[show abstract][hide abstract] ABSTRACT: Abstract Environmental factors, including viral infections, may explain an increasing and fluctuating incidence of childhood type 1 diabetes (T1D). Ljungan virus (LV) isolated from bank voles have been implicated, but it is unclear whether LV contributes to islet autoimmunity, progression to clinical onset, or both, of T1D. The aim was to test whether LV antibodies (LVAb) were related to HLA-DQ and islet autoantibodies in newly diagnosed T1D patients (n=676) and controls (n=309). Patients, 0-18 years of age, diagnosed with T1D in 1996-2005 were analyzed for LVAb, HLA-DQ genotypes, and all seven known islet autoantibodies (GADA, IA-2A, IAA, ICA, ZnT8RA, ZnT8WA, and ZnT8QA). LVAb at 75(th) percentile, defined as cut off, was 90 (range 6-3936) U/mL and 4(th) quartile LVAb were found in 25% (170/676) of which 64% were <10 (n=108, p<0.0001), and 27% were<5 (n=45; p<0.0001) years old. The 4(th) quartile LVAb in children <10 years of age correlated to HLA DQ2/8, 8/8, and 8/X (p<0.0001). Furthermore, in the group with 4(th) quartile LVAb, 55% were IAA positive (p=0.01) and correlation was found between 4(th) quartile LVAb and IAA in children <10 years of age (p=0.035). It is concluded that 1) LVAb were common among the young T1D patients and LVAb levels were higher in the younger age groups; 2) 4(th) quartile LVAb correlated with IAA; and 3) there was a correlation between 4(th) quartile LVAb and HLA-DQ8, particularly in the young patients. The presence of LVAb supports the notion that prior exposure to LV may be associated with T1D.
[show abstract][hide abstract] ABSTRACT: AIMS/HYPOTHESIS: We studied the decline of C-peptide during the first year after diagnosis of Type 1 diabetes (T1D), and its relation to various factors. METHODS: 3824/4017 newly diagnosed patients (95%) were classified as T1D in a national study. In a non-selected subgroup of 1669 T1D patients we determined non-fasting C-peptide both at diagnosis and after 1 year, and analyzed decline in relation to clinical symptoms and signs, initial C-peptide and occurrence of auto-antibodies. RESULTS: Younger children lost more C-peptide (p<0.001) and the higher the C-peptide at diagnosis the larger the decline during the first year (p<0.0000). Patients with higher BMI had higher C-peptide at diagnosis but lost more (p<0.01), and those with lower HbA1c, without symptoms and signs at diagnosis, and with higher BMI, had higher C-peptide at diagnosis, but lost more during the first year (p<0.001). Finally, patients diagnosed during autumn had higher C-peptide at diagnosis, but lost more during the coming year (p<0.001). Occurrence of auto-antibodies did not correlate with C-peptide decline, except possibly for a more rapid loss in IAA-positive patients. CONCLUSIONS/INTERPRETATION: Even in a restricted geographical area and narrow age range (<18 years), the natural course of Type 1 diabetes is heterogeneous. This should be considered in clinical trials.
Diabetes research and clinical practice 03/2013; 100(2):203-9. · 2.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: AIMS: Children with type 1 diabetes (T1D) risk and islet autoantibodies are recruited to a secondary prevention study. The aims were to determine metabolic control in relation to human leukocyte antigen (HLA) genetic risk and islet autoantibodies in prepubertal children. METHODS: In 47 healthy children with GADA and at least one additional islet autoantibody, intravenous glucose tolerance test (IvGTT) and oral glucose tolerance test (OGTT) were performed 8-65 d apart. Hemoglobin A1c, plasma glucose as well as serum insulin and C-peptide were determined at fasting and during IvGTT and OGTT. RESULTS: All children aged median 5.1 (4.0-9.2) yr had autoantibodies to two to six of the beta-cell antigens GAD65, insulin, IA-2, and the three amino acid position 325 variants of the ZnT8 transporter. In total, 20/47 children showed impaired glucose metabolism. Decreased (≤30 μU/mL insulin) first-phase insulin response (FPIR) was found in 14/20 children while 11/20 had impaired glucose tolerance in the OGTT. Five children had both impaired glucose tolerance and FPIR ≤30 μU/mL insulin. Number and levels of autoantibodies were not associated with glucose metabolism, except for an increased frequency (p = 0.03) and level (p = 0.01) of ZnT8QA in children with impaired glucose metabolism. Among the children with impaired glucose metabolism, 13/20 had HLA-DQ2/8, compared to 9/27 of the children with normal glucose metabolism (p = 0.03). CONCLUSION: Secondary prevention studies in children with islet autoantibodies are complicated by variability in baseline glucose metabolism. Evaluation of metabolic control with both IvGTT and OGTT is critical and should be taken into account before randomization. All currently available autoantibody tests should be analyzed, including ZnT8QA.
