Seroconversion to Multiple Islet Autoantibodies and Risk of Progression to Diabetes in Children

AimThe aim of the present study was to assess beta cell function based on an oral glucose tolerance test (OGTT) in participants with single islet autoantibody or an intravenous glucose tolerance test (IvGTT) in participants with multiple islet autoantibodies.Materials and methodsHealthy participants in Sweden and Finland, between 2 and 49.99 years of age previously identified as positive for a single (n = 30) autoantibody to either insulin, glutamic acid decarboxylase, islet antigen‐2, zinc transporter 8 or islet cell antibodies or multiple autoantibodies (n = 46), were included. Participants positive for a single autoantibody underwent a 6‐point OGTT while participants positive for multiple autoantibodies underwent an IvGTT. Glucose, insulin and C‐peptide were measured from OGTT and IvGTT samples.ResultsAll participants positive for a single autoantibody had a normal glucose tolerance test with 120 minutes glucose below 7.70 mmol/L and HbA1c values within the normal range (<42 mmol/mol). Insulin responses to the glucose challenge on OGTT ranged between 13.0 and 143 mIU/L after 120 minutes with C‐peptide values between 0.74 and 4.60 nmol/L. In Swedish participants, the first‐phase insulin response (FPIR) on IvGTT was lower in those positive for three or more autoantibodies (n = 13; median 83.0 mIU/L; range 20.0‐343) compared to those with two autoantibodies (n = 15; median 146 mIU/L; range 19.0‐545; P = .0330).ConclusionParticipants positive for a single autoantibody appeared to have a normal beta cell function. Participants positive for three or more autoantibodies had a lower FPIR as compared to participants with two autoantibodies, supporting the view that their beta cell function had deteriorated.

To the Editor: Multiple islet autoantibodies mark a pre-clinical stage of type 1 diabetes, with 70% progression to clinical diabetes within 10 years of seroconversion [1]. Broad application of screening for multiple islet autoantibodies may, therefore, become an attractive instrument to identify asymptomatic type 1 diabetes and prevent severe metabolic disarrangements and ketoacidosis. In contrast to multiple islet autoantibodies, only a minority of children who are, and remain, single islet autoantibody-positive develop type 1 diabetes within 10 years of follow-up. Nevertheless, many multiple islet autoantibody-positive children are likely to have transitioned from single to multiple islet autoantibodies. We [2, 3], and others [4] have reported that multiple islet autoantibody-positive children frequently seroconvert in the first 2 years of life, but little is known of the timing of transition from single to multiple islet autoantibody positivity. This knowledge is important for the design of screening and re-screening strategies. Here we analysed the prospectively followed German BABYDIAB/BABYDIET birth cohort [2, 5] to address this. Children in the BABYDIAB/BABYDIET studies were routinely tested for islet autoantibodies at the ages of 9 months and 2 years, and every 3 years thereafter; children who were positive for one or more islet autoantibodies were tested every 6 months. In a subgroup of children with high genetic risk participating in the BABYDIET intervention study, routine testing for islet autoantibodies was carried out at 3 month intervals from the age of 3 months to 3 years and annually thereafter. Persistent islet autoantibody positivity was defined as a positive result for the same islet autoantibody in at least two consecutive samples. A total of 227 children (114 boys) in the cohort developed persistent islet autoantibodies. Of these, 62 (27.3%) were multiple islet autoantibody positive already at their seroconversion sample and had a median age at seroconversion of 2.2 years (interquartile range [IQR] 1.97–5.02 years). The remaining 165 were single islet autoantibody positive at seroconversion and had a median age at seroconversion of 5.01 years (IQR 1.89–8.13 years, p=0.01). A total of 55 (25.2%) children transitioned from single to multiple islet autoantibodies during 8 years of follow-up. The longest observed period of multiple islet autoantibody positivity was 7.36 years after the seroconversion sample. The rate of Anette-Gabriele Ziegler and Ezio Bonifacio share senior authorship. R. Chmiel : E. Z. Giannopoulou :C. Winkler : P. Achenbach : A.<G. Ziegler (*) Institute of Diabetes Research, Helmholtz Zentrum Munchen, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universitat Munchen, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany e-mail: anette-g.ziegler@helmholtz-muenchen.de

212-LB: Reporting History of Diabetes Symptoms and Random Blood Glucose Testing to Detect Presymptomatic Type 1 Diabetes (T1D) in the General Pediatric Population

