Landmark models to define the age-adjusted risk of developing stage 1 type 1 diabetes across childhood and adolescence.

BACKGROUND: Autoimmune diseases are often preceded by an asymptomatic autoantibody-positive phase. In type 1 diabetes, the detection of autoantibodies to pancreatic islet antigens in genetically at-risk children is prognostic for future clinical diabetes. Testing for islet autoantibodies is, therefore, performed in a range of clinical studies. Accurate risk estimates that consider the a priori genetic risk and other risk modifiers are an important component of screening. The age of an individual is an under-appreciated risk modifier. The aim of this study was to provide age-adjusted risk estimates for the development of autoantibodies across childhood in genetically at-risk children. METHODS: The prospective BABYDIAB and BABYDIET studies included 2441 children from birth who had a first-degree relative with type 1 diabetes. Children were born between 1989 and 2006 and were regularly followed from birth for the development of islet autoantibodies and diabetes. A landmark analysis was performed to estimate the risk of islet autoantibodies at birth and at the age 3.5, 6.5 and 12.5 years. Exponential decay curves were fitted for the risk by the age of 20 years. RESULTS: The risk of islet autoantibodies by the age of 20 years was 8%, 4.6%, 2.6% and 0.9%, at the landmark ages of birth, 3.5, 6.5 and 12.5 years, respectively. The short-term risks (within 6 years of follow-up) at these landmark ages were 5.3%, 2.9%, 1.8% and 1%, respectively. The decline in autoantibody risk with age was modelled using a one-phase exponential decay curve (r = 0.99) with a risk half-life of 3.7 years. This risk decay model was remarkably consistent when the outcome was defined as islet autoantibody-positive or multiple islet autoantibody-positive and when the study cohort was stratified by HLA risk genotype. A similar decay model was observed for coeliac disease-associated transglutaminase antibodies in the same cohort. Unlike the risk of developing islet autoantibodies, the rate of developing clinical diabetes in children who were islet autoantibody-positive did not decline with age. CONCLUSION: The risk of developing autoantibodies drops exponentially with age in children with a first-degree relative with type 1 diabetes.

A novel approach for the analysis of longitudinal profiles reveals delayed progression to type 1 diabetes in a subgroup of multiple-islet-autoantibody-positive children.

AIMS/HYPOTHESIS: Progression to type 1 diabetes in children and adolescents is not uniform. Based on individual genetic background and environment, islet autoimmunity may develop at variable age, exhibit different autoantibody profiles and progress to clinical diabetes at variable rates. Here, we aimed to quantify the qualitative dynamics of sequential islet autoantibody profiles in order to identify longitudinal patterns that stratify progression rates to type 1 diabetes in multiple-autoantibody-positive children. METHODS: Qualitative changes in antibody status on follow-up and progression rate to diabetes were analysed in 88 children followed from birth in the prospective BABYDIAB study who developed multiple autoantibodies against insulin (IAA), GAD (GADA), insulinoma-associated antigen-2 (IA-2A) and/or zinc transporter 8 (ZnT8A). An algorithm was developed to define similarities in sequential autoantibody profiles and hierarchical clustering was performed to group children with similar profiles. RESULTS: We defined nine clusters that distinguished children with respect to their sequential profiles of IAA, GADA, IA-2A and ZnT8A. Progression from first autoantibody appearance to clinical diabetes between clusters ranged from 6% (95% CI [0, 16.4]) to 73% (28.4, 89.6) within 5 years. Delayed progression was observed in children who were positive for only two autoantibodies, and for a cluster of 12 children who developed three or four autoantibodies but were IAA-negative in their last samples, nine of whom lost IAA positivity during follow-up. Among all children who first seroconverted to IAA positivity and developed at least two other autoantibodies (n = 57), the 10 year risk of diabetes was 23% (0, 42.9) in those who became IAA-negative during follow-up compared with 76% (58.7, 85.6) in those who remained IAA-positive (p = 0.004). CONCLUSIONS/INTERPRETATION: The novel clustering approach provides a tool for stratification of islet autoantibody-positive individuals that has prognostic relevance, and new opportunities in elucidating disease mechanisms. Our data suggest that losing IAA reactivity is associated with delayed progression to type 1 diabetes in multiple-islet-autoantibody-positive children.