[show abstract][hide abstract] ABSTRACT: Aims/hypothesis
The aim of this work was to investigate, in children newly diagnosed with type 1 diabetes: (1) the prevalence of autoantibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TGAb); and (2) the association between TPOAb, TGAb or both, with either islet autoantibodies or HLA-DQ genes.
Blood samples from 2,433 children newly diagnosed with type 1 diabetes were analysed for TPOAb and TGAb in addition to autoantibodies against arginine zinc transporter 8 (ZnT8RA), tryptophan zinc transporter 8 (ZnT8WA), glutamine zinc transporter 8 (ZnT8QA), glutamic acid decarboxylase (GADA), insulin (IAA), insulinoma-associated protein-2 (IA-2A), HLA-DQA-B1 genotypes, thyroid-stimulating hormone (TSH) and free thyroxine (T4).
At type 1 diabetes diagnosis, 12% of the children had thyroid autoantibodies (60% were girls; p < 0.0001). GADA was positively associated with TPOAb (p < 0.001) and with TGAb (p < 0.001). In addition, ZnT8A was associated with both TPOAb (p = 0.039) and TGAb (p = 0.015). DQB1*05:01 in any genotype was negatively associated with TPOAb (OR 0.55, 95% CI 0.37, 0.83, p value corrected for multiple comparisons (p
c) = 0.012) and possibly with TGAb (OR 0.55, 95% CI 0.35, 0.87, p
c = 0.07). Thyroid autoimmunity in children newly diagnosed with type 1 diabetes was rarely (0.45%) associated with onset of clinical thyroid disease based on TSH and free T4.
GADA and ZnT8A increased the risk for thyroid autoimmunity at the time of clinical diagnosis of type 1 diabetes, while HLA-DQB1*05:01 reduced the risk. However, the associations between thyroid autoimmunity and HLA-DQ genotype were weak and did not fully explain the co-occurrence of islet and thyroid autoimmunity.
[show abstract][hide abstract] ABSTRACT: In recent years, some perfluorinated compounds (PFCs) have been identified as potentially hazardous substances which are harmful to the environment and human health. According to limited data, PFC levels in humans could be influenced by several determinants. However, the findings are inconsistent. In the present study, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were measured in paired maternal and cord serum samples (N = 237) collected between 1978 and 2001 in Southern Sweden to study the relationship between these and to investigate several potential determinants of maternal and fetal exposure to PFCs. Time trends of PFCs in Swedish women were also evaluated. The study is a part of the Fetal Environment and Neurodevelopment Disorders in Epidemiological Research project. PFOS, PFOA, and PFNA levels (median) were higher in maternal serum (15, 2.1, and 0.24 ng/ml, respectively) than in cord serum (6.5, 1.7, and 0.20 ng/ml, respectively). PFC levels were among the highest in women originating from the Nordic countries and the lowest in women from the Middle East, North Africa, and sub-Saharan Africa. Multiparous women had lower serum PFOA levels (1.7 ng/ml) than primiparous women (2.4 ng/ml). Maternal age, body mass index, cotinine levels, and whether women carried male or female fetuses did not affect serum PFC concentrations. Umbilical cord serum PFC concentrations showed roughly similar patterns as the maternal except for the gestational age where PFC levels increased with advancing gestational age. PFOS levels increased during the study period in native Swedish women. In summary, PFOS levels tend to increase while PFOA and PFNA levels were unchanged between 1978 and 2001 in our study population. Our results demonstrate that maternal country of origin, parity, and gestational age might be associated with PFC exposure.
