complex relationship between genetic and environmental risk for type 1 diabetes, and current methods for prediction of type 1 diabetes. The article also reviews the current management of children who have new-onset type 1 diabetes, age-appropriate management goals, and diabetes complications. Finally, the article discusses the future of diabetes screening programs and the progress toward the ultimate goal of curing type 1 diabetes.

The A2 milk case: a critical review

This review outlines a hypothesis that A1 one of the common variants of beta-casein, a major protein in cows milk could facilitate the immunological processes that lead to type I diabetes (DM-I). It was subsequently suggested that A1 beta-casein may also be a risk factor for coronary heart disease (CHD), based on between-country correlations of CHD mortality with estimated national consumption of A1 beta-casein in a selected number of developed countries. A company, A2 Corporation was set up in New Zealand in the late 1990s to test cows and market milk in several countries with only the A2 variant of beta-casein, which appeared not to have the disadvantages of A1 beta-casein. The second part of this review is a critique of the A1/A2 hypothesis. For both DM-I and CHD, the between-country correlation method is shown to be unreliable and negated by recalculation with more countries and by prospective studies in individuals. The animal experiments with diabetes-prone rodents that supported the hypothesis about diabetes were not confirmed by larger, better standardised multicentre experiments. The single animal experiment supporting an A1 beta-casein and CHD link was small, short, in an unsuitable animal model and had other design weaknesses. The A1/A2 milk hypothesis was ingenious. If the scientific evidence had worked out it would have required huge adjustments in the world's dairy industries. This review concludes, however, that there is no convincing or even probable evidence that the A1 beta-casein of cow milk has any adverse effect in humans. This review has been independent of examination of evidence related to A1 and A2 milk by the Australian and New Zealand food standard and food safety authorities, which have not published the evidence they have examined and the analysis of it. They stated in 2003 that no relationship has been established between A1 or A2 milk and diabetes, CHD or other diseases.

A new model for understanding the role of environmental factors in the origins of chronic illness: a case study of type 1 diabetes mellitus

There is a need for a new pathophysiological model explaining and linking the role of numerous non-genetic factors believed to contribute to origins of many chronic physical diseases. This article presents a theoretical model for explaining the confusing and often contradictory findings regarding the role of environmental influences in type 1 diabetes, a disease that has been widely studied, for which clear diagnostic criteria exist, and for which development of effective prevention strategies represents significant challenges. The model is formulated from the large database of research regarding increasing understanding of the interaction between environmental factors, physiology, and autonomic regulatory function. Data is integrated from research in the fields of the experience-dependent maturation of the nervous system and the neurophysiology of traumatic stress to demonstrate how disruptions in early bonding and attachment, including adverse events such as traumatic stress, are capable of causing: (1) long-term imbalances in autonomic regulatory function and (2) relative dominance of sympathetic or parasympathetic activity. The proposed model of autonomic dysfunction suggests that ongoing mechanisms promoting high glucose in the context of decreasing insulin production in type 1 diabetes represent a state of relative sympathetic dominance influenced by environmental factors affecting autonomic, immune and endocrine systems during critical period programming. The model further identifies a link between the many seemingly unrelated non-genetic risk factors, and appears capable of explaining contradictions and enigmas in epidemiological and clinical studies regarding non-genetic origins of type 1 diabetes, including the role of stress, variation in age of onset, and duration of the preclinical phase.

Genetics and type 1 diabetes: online resources for diabetes educators

PURPOSE

Genetic education Internet sites and peer-reviewed medical literature were reviewed and critiqued to develop tables summarizing online resources for diabetes health professionals.

METHODS

Using Internet search engines, each Web site identified for this project met the following criteria: (1) accurate and valid site content based on widely accepted genetic texts, (2) credibility of the organization that maintained the Web site, (3) ease of navigation, and (4) provision of continuing education credits. PubMed was used to find journal articles using similar criteria.

RESULTS

There were 33 Web sites on genetic education for diabetes health professionals that met the inclusion criteria. The literature search identified 36 articles regarding the importance of genetic education for nurses and other health professionals, as well as information regarding genetics and diabetes.