Early infant growth is associated with the risk of islet autoimmunity in genetically susceptible children.

BACKGROUND: Islet autoimmunity commonly develops early in infancy. We assessed whether specific parameters of early growth (including weight gain) were associated with the development of islet autoimmunity in children of type 1 diabetes patients, taking individual developmental patterns into account. METHODS: Growth parameters were estimated in n = 1011 children followed from birth in the prospective BABYDIAB and BABYDIET studies using longitudinal models. Cox proportional hazard models, adjusted for study, sex, gestational age, birth weight percentile, and maternal type 1 diabetes status, were calculated to assess hazard ratios (HR) for islet autoimmunity with corresponding 95% confidence intervals (95% CI) by 2 SD increases in growth parameters. In a subset of n = 170 infants, we investigated whether the growth hormones insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) were in the causal pathway. RESULTS: We found an early age at infant body mass index (BMI) peak to be associated with the development of islet autoimmunity [HR 0.60 (95% CI 0.41-0.87), per 2 SD increase in age]. Islet autoimmunity was also associated with BMI difference between infant BMI peak and childhood BMI rebound [HR 1.52 (95% CI 1.04-2.22)], but not after adjustment for age at infant BMI peak, and not with other parameters such as peak height and weight velocity during infancy. Serum concentrations of IGF-1 and IGFBP-3 at birth, 9 months, and 2 yr, respectively, were not significantly different between children with and without later islet autoimmunity. CONCLUSIONS: Variations in early growth rate have subtle effects on the risk of islet autoimmunity with growth hormones unlikely to be in the causal pathway.

Age, HLA, and Sex Define a Marked Risk of Organ-Specific Autoimmunity in First-Degree Relatives of Patients With Type 1 Diabetes.

OBJECTIVE: Autoimmune diseases can be diagnosed early through the detection of autoantibodies. The aim of this study was to determine the risk of organ-specific autoimmunity in individuals with a family history of type 1 diabetes. RESEARCH DESIGN AND METHODS: The study cohort included 2,441 first-degree relatives of patients with type 1 diabetes who were prospectively followed from birth to a maximum of 29.4 years (median 13.2 years). All were tested regularly for the development of autoantibodies associated with type 1 diabetes (islet), celiac disease (transglutaminase), or thyroid autoimmunity (thyroid peroxidase). The outcome was defined as an autoantibody-positive status on two consecutive samples. RESULTS: In total, 394 relatives developed one (n = 353) or more (n = 41) of the three disease-associated autoantibodies during follow-up. The risk by age 20 years was 8.0% (95% CI 6.8-9.2%) for islet autoantibodies, 6.3% (5.1-7.5%) for transglutaminase autoantibodies, 10.7% (8.9-12.5%) for thyroid peroxidase autoantibodies, and 21.5% (19.5-23.5%) for any of these autoantibodies. Each of the three disease-associated autoantibodies was defined by distinct HLA, sex, genetic, and age profiles. The risk of developing any of these autoantibodies was 56.5% (40.8-72.2%) in relatives with HLA DR3/DR3 and 44.4% (36.6-52.2%) in relatives with HLA DR3/DR4-DQ8. CONCLUSIONS: Relatives of patients with type 1 diabetes have a very high risk of organ-specific autoimmunity. Appropriate counseling and genetic and autoantibody testing for multiple autoimmune diseases may be warranted for relatives of patients with type 1 diabetes.

Predictors of postpartum diabetes in women with gestational diabetes mellitus.