Environmental Science and Pollution Research 02/2013; · 2.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: The major histocompatibility complex class II transactivator (CIITA) gene (16p13) has been reported to associate with susceptibility to multiple sclerosis, rheumatoid arthritis and myocardial infarction, recently also to celiac disease at genome-wide level. However, attempts to replicate association have been inconclusive. Previously, we have observed linkage to the CIITA region in Scandinavian type 1 diabetes (T1D) families. Here we analyze five Swedish T1D cohorts and a combined control material from previous studies of CIITA. We investigate how the genotype distribution within the CIITA gene varies depending on age, and the association to T1D. Unexpectedly, we find a significant difference in the genotype distribution for markers in CIITA (rs11074932, P=4 × 10(-5) and rs3087456, P=0.05) with respect to age, in the collected control material. This observation is replicated in an independent cohort material of about 2000 individuals (P=0.006, P=0.007). We also detect association to T1D for both markers, rs11074932 (P=0.004) and rs3087456 (P=0.001), after adjusting for age at sampling. The association remains independent of the adjacent T1D risk gene CLEC16A. Our results indicate an age-dependent variation in CIITA allele frequencies, a finding of relevance for the contrasting outcomes of previously published association studies.Genes and Immunity advance online publication, 11 October 2012; doi:10.1038/gene.2012.44.
Genes and immunity 10/2012; 13(8):632-40. · 4.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: To report C-peptide results in newly diagnosed patients and the relation to clinical diagnosis of diabetes.
A nation-wide cohort, the Better Diabetes Diagnosis study was used to determine serum C-peptide at diagnosis in 2734 children and adolescents. Clinical data were collected at diagnosis and follow-up. C-peptide was determined in a validated and controlled time-resolved fluoroimmunoassay.
The clinical classification of diabetes, before any information on human leukocyte antigen, islet autoantibodies, or C-peptide was received, was type 1 diabetes (T1D) in 93%, type 2 diabetes (T2D) in 1.9%, maturity onset diabetes of the young (MODY) in 0.8%, secondary diabetes (0.6%), while 3.3% could not be classified. In a random, non-fasting serum sample at diagnosis, 56% of the patients had a C-peptide value >0.2 nmol/L. Children classified as T2D had the highest mean C-peptide (1.83 + 1.23 nmol/L) followed by MODY (1.04 ± 0.71 nmol/L) and T1D (0.28 ± 0.25 nmol/L). Only 1/1037 children who had C-peptide <0.2 nmol/L at diagnosis was classified with a type of diabetes other than T1D. Predictive value of C-peptide >1.0 nmol/L for the classification of either T2D or MODY was 0.46 [confidence interval 0.37-0.58].
More than half of children with newly diagnosed diabetes have clinically important residual beta-cell function. As the clinical diagnosis is not always straightforward, a random C-peptide taken at diagnosis may help to classify diabetes. There is an obvious use for C-peptide determinations to evaluate beta-cell function in children with diabetes.
[show abstract][hide abstract] ABSTRACT: We examined whether zinc transporter 8 autoantibodies (ZnT8A; arginine ZnT8-RA, tryptophan ZnT8-WA, and glutamine ZnT8-QA variants) differed between immigrant and Swedish patients due to different polymorphisms of SLC30A8, HLA-DQ, or both. Newly diagnosed autoimmune (≥1 islet autoantibody) type 1 diabetic patients (n = 2,964, <18 years, 55% male) were ascertained in the Better Diabetes Diagnosis study. Two subgroups were identified: Swedes (n = 2,160, 73%) and immigrants (non-Swedes; n = 212, 7%). Non-Swedes had less frequent ZnT8-WA (38%) than Swedes (50%), consistent with a lower frequency in the non-Swedes (37%) of SLC30A8 CT+TT (RW+WW) genotypes than in the Swedes (54%). ZnT8-RA (57 and 58%, respectively) did not differ despite a higher frequency of CC (RR) genotypes in non-Swedes (63%) than Swedes (46%). We tested whether this inconsistency was due to HLA-DQ as 2/X (2/2; 2/y; y is anything but 2 or 8), which was a major genotype in non-Swedes (40%) compared with Swedes (14%). In the non-Swedes only, 2/X (2/2; 2/y) was negatively associated with ZnT8-WA and ZnT8-QA but not ZnT8-RA. Molecular simulation showed nonbinding of the relevant ZnT8-R peptide to DQ2, explaining in part a possible lack of tolerance to ZnT8-R. At diagnosis in non-Swedes, the presence of ZnT8-RA rather than ZnT8-WA was likely due to effects of HLA-DQ2 and the SLC30A8 CC (RR) genotypes.