CONCLUSIONS

Valid and credible information on genetics and type 1 diabetes is available for diabetes health professionals on the Internet and in the medical literature.

Endocrine autoantibodies

The autoantibody assays that exist and that are being refined are of increasing importance to a broad spectrum of endocrine disorders. This is particularly true for type IA diabetes, which is one of the best-studied organ-specific autoimmune diseases. Autoantibodies are used as valuable markers in prediction and prevention studies of type IA diabetes. Autoantibodies related to other endocrine organs are also important because multiple related autoimmune endocrine and non-endocrine disorders are increased in frequency in patients and their families with autoimmunity. The availability of highly sensitive and specific autoantibody assays for the various endocrine disorders can allow physicians to better diagnose and promptly treat these conditions.

Nutritional risk predictors of beta cell autoimmunity and type 1 diabetes at a young age

Type 1 diabetes is an immune-mediated disease characterized by a preclinical prodrome during which beta cell autoimmunity proceeds at a variable rate. Large geographic differences and a conspicuous increase in incidence, especially among young children since the 1950s, and the relatively low concordance in identical twins are factors that favor a critical role of environmental factors in the etiology of this disease. Only approximately 5% or fewer subjects with HLA-conferred genetic susceptibility to type 1 diabetes actually develop the clinical disease. Breastfeeding, nicotinamide, zinc, and vitamins C, D, and E have been reported as possibly protecting against type 1 diabetes, whereas N-nitroso compounds, cow milk, increased linear growth, and obesity may increase the risk. Thus far, only the significance of infant feeding, cow milk, and vitamin D have been studied in both case-control and cohort settings. The major shortcoming of most studies done so far is that only single dietary exposures have been assessed at single time points. Putative nutritional and other confounding factors have received little attention as have the limitations of the dietary methods used. There is little firm evidence of the significance of nutritional factors in the etiology of type 1 diabetes. The availability of good markers of preclinical type 1 diabetes and of genetic risk have decreased the sample sizes needed and made longitudinal cohort studies of the assessment of children's diets feasible.

Weaning of infants

The WHO 2001 global recommendation is a one size fits all approach to weaning, an approach which may not take sufficient account of the special needs of some infants and fails to allow for the different problems encountered in the industrialised nations compared with economically developing countries. For the healthy normal birth weight full term infant born in an industrialised country, current research supports the benefit of exclusive breast milk feeding until 4-6 months. Evidence of harm through introducing solid food to these infants earlier than this is weak. Infants should be managed individually according to their needs.

Regional distribution of risk for childhood diabetes in Austria and possible association with body mass index

This study was performed to investigate whether the body mass index (BMI) of diabetic children at manifestation is related to the non-random risk distribution in Austria and whether there is an association with the BMI of the background population. All newly diagnosed cases aged <15 years (n=1644) from 1989 to 2000 were allocated to districts using the postal code. BMI at the time of diagnosis was derived from the Austrian incidence data sheet in 99.3% of the registered cases. Data on BMI of the whole population >14 years of age for the year 1991 and birth weight for the years 1989-1999 were derived from Statistics Austria. Linear regression as well as ecological regression (Poisson) models with correction for non-linearity were used. BMI at diabetes manifestation was positively associated with year of diagnosis (P<0.05) and the age at diagnosis (P<0.01). An increase in BMI when moving from West to East (P<0.01) and a higher BMI at diagnosis in boys than girls (P<0.01) was observed. The ecological regression model showed a positive significant association of BMI in newborns and a positive trend of BMI in the background population with incidence rates.

CONCLUSION

our data support the hypothesis that obesity may be a risk factor not only for type 2 but for type 1 in children acting as an accelerator for the clinical manifestation.