OBJECTIVE: To utilize islet autoantibody titers to improve the estimation of future type 1 diabetes risk in children. &lt;p&gt;RESEARCH DESIGN AND METHODS: Prospective cohort studies in Finland, Germany, Sweden and the US followed 24,662 children at increased genetic or familial risk to develop islet autoimmunity and diabetes. For 1,604 children with confirmed positivity, titers of autoantibodies against insulin (IAA), glutamic acid decarboxylase (GADA) and insulinoma-associated antigen-2 (IA-2A) were harmonized for diabetes risk analyses.&lt;/p&gt; &lt;p&gt;RESULTS: Survival analysis from time of confirmed positivity revealed markedly different 5-year diabetes risks associated with IAA (n=909), GADA (n=1076) or IA-2A (n=714), when stratified by quartiles of titer, ranging from 19% (GADA 1&lt;sup&gt;st&lt;/sup&gt; quartile) to 60% (IA-2A 4&lt;sup&gt;th&lt;/sup&gt; quartile). The minimum titer associated with a maximum difference in 5-year risk differed for each autoantibody, corresponding to the 58.6&lt;sup&gt;th&lt;/sup&gt;, 52.4&lt;sup&gt;th&lt;/sup&gt; and 10.2&lt;sup&gt;nd&lt;/sup&gt; percentile of children specifically positive for each of IAA, GADA and IA-2A, respectively. Using these autoantibody type-specific titer thresholds in the 1,481 children with all autoantibodies tested, the 5-year risk conferred by single (n=954) and multiple (n=527) autoantibodies could be stratified from 6% to 75% (p&lt;0.0001). The thresholds effectively identified children with 50% or higher 5-year risk when considering age-specific autoantibody screening (57-65% positive predictive value and 56-74% sensitivity for ages 1-5 years). Multivariable analysis confirmed the significance of associations between the three autoantibody titers and diabetes risk, informing a childhood risk surveillance strategy.&lt;/p&gt; &lt;p&gt;CONCLUSIONS: This study defined islet autoantibody type-specific titer thresholds that significantly improved type 1 diabetes risk stratification in children.&lt;/p&gt;

OBJECTIVE: To utilize islet autoantibody titers to improve the estimation of future type 1 diabetes risk in children. &lt;p&gt;RESEARCH DESIGN AND METHODS: Prospective cohort studies in Finland, Germany, Sweden and the US followed 24,662 children at increased genetic or familial risk to develop islet autoimmunity and diabetes. For 1,604 children with confirmed positivity, titers of autoantibodies against insulin (IAA), glutamic acid decarboxylase (GADA) and insulinoma-associated antigen-2 (IA-2A) were harmonized for diabetes risk analyses.&lt;/p&gt; &lt;p&gt;RESULTS: Survival analysis from time of confirmed positivity revealed markedly different 5-year diabetes risks associated with IAA (n=909), GADA (n=1076) or IA-2A (n=714), when stratified by quartiles of titer, ranging from 19% (GADA 1&lt;sup&gt;st&lt;/sup&gt; quartile) to 60% (IA-2A 4&lt;sup&gt;th&lt;/sup&gt; quartile). The minimum titer associated with a maximum difference in 5-year risk differed for each autoantibody, corresponding to the 58.6&lt;sup&gt;th&lt;/sup&gt;, 52.4&lt;sup&gt;th&lt;/sup&gt; and 10.2&lt;sup&gt;nd&lt;/sup&gt; percentile of children specifically positive for each of IAA, GADA and IA-2A, respectively. Using these autoantibody type-specific titer thresholds in the 1,481 children with all autoantibodies tested, the 5-year risk conferred by single (n=954) and multiple (n=527) autoantibodies could be stratified from 6% to 75% (p&lt;0.0001). The thresholds effectively identified children with 50% or higher 5-year risk when considering age-specific autoantibody screening (57-65% positive predictive value and 56-74% sensitivity for ages 1-5 years). Multivariable analysis confirmed the significance of associations between the three autoantibody titers and diabetes risk, informing a childhood risk surveillance strategy.&lt;/p&gt; &lt;p&gt;CONCLUSIONS: This study defined islet autoantibody type-specific titer thresholds that significantly improved type 1 diabetes risk stratification in children.&lt;/p&gt;