The aim of this study was to stratify risk for postpartum diabetes in women who have gestational diabetes. Women with gestational diabetes were recruited between 1989 and 1999, and 302 were followed with oral glucose tolerance tests at 9 months and 2, 5, 8, and 11 years postpregnancy. The 8-year postpartum diabetes risk was 52.7% (130 diabetic cases). Risk was increased in women with autoantibodies to GAD and/or insulinoma antigen-2 (adjusted hazard ratio 4.1; P < 0.0001), women who required insulin during pregnancy (4.7; P < 0.0001), women with BMI >30 kg/m2 (1.5; P = 0.04), and women with more than two prior pregnancies (2.5; P = 0.02). Women without these risk factors had a postpartum diabetes risk of 14% by 8 years, and risk rose incrementally to 96% by 8 years in autoantibody-positive women. Parity status, C-reactive protein concentration, a diabetes family history, maternal age, weeks of gestation, and the child's birth weight did not significantly affect risk in multivariate analysis. Prospective diabetes assessment is indicated and intervention should be considered in women with gestational diabetes who are autoantibody positive, require insulin treatment during pregnancy, or are obese.

Mature high-affinity immune responses to (pro)insulin anticipate the autoimmune cascade that leads to type 1 diabetes.

Children at risk for type 1 diabetes can develop early insulin autoantibodies (IAAs). Many, but not all, of these children subsequently develop multiple islet autoantibodies and diabetes. To determine whether disease progression is reflected by autoantibody maturity, IAA affinity was measured by competitive radiobinding assay in first and subsequent IAA-positive samples from children followed from birth in the BABYDIAB cohort. IAA affinity in first positive samples ranged from less than 10(6) l/mol to more than 10(11) l/mol. High affinity was associated with HLA DRB1*04, young age of IAA appearance, and subsequent progression to multiple islet autoantibodies or type 1 diabetes. IAA affinity in multiple antibody-positive children was on average 100-fold higher than in children who remained single IAA positive or became autoantibody negative. All high-affinity IAAs required conservation of human insulin A chain residues 8-13 and were reactive with proinsulin. In contrast, most lower-affinity IAAs were dependent on COOH-terminal B chain residues and did not bind proinsulin. These data are consistent with the concept that type 1 diabetes is associated with sustained early exposure to (pro)insulin in the context of HLA DR4 and show that high-affinity proinsulin-reactive IAAs identify children with the highest diabetes risk.

Vaccinations in early life are not associated with development of islet autoimmunity in type 1 diabetes high-risk children: Results from prospective cohort data.

AIMS/HYPOTHESIS: Vaccinations in early childhood potentially stimulate the immune system and may thus be relevant for the pathogenesis of autoimmune diseases such as type 1 diabetes (T1D). We determined the association of vaccination burden with T1D-associated islet autoimmunity in children with high familial risk followed prospectively from birth. METHODS: A total of 20,570 certified vaccination records from 1918 children were correlated with time to onset of T1D-associated islet autoimmunity using Cox regression, considering multiple time periods up until age two years and vaccination types, and adjusting for HLA genotype, sex, delivery mode, season of birth, preterm delivery and maternal T1D status. Additionally, prospective claims data of 295,420 subjects were used to validate associations for the tick-borne encephalitis (TBE) vaccination. RESULTS: Most vaccinations were not associated with a significantly increased hazard ratio (HR) for islet autoimmunity (e.g. HR [95% confidence interval]: 1.08 [0.96-1.21] per additional vaccination against measles, mumps and rubella at age 0-24months). TBE vaccinations within the first two years of life were nominally associated with a significantly increased autoimmunity risk (HR: 1.44 [1.06-1.96] per additional vaccination at age 0-24months), but this could not be confirmed with respect to outcome T1D in the validation cohort (HR: 1.02 [0.90-1.16]). CONCLUSIONS: We found no evidence that early vaccinations increase the risk of T1D-associated islet autoimmunity development. The potential association with early TBE vaccinations could not be confirmed in an independent cohort and appears to be a false positive finding.

Type 1 diabetes vaccine candidates promote human Foxp3(+)Treg induction in humanized mice.