17. Immunologic endocrine disorders

Immune-mediated tissue destruction or disregulation is the cause of multiple common, as well as rare, endocrine disorders including type 1 diabetes, Graves' disease, Hashimoto thyroiditis, and Addison's disease. Each of these disorders can be divided into a series of stages beginning with genetic susceptibility, environmental triggering events, and active autoimmunity, followed by metabolic abnormalities with overt disease. Common genetic susceptibility is suggested by the clustering of a series of disorders in the same individual and his or her family. A major portion of the genetic susceptibility lies in the HLA region, but for several disorders, mutation of transcription factors underlies disease susceptibility (eg, X-linked polyendocrinopathy, immune deficiency and diarrhea, and autoimmune polyendocrine syndrome type 1). With improving immunogenetic and pathogenic understanding, type 1A diabetes is now predictable, and excellent autoantibody screening assays are available. This knowledge, combined with studies in animal models, has led to trials for the prevention of diabetes. In addition, aberrant immunologic reactions (eg, insulin autoantibodies after insulin therapy, Graves' disease after monoclonal anti-T-cell therapy in multiple sclerosis) can complicate standard and experimental therapies. We therefore believe that an understanding of the immunogenetics and immunopathogenesis of endocrine disorders can aid in the prevention of morbidity and mortality for these related diseases.

Antibodies to food antigens in Japanese patients with type 1 diabetes mellitus

To examine humoral and mucosal immune responses to food antigens and their relation to the pathophysiology of type 1 diabetes mellitus, IgA and IgG antibodies to cow's milk antigens (bovine serum albumin (BSA) and beta-lactoglobulin (BLG)) and another food antigen (ovalbumin, (OVA)) in human serum were assessed by enzyme-linked immunosorbent assay (ELISA). If anti-idiotype antibodies to the antibodies were present in serum, they might interfere with the ELISA assay, so suitable microtiter plates were employed to minimize such interference. The levels of IgA and IgG antibodies to the above antigens (P<0.001-P<0.01) and the prevalence of positive sera (P<0.001-P<0.05) in the patient group (n=52, aged 14.5+/-4.1 (S.D.) years) were significantly higher than those in the control group (n=41, aged 13.3+/-6.8 (S.D.) years). Interestingly, the levels of IgA antibodies to all the food antigens examined were elevated in 26 (50%) patients, while the elevation was seen in 3 (7%) healthy controls. The elevation of IgA antibodies in the patients was well correlated with increased concentrations of IgA and transforming growth factor (TGF)-beta, which induces IgA-producing B-cells, in serum. Although the cytokine TGF-beta is secreted from regulatory T-cells (Th3), and is related to oral tolerance, the interleukin-2 (IL-2, Th1)/IL-4 (Th2) ratio in the patient group was significantly elevated (P<0.001), which might indicate that the oral tolerance is impaired in patients. Thus, we demonstrated that both IgA and IgG antibodies to several food antigens are elevated in patients. We suggest that impairment of oral tolerance might be related to the pathogenesis of type 1 diabetes mellitus.

Islet autoantibodies in cord blood: maternal, fetal, or neither?

In high-risk type 1 diabetes populations, up to 3% of the general population newborns may express islet autoantibodies in cord blood and the vast majority of those appear to be maternal autoantibodies that disappear usually before the age of 9 months. Despite recent progress in standardization of autoantibody assays, some of the findings appear to be artifacts or non-IgG-mediated binding phenomena. It remains unclear whether transplacentally transmitted maternal autoantibodies play any role in protecting the offspring of diabetic women from diabetes. The evidence for fetal production of islet autoantibodies is very limited and remains to be validated in large prospective studies currently underway.

Breast-feeding in Spain

Human milk is the best way to nurture the human infant. By breast-feeding their babies, mothers provide them with the best opportunities to wholly develop their potential, while protecting the infants and themselves from a whole range of diseases in the near future and in the years to come. Even though these benefits are widely known and there is ample scientific evidence on the topic, it seems from published data that Spanish women are not breast-feeding their babies as much and for as long as they should. Less than 90% start breast-feeding, at 1 month there is already an attrition of 30%, at 3 months more than half of the infants are taking artificial milk and by 6 months only 10% continue to breast-feed their infants. Low birth weight, Caesarean section and low study level are among the more significant factors that negatively affect breast-feeding. There is still work to do to improve this situation. Promotion of breast-feeding among the general population, mothers and health professionals is needed.