Islet autoantibodies herald early type 1 diabetes. However, less is known of the evolution of autoantibodies to the islet autoantigen ZnT8. Our primary aim was to characterise the development of islet autoantibodies in a pregnancy-birth at-risk cohort and to provide new knowledgeabout ZnT8A. Islet autoantibodies were measured every 3-6 months in 1277/1473 children with a first-degree relative with type 1 diabetes who were followed prospectively from pregnancy in the Environmental Determinants of Islet Autoimmunity (ENDIA) cohort for 7.0 (IQR 5.8-8.3) years. Islet autoantibodies were also measured in the mothers and/or in cord blood in 901 pregnancies with type 1 diabetes. The development of persistent IAA reached a probability of 0.02 by 2 years of age. A combination of IAA- and GADA-first, GADA-first and ZnT8A-first all reached a similar probability by 5 years of age. ZnT8A appeared as the first islet autoantibody, alone or in combination, in 43 (32%) of the 134/1473 children with persistent islet autoantibodies. Persistent single ZnT8A, detected only by ELISA, usually appeared after 4 years of age. ZnT8A that progressed to multiple islet autoantibodies or type 1 diabetes were detected in younger children (p=0.006) and in multiple assay formats. ZnT8A were confirmed in additional assay formats when present with multiple islet autoantibodies, but not when remaining as a single islet autoantibody, unlike IAA and GADA. Maternal islet GADA were detected until 15 months of age and transmission of any islet antibody/autoantibody did not relate to islet autoantibody development in the offspring (χ2=3.32, df=2, p=0.19). Persistent single ZnT8A, which are detected only by ELISA and no other test format, appear not to confer an increased risk of progression to type 1 diabetes.

Transmission of maternal islet antibodies and risk of autoimmune diabetes in offspring of mothers with type 1 diabetes.

1292-P: Loss of Multiple Islet Autoantibody Status during Progression to Type 1 Diabetes

The development of type 1 diabetes mellitus is preceded by autoimmunity against islet beta cells. To determine the risk for islet autoimmunity and childhood diabetes in offspring of affected parents. Prospective cohort study. German BABYDIAB study. 1610 offspring of parents with type 1 diabetes. Autoantibodies to islet autoantigens were measured at 9 months, 2 years, 5 years, and 8 years of age. 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). The findings are limited to childhood diabetes in affected families. Childhood autoimmune diabetes is associated with autoimmunity that starts before 2 years of age.

Vitamin D deficiency is common in people with type 1 diabetes, but its role in disease progression is unclear. Our aim was to assess the prevalence of vitamin D deficiency in prediabetes (defined as the presence of multiple islet autoantibodies), and investigate whether or not progression to type 1 diabetes is faster in children with vitamin D deficiency and multiple islet autoantibodies. Levels of 25-hydroxyvitamin D [25(OH)D] were measured in 108 children with multiple islet autoantibodies within 2 years of islet autoantibody seroconversion, in 406 children who remained islet autoantibody-negative and in 244 patients with newly diagnosed type 1 diabetes. Children with multiple islet autoantibodies were prospectively followed for a median of 5.8 years (interquartile range 3.4-8.6 years) to monitor progression to type 1 diabetes. In the cross-sectional analysis, 25(OH)D levels were lower and the prevalence of vitamin D deficiency (<50 nmol/l) was higher in children with prevalent multiple islet autoantibodies than in islet autoantibody-negative children (59.9 ± 3.0 vs 71.9 ± 1.5 nmol/l; p < 0.001; 39.8% vs 28.3%; p = 0.021). The differences in vitamin D levels between the groups were greatest in summer. The cumulative incidence of type 1 diabetes at 10 years after seroconversion was similar between children with vitamin D deficiency and those with sufficient vitamin D levels (51.8% [95% CI 29.3, 74.3] vs 55.4% [95% CI 35.5, 72.3], p = 0.8). Vitamin D levels were lower in children with multiple islet autoantibodies and in children with type 1 diabetes than in autoantibody-negative children. However, vitamin D deficiency was not associated with faster progression to type 1 diabetes in children with multiple islet autoantibodies.

Autoantibodies that precede type 1 diabetes frequently develop in early childhood and target distinct beta cell proteins. The aim of this study was to determine the heterogeneity of islet autoantibody development and fate. The ages of development of insulin autoantibodies (IAA) and GAD autoantibodies (GADA), followed by multiple islet autoantibodies and progression to diabetes were examined in 2,441 children participating in two German birth cohorts. In 218 children who developed islet autoantibodies, the first islet autoantibody-positive sample was characterised by single IAA in 80 (37%), multiple islet autoantibodies in 68 (31%) and single GADA in 63 (29%) children. Of the children who were single antibody positive at seroconversion, 35 (44%) IAA-positive and 15 (24%) GADA-positive children developed multiple islet autoantibodies. Single persistent antibodies had heterogeneous affinities; GADA were also heterogeneous in their binding to N-terminally truncated GAD65 and in an ELISA. Progression to diabetes occurred in >50% of children within 10 years in all groups that developed multiple islet autoantibodies and in 44% of children with persistent single high-affinity IAA or persistent single GADA that were positive in both a radiobinding assay and ELISA. The earliest autoantibody development was seen in children with single IAA that progressed to multiple islet autoantibodies or in those with persistent high-affinity single IAA, with a sharp peak in incidence observed at age 9 months. The peak incidence occurred at age 2 years for children who underwent seroconversion directly to multiple islet autoantibodies and at 5 years for children who first seroconverted to GADA and subsequently developed other autoantibodies. Seroconversion to low-affinity IAA or persistent single GADA occurred at a low incidence after the age of 9 months. Children of different ages have differing susceptibilities to autoimmunisation against specific beta cell autoantigens.