Immune tolerance is executed partly by Foxp3(+)regulatory T (Treg) cells, which suppress autoreactive T cells. In autoimmune type 1 diabetes (T1D) impaired tolerance promotes destruction of insulin-producing ß-cells. The development of autoantigen-specific vaccination strategies for Foxp3(+)Treg-induction and prevention of islet autoimmunity in patients is still in its infancy. Here, using human haematopoietic stem cell-engrafted NSG-HLA-DQ8 transgenic mice, we provide direct evidence for human autoantigen-specific Foxp3(+)Treg-induction in vivo. We identify HLA-DQ8-restricted insulin-specific CD4(+)T cells and demonstrate efficient human insulin-specific Foxp3(+)Treg-induction upon subimmunogenic vaccination with strong agonistic insulin mimetopes in vivo. Induced human Tregs are stable, show increased expression of Treg signature genes such as Foxp3, CTLA4, IL-2Rα and TIGIT and can efficiently suppress effector T cells. Such Foxp3(+)Treg-induction does not trigger any effector T cells. These T1D vaccine candidates could therefore represent an expedient improvement in the challenge to induce human Foxp3(+)Tregs and to develop novel precision medicines for prevention of islet autoimmunity in children at risk of T1D.

Brief communication: early appearance of islet autoantibodies predicts childhood type 1 diabetes in offspring of diabetic parents.

BACKGROUND: The development of type 1 diabetes mellitus is preceded by autoimmunity against islet beta cells. OBJECTIVE: To determine the risk for islet autoimmunity and childhood diabetes in offspring of affected parents. DESIGN: Prospective cohort study. SETTING: German BABYDIAB study. PARTICIPANTS: 1610 offspring of parents with type 1 diabetes. MEASUREMENTS: Autoantibodies to islet autoantigens were measured at 9 months, 2 years, 5 years, and 8 years of age. RESULTS: By 5 years of age, the frequency of islet autoantibodies was 5.9% (95% CI, 4.6% to 7.2%), the frequency of multiple islet autoantibodies was 3.5% (CI, 2.5% to 4.5%), and the frequency of diabetes was 1.5% (CI, 0.9% to 2.1%). The risk for diabetes was highest in offspring with multiple autoantibodies (40% within 5 years vs. 3% in offspring with single autoantibodies; P = 0.005). Progression to multiple islet autoantibodies was fastest in children who were autoantibody positive by age 2 years (P < 0.001), and progression to diabetes was inversely related to the age of positivity for multiple autoantibodies (P = 0.02). LIMITATIONS: The findings are limited to childhood diabetes in affected families. CONCLUSIONS: Childhood autoimmune diabetes is associated with autoimmunity that starts before 2 years of age.

Early infant feeding and risk of developing islet autoimmunity and type 1 diabetes.

We investigated whether food supplementation within the first year life or age at introduction of gluten-containing foods influenced the risk of developing islet autoimmunity and type 1 diabetes. A total of 2,291 children with a family history of type 1 diabetes were prospectively followed from birth for 28,983 patient years (median 13.1 years). Dietary exposure data were collected by questionnaires, food records and by family interview. Exposure to gluten-containing foods before age 3 months, which occurred in 19 children, increased the risk of developing islet autoantibodies (n = 4), multiple islet autoantibodies (n = 4), and type 1 diabetes (n = 3) compared to exclusive breastfeeding within the first 3 months [adjusted hazard ratio (HR) 3.97 (95 % confidence interval 1.41-11.17), 5.39 (1.89-15.35), and 3.45 (1.04-11.48), respectively] and also compared to first exposure to gluten between 3.1 and 6.0 months of age [adjusted HR 3.40 (1.19-9.70), 4.25 (1.47-12.26), and 3.43 (1.01-11.66), respectively]. Children who received infant formula or other solid food within the first 3 months and children who received gluten-containing foods after age 6 months did not have an increased risk of islet autoantibodies, multiple islet autoantibodies or type 1 diabetes. Our present data affirm that compliance to infant feeding guidelines is a possible way to reduce type 1 diabetes risk in genetically susceptible children.