| 1. |
- Rewers, Marian, et al.
(författare)
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The Environmental Determinants of Diabetes in the Young (TEDDY) Study
- 2008
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1150, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- The etiology of type 1 diabetes (T1D) remains unknown, but a growing body of evidence points to infectious agents and/or components of early childhood diet. The National Institutes of Health has established the TEDDY Study consortium of six clinical centers in the United States and Europe and a data coordinating center to identify environmental factors predisposing to, or protective against, islet autoimmunity and T1D. From 2004-2009, TEDDY will screen more than 360,000 newborns from both the general population and families already affected by T1D to identify an estimated 17,804 children with high-risk HLA-DR,DQ genotypes. Of those, 7,801 (788 first-degree relatives and 7,013 newborns with no family history of T1D) will be enrolled in prospective follow-up beginning before the age of 4.5 months. As of May 2008, TEDDY has screened more than 250,000 newborns and enrolled nearly 5,000 infants--approximately 70% of the final cohort. Participants are seen every 3 months up to 4 years of age, with subsequent visits every 6 months until the subject is 15 years of age. Blood samples are collected at each visit for detection of candidate infectious agents and nutritional biomarkers; monthly stool samples are collected for infectious agents. These samples are saved in a central repository. Primary endpoints include (1) appearance of one or more islet autoantibodies (to insulin, GAD65 or IA-2) confirmed at two consecutive visits; (2) development of T1D. By age 15, an estimated 800 children will develop islet autoimmunity and 400 will progress to T1D; 67 and 27 children have already reached these endpoints.
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| 2. |
- TEDDY study group, The, et al.
(författare)
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The environmental determinants of diabetes in the young (TEDDY) study: Study design
- 2007
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Ingår i: Pediatric Diabetes. - : Hindawi Limited. - 1399-543X .- 1399-5448. ; 8:5, s. 286-298
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Tidskriftsartikel (refereegranskat)abstract
- The primary objective of this multicenter, multinational, epidemiological study is the identification of infectious agents, dietary factors, or other environmental exposures that are associated with increased risk of autoimmunity and type 1 diabetes mellitus (T1DM). Factors affecting specific phenotypic manifestations such as early age of onset or rate of progression or with protection from the development of T1DM will also be identified. The Environmental Determinants of Diabetes in the Young (TEDDY) is an observational cohort study in which newborns who are younger than 4 months and have high-risk human leukocyte antigen alleles in the general population or are first-degree relatives (FDRs) of patients affected with T1DM will be enrolled. Six clinical centers in the USA and Europe will screen 361 588 newborns, of which it is anticipated that 17 804 will be eligible for enrollment with just over 7800 followed. Recruitment will occur over 5 yr, with children being followed to the age of 15 yr. Identification of such factors will lead to a better understanding of disease pathogenesis and result in new strategies to prevent, delay, or reverse T1DM.
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| 3. |
- Haghighi, Mona, et al.
(författare)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 4. |
- Jensen, Richard A., et al.
(författare)
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Multiple factors affect the loss of measurable C-peptide over 6 years in newly diagnosed 15- to 35-year-old diabetic subjects
- 2007
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Ingår i: Journal of diabetes and its complications. - : Elsevier BV. - 1056-8727 .- 1873-460X. ; 21:4, s. 205-213
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study is to identify risk factors for the loss of measurable plasma C-peptide in newly diagnosed 15- to 35-year-old diabetic subjects. Methods: This Swedish study included 778 subjects. C-peptide levels were obtained each year for 6 years after diagnosis. Loss of measurable C-peptide was defined as a level at or below the lower detection limit of the local assay (0.13 nmol/l). In addition to C-peptide, other baseline covariates included gender, age, body mass index, HLA genotype, and autoantibody levels. Results: Compared with autoantibody-negative subjects, autoantibody-positive subjects had lower median baseline C-peptide (0.27 vs. 0.50, P<001), their levels declined over the study period, and the risk of losing measurable C-peptide was significantly higher when more than one autoantibody was present [odds ratio (OR), 4.0; 95% confidence interval (CI), 2.13-7.54]. Among autoantibody-positive individuals, the presence of GAD65Ab (OR, 1.8; 95% Cl, 1.24-2.51) and islet cell antibodies (OR, 1.6; 95% CI, 1.19-2.18) conferred a higher risk for loss of measurable C-peptide as did female gender (OR, 1.6; 95% CI, 1.17-2.11) and time after diagnosis (OR, 1.5 for each additional year postdiagnosis; 95% CI, 1.41-1.57). Higher baseline C-peptide levels were protective (OR, 0.5 for each additional log nanomoles per liter; 95% CI, 0.36-0.58). Conclusions: This study identified autoantibody status, gender, and baseline C-peptide levels as factors that will be useful for predicting the disease course of 15- to 35-year-old diabetic individuals.
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| 5. |
- Jensen, R., et al.