[show abstract][hide abstract] ABSTRACT: We have previously performed a genome-wide linkage study in Scandinavian Type 1 diabetes (T1D) families. In the Swedish families, we detected suggestive linkage (LOD≤2.2) to the chromosome 5p13-q13 region. The aim of our study was to investigate the linked region in search for possible T1D susceptibility genes.
Microsatellites were genotyped in the Scandinavian families to fine-map the previously linked region. Further, SNPs were genotyped in Swedish and Danish families as well as Swedish sporadic cases. In the Swedish families we detected genome-wide significant linkage to the 5-hydroxytryptamine receptor 1A (HTR1A) gene (LOD 3.98, p<9.8×10(-6)). Markers tagging two separate genes; the ring finger protein 180 (RNF180) and HTR1A showed association to T1D in the Swedish and Danish families (p<0.002, p<0.001 respectively). The association was not confirmed in sporadic cases. Conditional analysis indicates that the primary association was to HTR1A. Quantitative PCR show that transcripts of both HTR1A and RNF180 are present in human islets of Langerhans. Moreover, immunohistochemical analysis confirmed the presence of the 5-HTR1A protein in isolated human islets of Langerhans as well as in sections of human pancreas.
We have identified and confirmed the association of both HTR1A and RFN180, two genes in high linkage disequilibrium (LD) to T1D in two separate family materials. As both HTR1A and RFN180 were expressed at the mRNA level and HTR1A as protein in human islets of Langerhans, we suggest that HTR1A may affect T1D susceptibility by modulating the initial autoimmune attack or either islet regeneration, insulin release, or both.
PLoS ONE 01/2012; 7(5):e35439. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Type 1 diabetes and obesity has increased in childhood. We therefore tested the hypothesis that type 1 diabetes human leukocyte antigen DQ (HLA-DQ) risk genotypes may be associated with increased body mass index (BMI).
The type 1 diabetes high-risk HLA-DQ A1*05:01-B1*02:01/A1*03:01-B1*03:02 genotype along with lower risk DQ genotypes were determined at the time of clinical onset by PCR and hybridization with allele-specific probes. BMI was determined after diabetes was stabilized.
A total of 2403 incident type 1 diabetes children below 18 years of age were ascertained in the Swedish national Better Diabetes Diagnosis (BDD) study between May 2005 to September 2009. All children classified with type 1 diabetes, including positivity for at least one islet autoantibody, were investigated.
Overall, type 1 diabetes HLA-DQ risk was negatively associated with BMI (P<0.0008). The proportion of the highest risk A1*05:01-B1*02:01/A1*03:01-B1)03:02 genotype decreased with increasing BMI (P<0.0004). However, lower risk type 1 diabetes DQ genotypes were associated with an increased proportion of patients who were overweight or obese (P<0.0001). Indeed, the proportion of patients with the low-risk A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype increased with increasing BMI (P<0.003). The magnitude of association on the multiplicative scale between the A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype and increased BMI was significant (P<0.006). The odds ratio in patients with this genotype of being obese was 1.80 (95% confidence interval 1.21-2.61; P<0.006). The increased proportion of overweight type 1 diabetes children with the A1*05:01-B1*02:01 haplotype was most pronounced in children diagnosed between 5 and 9 years of age.
Susceptibility for childhood type 1 diabetes was unexpectedly found to be associated with the A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype and an increased BMI. These results support the hypothesis that overweight may contribute to the risk of type 1 diabetes in children positive for HLA-DQ A1*05:01-B1*02:01.