Risk of beta-cell autoimmunity presence for progression to type 1 diabetes: A systematic review and meta-analysis

Aims/hypothesisDuring the A/H1N1 2009 (A/California/04/2009) pandemic, mass vaccination with a squalene-containing vaccine, Pandemrix®, was performed in Sweden and Finland. The vaccination was found to cause narcolepsy in children and young adults with the HLA-DQ 6.2 haplotype. The aim of this study was to investigate if exposure to Pandemrix® similarly increased the risk of islet autoimmunity or type 1 diabetes.MethodsIn The Environmental Determinants of Diabetes in the Young (TEDDY) study, children are followed prospectively for the development of islet autoimmunity and type 1 diabetes. In October 2009, when the mass vaccination began, 3401 children at risk for islet autoimmunity and type 1 diabetes were followed in Sweden and Finland. Vaccinations were recorded and autoantibodies against insulin, GAD65 and insulinoma-associated protein 2 were ascertained quarterly before the age of 4 years and semi-annually thereafter.ResultsBy 5 August 2010, 2413 of the 3401 (71%) children observed as at risk for an islet autoantibody or type 1 diabetes on 1 October 2009 had been vaccinated with Pandemrix®. By 31 July 2016, 232 children had at least one islet autoantibody before 10 years of age, 148 had multiple islet autoantibodies and 96 had developed type 1 diabetes. The risk of islet autoimmunity was not increased among vaccinated children. The HR (95% CI) for the appearance of at least one islet autoantibody was 0.75 (0.55, 1.03), at least two autoantibodies was 0.85 (0.57, 1.26) and type 1 diabetes was 0.67 (0.42, 1.07). In Finland, but not in Sweden, vaccinated children had a lower risk of islet autoimmunity (0.47 [0.29, 0.75]), multiple autoantibodies (0.50 [0.28, 0.90]) and type 1 diabetes (0.38 [0.20, 0.72]) compared with those who did not receive Pandemrix®. The analyses were adjusted for confounding factors.Conclusions/interpretationChildren with an increased genetic risk for type 1 diabetes who received the Pandemrix® vaccine during the A/H1N1 2009 pandemic had no increased risk of islet autoimmunity, multiple islet autoantibodies or type 1 diabetes. In Finland, the vaccine was associated with a reduced risk of islet autoimmunity and type 1 diabetes.

To investigate the prevalence, clinical significance and antepartum to postpartum trajectory of zinc transporter 8 autoantibodies, a novel marker of islet autoimmunity, in women with gestational diabetes mellitus. A total of 302 consecutive women attending a multi-ethnic Australian gestational diabetes clinic were prospectively studied. Zinc transporter 8 autoantibodies were measured at gestational diabetes diagnosis and 3months postpartum using an enzyme-linked immunosorbent assay, and were correlated with maternal phenotype, antepartum and postpartum glucose tolerance, treatment and perinatal outcomes. Of the 302 women, 30 (9.9%) were positive for one islet autoantibody antepartum. No participant had multiple islet autoantibodies. Zinc transporter 8 autoantibodies were the most prevalent autoantibody [zinc transporter 8 autoantibodies: 13/271 women (4.8%); glutamic acid decarboxylase 7/302 women (2.3%); insulinoma-associated antigen-2: 6/302 women (2.0%); insulin: 4/302 women (1.3%)]. Zinc transporter 8 autoantibody positivity was associated with a higher fasting glucose level on the antepartum oral glucose tolerance test, but not with BMI, insulin use, perinatal outcomes or postpartum glucose intolerance. Five of the six women who tested positive for zinc transporter 8 autoantibodies antepartum were negative for zinc transporter 8 autoantibodies postpartum, which corresponded to a significant decline in titre antepartum to postpartum (26.5 to 3.8 U/ml; P=0.03). This was in contrast to the antepartum to postpartum trajectory of the other islet autoantibodies, which remained unchanged. Zinc transporter 8 autoantibodies were the most common islet autoantibody in gestational diabetes. Zinc transporter 8 autoantibody positivity was associated with slightly higher fasting glucose levels and, unlike other islet autoantibodies, titres declined postpartum. Zinc transporter 8 autoantibodies may be a marker for islet autoimmunity in a proportion of women with gestational diabetes, but the clinical relevance of zinc transporter 8 autoantibodies in pregnancy and gestational diabetes requires further investigation.

GAD65 Autoantibodies Detected by Electrochemiluminescence Assay Identify High Risk for Type 1 Diabetes