(författare)
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Islet cell autoantibody levels after the diagnosis of young adult diabetic patients
- 2007
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Ingår i: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 24:11, s. 1221-1228
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Tidskriftsartikel (refereegranskat)abstract
- Aims The aim was to determine the course of islet cell antibodies [glutamate decarboxylase (GADA), tyrosine phosphatase-like islet antigen 2 (IA-2A) and islet cell (ICA)] after the diagnosis of the diabetic patient. Methods The Diabetes Incidence Study in Sweden (DISS) attempted to prospectively enrol all newly diagnosed diabetic patients aged 15–34 years during 1992 and 1993. C-peptide and autoantibody levels were determined from venous blood samples at diagnosis and again at yearly intervals for 6 years. Results After the first year, the odds of remaining GADA positive decreased by 9% per year [odds ratio (OR) = 0.91, 95% confidence interval (CI) = 0.85–0.96] while the mean GADA index remained unchanged ( = 0.8, P = 0.37). There was no change in the percentage of subjects testing IA-2A positive after the first year ( = 0.1, P = 0.75). However, the mean index decreased 0.04 per year (95% CI: 0.03–0.05)—a 7.9% decline (95% CI: 5.4–10.4%). The odds of a subject testing positive for ICA decreased by 24% per year (OR = 0.76, 95% CI = 0.70–0.82). The mean ICA levels decreased 0.75 per year (95% CI: 0.66–0.84)—a 16.4% decline (95% CI: 14.1–18.6%). The rate of change in titres for all three autoantibodies was independent of gender, human leucocyte antigen genotype and C-peptide status. Conclusions GADA levels remained high while ICA levels declined. In contrast to a previous study, we found that the proportion of IA-2A subjects remaining positive did not decrease after the first year, while the average index decreased slightly.
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| 6. |
- Larsson, Helena, et al.
(författare)
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Diabetes-associated HLA genotypes affect birthweight in the general population.
- 2005
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 48:Jul 1, s. 1484-1491
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesisThe aim of our study was to test the hypothesis that HLA genotypes conferring risk of diabetes, cord blood autoantibodies, or both are associated with increased birthweight. Methods: HLA genotypes were determined in dried blood spots of cord blood from a total of 16,709 children born to healthy mothers in the Diabetes Prediction in Skane (DiPiS) study, a population-based observational clinical investigation of newborn children. Children born to mothers with diabetes or gestational diabetes were excluded. Autoantibodies to glutamic acid decarboxylase (GAD65Ab) and insulinoma-associated protein 2 were determined in standard radioligand binding assays. Birthweight was adjusted for gestational age and divided into quartiles. The upper quartile was defined as high relative birthweight (HrBW) and the lower quartile as low relative birthweight (LrBW). Results: Genotypes conferring risk of type 1 diabetes were strongly associated with relative birthweight (rBW) (p=0.01). The high-risk HLA-DQ2/8, DQ8/0604 and DQ8/X genotypes were associated with HrBW (odds ratio [OR] [95% CI]=1.20 [1.08-1.33], p=0.0006). The HLA-DQB1*0603 allele, which is negatively associated with type 1 diabetes, was also associated with HrBW (p=0.025), confirming a previous report on DQB1*0603-linked HLA-DR13. GAD65Ab were negatively associated with HrBW (OR [95% CI]=0.72 [0.56-0.93], p=0.01). Regression analysis showed that the HLA-associated increase in rBW was independent of confounding factors. Conclusions/Interpreation: HLA genotypes may be associated with intrauterine growth independent of type 1 diabetes risk. The epidemiological observation that high birthweight is a risk factor for type 1 diabetes could possibly result from a moderating effect on intrauterine growth of HLA genotypes conferring a high risk of diabetes.
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| 7. |
- Larsson, Helena, et al.
(författare)
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Relationship between increased relative birthweight and infections during pregnancy in children with a high-risk diabetes HLA genotype.
- 2007
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 50:6, s. 1161-1169
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Children with high-risk type 1 diabetes HLA genotype have increased risk of high relative birthweight (HrBW), while cord blood islet autoantibodies decrease the risk. As gestational infections may affect offspring type 1 diabetes risk, the aims were to test whether: (1) children of mothers reporting gestational infections have increased HrBW; (2) gestational infections explain islet autoantibody reduction of HrBW; and (3) gestational infections affect the association between HLA and HrBW. Subjects and methods HLA genotypes and autoantibodies to glutamic acid decarboxylase, insulinoma-associated protein 2 and insulin were determined in cord blood of children born to non-diabetic mothers in the Diabetes Prediction in Skane (DiPiS) study. Mothers reported gestational infections when the child was 2 months old. Results Fever or gastroenteritis during pregnancy was reported by 2,848/19,756 mothers (14%); 339 in more than one trimester. Children whose mothers reported infections had increased risk of HrBW (p=0.0003), particularly in the absence of cord blood islet autoantibodies (interaction between HrBW, islet autoantibodies and infections, p=0.0005). The effect on HrBW by high-risk HLA-DQ2/8 was aggravated by infections in more than one trimester (odds ratio [OR]=5.24; p=0.003) (interaction; p=0.022). When infections were reported, cord blood islet autoantibodies decreased HrBW (OR=0.34; p=0.0002). Conclusions/intrepretation This study revealed that: (1) gestational fever, gastroenteritis, or both, increased the risk of HrBW; (2) cord blood islet autoantibodies decreased the risk of HrBW only in combination with infections; and (3) infections aggravated the association between HLA-DQ2/8 and HrBW. These data suggest an interaction between HLA, gestational infections, islet autoantibodies and fetal growth.