International journal of obesity (2005) 06/2011; 36(5):718-24. · 5.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: Autoantibodies against the zinc transporter 8 (ZnT8A) are common in type 1 diabetes (T1D). ZnT8A analyses are complicated by the fact that there are three variants of the autoantigen at amino acid position 325 representing ZnT8-R (Arginine), ZnT8-W (Tryptophan) and ZnT8-Q (Glutamin). The aims of the study were: 1) to develop an autoantigen triple mix Radio-Binding Assay (RBA) for ZnT8A; 2) to identify the individual ZnT8-R,-W,-QA reactivity and 3) to validate the triple mix ZnT8A RBA in children with newly diagnosed T1D.
Serum samples were obtained from 2664 (56% males, n=1436) patients in the Swedish nationwide Better Diabetes Diagnosis (BDD) study representing patients with T1D (97%, n=2582), T2D (1.7%, n=46), MODY (1.0%, n=28) and secondary diabetes (0.3%, n=8). cDNA coding for the C-terminal end of each variant was prepared by site-directed mutagenesis and subcloned into a high efficiency in vitro transcription translation vector. The ZnT8 variants were labeled with 35S-methionine and used in a standard RBA separating free from autoantibody-bound autoantigen with Protein A-Sepharose.
ZnT8-TripleA was detected in 1678 (65%) patients with T1D, 4 (9%) T2D, 3 (11%) MODY and in none (0%) of the patients with secondary diabetes. Among the T1D patients ZnT8-RA was detected in 1351 (52%) patients, ZnT8-WA in 1209 (47%) and ZnT8-QA in 790 (31%) demonstrating that 1661 (64%) had one or several ZnT8A. The ZnT8-TripleA assay showed a false positive rate of 1.9% (n=49). Only 1.2% (n=32) of the T1D patients were false negative for ZnT8-TripleA compared to 0/46 (0%) of the T2D patients. The precision (intra assay CV) and reproducibility (inter assay CV) of the ZnT8-TripleA assay did not differ from the RBA of the individual ZnT8 variants.
We conclude that the ZnT8-TripleA assay had low false positive and false negative rates. The ZnT8-TripleA assay would therefore be highly suitable not only to analyze patient with newly diagnosed diabetes but also for screening the general population since this assay demonstrated high sensitivity and very high specificity.
Journal of immunological methods 06/2011; 371(1-2):25-37. · 2.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: To test whether the TCF7L2 gene was associated with gestational diabetes, whether the association between TCF7L2 and gestational diabetes was independent of HLA-DQB1*0602 and islet cell autoantibodies, as well as maternal age, number of pregnancies, family history of diabetes and the HLA-DQB1 genotypes, and to test whether the distribution of HLA-DQB1 alleles was affected by country of birth.
We genotyped the rs7903146, rs12255372 and rs7901695 single nucleotide polymorphisms of the TCF7L2 gene in 826 mothers with gestational diabetes and in 1185 healthy control subjects in the Diabetes Prediction in Skåne Study. The mothers were also typed for HLA-DQB1 genotypes and tested for islet cell autoantibodies against GAD65, insulinoma-associated antigen-2 and insulin.
The heterozygous genotypes CT, GT and TC of the rs7903146 (T is risk for Type 2 diabetes), rs12255372 (T is risk for Type 2 diabetes) and rs7901695 (C is risk for Type 2 diabetes), respectively, as well as the homozygous genotypes TT, TT and CC of the rs7903146, rs12255372 and rs7901695, respectively, were strongly associated with gestational diabetes (P < 0.0001). These associations remained statistically significant after adjusting for maternal age, number of pregnancies, family history of diabetes and HLA-DQ genotypes and were independent of the presence of islet cell autoantibodies. No interaction was observed between TCF7L2 and HLA-DQB1*0602, which was shown to be negatively associated with gestational diabetes in mothers born in Sweden (P = 0.010).
The TCF7L2 was associated with susceptibility for gestational diabetes independently of the presence of HLA-DQB1*0602 and islet cell autoantibodies and other factors such as maternal age, number of pregnancies, family history of diabetes and other HLA-DQ genotypes. The HLA-DQB1*0602 was negatively associated with gestational diabetes in mothers born in Sweden.
