Åke Lernmark

Non-compliance with food record submission can induce bias in nutritional epidemiological analysis and make it difficult to draw inference from study findings. We examined the impact of demographic, lifestyle and psychosocial factors on such non-compliance during the first 3 years of participation in a multidisciplinary prospective paediatric study. The Environmental Determinants of Diabetes in the Young (TEDDY) study collects a 3 d food record quarterly during the first year of life and semi-annually thereafter. High compliance with food record completion was defined as the participating families submitting one or more days of food record at every scheduled clinic visit. Three centres in the USA (Colorado, Georgia/Florida and Washington) and three in Europe (Finland, Germany and Sweden). Families who finished the first 3 years of TEDDY participation (n 8096). High compliance was associated with having a single child, older maternal age, higher maternal education and father respondi...

Intraportal islet transplantation can restore insulin production in type 1 diabetes patients but its effect is subject to several interfering processes. To assess the influence of beta-cell loss before and during engraftment we search for a real-time marker of beta-cell destruction. Previous studies showed that GAD65 is discharged by chemically damaged rat beta cells. We therefore examined the utility of the GAD65 assay to detect and quantify destruction of human beta cells in vitro and in vivo. A time-resolved fluorescence immunoassay was used to measure GAD65 discharge from beta cells after administration of toxins or following intraportal transplantation. The study in patients involved type 1 diabetes recipients of 56 implants. GAD65 was discharged from cultured human beta cells between 4 and 24 hours following acute insult and proportional to the number of dying cells. It was also detected in plasma during the first 24 hours following intraportal transplantation of human islet c...

Body size is postulated to modulate type 1 diabetes as either a trigger of islet autoimmunity or an accelerator to clinical onset after seroconversion. As overweight and obesity continue to rise among children, the aim of this study was to determine whether human leukocyte antigen DQ (HLA-DQ) genotypes may be related to body size among children genetically at risk for type 1 diabetes. Repeated measures of weight and height were collected from 5969 children 2-4 years of age enrolled in The Environmental Determinants of Diabetes in the Young prospective study. Overweight and obesity was determined by the International Obesity Task Force cutoff values that correspond to body mass index (BMI) of 25 and 30 kg m(-)(2) at age 18. The average BMI was comparable across specific HLA genotypes at every age point. The proportion of overweight was not different by HL A, but percent obesity varied by age with a decreasing trend among DQ2/8 carriers (P for trend=0.0315). A multivariable regression...

Type 1 (insulin-dependent) diabetes mellitus is strongly associated with autoimmune phenomena connected to the loss of beta-cells in the pancreatic islets. Despite considerable progress in our understanding of genetic susceptibility factors and islet autoimmunity preceding the clinical onset of Type 1 diabetes there are considerable gaps in our knowledge. First, the etiology is unclear. It is speculated that multiple etiological factors may initiate a common pathogenic pathway which results in immune-mediated beta-cell destruction. In 1998 we will need to learn more about the possible importance of gestational infections, as well as isolation of viral DNA or RNA from the blood of new-onset patients or marker-positive individuals. The scan of the whole genome has provided a smorgasbord of genetic regions which confer diabetes risk either alone or in combination. HLA remains the major genetic risk factor, and while HLA peptide binding information is considerable, we understand less of...

Autoantibodies against the smaller isoform of glutamic acid de- carboxylase (GAD) are markers for Type 1 diabetes. GAD65 autoan- tibody (GAD65Ab)-positive individuals in the general population are, however, mostly at low risk of developing Type 1 diabetes, suggesting that GAD65Ab phenotypes may be associated with different under- lying pathogenic processes. The aim of this study was to test the hypothesis

