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The Environmental Determinants of Diabetes in the Young (TEDDY) Study
What is the purpose of TEDDY?
The TEDDY study - T he E nvironmental D eterminants of D iabetes in the Y oung - is looking for the causes of type 1 diabetes mellitus (T1DM). T1DM used to be called childhood diabetes or insulin-dependent diabetes. T1DM occurs when special cells in the body, called the beta cells of the pancreas, are destroyed by the body's infection fighting cells, called immune cells. When these beta cells are destroyed, the body cannot make the chemical insulin. Insulin is needed for the body to use food. Insulin helps keep the sugar level in the blood normal. If there is no insulin in the body, the sugar in the blood becomes high and this makes someone sick. Children with type 1 diabetes must take insulin shots and monitor their blood sugar levels several times a day to stay alive and healthy.
Research tells us that children who get diabetes have certain kind of genes. Other children who have these genes are at higher risk for getting diabetes. However, not all children who are higher risk get diabetes. We think that something happens that "triggers" or causes a child with higher risk genes to actually get diabetes. It is the purpose of this study to try and find out what are the triggers that cause children to get diabetes.
Who is doing TEDDY?
Six groups of research doctors from across the world are working together in this study. All of the centers are following children with higher risk genes. All of the centers are going to get the same information about the lives of the children in the study.
How is TEDDY done?
We will keep track of your child's diet, illnesses, allergies and other life experiences. We will get a blood sample from your child every 3 months for 4 years. After 4 years, children will be seen every 6 months until your child is 15 years old. We will test your child's blood for a reaction against the beta cells, called autoantibodies. We will test your child for 3 different autoantibodies. The presence of one or more of these autoantibodies means the immune cells are attacking the beta cells and that the beta cells might be destroyed. This might lead to diabetes. However, not all children who get autoantibodies will get diabetes. We will compare the life experiences and blood and stool tests of the children who get autoantibodies and diabetes with some of those children who do not get autoantibodies or diabetes. In this way we hope to find the triggers of T1DM in children with higher risk genes. In the future, this information will be used to try to prevent diabetes in other children.
A consortium of six Clinical Centers (CC) and a Data Coordinating Center (DCC) has been created to develop and carry out studies to identify environmental causes of T1DM in genetically susceptible individuals. This consortium has been established by:
- The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- National Institute of Allergy and Infectious Diseases (NIAID)
- National Institute of Child Health and Human Development (NICHD)
- National Institute of Environmental Health Sciences (NIEHS)
- Juvenile Diabetes Research Foundation (JDRF)
- Centers for Disease Control and Prevention (CDC)
The Environmental Determinants of Diabetes in the Young (TEDDY) study will investigate:
- genetic and genetic-environmental interactions, including gestational infection or other gestational events
- childhood infections or other environmental factors after birth in relation to the development of prediabetic autoimmunity and Type I Diabetes Mellitus (T1DM). The consortium of six centers has been assembled to participate in the development and implementation of studies to identify environmental factors that trigger the development of T1DM in genetically susceptible individuals.
Epidemiologic patterns suggest that viruses, nutrition, toxic agents or socioeconomic psychosocial factors may contribute to the etiology alone or in combination. Elucidation is confounded by the long interval between exposure and onset of clinical disease, as well as the interaction of multiple genes and/or insults, which appear to interact in a complex manner.
The CCs will recruit and enroll subjects, including obtaining informed consent from parents prior to or shortly after birth, obtain genetic and other samples from neonates and parents, and prospectively follow selected neonates throughout childhood or until development of islet autoimmunity or T1DM.
The TEDDY Consortium will allow for a coordinated, multi-disciplinary approach to this complex disease. Collection of information and samples in a standardized manner will achieve greater statistical power than smaller independent investigations. The TEDDY study will establish a central repository of data and biologic samples for subsequent hypothesis based research.
Data will be gathered from cohorts of newborns from the general population and newborn first-degree relatives of probands with T1DM. Newborns will first be identified to be at genetic risk for T1DM before long term follow-up. These cohorts are to be followed for 15 years for the appearance of various beta-cell autoantibodies and diabetes, with documentation of early childhood diet, reported and measured infections, vaccinations, and psychosocial stressors.
The TEDDY study proposes to newly recruit 7,013 neonates from the general population with a pre-determined type 1 diabetes risk of 3% and 788 neonates with first degree relatives who have type 1 diabetes and who have a pre-determined type 1 diabetes risk of 10%. Thus, we propose to study a total of 7,801 participants across six clinical centers worldwide (Finland, Germany, Sweden and three in North America). The participants will be followed with blood sampling every three months for islet autoantibody measurements until age 4 years and then every six months until the age of 15.
Results from previous studies have been confounded by imprecise assessment of exposure, recall bias, failure to account for genetic susceptibility, failure to assess exposures at very early ages or the inability to follow a sufficient sample of children long-term with high intensity. The present multi-center study will provide an opportunity to fill important gaps in our understanding of the events leading to T1DM by studying from birth high-risk general population children and relatives and by systematic screening of candidate environmental and genetic factors. We will apply "cutting edge" molecular immunologic and genetic techniques to samples collected in six cohorts of high-risk children. In addition, samples collected by TEDDY will create a valuable resource for investigators proposing innovative hypotheses concerning candidate environmental and genetic factors.
The long-term goal of the TEDDY study is the identification of infectious agents, dietary factors, or other environmental agents, including psychosocial factors which trigger T1DM in genetically susceptible individuals or which protect against the disease. Identification of such factors will lead to a better understanding of disease pathogenesis and result in new strategies to prevent, delay or reverse T1DM.