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| 8. |
- Larsson, K, et al.
(författare)
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Genetic and perinatal factors as risk for childhood type 1 diabetes
- 2004
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Ingår i: Diabetes/Metabolism Research & Reviews. - : Wiley. - 1520-7552. ; 20:6, s. 429-437
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Forskningsöversikt (refereegranskat)abstract
- The mechanisms by which gestational infections, blood incompatibility, birth weight, mother's age and other prenatal or neonatal events increase the risk for type 1 diabetes are not understood. Studies so far have been retrospective, and there is a lack of population-based prospective studies. The possibility identifying children at type 1 diabetes risk among first-degree relatives has resulted in prospective studies aimed at identifying postnatal events associated with the appearance of autoantibody markers for type 1 diabetes and a possible later onset of diabetes. However, the majority (85%) of new onset type 1 diabetes children do not have a first-degree relative with the disease. Population-based studies are therefore designed to prospectively analyse pregnant mothers and their offspring. One such study is DiPiS (Diabetes Prediction in Skane), which is examining a total of about 10 000 pregnancies expected every year in the Skane (Scania) region of Sweden that has 1.1 million inhabitants. Blood samples from all mothers in this region are obtained during pregnancy and at the time of delivery. Cord blood is analysed for HLA high-risk alleles and for autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GADA), the protein tyrosine phosphatase-related IA-2 antigen (IA-2A) and insulin (IAA) as a measure of prenatal autoimmune exposure. Identifying high-risk children by genetic, autoimmune and gestational risk factors followed by prospective analyses will make it possible to test the hypothesis that gestational events may trigger beta cell autoimmunity as a prerequisite for childhood type 1 diabetes. Copyright (C) 2004 John Wiley Sons, Ltd.
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| 9. |
- Lernmark, Barbro, et al.
(författare)
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Cord blood islet autoantibodies are related to stress in the mother during pregnancy.
- 2006
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923. ; 1079:1079, s. 345-349
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Tidskriftsartikel (refereegranskat)abstract
- A 2-month psychological questionnaire concerning pregnancy was answered by 20,920 nondiabetic mothers of singletons. Retrospective analysis showed increased levels of islet autoantibodies (1A) in 290 (1.4%) newborns. High IA levels in the child's cord blood correlated strongly with IA levels in the mother (GADA r = 0.91, P < 0.0001; IA-2A r = 0.75, P = 0.0001). High IA levels were found in newborns whose mothers during pregnancy had been more worried than usual (P = 0.04), had worried that the child would be sick (P = 0.01) or not survive (P = 0.002), or had experienced serious life events, like "serious accident in the family" (P < 0.0001) or "experienced violence" (P = 0.02). Associations with increased worries by the mother remained in newborns with high type 1 diabetes mellitus (T1DM)-human leukocyte antigen (HLA) risk, but not in non-HLA risk children. ne prospective follow-up of these children will determine the importance of this early 1A for postnatal islet autoimmunity, type I diabetes, or both.
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| 10. |
- Lynch, Kristian, et al.
(författare)
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Cord blood islet autoantibodies and seasonal association with the type 1 diabetes high-risk genotype.
- 2008
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Ingår i: Journal of Perinatology. - : Springer Science and Business Media LLC. - 0743-8346 .- 1476-5543. ; 28:3, s. 211-217
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Tidskriftsartikel (refereegranskat)abstract
- Objective:Human leukocyte antigen DQ (HLA-DQ) genetic factors and islet autoantibodies are strongly associated with type 1 diabetes (T1D) and are currently used to predict T1D. This study examined whether islet autoantibodies in the cord blood of newborns to nondiabetic mothers were associated with the (T1D) high-risk genotype HLA-DQ2/8, gestational infections or both.Study Design:Cord blood samples were taken from 33 683 newborns and used for HLA typing and analyses of islet autoantibodies. Parents completed questionnaires when the child was 2 months of age.Result:The prevalence of newborn islet autoantibodies consistently varied with season over 4 years (P<0.0001); lowest in first quarter (1.2%) and highest in third (2.4%). Cord blood islet autoantibodies were associated with HLA-DQ2/8 in the second (OR, 2.30; P=0.02), third (OR, 2.12; P=0.008) and fourth quarters (OR, 2.49; P=0.007), but not in the first (OR, 1.13). Reported gastroenteritis was additionally associated with islet autoantibodies in the third quarter (OR, 1.80, P=0.04).Conclusion:An association between HLA and islet autoimmunity may depend on environmental exposure during pregnancy. Follow-up of mothers and children will determine risk of T1D.Journal of Perinatology (2008) 28, 211-217; doi:10.1038/sj.jp.7211912; published online 14 February 2008.
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