Diabetic Medicine 06/2011; 28(9):1018-27. · 3.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: We tested whether autoantibodies to all three ZnT8RWQ variants, GAD65, insulinoma-associated protein 2 (IA-2), insulin and autoantibodies to islet cell cytoplasm (ICA) in combination with human leukocyte antigen (HLA) would improve the diagnostic sensitivity of childhood type 1 diabetes by detecting the children who otherwise would have been autoantibody-negative.
A total of 686 patients diagnosed in 1996-2005 in Skåne were analyzed for all the seven autoantibodies [arginin 325 zinc transporter 8 autoantibody (ZnT8RA), tryptophan 325 zinc transporter 8 autoantibody (ZnT8WA), glutamine 325 Zinc transporter 8 autoantibody (ZnT8QA), autoantibodies to glutamic acid decarboxylase (GADA), Autoantibodies to islet-antigen-2 (IA-2A), insulin autoantibodies (IAA) and ICA] in addition to HLA-DQ genotypes.
Zinc transporter 8 autoantibody to either one or all three amino acid variants at position 325 (ZnT8RWQA) was found in 65% (449/686) of the patients. The frequency was independent of age at diagnosis. The ZnT8RWQA reduced the frequency of autoantibody-negative patients from 7.5 to 5.4%-a reduction by 28%. Only 2 of 108 (2%) patients who are below 5 years of age had no autoantibody at diagnosis. Diagnosis without any islet autoantibody increased with increasing age at onset. DQA1-B1(*)X-0604 was associated with both ZnT8RA (p = 0.002) and ZnT8WA (p = 0.01) but not with ZnT8QA (p = 0.07). Kappa agreement analysis showed moderate (>0.40) to fair (>0.20) agreement between pairs of autoantibodies for all combinations of GADA, IA-2A, ZnT8RWQA and ICA but only slight ( < 0.19) agreement for any combination with IAA.
This study revealed that (1) the ZnT8RWQA was common, independent of age; (2) multiple autoantibodies were common among the young; (3) DQA1-B1(*)X-0604 increased the risk for ZnT8RA and ZnT8WA; (4) agreement between autoantibody pairs was common for all combinations except IAA. These results suggest that ZnT8RWQA is a necessary complement to the classification and prediction of childhood type 1 diabetes as well as to randomize the subjects in the prevention and intervention of clinical trials.
[show abstract][hide abstract] ABSTRACT: Islet autoantibodies are currently used to classify type 1 diabetes at diagnosis as they reflect the autoimmune pathogenesis of the disease. The presence of maternal autoantibodies reactive with pancreatic islet antigens is thought to increase the risk for type 1 diabetes in the offspring. The objective of this study was to determine seroconversion to islet autoantibodies in non-diabetic mothers during pregnancy. Screening of 33,682 mothers between September 2000 and August 2004 in the Diabetes Prediction in Skåne (DiPiS) study showed that at delivery, 242 non-diabetic mothers had increased titers of islet autoantibodies reactive with glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A) or insulin (IAA), alone or in combination. Control mothers (n=1419), who were islet autoantibody negative at delivery, were randomly selected and matched by age, parity and pregnancy sampling date. Mothers positive for GADA (92%), IA-2A (84%) or IAA (65%) at delivery had increased titers already evident in early pregnancy. Titers declined for GADA (p<0.0001), IA-2A (p<0.0001) and IAA (p<0.0001). Seroconversion during pregnancy was observed for GADA in 10 (8%), IA-2A in 3 (16%) and IAA in 37 (35%) mothers. It is concluded that non-diabetic mothers with islet autoantibodies at delivery had significantly higher titers during early pregnancy than at delivery. As the statistical power in the seroconverting mothers was insufficient, further studies are needed to determine if the risk for type 1 diabetes in the offspring differs between mothers who already had increased titers of islet autoantibodies during early pregnancy or acquired them during pregnancy.
Journal of Reproductive Immunology 01/2011; 88(1):72-9. · 2.34 Impact Factor