Islet amyloid polypeptide (IAPP) is a beta cell hormone secreted together with insulin upon glucose stimulation. IAPP participates in normal glucose regulation, but IAPP is also known for its ability to misfold and form islet amyloid. Amyloid fibrils form through smaller cell toxic intermediates and deposited amyloid disrupts normal islet architecture. Even though IAPP and amyloid formation are much discussed in type 2 diabetes, our aim was to study the significance of IAPP in type 1 diabetes. Plasma IAPP levels in children and adolescents with newly diagnosed type 1 diabetes (n = 224) were analysed and concentrations exceeding 100 pmol/L (127.2-888.7 pmol/L) were found in 11% (25/224). The IAPP increase did not correlate with C-peptide levels. Plasma levels of IAPP and insulin deviate in a subpopulation of young with newly-diagnosed type 1 diabetes. The determined elevated levels of IAPP might increase the risk for IAPP misfolding and formation of cell toxic amyloid in beta cells. This finding add IAPP-aggregation to the list over putative pathological factors causing type 1 diabetes.

The Environmental Determinants of Diabetes in the Young (TEDDY) study prospectively follows 8,677 children enrolled from birth, who carry HLA-susceptibility genotypes for development of islet autoantibodies (IA) and type 1 diabetes (T1D). During the median follow-up time of 57 months, 350 children developed at least one persistent IA (GADA, IA-2A or mIAA) and 84 of them progressed to T1D. We genotyped 5,164 Caucasian children for 41 non-HLA SNPs that achieved genome-wide significance for association with T1D in the GWAS meta-analysis conducted by the Type 1 Diabetes Genetics Consortium. In TEDDY-participants carrying high-risk HLA-genotypes, eight SNPs achieved significant association to development of IA using time-to-event analysis (p<0.05), whereof four were significant after adjustment for multiple testing (p<0.0012): rs2476601 in PTPN22 (hazard ratio [HR] 1.54 [95% CI 1.27-1.88]), rs2292239 in ERBB3 (HR 1.33 [95% CI 1.14-1.55]), rs3184504 in SH2B3 (HR 1.38 [95% CI 1.19-1.61]) and rs1004446 in INS (HR 0.77 [0.66-0.90]). These SNPs were also significantly associated with T1D in particular: rs2476601 (HR 2.42 [95% CI 1.70-3.44]). Although genes in the HLA-region remain the most important genetic risk factors for T1D, other non-HLA genetic factors contribute to IA, a first step in the pathogenesis of T1D, and the progression of the disease.

We evaluated a biotin–glutamic acid decarboxylase 65 (GAD65)-based enzyme-linked immunosorbent assay (B-ELISA) to detect GAD65 autoantibodies (GAD65Ab) in 78 sera from individuals with newly diagnosed type 1 diabetes. The GAD65Ab index of patients with type 1 diabetes (mean value of GAD65Ab index of 1.891) was significantly higher than those in 50 sera from healthy control group (mean value of 0.068).

Antibodies to the smaller isoform of glutamic acid decarboxylase (GAD65Ab) have been linked to the presence of neuropathy in Type 1 diabetes in several small studies. We attempted to confirm this association by measuring GAD65Ab, GAD65Ab epitopes and IA-2Ab in 511 patients who participated in the Diabetes Control and Complications Trial (DCCT). We also tested for correlations between these autoantibodies and C-peptide and glycemic control. We only included patients for whom serum was available from the first 4 years of their illness. The presence or absence of neuropathy was determined by electrophysiological studies, autonomic testing and clinical evaluation at baseline and 5 years into the trial or at close out. Samples from controls (patients without neuropathy at 5 years) were selected for patients who had similar C-peptide responses to a standardized meal at baseline. The GAD65Ab index correlated with HgbA(1c) only in the adult participants and only at baseline. The adults initially in poor control (upper tertile for glycemia) had higher GAD65Ab and lower C-peptides. The GAD65Ab index was not significantly different in patients with confirmed clinical neuropathy at 5 years versus controls matched for C-peptide (.248+/-.03 versus .278+/-.03). Epitope analysis, based on the blocking of conformational epitopes by recombinant Fab, revealed that the binding to multiple epitopes was decreased in the patients with neuropathy.